Intensity-modulated particle therapy(IMPT)with carbon ions is comparatively susceptible to various uncertainties caused by breathing motion,including range,setup,and target positioning uncertainties.To determine relat...Intensity-modulated particle therapy(IMPT)with carbon ions is comparatively susceptible to various uncertainties caused by breathing motion,including range,setup,and target positioning uncertainties.To determine relative biological effectiveness-weighted dose(RWD)distributions that are resilient to these uncertainties,the reference phase-based four-dimensional(4D)robust optimization(RP-4DRO)and each phase-based 4D robust optimization(EP-4DRO)method in carbon-ion IMPT treatment planning were evaluated and compared.Based on RWD distributions,4DRO methods were compared with 4D conventional optimization using planning target volume(PTV)margins(PTV-based optimization)to assess the effectiveness of the robust optimization methods.Carbon-ion IMPT treatment planning was conducted in a cohort of five lung cancer patients.The results indicated that the EP-4DRO method provided better robustness(P=0.080)and improved plan quality(P=0.225)for the clinical target volume(CTV)in the individual respiratory phase when compared with the PTV-based optimization.Compared with the PTV-based optimization,the RP-4DRO method ensured the robustness(P=0.022)of the dose distributions in the reference breathing phase,albeit with a slight sacrifice of the target coverage(P=0.450).Both 4DRO methods successfully maintained the doses delivered to the organs at risk(OARs)below tolerable levels,which were lower than the doses in the PTV-based optimization(P<0.05).Furthermore,the RP-4DRO method exhibited significantly superior performance when compared with the EP-4DRO method in enhancing overall OAR sparing in either the individual respiratory phase or reference respiratory phase(P<0.05).In general,both 4DRO methods outperformed the PTV-based optimization in terms of OAR sparing and robustness.展开更多
<strong>Introduction:</strong> Radiotherapy alone or combined with surgery and/or chemotherapy is being investigated in the treatment of malignant pleural mesothelioma (MPM). This study aimed to simulate a...<strong>Introduction:</strong> Radiotherapy alone or combined with surgery and/or chemotherapy is being investigated in the treatment of malignant pleural mesothelioma (MPM). This study aimed to simulate a Volumetric Modulated Arc Therapy (VMAT) treatment of a patient with MPM. <strong>Materials and Methods:</strong> CT images from a patient with intact lungs were imported via DICOM into the Pinnacle3 treatment planning (TP) system (TPS) and used as a model for MPM to delineate organs at risk (OAR) and both clinical and planning target volumes (CTV and PTV) with a margin of 5 mm. Elekta Synergy with 6 MV photons and 80 leafs MLCi2 was employed. VMAT plans were generated using two coplanar arcs with gantry rotation angles of 178<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span> - 182<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>, the collimator angles of each arc were set to 90<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>, Octavius<span style="white-space:nowrap;"><sup>®</sup></span> 4D 729 was employed for quality assurance while the calculated and measured doses were compared using VeriSoft. <strong>Results:</strong> A TP was achieved. The Gamma volume analysis with criteria of 3 mm distance to agreement and 3% dose difference yielded the gamma passing rate = 99.9%. The reference isodose was 42.75 Gy with the coverage constraints for the PTV D95 and V95 = 95.0% of 45 Gy. The remaining dosimetric parameters met the recommendations from the clinically acceptable guidelines for the radiotherapy of MPM. <strong>Conclusion:</strong> Using well-defined TV and VMAT, a consistent TP compared to similar ones from publications was achieved. We obtained a high agreement between the 3D dose reconstructed and the dose calculated.展开更多
Introduction: Field-in-Field (FIF) and Intensity Modulated Radiation Therapy (IMRT) are two advanced radiation therapy planning techniques. Both of them are being used to achieve the same two related aims which are, t...Introduction: Field-in-Field (FIF) and Intensity Modulated Radiation Therapy (IMRT) are two advanced radiation therapy planning techniques. Both of them are being used to achieve the same two related aims which are, to expose the targeted tumor to the full radiation dose and to spare the nearby normal tissues (or organs) from being exposed to high amounts of radiation more than its tolerance dose limits. FIF is a forward planning while IMRT is an inverse planning and FIF is a forward IMRT. Aim: The purpose of this study was to compare between Field-in-Field and IMRT techniques in prostate cancer radiotherapy. Method: A treatment planning system supporting both inverse and forward planning facilities is used. Ten prostate cancer patients were planned with both FIF and IMRT planning techniques. Doses received by the Planning Target Volume (PTV) and Organs at Risk (OARs) were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that the IMRT planning technique achieved better dose coverage to the PTV than the FIF planning technique but, except RT and LT Femoral Heads, FIF achieved a better protection to the Rectum and the Bladder (OARs) than IMRT. Conclusions: The results showed that the inverse planning based IMRT technique is better and recommended in the prostate cancer radiotherapy than the FIF technique.展开更多
CEM43 thermal dose is a very common concept in thermal oncology.Thermal dose is the maximum amount of energy that can be transmitted during hyperthermia therapy conducted on temperature-sensitive tissue.Thermal dose i...CEM43 thermal dose is a very common concept in thermal oncology.Thermal dose is the maximum amount of energy that can be transmitted during hyperthermia therapy conducted on temperature-sensitive tissue.Thermal dose is also the maximum value of local energy accumulation in human bodies,which can lead to tissue injury and pain.Thermal dose can also decrease the finishing temperature and reduce the energy to the tolerable range.There are two functions of the individualized hyperthermia treatment plan:it determines the setting and location that can realize the best tumor hyperthermia therapy;at the same time,it can decrease the effect of hyperthermia therapy on healthy tissues.There are four steps in the treatment plan of hyperthermia therapy for tumors:the first step is to establish a three dimensional human body model and its corresponding an atomical structure that can be used in numerical algorithm via medical imaging resources;the second step is to determine the volume of the electromagnetic energy accumulation.Based on the peculiarity of frequency and materials,even full-wave electromagnetic wave or quasi-static technique can be used to determine the tissue distribution.Evaluation of the therapy can be conducted based on thermal dose and the corresponding tissue damage model;the third step is to use Arrhenius model to provide direct evaluation of tissues in the thermal ablation zone,solidification zone,as well as the necrotic area;the last step is the optimization of the treatment plan.展开更多
AIM:To compare the volumetric-modulated arc therapy AT plans ith conventional sliding indo intensity-modulated radiotherapy c-I RT plans in esophageal cancer EC . METHODS:Tenty patients ith EC ere selected, including ...AIM:To compare the volumetric-modulated arc therapy AT plans ith conventional sliding indo intensity-modulated radiotherapy c-I RT plans in esophageal cancer EC . METHODS:Tenty patients ith EC ere selected, including 5 cases located in the cervical, the upper, the middle and the lo er thorax, respectively. Five plans ere generated ith the eclipse planning system:three using c-IMRT with 5 fields (5F), 7 fields (7F) and 9 fields (9F), and two using VMAT with a single arc 1A and double arcs 2A . The treatment plans ere designed to deliver a dose of 60 Gy to the plan-ning target volume Tith the same constrains in a 2.0 Gy daily fraction, 5 d a eek. lans ere normalized to 95% of the T that received 100% of the prescribed dose. We examined the dose-volume histogram parameters of T and the organs at risk OAR such as lungs, spinal cord and heart. onitor units U and normal tissue complication probability NTC of OAR ere also reported. RESULTS:Both c-I RT and AT plans resulted in abundant dose coverage of T for EC of different locations. The dose conformity to T as improved as the number of field in c-IMRT or rotating arc in VMAT as increased. The doses to T and OAR in AT plans ere not statistically different in comparison ith c-I RT plans, ith the follo ing exceptions:in cervical and upper thoracic EC, the conformity index CI as higher in VMAT (1A 0.78 and 2A 0.8) than in c-IMRT (5F 0.62, 7F 0.66 and 9F 0.73) and homogeneity was slightly better in c-IMRT (7F 1.09 and 9F 1.07) than in VMAT (1A 1.1 and 2A 1.09). Lung V30 was lower in VMAT (1A 12.52 and 2A 12.29) than in c-IMRT (7F 14.35 and 9F 14.81). The humeral head doses were significantly increased in AT as against c-I RT. In the middle and lower thoracic EC, CI in VMAT (1A 0.76 and 2A 0.74) was higher than in c-IMRT (5F 0.63 Gy and 7F 0.67 Gy), and homogeneity was almost similar bet een AT and c-I RT. 20 2A 21.49 Gy vs 7F 24.59 Gy and 9F 24.16 Gy) and V30 (2A 9.73 Gy vs 5F 12.61 Gy, 7F 11.5 Gy and 9F 11.37 Gy) of lungs in AT ere lo er than in c-I RT, but lo doses to lungs (V5 and V10) were increased. V30 (1A 48.12 Gy vs 5F 59.2 Gy, 7F 58.59 Gy and 9F 57.2 Gy), V40 and 50 of heart in AT as lo er than in c-I RT. Us in AT plans ere significantly reduced in comparison ith c-I RT, maximum doses to the spinal cord and mean doses of lungs ere similar bet een the t o techniques. NTC of spinal cord as 0 for all cases. NTC of lungs and heart in AT ere lo er than inc-I RT. The advantage of AT plan as enhanced by doubling the arc. CONCLUSION:Compared ith c-I RT, AT, especially the 2A, slightly improves the OAR dose sparing, such as lungs and heart, and reduces NTC and U ith a better T coverage.展开更多
