Ionizing radiation is extensively used in medicine and its contribution to both diagnosis and therapy is undisputable.However,the use of ionizing radiation also involves a certain risk since it may cause damage to tis...Ionizing radiation is extensively used in medicine and its contribution to both diagnosis and therapy is undisputable.However,the use of ionizing radiation also involves a certain risk since it may cause damage to tissues and organs and trigger carcinogenesis.Computed tomography(CT) is currently one of the major contributors to the collective population radiation dose both because it is a relatively high dose examination and an increasing number of people are subjected to CT examinations many times during their lifetime.The evolution of CT scanner technology has greatly increased the clinical applications of CT and its availability throughout the world and made it a routine rather than a specialized examination.With the modern multislice CT scanners,fast volume scanning of the whole human body within less than 1 min is now feasible.Two dimensional images of superb quality can be reconstructed in every possible plane with respect to the patient axis(e.g.axial,sagital and coronal).Furthermore,three-dimensional images of all anatomic structures and organs can be produced with only minimal additional effort(e.g.skeleton,tracheobronchial tree,gastrointestinal system and cardiovascular system).All these applications,which are diagnostically valuable,also involve a significant radiation risk.Therefore,all medical professionals involved with CT,either as referring or examining medical doctors must be aware of the risks involved before they decide to prescribe or perform CT examinations.Ultimately,the final decision concerning justification for a prescribed CT examination lies upon the radiologist.In this paper,we summarize the basic information concerning the detrimental effects of ionizing radiation,as well as the CT dosimetry background.Furthermore,after a brief summary of the evolution of CT scanning,the current CT scanner technology and its special features with respect to patient doses are given in detail.Some numerical data is also given in order to comprehend the magnitude of the potential radiation risk involved in comparison with risk from exposure to natural background radiation levels.展开更多
For precise and accurate patient dose delivery,the dosimetry system must be calibrated properly according to the recommendations of standard dosimetry protocols such as TG-51 and TRS-398. However, the dosimetry protoc...For precise and accurate patient dose delivery,the dosimetry system must be calibrated properly according to the recommendations of standard dosimetry protocols such as TG-51 and TRS-398. However, the dosimetry protocol followed by a calibration laboratory is usually different from the protocols that are followed by different clinics, which may result in variations in the patient dose.Our prime objective in this study was to investigate the effect of the two protocols on dosimetry measurements.Dose measurements were performed for a Co-60 teletherapy unit and a high-energy Varian linear accelerator with 6 and 15 MV photon and 6, 9, 12, and 15 MeV electron beams, following the recommendations and procedures of the AAPM TG-51 and IAEA TRS-398 dosimetry protocols. The dosimetry systems used for this study were calibrated in a Co-60 radiation beam at the Secondary Standard Dosimetry Laboratory(SSDL) PINSTECH,Pakistan, following the IAEA TRS-398 protocol. The ratio of the measured absorbed doses to water in clinical setting,D_w(TG-51/TRS-398), was 0.999 and 0.997 for 6 and15 MV photon beams,whereas these ratios were 1.013,1.009, 1.003, and 1.000 for 6, 9, 12, and 15 MeV electron beams, respectively. This difference in the absorbed dosesto-water D_w ratio may be attributed mainly due to beam quality(K_Q) and ion recombination correction factor.展开更多
Medical diagnostic X-rays are the largest manmade source of ionizing radiation received by the members of the general public. The aim of this study was to evaluate the radiographic reject/repeat rate and also to deter...Medical diagnostic X-rays are the largest manmade source of ionizing radiation received by the members of the general public. The aim of this study was to evaluate the radiographic reject/repeat rate and also to determine dose to the patients from radiographic rejects/repeats in radiology centers of Urmia University of Medical Sciences. During a 4 month period the most frequently examinations were chosen in three radiology centers. A form was designed as a reject/repeat analysis form for radiographers to complete each time a film was rejected by radiologists or repeated. The collected data were compiled at the end of each week and entered into a computer for analysis at the end of study. The results of this study showed that highest and lowest repetition rates were for pelvis, 14.01% and upper limb, 4.17%, respectively. The main reasons of repetition of radiographs were due to exposure (54%) and positioning (18%) errors. The average repeat rate in all three hospitals was 7.20%. It was found that human error has important role to repetition of radiographs. It is demonstrated that those patients having repeated radiographs received an average of 3.23 Gy·cm2. Based on the findings of this study it must be remembered that the highest repetition rate was for pelvis. Considering the radiosensitive organs related to pelvis especially in pediatric patients some special considerations must be applied for pelvis examinations.展开更多
Background: Among medical technologies that use ionizing radiation, CT is currently the radio diagnostic technic that can deliver the highest radiation to the Patient compared with other conventional procedures. In de...Background: Among medical technologies that use ionizing radiation, CT is currently the radio diagnostic technic that can deliver the highest radiation to the Patient compared with other conventional procedures. In developing countries, the uses and risks of CT have not been well characterized. Objective: To estimate the lifetime attributable risk (LAR) incidence and mortality for cancer for each procedure for adult’s patients who had Computed Tomography examinations in 10 imaging centers in the city of Douala-Cameroon so as to provide a reference data. Materials and Methods: We conducted a cross-sectional study describing radiation dose associated with the 8 most common types of diagnostic CT studies performed on 1287 consecutive adult patients at 10 Douala radiology department. We estimated lifetime attributable risks of cancer by study type from these measured doses. Estimation of LAR for cancer incidence and mortality was based on the effective dose, patient’s sex and age at exposure using the BIER VII preferred models. Results: Mean effective dose from CT scans examinations varied from: 0.30 and 8.81 mSv. The highest doses were observed for lumbar spine CT (8.81 mSv), followed by abdomen-pelvis procedure (6.46 mSv), chest-abdomen-pelvic CT (6.61 mSv), chest CT (3.90 mSv), cervical Spine CT (3.05 mSv), head CT (1.7 mSv) and lower for sinus CT (0.30 mSv). The LAR values of all cancer from patients’ CT scans obtained vary from 67.13 excess per 100,000 (about 1 in 1489) and 0.45 excess per 100,000 (about 1 in 222,222). All cancer risk was high for lumbar spine CT in women 20 years old (67.13 excess deaths in 100,000 scans) followed by chest-abdomen-pelvic CT (50.36 excess deaths in 100,000 scans) and abdomen-pelvic CT (49.22 excess deaths in 100,000 scans) for the same age group. The LAR of incidence and mortality values were higher from female’s patients than males and higher for younger than older patients. Conclusion: This study was set out to estimate the LAR values associated with adult common CT scans procedures. The data indicates, LAR risks related to induced cancer from CT exposures were estimated to be low. This risk can be relatively significant for younger age group compared to older age group. The LAR values obtained will help to better evaluate radiation exposure risk, before ordering a CT scans examinations.展开更多
Every year there are new 1,600 cases of breast cancer in Bosnia and Herzegovina. The most effective method for early detection of breast cancer is mammography. To examine risks and benefits of this diagnostic method i...Every year there are new 1,600 cases of breast cancer in Bosnia and Herzegovina. The most effective method for early detection of breast cancer is mammography. To examine risks and benefits of this diagnostic method it is necessary to determine patient doses. Mainly, almost all published data about patient doses refer to two specific age groups: 40-49 and 50-64 years of age. Very little data about patient doses applied during a routine mammography for patients from 65-80 years of age are available. During the conducted research, one calculated doses for the complete mammographic examination of 42 patients from this age group. The calculated patient doses are related to the whole spectrum of technical, physical, clinical and diagnostic parameters which compose a complete mammographic examination.展开更多