Objective: We studied the application of CT image fusion in the evaluation of radiation treatment planning for non-small cell lung cancer (NSCLC). Methods: Eleven patients with NSCLC, who were treated with three-dimen...Objective: We studied the application of CT image fusion in the evaluation of radiation treatment planning for non-small cell lung cancer (NSCLC). Methods: Eleven patients with NSCLC, who were treated with three-dimensional con-formal radiation therapy, were studied. Each patient underwent twice sequential planning CT scan, i.e., at pre-treatment, and at mid-treatment for field reduction planning. Three treatment plans were established in each patient: treatment plan A was based on the pre-treatment planning CT scans for the first course of treatment, plan B on the mid-treatment planning CT scans for the second course of treatment, and treatment plan F on the fused images for the whole treatment. The irradiation doses received by organs at risk in the whole treatment with treatment A and B plans were estimated by the plus of the parameters in treatment plan A and B, assuming that the parameters involve the different tissues (i.e. V20=AV20+BV20), or the same tissues within an organ (i.e. Dmax=ADmax+BDmax). The assessment parameters in the treatment plan F were calculated on the basis of the DVH of the whole treatment. Then the above assessment results were compared. Results: There were marked differ-ences between the assessment results derived from the plus of assessment parameters in treatment plan A and B, and the ones derived from treatment plan F. Conclusion: When a treatment plan is altered during the course of radiation treatment, image fusion technique should be performed in the establishment of a new one. The estimation of the assessment parameters for the whole treatment with treatment plan A and B by simple plus, is inaccurate.展开更多
18-fluorodeoxygluocose positron emission tomography/computed tomography(18FDG-PET/CT) provides significant information in multiple settings in the management of head and neck cancers(HNC). This article seeks to define...18-fluorodeoxygluocose positron emission tomography/computed tomography(18FDG-PET/CT) provides significant information in multiple settings in the management of head and neck cancers(HNC). This article seeks to define the additional benefit of PET/CT as related to radiation treatment planning for squamous cell carcinomas(SCCs) of the head and neck through a review of relevant literature. By helping further define both primary and nodal volumes, radiation treatment planning can be improved using PET/CT. Special attention is paid to the independent benefit of PET/CT in targeting mucosal primaries as well as in detecting nodal metastases. The utility of PET/CT is also explored for treatment planning in the setting of SCC of unknown primary as PET/CT may help define a mucosal target volume by guiding biopsies for examination under anesthesia thus changing the treatment paradigm and limiting the extent of therapy. Implications of the use of PET/CT for proper target delineation in patients with artifact from dental procedures are discussed and the impact of dental artifact on CT-based PET attenuation correction is assessed. Finally, comment is made upon the role of PET/CT in the high-risk post-operative setting, particularly in the context of radiation dose escalation. Real case examples are used in these settings to elucidate the practical benefits of PET/CT as related to radiation treatment planning in HNCs.展开更多
Recently published Medical Physics Practice Guideline 5.a. (MPPG 5.a.) by American Association of Physicists in Medicine (AAPM) sets the minimum requirements for treatment planning system (TPS) dose algorithm commissi...Recently published Medical Physics Practice Guideline 5.a. (MPPG 5.a.) by American Association of Physicists in Medicine (AAPM) sets the minimum requirements for treatment planning system (TPS) dose algorithm commissioning and quality assurance (QA). The guideline recommends some validation tests and tolerances based primarily on published AAPM task group reports and the criteria used by IROC Houston. We performed the commissioning and validation of the dose algorithms for both megavoltage photon and electron beams on three linacs following MPPG 5.a. We designed the validation experiments in an attempt to highlight the evaluation method and tolerance criteria recommended by the guideline. It seems that comparison of dose profiles using in-water scan is an effective technique for basic photon and electron validation. IMRT/VMAT dose calculation is recommended to be tested with some TG-119 and clinical cases, but no consensus of the tolerance exists. Extensive validation tests have provided the better understanding of the accuracy and limitation of a specific dose calculation algorithm. We believe that some tests and evaluation criteria given in the guideline can be further refined.展开更多
The current simulation planning systems for maxillofacial prosthesis surgery were used to extrapolate 3D surgical movements and outcomes based on the 2D radiographs, which were inadequate for complex surgical movement...The current simulation planning systems for maxillofacial prosthesis surgery were used to extrapolate 3D surgical movements and outcomes based on the 2D radiographs, which were inadequate for complex surgical movements.A 3D treatment planning system based on the computerized tomography (CT) data was presented. A 3D data field was constructed out of the sectional image stack through linear interpolation. After objective tissue segmentation and using the marching cubes algorithm method, the triangular mesh model and 3D geometric model of diseased facial skeleton were reconstructed. Then the model was cut, the segments were moved or rotated to their predicted positions, and angles and distances were measured. After triangular mesh model was decimated, a RP model was manufactured for surgical simulation and prosthesis design. The system was used in clinic with more than fifty cases and technically validated with success.展开更多
Objective The aim of the study was to compare the dose to lung volume in the supine and prone position while designing Cyber Knife treatment plans to treat metastatic tumors in the spinous processes of the thoracic ve...Objective The aim of the study was to compare the dose to lung volume in the supine and prone position while designing Cyber Knife treatment plans to treat metastatic tumors in the spinous processes of the thoracic vertebrae, and offer a reference for reducing damage to normal tissues. Methods Nine cases of metastatic tumors in the spinous processes of the thoracic vertebrae were selected, and then we designed treatment plans based on the supine and prone positions and compared the results. Results In contrast with the treatment plan based on the prone position, the one for the supine position required 14862–36337 MU more; the lung D5% was 5.20–7.90 Gy higher; and the lung D20% was 2.61–5.73 Gy higher. The difference of dose to spine volume between the two plans was –2.21–2.67 Gy; to the skin volume was –3.93–7.85 Gy; and to the esophagus was 0.28–6.39 Gy. Conclusion The treatment plan based on the prone position of patients can better protect lung tissues than the one based on the supine position, and can also improve the availability of beams.展开更多
Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not ...Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not be taken into account during that calculation process. During IMRT routine practical work, it is noticed that there are some non-delineated normal tissue volumes that received un-aimed dose. Aim: The purpose of this study was to study the effect of unusually delineated normal volumes in IMRT treatment for left sided breast cancer. Method: Ten left sided breast cancer patients were planned with IMRT inverse planning system. The unusually delineated normal volumes were delineated and taken into account in IMRT dose constraints as an Organ at Risk. Doses received by that volume were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that doses received by the unusually delineated volume when they were delineated and taken into account in IMRT dose constraints were significantly higher than when they were not. Conclusions: The results showed that for IMRT planning technique used for treating left-sided breast cancer, all of the normal tissues/structures that are closed to the treatment targets must be delineated and taken into account in the IMRT planning dose constraints.展开更多
Aim: This study aims to evaluate the difference between depth data from an intraoral cone and a conventional irradiation tube calculated using a treatment planning system (TPS), and that measured using an intraoral co...Aim: This study aims to evaluate the difference between depth data from an intraoral cone and a conventional irradiation tube calculated using a treatment planning system (TPS), and that measured using an intraoral cone for electron radiotherapy. Background: A TPS is only compatible with conventional irradiation tubes. However, such systems are not suitable for determining dose distributions when a special cone is employed. Materials and Methods: Dose distributions were calculated using the beam data for mounted intraoral cones using a TPS. Then, the dose distribution by field size was calculated for a low-melting-point lead alloy using the beam data for a mounted conventional tube. The calculated data were evaluated against the measured intraoral-cone depth data based on the dose and depth differences. Results: The calculated data for the intraoral cone case did not match the measured data. However, the depth data obtained considering the field size determined for the lead alloy using the conventional tube were close to the measured values for the intraoral cone case. The difference in the depth at which the absorbed dose was 50% of the maximum value of the percentage depth dose was less than ±4 mm for the generalized Gaussian pencil beam convolution algorithm and less than ±1 mm for the electron Monte Carlo algorithm. Conclusion: It was found that the measured and calculated dose distributions were in agreement, especially when then electron Monte Carlo algorithm was used. Thus, the TPS can be employed to determine dose distributions for intraoral cone applications.展开更多
Cone-beam CT (CBCT) images acquired during radiation treatment can be used to recalculate the dose distribution as well as to confirm the treatment location. However, it is difficult to obtain the electron densities (...Cone-beam CT (CBCT) images acquired during radiation treatment can be used to recalculate the dose distribution as well as to confirm the treatment location. However, it is difficult to obtain the electron densities (EDs) necessary for dose calculation from CBCT images because of the effects of scatter contamination during CBCT image acquisition. This paper presents a mathematical method for converting the pixel values of CBCT images (CBCT values) into Hounsfield units (HUs) of radiation treatment simulation CT (simCT) images for use in radiation treatment planning. CBCT values are converted into HUs by matching the histograms of the CBCT values with the histograms of the HUs for each slice via linear scaling of the CBCT values. For prostate cancer and head-and-neck cancer patients, the EDs obtained from converted CBCT values (mCBCT values) show good agreement with the EDs obtained from HUs, within approximately 3.0%, and the dose calculated on the basis of CBCT images shows good agreement with the dose calculated on the basis of the simCT images, within approximately 2.0%. Because the CBCT values are converted for each slice, this conversion method can account for variation in the CBCT values associated with differences in body size, body shape, and inner tissue structures, as well as in longitudinally displaced positions from the isocenter, unlike conventional methods that use electron density phantoms. This method improves on conventional CBCT-ED conversion and shows considerable potential for improving the accuracy of radiation treatment planning using CBCT images.展开更多
Purpose: To introduce a practical method of using an Electron Density Phantom (EDP) to evaluate different dose calculation algorithms for photon beams in a treatment planning system (TPS) and to commission the Anisotr...Purpose: To introduce a practical method of using an Electron Density Phantom (EDP) to evaluate different dose calculation algorithms for photon beams in a treatment planning system (TPS) and to commission the Anisotropic Analytical Algorithm (AAA) with inhomogeneity correction in Varian Eclipse TPS. Methods and Materials: The same EDP with various tissue-equivalent plugs (water, lung exhale, lung inhale, liver, breast, muscle, adipose, dense bone, trabecular bone) used to calibrate the computed tomography (CT) simulator was adopted to evaluate different dose calculation algorithms in a TPS by measuring the actual dose delivered to the EDP. The treatment plans with a 6-Megavolt (MV) single field of 20 × 20, 10 × 10, and 4 × 4 cm2 field sizes were created based on the CT images of the EDP. A dose of 200 cGy was prescribed to the exhale-lung insert. Dose calculations were performed with AAA with inhomogeneity correction, Pencil Beam Convolution (PBC), and AAA without inhomogeneity correction. The plans were delivered and the actual doses were measured using radiation dosimetry devices MapCheck, EDR2-film, and ionization chamber respectively. Measured doses were compared with the calculated doses from the treatment plans. Results: The calculated dose using the AAA with inhomogeneity correction was most consistent with the measured dose. The dose discrepancy for all types of tissues covered by beam fields is at the level of 2%. The effect of AAA inhomogeneity correction for lung tissues is over 14%. Conclusions: The use of EDP and Map Check to evaluate and commission the dose calculation algorithms in a TPS is practical. In Varian Eclipse TPS, the AAA with inhomogeneity correction should be used for treatment planning especially when lung tissues are involved in a small radiation field.展开更多
Water safety plan as conceived by WHO can lead to prevention of pollution in each component of water supply chain which leads to ensuring safe drinking water. Risk assessment is one of the key components during the de...Water safety plan as conceived by WHO can lead to prevention of pollution in each component of water supply chain which leads to ensuring safe drinking water. Risk assessment is one of the key components during the development of water safety plan, achieved by identifying hazardous events and estimating their risk towards implementing control measures. This study reports the risk assessment from catchment to consumers in Maiduguri water treatment plant in Northeast Nigeria. Tools such as the field visits, key informant interviews, questionnaire and water quality monitoring were used to identify the hazards and estimate their risk using semi-quantitative matrix. With the existing control measures, the study showed a total of 33 hazardous events;5 in catchment, 16 in treatment plant, 6 in distribution system and 6 at consumers’ points. The risk score indicated 6 are of medium risk and 9 of high risk. Catchment activities, upgrade of treatment facilities and lack of routine maintenance in the treatment plant, pipeline damages in distribution lines, and consumers’ lack of hygiene knowledge and awareness were found to be the major contributory factors which affect the desired quality. Therefore participation and commitment by all relevant stakeholders are fundamental requisite to manage the identified health risks.展开更多
OBJECTIVE:To investigate the clinical efficacy and safety of a diagnosis and treatment plan for moderate coronavirus disease 2019(COVID-19)that integrates traditional Chinese(TCM)and western medicine.METHODS:One hundr...OBJECTIVE:To investigate the clinical efficacy and safety of a diagnosis and treatment plan for moderate coronavirus disease 2019(COVID-19)that integrates traditional Chinese(TCM)and western medicine.METHODS:One hundred twenty patients with moderate COVID-19 were randomized 1∶2 to the control group(n=40)and experimental group(n=80).Both groups received conventional western medicine treatment,and the experimental group also received TCM decoction.Over a 2-week period from diagnosis,we observed the time to clinical recovery(TTCR),rate of improvement on lung computed tomography(CT)imaging,time to defervescence,cough remission time,hospital discharge rate,average hospitalization stay,modified Medical Research Council(m MRC)scale score,clinical cure rate,laboratory findings,incidence of progression to severe or critical disease,and adverse events.RESULTS:Among 120 enrolled patients,108 completed the study.The baseline data did not differ between the experimental and control groups(all P>0.05).After treatment,the TTCR,rate of lung CT imaging improvement,time to defervescence,cough remission time,hospital discharge rate,average hospitalization stay(among discharged patients),m MRC scale score,clinical cure rate,and rates of normal values for laboratory findings were better in the experimental group than in the control group(P<0.05 or<0.01).The incidence of progression to severe or critical disease and the incidence of adverse events did not differ between the two groups(P>0.05).CONCLUSION:The diagnosis and treatment plan integrating Chinese and western medicine showed improved clinical efficacy compared with western medicine alone for patients with moderate COVID-19 and is worthy of clinical promotion and application.展开更多