Hyperthyroidism refers to a clinical state that results from inappropriately hight hyroid hormone levels in the tissues;.Ⅰ-131 therapy plays a critical role and provides a remarkable curative effect in targeting thyr...Hyperthyroidism refers to a clinical state that results from inappropriately hight hyroid hormone levels in the tissues;.Ⅰ-131 therapy plays a critical role and provides a remarkable curative effect in targeting thyroid diseases. Thyroid cells can take up isotope I-131, which emits not only beta rays but also展开更多
Information about the peak skin dose and Dose Area product (DAP) from percutaneous transluminal coronary angioplasty (PTCA) and coronary angiography (CA) was collected from three catheter application rooms. The range ...Information about the peak skin dose and Dose Area product (DAP) from percutaneous transluminal coronary angioplasty (PTCA) and coronary angiography (CA) was collected from three catheter application rooms. The range of maximum photon energy was 50 - 125 kVp and the fluoroscopy time was 0.6 - 52 seconds. Values of up to 143 Gy·cm2 for DAP and 0.752 mGy for cumulative dose (CD) were found in CA procedures. Otherwise the DAP and CD for PTCA were found to be 143 Gy·cm2 and 2.287 mGy respectively in 3rd Quartile. The relation between the fluoroscopy time and the DAP is also considered. Objectives: The objective of this study is to obtain information about patient peak skin doses (PSD), dose area product (DAP), Fluoroscopy Time (FT) and Cumulative Dose (CD) from PTCA and CA which is the most predominant with respect to high skin doses in addition to other procedures. The aim of this study is also to assess the radiation dose received by patients undergoing interventional radiology procedures, by identifying the procedures that deliver the highest doses. This study is also helpful to establish the reference dose level for adult patients undergoing interventional procedure, and to provide recommendations on how to reduce dose on selected procedures that have been identified to deliver patient dose values near the ICRP (International Commission on Radiological Protection) threshold values.展开更多
AIM To determine the clinical characteristics of elderly patients of hemorrhagic gastroduodenal ulcer on low-dose aspirin(LDA)therapy.METHODS A total of 1105 patients with hemorrhagic gastroduodenal ulcer treated in o...AIM To determine the clinical characteristics of elderly patients of hemorrhagic gastroduodenal ulcer on low-dose aspirin(LDA)therapy.METHODS A total of 1105 patients with hemorrhagic gastroduodenal ulcer treated in our hospital between January 2000 and March 2016 were grouped by age and drugs used,and these groups were compared in several factors.These groups were compared in terms of length of hospital stay,presence/absence of hemoglobin(Hb)decrease,presence/absence of blood transfusion,Forrest Ⅰ,percentage of Helicobacter pylori infection,presence/absence of underlying disease,and percentage of severe cases.RESULTS The percentage of blood transfusion(62.6%vs 47.7%,P<0.001),Hb decrease(53.8% vs 40.8%,P<0.001),and the length of hospital stay(23.5 d vs 16.7 d,P<0.001)were significantly greater in those on drug therapy.The percentage of blood transfusion(65.3%vs 47.8%,P<0.001),Hb decrease(54.2%vs 42.1%,P<0.001),and length of hospital stay(23.3 d vs 17.5 d,P<0.001)were significantly greater in the elderly.In comparison with the LDA monotherapy group,the percentage of severe cases was significantly higher in the LDA combination therapy group when elderly patients were concerned(16.1%vs34.0%,P=0.030).Meanwhile,among those on LDA monotherapy,there was no significant difference between elderly and non-elderly(16.1%vs 16.0%,P=0.985).CONCLUSION A combination of LDA with antithrombotic drugs or nonsteroidal anti-inflammatory drugs(NSAIDs)contributes to aggravation.And advanced age is not an aggravating factor when LDA monotherapy is used.展开更多
We use a nuclear technique based on the determination of the detection efficiencies of solid state nuclear track detectors CR-39 and LR-115 type II (SSNTDs) for alpha particles emitted from the series of uranium-238 a...We use a nuclear technique based on the determination of the detection efficiencies of solid state nuclear track detectors CR-39 and LR-115 type II (SSNTDs) for alpha particles emitted from the series of uranium-238 and thorium-232 in a phytotherapeutic sample and the measurement of alpha track densities registered on these detectors to assess alpha activities due to uranium-238;thorium-232;radon and thoron in samples of phytotherapeutic preparations consumed by Moroccan adult patients. For modern preparations, the alpha activities due to <sup>238</sup>U, <sup>232</sup>Th and <sup>222</sup>Rn range from 14.27 mBq/kg to 22.02 mBq/kg, from 6.27 mBq/kg to 9.64 mBq/kg and from 14.27 Bq/kg to 22.02 Bq/kg respectively. For classical preparations, the alpha activities due to <sup>238</sup>U, <sup>232</sup>Th and <sup>222</sup>Rn range from 16.73 mBq/kg to 24 mBq/kg, from 7.34 mBq/kg to 10.82 mBq/kg and from 16.73 Bq/kg to 24.72 Bq/kg respectively. A dosimetric model for ingestion has been highlighted to determine committed equivalent dose to different compartments of human gastrointestinal system due to the ingestion of phytotherapeutic preparations by Moroccan adult patients. The maximum overall effective dose due to <sup>238</sup>U, <sup>232</sup>Th, and <sup>222</sup>Rn after the ingestion of the studied phytotherapeutic preparations, was found equal to 38 × 10<sup>-8</sup> S·vy<sup>-1</sup> which is less than the dose limit given by the international commission for radiological protection in it publication 56.展开更多
Objectives: Patients undergoing 18F-FDG PET/CT imaging are considered external radiation sources. Accurate dose rate estimates are important for conducting realistic risk assessments and performing dose reconstruction...Objectives: Patients undergoing 18F-FDG PET/CT imaging are considered external radiation sources. Accurate dose rate estimates are important for conducting realistic risk assessments and performing dose reconstruction in cases of accidental exposures. The patient radiation self-attenuation factor is assumed to be a function of the patient’s body size metrics, but we can use these metrics to predict the dose rate around the patients with accuracy. The objective of this work was first to measure the patient attenuation factor by performing direct dose rate measurements from patients undergoing PET/CT imaging studies using 18F-FDG. The second objective was to study the possible correlation between the measured dose rate constant per unit activity from the patients and their body size metrics;five metrics were tested in this work. The last objective was to measure the patients’ voiding factor. Methods: We have measured dose rates at one meter from 57 patients and noted the patient’s height (H), weight (W) and calculated patient size metrics namely: Equivalent Cylindrical Diameter (ECD), Equivalent Spherical Diameter (ESD) and the Body Mass Index (BMI). Results: The measured average dose rate was 92.2 ± 14 μSv·h-1·GBq-1 measured at one meter. Therefore, the dose rate constant of 92 μSv·h-1·GBq-1 proposed by the AAPM, TG-108 report is adequate for radiation protection purposes. There was no statistically significant correlation between the dose rate constant per unit activity and the patient body size metrics. We have measured a patient voiding factor of 0.89 ± 0.06 in comparison with 0.85 recommended by the AAPM. Conclusions: The presented data can be used by medical physicist working in nuclear medicine in formulating more accurate risk estimations resulting from radiation exposure from patients undergoing 18F-FDG PET/CT imaging.展开更多
目的应用序贯法探讨丙泊酚或不同剂量瑞马唑仑对舒芬太尼抑制老年患者气管插管反应的半数有效剂量(50%effective dose,ED_(50))的影响。方法选择2022年10至12月在气管插管全身麻醉下接受择期手术的老年患者,美国麻醉医师协会(American S...目的应用序贯法探讨丙泊酚或不同剂量瑞马唑仑对舒芬太尼抑制老年患者气管插管反应的半数有效剂量(50%effective dose,ED_(50))的影响。方法选择2022年10至12月在气管插管全身麻醉下接受择期手术的老年患者,美国麻醉医师协会(American Society of Anesthesiologists,ASA)分级Ⅰ、Ⅱ级,年龄65~80岁,将患者采用随机数字表法分为4组:丙泊酚组(P组,诱导时给予丙泊酚2mg/kg)和瑞马唑仑组(R1、R2、R3组,诱导时分别静脉注射瑞马唑仑0.2、0.3、0.4mg/kg)。麻醉诱导时给予Dixon序贯法设定剂量的舒芬太尼后,静脉注射丙泊酚或相应剂量瑞马唑仑及顺式阿曲库铵0.15mg/kg,待4个成串刺激(train of four,TOF)计数为0时行气管插管。若气管插管反应阳性,则下一例患者舒芬太尼剂量提高1个浓度梯度,否则降低1个浓度梯度,各相邻浓度之间的比为1∶1.1,直至出现7个转折点终止研究。采用Probit回归分析计算舒芬太尼抑制老年患者气管插管反应ED_(50)和95%有效剂量(95%effective dose,ED_(95))以及相应的95%置信区间(confidenceinterval,CI)。记录所有患者低血压、心动过缓、注射痛等不良反应的发生情况。结果本研究共纳入老年患者113例,P、R1、R2、R3组分别24、28、30、31例。丙泊酚2mg/kg或0.2、0.3、0.4mg/kg瑞马唑仑时舒芬太尼抑制老年患者气管插管反应的ED_(50)和ED_(95)及相应95%CI分别为:P组ED_(50)为0.236μg/kg(95%CI:0.218~0.256),ED_(95)为0.266μg/kg(95%CI:0.250~0.398);R1组ED_(50)为0.284μg/kg(95%CI:0.265~0.309),ED_(95)为0.329μg/kg(95%CI:0.306~0.478);R2组ED_(50)为0.239μg/kg(95%CI:0.221~0.260),ED_(95)为0.282μg/kg(95%CI:0.261~0.415);R3组ED_(50)为0.198μg/kg(95%CI:0.182~0.211),ED_(95)为0.231μg/kg(95%CI:0.216~0.303)。与P组相比,R1、R2、R3组低血压、心动过缓、注射痛发生率较低(P<0.05)。R2组舒芬太尼ED_(50)与P组相类似,但低血压、注射痛发生率与P组相比较低。结论随着瑞马唑仑剂量的增加,舒芬太尼抑制老年患者气管插管反应的ED_(50)逐渐降低;在ED_(50)相近的情况下,瑞马唑仑相较于丙泊酚诱导的低血压、心动过缓、注射痛发生率更低,因而在老年患者气管插管全身麻醉中,使用瑞马唑仑诱导更具有优势。展开更多