Objective:To explore treatment planning approaches using volumetric modulated arc therapy(VMAT)for head and neck cancer patients with metallic dental fillings.Methods:Fifty-six patients with metallic dental fillings t...Objective:To explore treatment planning approaches using volumetric modulated arc therapy(VMAT)for head and neck cancer patients with metallic dental fillings.Methods:Fifty-six patients with metallic dental fillings treated with radiotherapy were selected,and three VMAT plans,the jaw-tracking plan,fixed-jaw plan,and non-coplanar plan,were designed for each patient.In the jawtracking plan,two coplanar partial arc fields that avoid the metal area were set,and the jaw was automatically tracked.In the fixed-jaw plan,different fields were set in three sections according to the fixed-jaw method.The fields were the same as those in the jaw-tracking plan for the section containing metal implants,while full arc fields were set in the nonmetal sections.In the non-coplanar plan,a non-coplanar arc field was added based on the jaw-tracking plan.The treatment plan in the jaw-tracking plan was optimized,and the constraints on the planning target volume(PTV)or organs at risk(OARs)in the jaw-tracking plan were copied to the other two plans.The dose distribution in PTV and OARs of the patients in the three treatment plans was compared.Results:There were no significant differences in the maximum doses to the spinal cord or optic nerves among the three treatment plans.However,compared with the jaw-tracking plan,the fixed-jaw plan showed lower mean doses to the pharynx[(42.9±7.1)Gy vs.(44.1±7.1)Gy,P<0.05]and larynx[(43.9±3.9)Gy vs.(45.4±4.7)Gy,P<0.05],while the non-coplanar plan obtained significantly better dose distribution in PTV and all OARs except for the spinal cord and optic nerves.Meanwhile,the non-coplanar plan performed significantly better than the fixed-jaw plan in terms of the maximum doses to the brainstem[(50.24.0)Gy vs.(51.4±4.6)Gy,P<0.05],left lens[(5.8±0.2)Gy vs.(6.3±0.4 Gy),P<0.05],and right lens[(5.9±0.3)Gy vs.(6.2±0.3)Gy,P<0.05].Conclusions:The non-coplanar VMAT is an optimal method for treating head and neck cancer patients with metallic dental fillings since it can provide better dose distribution in PTV and reduce doses to OARs.展开更多
Introduction: Radiation therapy after breast surgery is an integral part of the treatment of early breast cancer. The goal of radiation therapy is to achieve the best possible coverage of the planning target volume (P...Introduction: Radiation therapy after breast surgery is an integral part of the treatment of early breast cancer. The goal of radiation therapy is to achieve the best possible coverage of the planning target volume (PTV), while reducing the dose to organs at risk (OARs) which are normal tissues whose sensitivity to irradiation could cause damage that can lead to modification of the treatment plan. In the last decade, radiation oncologist started to use the Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for irradiating the breast, in order to achieve better dose distribution and target dose to the PTV and OAR. The aim of this study is to compare 2 external radiotherapy techniques (VMAT vs 3D) for patients with node-positive left breast cancer. Patients and Methods: We randomly selected 10 cases of postoperative radiotherapy for breast cancer in our hospital. The patients are all female, the average age was 45.4 years old, and the primary lesions are left breast. The ANOVA test was used to compare the mean difference between subgroups, and the p value Results: Dose volume histogram (DVH) was used to analyze each evaluation dose of clinical target volume (CTV) and organs at risk (OARs). Compared to 3DCRT plans, VMAT provided more uniform coverage to the breast and regional lymph nodes. The max point dose for tVMAT was lower on average (106.4% for VMAT versus 109% for 3DCRT). OAR sparing was improved with tVMAT, with a lower average V17Gy for the left lung (27.91% for VMAT versus 30.04% for 3DCRT, p and lower for V28Gy (13.75% for VMAT versus 22.34% for 3DCRT, p = 0.01). We also found a lower V35Gy for the heart on VMAT plan (p = 0.02). On the contrary, dose of contralateral breast was lower in 3DCRT than VMAT (0.59 Gy vs 3.65 Gy, p = 0.00). Conclusion: The both types of plans can meet the clinical dosimetry demands of postoperative radiotherapy for left breast cancer. The VMAT plan has a better conformity, but 3CDRT can provide a lower dose to the contralateral organs (breast and lung) to avoid the risk of secondary cancers.展开更多
Objective:This paper aims to discuss the prevention and treatment strategies of gastrointestinal diseases in college students.Methods:A sample of 60 college students suffering from gastrointestinal diseases,from Augus...Objective:This paper aims to discuss the prevention and treatment strategies of gastrointestinal diseases in college students.Methods:A sample of 60 college students suffering from gastrointestinal diseases,from August 2021 to August 2022,was used to discuss the symptoms,causes,prevention strategies,and treatment strategies of gastrointestinal diseases based on questionnaire survey.Results:The high-incidence types of gastrointestinal diseases in college students mainly included chronic gastritis,acute gastritis,duodenal ulcer,and dyspepsia,which were closely related to mental state,diet,and living habits.Conclusion:There are many causes of gastrointestinal diseases in college students.During the period of active symptomatic treatment,it is necessary to focus on the prevention of gastrointestinal diseases in colleges and universities,correct the unhealthy lifestyle of students,and reduce the risk of gastrointestinal diseases.展开更多
This study compares and analyzes stereotactic radiotherapy using tomotherapy and linac-based fractionated stereotactic radiotherapy in the treatment of intra-cranial tumors,according to some cases.In this study,linac-...This study compares and analyzes stereotactic radiotherapy using tomotherapy and linac-based fractionated stereotactic radiotherapy in the treatment of intra-cranial tumors,according to some cases.In this study,linac-based fractionated stereotactic radiotherapy and tomotherapy treatment were administered to five patients diagnosed with intra-cranial cancer in which the dose of 18–20 Gy was applied on 3–5 separate occasions.The tumor dosing was decided by evaluating the inhomogeneous index (II) and conformity index (CI).Also,the radiation-sensitive tissue was evaluated using low dose factors V1,V2,V3,V4,V5,and V10,as well as the non-irradiation ratio volume (NIV).The values of the II for each prescription dose in the linacbased non-coplanar radiotherapy plan and tomotherapy treatment plan were (0.125±0.113) and (0.090±0.180),respectively,and the values of the CI were (0.899±0.149) and (0.917±0.114),respectively.The low dose areas,V1,V2,V3,V4,V5,and V10,in radiation-sensitive tissues in the linac-based non-coplanar radiotherapy plan fell into the ranges 0.3%–95.6%,0.1%–87.6%,0.1%–78.8%,38.8%–69.9%,26.6%–65.2%,and 4.2%–39.7%,respectively,and the tomotherapy treatment plan had ranges of 13.6%–100%,3.5%–100%,0.4%–94.9%,0.2%– 82.2%,0.1%–78.5%,and 0.3%–46.3%,respectively.Regarding the NIV for each organ,it is possible to obtain similar values except for the irradiation area of the brain stem.The percentages of NIV10%,NIV20%,and NIV30%for the brain stem in each patient were 15%–99.8%,33.4%–100%,and 39.8%–100%,respectively,in the fractionated stereotactic treatment plan and 44.2%–96.5%,77.7%–99.8%,and 87.8%–100%,respectively,in the tomotherapy treatment plan.In order to achieve higher-quality treatment of intra-cranial tumors,treatment plans should be tailored according to the isodose target volume,inhomogeneous index,conformity index,position of the tumor upon fractionated stereotactic radiosurgery,and radiation dosage for radiation-sensitive tissues.展开更多
基金supported by National Key Research and Development Program of China(No.2022YFC2401503)National Natural Science Foundation of China(Nos.11875299,61631001,U1532264,and 12005271).
文摘Intensity-modulated particle therapy(IMPT)with carbon ions is comparatively susceptible to various uncertainties caused by breathing motion,including range,setup,and target positioning uncertainties.To determine relative biological effectiveness-weighted dose(RWD)distributions that are resilient to these uncertainties,the reference phase-based four-dimensional(4D)robust optimization(RP-4DRO)and each phase-based 4D robust optimization(EP-4DRO)method in carbon-ion IMPT treatment planning were evaluated and compared.Based on RWD distributions,4DRO methods were compared with 4D conventional optimization using planning target volume(PTV)margins(PTV-based optimization)to assess the effectiveness of the robust optimization methods.Carbon-ion IMPT treatment planning was conducted in a cohort of five lung cancer patients.The results indicated that the EP-4DRO method provided better robustness(P=0.080)and improved plan quality(P=0.225)for the clinical target volume(CTV)in the individual respiratory phase when compared with the PTV-based optimization.Compared with the PTV-based optimization,the RP-4DRO method ensured the robustness(P=0.022)of the dose distributions in the reference breathing phase,albeit with a slight sacrifice of the target coverage(P=0.450).Both 4DRO methods successfully maintained the doses delivered to the organs at risk(OARs)below tolerable levels,which were lower than the doses in the PTV-based optimization(P<0.05).Furthermore,the RP-4DRO method exhibited significantly superior performance when compared with the EP-4DRO method in enhancing overall OAR sparing in either the individual respiratory phase or reference respiratory phase(P<0.05).In general,both 4DRO methods outperformed the PTV-based optimization in terms of OAR sparing and robustness.
文摘<strong>Introduction:</strong> Radiotherapy alone or combined with surgery and/or chemotherapy is being investigated in the treatment of malignant pleural mesothelioma (MPM). This study aimed to simulate a Volumetric Modulated Arc Therapy (VMAT) treatment of a patient with MPM. <strong>Materials and Methods:</strong> CT images from a patient with intact lungs were imported via DICOM into the Pinnacle3 treatment planning (TP) system (TPS) and used as a model for MPM to delineate organs at risk (OAR) and both clinical and planning target volumes (CTV and PTV) with a margin of 5 mm. Elekta Synergy with 6 MV photons and 80 leafs MLCi2 was employed. VMAT plans were generated using two coplanar arcs with gantry rotation angles of 178<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span> - 182<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>, the collimator angles of each arc were set to 90<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>, Octavius<span style="white-space:nowrap;"><sup>®</sup></span> 4D 729 was employed for quality assurance while the calculated and measured doses were compared using VeriSoft. <strong>Results:</strong> A TP was achieved. The Gamma volume analysis with criteria of 3 mm distance to agreement and 3% dose difference yielded the gamma passing rate = 99.9%. The reference isodose was 42.75 Gy with the coverage constraints for the PTV D95 and V95 = 95.0% of 45 Gy. The remaining dosimetric parameters met the recommendations from the clinically acceptable guidelines for the radiotherapy of MPM. <strong>Conclusion:</strong> Using well-defined TV and VMAT, a consistent TP compared to similar ones from publications was achieved. We obtained a high agreement between the 3D dose reconstructed and the dose calculated.
文摘Introduction: Field-in-Field (FIF) and Intensity Modulated Radiation Therapy (IMRT) are two advanced radiation therapy planning techniques. Both of them are being used to achieve the same two related aims which are, to expose the targeted tumor to the full radiation dose and to spare the nearby normal tissues (or organs) from being exposed to high amounts of radiation more than its tolerance dose limits. FIF is a forward planning while IMRT is an inverse planning and FIF is a forward IMRT. Aim: The purpose of this study was to compare between Field-in-Field and IMRT techniques in prostate cancer radiotherapy. Method: A treatment planning system supporting both inverse and forward planning facilities is used. Ten prostate cancer patients were planned with both FIF and IMRT planning techniques. Doses received by the Planning Target Volume (PTV) and Organs at Risk (OARs) were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that the IMRT planning technique achieved better dose coverage to the PTV than the FIF planning technique but, except RT and LT Femoral Heads, FIF achieved a better protection to the Rectum and the Bladder (OARs) than IMRT. Conclusions: The results showed that the inverse planning based IMRT technique is better and recommended in the prostate cancer radiotherapy than the FIF technique.
文摘CEM43 thermal dose is a very common concept in thermal oncology.Thermal dose is the maximum amount of energy that can be transmitted during hyperthermia therapy conducted on temperature-sensitive tissue.Thermal dose is also the maximum value of local energy accumulation in human bodies,which can lead to tissue injury and pain.Thermal dose can also decrease the finishing temperature and reduce the energy to the tolerable range.There are two functions of the individualized hyperthermia treatment plan:it determines the setting and location that can realize the best tumor hyperthermia therapy;at the same time,it can decrease the effect of hyperthermia therapy on healthy tissues.There are four steps in the treatment plan of hyperthermia therapy for tumors:the first step is to establish a three dimensional human body model and its corresponding an atomical structure that can be used in numerical algorithm via medical imaging resources;the second step is to determine the volume of the electromagnetic energy accumulation.Based on the peculiarity of frequency and materials,even full-wave electromagnetic wave or quasi-static technique can be used to determine the tissue distribution.Evaluation of the therapy can be conducted based on thermal dose and the corresponding tissue damage model;the third step is to use Arrhenius model to provide direct evaluation of tissues in the thermal ablation zone,solidification zone,as well as the necrotic area;the last step is the optimization of the treatment plan.
基金Supported by The National Natural Science Foundation of China, No. 30870738
文摘AIM:To compare the volumetric-modulated arc therapy AT plans ith conventional sliding indo intensity-modulated radiotherapy c-I RT plans in esophageal cancer EC . METHODS:Tenty patients ith EC ere selected, including 5 cases located in the cervical, the upper, the middle and the lo er thorax, respectively. Five plans ere generated ith the eclipse planning system:three using c-IMRT with 5 fields (5F), 7 fields (7F) and 9 fields (9F), and two using VMAT with a single arc 1A and double arcs 2A . The treatment plans ere designed to deliver a dose of 60 Gy to the plan-ning target volume Tith the same constrains in a 2.0 Gy daily fraction, 5 d a eek. lans ere normalized to 95% of the T that received 100% of the prescribed dose. We examined the dose-volume histogram parameters of T and the organs at risk OAR such as lungs, spinal cord and heart. onitor units U and normal tissue complication probability NTC of OAR ere also reported. RESULTS:Both c-I RT and AT plans resulted in abundant dose coverage of T for EC of different locations. The dose conformity to T as improved as the number of field in c-IMRT or rotating arc in VMAT as increased. The doses to T and OAR in AT plans ere not statistically different in comparison ith c-I RT plans, ith the follo ing exceptions:in cervical and upper thoracic EC, the conformity index CI as higher in VMAT (1A 0.78 and 2A 0.8) than in c-IMRT (5F 0.62, 7F 0.66 and 9F 0.73) and homogeneity was slightly better in c-IMRT (7F 1.09 and 9F 1.07) than in VMAT (1A 1.1 and 2A 1.09). Lung V30 was lower in VMAT (1A 12.52 and 2A 12.29) than in c-IMRT (7F 14.35 and 9F 14.81). The humeral head doses were significantly increased in AT as against c-I RT. In the middle and lower thoracic EC, CI in VMAT (1A 0.76 and 2A 0.74) was higher than in c-IMRT (5F 0.63 Gy and 7F 0.67 Gy), and homogeneity was almost similar bet een AT and c-I RT. 20 2A 21.49 Gy vs 7F 24.59 Gy and 9F 24.16 Gy) and V30 (2A 9.73 Gy vs 5F 12.61 Gy, 7F 11.5 Gy and 9F 11.37 Gy) of lungs in AT ere lo er than in c-I RT, but lo doses to lungs (V5 and V10) were increased. V30 (1A 48.12 Gy vs 5F 59.2 Gy, 7F 58.59 Gy and 9F 57.2 Gy), V40 and 50 of heart in AT as lo er than in c-I RT. Us in AT plans ere significantly reduced in comparison ith c-I RT, maximum doses to the spinal cord and mean doses of lungs ere similar bet een the t o techniques. NTC of spinal cord as 0 for all cases. NTC of lungs and heart in AT ere lo er than inc-I RT. The advantage of AT plan as enhanced by doubling the arc. CONCLUSION:Compared ith c-I RT, AT, especially the 2A, slightly improves the OAR dose sparing, such as lungs and heart, and reduces NTC and U ith a better T coverage.
基金a grant from the Key Program of Science and Technology Foundation of Hubei Province (No. 2007A301B33).
文摘Objective: We studied the application of CT image fusion in the evaluation of radiation treatment planning for non-small cell lung cancer (NSCLC). Methods: Eleven patients with NSCLC, who were treated with three-dimensional con-formal radiation therapy, were studied. Each patient underwent twice sequential planning CT scan, i.e., at pre-treatment, and at mid-treatment for field reduction planning. Three treatment plans were established in each patient: treatment plan A was based on the pre-treatment planning CT scans for the first course of treatment, plan B on the mid-treatment planning CT scans for the second course of treatment, and treatment plan F on the fused images for the whole treatment. The irradiation doses received by organs at risk in the whole treatment with treatment A and B plans were estimated by the plus of the parameters in treatment plan A and B, assuming that the parameters involve the different tissues (i.e. V20=AV20+BV20), or the same tissues within an organ (i.e. Dmax=ADmax+BDmax). The assessment parameters in the treatment plan F were calculated on the basis of the DVH of the whole treatment. Then the above assessment results were compared. Results: There were marked differ-ences between the assessment results derived from the plus of assessment parameters in treatment plan A and B, and the ones derived from treatment plan F. Conclusion: When a treatment plan is altered during the course of radiation treatment, image fusion technique should be performed in the establishment of a new one. The estimation of the assessment parameters for the whole treatment with treatment plan A and B by simple plus, is inaccurate.
文摘18-fluorodeoxygluocose positron emission tomography/computed tomography(18FDG-PET/CT) provides significant information in multiple settings in the management of head and neck cancers(HNC). This article seeks to define the additional benefit of PET/CT as related to radiation treatment planning for squamous cell carcinomas(SCCs) of the head and neck through a review of relevant literature. By helping further define both primary and nodal volumes, radiation treatment planning can be improved using PET/CT. Special attention is paid to the independent benefit of PET/CT in targeting mucosal primaries as well as in detecting nodal metastases. The utility of PET/CT is also explored for treatment planning in the setting of SCC of unknown primary as PET/CT may help define a mucosal target volume by guiding biopsies for examination under anesthesia thus changing the treatment paradigm and limiting the extent of therapy. Implications of the use of PET/CT for proper target delineation in patients with artifact from dental procedures are discussed and the impact of dental artifact on CT-based PET attenuation correction is assessed. Finally, comment is made upon the role of PET/CT in the high-risk post-operative setting, particularly in the context of radiation dose escalation. Real case examples are used in these settings to elucidate the practical benefits of PET/CT as related to radiation treatment planning in HNCs.
文摘Recently published Medical Physics Practice Guideline 5.a. (MPPG 5.a.) by American Association of Physicists in Medicine (AAPM) sets the minimum requirements for treatment planning system (TPS) dose algorithm commissioning and quality assurance (QA). The guideline recommends some validation tests and tolerances based primarily on published AAPM task group reports and the criteria used by IROC Houston. We performed the commissioning and validation of the dose algorithms for both megavoltage photon and electron beams on three linacs following MPPG 5.a. We designed the validation experiments in an attempt to highlight the evaluation method and tolerance criteria recommended by the guideline. It seems that comparison of dose profiles using in-water scan is an effective technique for basic photon and electron validation. IMRT/VMAT dose calculation is recommended to be tested with some TG-119 and clinical cases, but no consensus of the tolerance exists. Extensive validation tests have provided the better understanding of the accuracy and limitation of a specific dose calculation algorithm. We believe that some tests and evaluation criteria given in the guideline can be further refined.
文摘The current simulation planning systems for maxillofacial prosthesis surgery were used to extrapolate 3D surgical movements and outcomes based on the 2D radiographs, which were inadequate for complex surgical movements.A 3D treatment planning system based on the computerized tomography (CT) data was presented. A 3D data field was constructed out of the sectional image stack through linear interpolation. After objective tissue segmentation and using the marching cubes algorithm method, the triangular mesh model and 3D geometric model of diseased facial skeleton were reconstructed. Then the model was cut, the segments were moved or rotated to their predicted positions, and angles and distances were measured. After triangular mesh model was decimated, a RP model was manufactured for surgical simulation and prosthesis design. The system was used in clinic with more than fifty cases and technically validated with success.
基金Supported by a grant of 2013 the General Logistics Department Military Logistic Research Project Key Programs(No.BWS13J031)
文摘Objective The aim of the study was to compare the dose to lung volume in the supine and prone position while designing Cyber Knife treatment plans to treat metastatic tumors in the spinous processes of the thoracic vertebrae, and offer a reference for reducing damage to normal tissues. Methods Nine cases of metastatic tumors in the spinous processes of the thoracic vertebrae were selected, and then we designed treatment plans based on the supine and prone positions and compared the results. Results In contrast with the treatment plan based on the prone position, the one for the supine position required 14862–36337 MU more; the lung D5% was 5.20–7.90 Gy higher; and the lung D20% was 2.61–5.73 Gy higher. The difference of dose to spine volume between the two plans was –2.21–2.67 Gy; to the skin volume was –3.93–7.85 Gy; and to the esophagus was 0.28–6.39 Gy. Conclusion The treatment plan based on the prone position of patients can better protect lung tissues than the one based on the supine position, and can also improve the availability of beams.
文摘Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not be taken into account during that calculation process. During IMRT routine practical work, it is noticed that there are some non-delineated normal tissue volumes that received un-aimed dose. Aim: The purpose of this study was to study the effect of unusually delineated normal volumes in IMRT treatment for left sided breast cancer. Method: Ten left sided breast cancer patients were planned with IMRT inverse planning system. The unusually delineated normal volumes were delineated and taken into account in IMRT dose constraints as an Organ at Risk. Doses received by that volume were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that doses received by the unusually delineated volume when they were delineated and taken into account in IMRT dose constraints were significantly higher than when they were not. Conclusions: The results showed that for IMRT planning technique used for treating left-sided breast cancer, all of the normal tissues/structures that are closed to the treatment targets must be delineated and taken into account in the IMRT planning dose constraints.
文摘Aim: This study aims to evaluate the difference between depth data from an intraoral cone and a conventional irradiation tube calculated using a treatment planning system (TPS), and that measured using an intraoral cone for electron radiotherapy. Background: A TPS is only compatible with conventional irradiation tubes. However, such systems are not suitable for determining dose distributions when a special cone is employed. Materials and Methods: Dose distributions were calculated using the beam data for mounted intraoral cones using a TPS. Then, the dose distribution by field size was calculated for a low-melting-point lead alloy using the beam data for a mounted conventional tube. The calculated data were evaluated against the measured intraoral-cone depth data based on the dose and depth differences. Results: The calculated data for the intraoral cone case did not match the measured data. However, the depth data obtained considering the field size determined for the lead alloy using the conventional tube were close to the measured values for the intraoral cone case. The difference in the depth at which the absorbed dose was 50% of the maximum value of the percentage depth dose was less than ±4 mm for the generalized Gaussian pencil beam convolution algorithm and less than ±1 mm for the electron Monte Carlo algorithm. Conclusion: It was found that the measured and calculated dose distributions were in agreement, especially when then electron Monte Carlo algorithm was used. Thus, the TPS can be employed to determine dose distributions for intraoral cone applications.
文摘Cone-beam CT (CBCT) images acquired during radiation treatment can be used to recalculate the dose distribution as well as to confirm the treatment location. However, it is difficult to obtain the electron densities (EDs) necessary for dose calculation from CBCT images because of the effects of scatter contamination during CBCT image acquisition. This paper presents a mathematical method for converting the pixel values of CBCT images (CBCT values) into Hounsfield units (HUs) of radiation treatment simulation CT (simCT) images for use in radiation treatment planning. CBCT values are converted into HUs by matching the histograms of the CBCT values with the histograms of the HUs for each slice via linear scaling of the CBCT values. For prostate cancer and head-and-neck cancer patients, the EDs obtained from converted CBCT values (mCBCT values) show good agreement with the EDs obtained from HUs, within approximately 3.0%, and the dose calculated on the basis of CBCT images shows good agreement with the dose calculated on the basis of the simCT images, within approximately 2.0%. Because the CBCT values are converted for each slice, this conversion method can account for variation in the CBCT values associated with differences in body size, body shape, and inner tissue structures, as well as in longitudinally displaced positions from the isocenter, unlike conventional methods that use electron density phantoms. This method improves on conventional CBCT-ED conversion and shows considerable potential for improving the accuracy of radiation treatment planning using CBCT images.
文摘Purpose: To introduce a practical method of using an Electron Density Phantom (EDP) to evaluate different dose calculation algorithms for photon beams in a treatment planning system (TPS) and to commission the Anisotropic Analytical Algorithm (AAA) with inhomogeneity correction in Varian Eclipse TPS. Methods and Materials: The same EDP with various tissue-equivalent plugs (water, lung exhale, lung inhale, liver, breast, muscle, adipose, dense bone, trabecular bone) used to calibrate the computed tomography (CT) simulator was adopted to evaluate different dose calculation algorithms in a TPS by measuring the actual dose delivered to the EDP. The treatment plans with a 6-Megavolt (MV) single field of 20 × 20, 10 × 10, and 4 × 4 cm2 field sizes were created based on the CT images of the EDP. A dose of 200 cGy was prescribed to the exhale-lung insert. Dose calculations were performed with AAA with inhomogeneity correction, Pencil Beam Convolution (PBC), and AAA without inhomogeneity correction. The plans were delivered and the actual doses were measured using radiation dosimetry devices MapCheck, EDR2-film, and ionization chamber respectively. Measured doses were compared with the calculated doses from the treatment plans. Results: The calculated dose using the AAA with inhomogeneity correction was most consistent with the measured dose. The dose discrepancy for all types of tissues covered by beam fields is at the level of 2%. The effect of AAA inhomogeneity correction for lung tissues is over 14%. Conclusions: The use of EDP and Map Check to evaluate and commission the dose calculation algorithms in a TPS is practical. In Varian Eclipse TPS, the AAA with inhomogeneity correction should be used for treatment planning especially when lung tissues are involved in a small radiation field.
文摘Water safety plan as conceived by WHO can lead to prevention of pollution in each component of water supply chain which leads to ensuring safe drinking water. Risk assessment is one of the key components during the development of water safety plan, achieved by identifying hazardous events and estimating their risk towards implementing control measures. This study reports the risk assessment from catchment to consumers in Maiduguri water treatment plant in Northeast Nigeria. Tools such as the field visits, key informant interviews, questionnaire and water quality monitoring were used to identify the hazards and estimate their risk using semi-quantitative matrix. With the existing control measures, the study showed a total of 33 hazardous events;5 in catchment, 16 in treatment plant, 6 in distribution system and 6 at consumers’ points. The risk score indicated 6 are of medium risk and 9 of high risk. Catchment activities, upgrade of treatment facilities and lack of routine maintenance in the treatment plant, pipeline damages in distribution lines, and consumers’ lack of hygiene knowledge and awareness were found to be the major contributory factors which affect the desired quality. Therefore participation and commitment by all relevant stakeholders are fundamental requisite to manage the identified health risks.
基金Supported by the National Key R&D Program“Public Security Risk Prevention and Control and Emergency Technology and Equipment”Key Special Project(2020YFC0841600)Hubei Provincial Department of Science and Technology,2020 Hubei Province New Pneumonia Emergency Science and Technology Project(2020FCA027)+2 种基金Hubei Provincial Health Commission,2021-2022 TCM Scientific Research Project Key Project(ZY2021Z003)Hubei Provincial Health Commission Key Support Projects from 2021 to 2022(WJ2021Z009)Hubei Provincial Department of Science and Technology,2020 Hubei Province Key R&D Program Project(2020BCB012)。
文摘OBJECTIVE:To investigate the clinical efficacy and safety of a diagnosis and treatment plan for moderate coronavirus disease 2019(COVID-19)that integrates traditional Chinese(TCM)and western medicine.METHODS:One hundred twenty patients with moderate COVID-19 were randomized 1∶2 to the control group(n=40)and experimental group(n=80).Both groups received conventional western medicine treatment,and the experimental group also received TCM decoction.Over a 2-week period from diagnosis,we observed the time to clinical recovery(TTCR),rate of improvement on lung computed tomography(CT)imaging,time to defervescence,cough remission time,hospital discharge rate,average hospitalization stay,modified Medical Research Council(m MRC)scale score,clinical cure rate,laboratory findings,incidence of progression to severe or critical disease,and adverse events.RESULTS:Among 120 enrolled patients,108 completed the study.The baseline data did not differ between the experimental and control groups(all P>0.05).After treatment,the TTCR,rate of lung CT imaging improvement,time to defervescence,cough remission time,hospital discharge rate,average hospitalization stay(among discharged patients),m MRC scale score,clinical cure rate,and rates of normal values for laboratory findings were better in the experimental group than in the control group(P<0.05 or<0.01).The incidence of progression to severe or critical disease and the incidence of adverse events did not differ between the two groups(P>0.05).CONCLUSION:The diagnosis and treatment plan integrating Chinese and western medicine showed improved clinical efficacy compared with western medicine alone for patients with moderate COVID-19 and is worthy of clinical promotion and application.
基金This work was funded by the General Program of Jiangsu Provincial Health Commission(No.M2020006)Changzhou Key Laboratory of Medical Physics(No.CM20193005)+2 种基金Changzhou Sci&Tech Program(No.CJ20200099)Young Talent Development Plan of Changzhou Health Commission(Nos.CZQM2020075 and CZQM2020067)the Science and Technology Programs for Young Talents of Changzhou Health Commission(No.QN201932).
文摘Objective:To explore treatment planning approaches using volumetric modulated arc therapy(VMAT)for head and neck cancer patients with metallic dental fillings.Methods:Fifty-six patients with metallic dental fillings treated with radiotherapy were selected,and three VMAT plans,the jaw-tracking plan,fixed-jaw plan,and non-coplanar plan,were designed for each patient.In the jawtracking plan,two coplanar partial arc fields that avoid the metal area were set,and the jaw was automatically tracked.In the fixed-jaw plan,different fields were set in three sections according to the fixed-jaw method.The fields were the same as those in the jaw-tracking plan for the section containing metal implants,while full arc fields were set in the nonmetal sections.In the non-coplanar plan,a non-coplanar arc field was added based on the jaw-tracking plan.The treatment plan in the jaw-tracking plan was optimized,and the constraints on the planning target volume(PTV)or organs at risk(OARs)in the jaw-tracking plan were copied to the other two plans.The dose distribution in PTV and OARs of the patients in the three treatment plans was compared.Results:There were no significant differences in the maximum doses to the spinal cord or optic nerves among the three treatment plans.However,compared with the jaw-tracking plan,the fixed-jaw plan showed lower mean doses to the pharynx[(42.9±7.1)Gy vs.(44.1±7.1)Gy,P<0.05]and larynx[(43.9±3.9)Gy vs.(45.4±4.7)Gy,P<0.05],while the non-coplanar plan obtained significantly better dose distribution in PTV and all OARs except for the spinal cord and optic nerves.Meanwhile,the non-coplanar plan performed significantly better than the fixed-jaw plan in terms of the maximum doses to the brainstem[(50.24.0)Gy vs.(51.4±4.6)Gy,P<0.05],left lens[(5.8±0.2)Gy vs.(6.3±0.4 Gy),P<0.05],and right lens[(5.9±0.3)Gy vs.(6.2±0.3)Gy,P<0.05].Conclusions:The non-coplanar VMAT is an optimal method for treating head and neck cancer patients with metallic dental fillings since it can provide better dose distribution in PTV and reduce doses to OARs.
文摘Introduction: Radiation therapy after breast surgery is an integral part of the treatment of early breast cancer. The goal of radiation therapy is to achieve the best possible coverage of the planning target volume (PTV), while reducing the dose to organs at risk (OARs) which are normal tissues whose sensitivity to irradiation could cause damage that can lead to modification of the treatment plan. In the last decade, radiation oncologist started to use the Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for irradiating the breast, in order to achieve better dose distribution and target dose to the PTV and OAR. The aim of this study is to compare 2 external radiotherapy techniques (VMAT vs 3D) for patients with node-positive left breast cancer. Patients and Methods: We randomly selected 10 cases of postoperative radiotherapy for breast cancer in our hospital. The patients are all female, the average age was 45.4 years old, and the primary lesions are left breast. The ANOVA test was used to compare the mean difference between subgroups, and the p value Results: Dose volume histogram (DVH) was used to analyze each evaluation dose of clinical target volume (CTV) and organs at risk (OARs). Compared to 3DCRT plans, VMAT provided more uniform coverage to the breast and regional lymph nodes. The max point dose for tVMAT was lower on average (106.4% for VMAT versus 109% for 3DCRT). OAR sparing was improved with tVMAT, with a lower average V17Gy for the left lung (27.91% for VMAT versus 30.04% for 3DCRT, p and lower for V28Gy (13.75% for VMAT versus 22.34% for 3DCRT, p = 0.01). We also found a lower V35Gy for the heart on VMAT plan (p = 0.02). On the contrary, dose of contralateral breast was lower in 3DCRT than VMAT (0.59 Gy vs 3.65 Gy, p = 0.00). Conclusion: The both types of plans can meet the clinical dosimetry demands of postoperative radiotherapy for left breast cancer. The VMAT plan has a better conformity, but 3CDRT can provide a lower dose to the contralateral organs (breast and lung) to avoid the risk of secondary cancers.
文摘Objective:This paper aims to discuss the prevention and treatment strategies of gastrointestinal diseases in college students.Methods:A sample of 60 college students suffering from gastrointestinal diseases,from August 2021 to August 2022,was used to discuss the symptoms,causes,prevention strategies,and treatment strategies of gastrointestinal diseases based on questionnaire survey.Results:The high-incidence types of gastrointestinal diseases in college students mainly included chronic gastritis,acute gastritis,duodenal ulcer,and dyspepsia,which were closely related to mental state,diet,and living habits.Conclusion:There are many causes of gastrointestinal diseases in college students.During the period of active symptomatic treatment,it is necessary to focus on the prevention of gastrointestinal diseases in colleges and universities,correct the unhealthy lifestyle of students,and reduce the risk of gastrointestinal diseases.
基金Supported by Nuclear R&D Programs from Ministry of Education,Science,and Technology in Republic of Korea
文摘This study compares and analyzes stereotactic radiotherapy using tomotherapy and linac-based fractionated stereotactic radiotherapy in the treatment of intra-cranial tumors,according to some cases.In this study,linac-based fractionated stereotactic radiotherapy and tomotherapy treatment were administered to five patients diagnosed with intra-cranial cancer in which the dose of 18–20 Gy was applied on 3–5 separate occasions.The tumor dosing was decided by evaluating the inhomogeneous index (II) and conformity index (CI).Also,the radiation-sensitive tissue was evaluated using low dose factors V1,V2,V3,V4,V5,and V10,as well as the non-irradiation ratio volume (NIV).The values of the II for each prescription dose in the linacbased non-coplanar radiotherapy plan and tomotherapy treatment plan were (0.125±0.113) and (0.090±0.180),respectively,and the values of the CI were (0.899±0.149) and (0.917±0.114),respectively.The low dose areas,V1,V2,V3,V4,V5,and V10,in radiation-sensitive tissues in the linac-based non-coplanar radiotherapy plan fell into the ranges 0.3%–95.6%,0.1%–87.6%,0.1%–78.8%,38.8%–69.9%,26.6%–65.2%,and 4.2%–39.7%,respectively,and the tomotherapy treatment plan had ranges of 13.6%–100%,3.5%–100%,0.4%–94.9%,0.2%– 82.2%,0.1%–78.5%,and 0.3%–46.3%,respectively.Regarding the NIV for each organ,it is possible to obtain similar values except for the irradiation area of the brain stem.The percentages of NIV10%,NIV20%,and NIV30%for the brain stem in each patient were 15%–99.8%,33.4%–100%,and 39.8%–100%,respectively,in the fractionated stereotactic treatment plan and 44.2%–96.5%,77.7%–99.8%,and 87.8%–100%,respectively,in the tomotherapy treatment plan.In order to achieve higher-quality treatment of intra-cranial tumors,treatment plans should be tailored according to the isodose target volume,inhomogeneous index,conformity index,position of the tumor upon fractionated stereotactic radiosurgery,and radiation dosage for radiation-sensitive tissues.