This study designed to evaluate the entrance surface air kerma (ESAK) to the patient during X-ray examination to the skull antero-posterior (AP), skull Lateral (LAT), chest postero-anterior (PA), Lumber spine AP/LAT a...This study designed to evaluate the entrance surface air kerma (ESAK) to the patient during X-ray examination to the skull antero-posterior (AP), skull Lateral (LAT), chest postero-anterior (PA), Lumber spine AP/LAT and Pelvis AP. Totally, 408 patients were included in this study using computed radiography (CR) in different three hospitals in Khartoum;five X-ray machines were covered. The entrance surface air kerma (ESAK) was calculated for each patient from the exposure parameters using different peak tube voltages. Patient’s data such as (age and weight) and exposure parameters (kVp) and (mAs) were recorded. The result obtained showed that, the entrance surface air kerma ranged from 0.88 to 3.30 mGy for Skull (AP), 0.588 to 1.87 mGy for skull (LAT), 0.03 to 2 mGy for chest PA, 1.50 to 3.40 mGy Lumbar spine AP, 2.60 to 5.15 mGy for Lumbar spine (LAT), and 1.05 to 4.40 mGy for Pelvis. This study provides additional data that can help the regulatory authority to establish reference dose level for diagnostic radiology in Sudan. This study recommends that the CR operator must be used to optimize the patient dose by using the best strategies available for reducing radiation dose. Computed radiography must be used with high level training for medical staff to reduce the dose;each radiology department should implement a patient dose measurement quality assurance programme. Doses to the patients should be regularly monitored and the proposed national DRLs should be taken as guidance for optimization.展开更多
文摘Ionizing radiation is extensively used in medicine and its contribution to both diagnosis and therapy is undisputable.However,the use of ionizing radiation also involves a certain risk since it may cause damage to tissues and organs and trigger carcinogenesis.Computed tomography(CT) is currently one of the major contributors to the collective population radiation dose both because it is a relatively high dose examination and an increasing number of people are subjected to CT examinations many times during their lifetime.The evolution of CT scanner technology has greatly increased the clinical applications of CT and its availability throughout the world and made it a routine rather than a specialized examination.With the modern multislice CT scanners,fast volume scanning of the whole human body within less than 1 min is now feasible.Two dimensional images of superb quality can be reconstructed in every possible plane with respect to the patient axis(e.g.axial,sagital and coronal).Furthermore,three-dimensional images of all anatomic structures and organs can be produced with only minimal additional effort(e.g.skeleton,tracheobronchial tree,gastrointestinal system and cardiovascular system).All these applications,which are diagnostically valuable,also involve a significant radiation risk.Therefore,all medical professionals involved with CT,either as referring or examining medical doctors must be aware of the risks involved before they decide to prescribe or perform CT examinations.Ultimately,the final decision concerning justification for a prescribed CT examination lies upon the radiologist.In this paper,we summarize the basic information concerning the detrimental effects of ionizing radiation,as well as the CT dosimetry background.Furthermore,after a brief summary of the evolution of CT scanning,the current CT scanner technology and its special features with respect to patient doses are given in detail.Some numerical data is also given in order to comprehend the magnitude of the potential radiation risk involved in comparison with risk from exposure to natural background radiation levels.
文摘For precise and accurate patient dose delivery,the dosimetry system must be calibrated properly according to the recommendations of standard dosimetry protocols such as TG-51 and TRS-398. However, the dosimetry protocol followed by a calibration laboratory is usually different from the protocols that are followed by different clinics, which may result in variations in the patient dose.Our prime objective in this study was to investigate the effect of the two protocols on dosimetry measurements.Dose measurements were performed for a Co-60 teletherapy unit and a high-energy Varian linear accelerator with 6 and 15 MV photon and 6, 9, 12, and 15 MeV electron beams, following the recommendations and procedures of the AAPM TG-51 and IAEA TRS-398 dosimetry protocols. The dosimetry systems used for this study were calibrated in a Co-60 radiation beam at the Secondary Standard Dosimetry Laboratory(SSDL) PINSTECH,Pakistan, following the IAEA TRS-398 protocol. The ratio of the measured absorbed doses to water in clinical setting,D_w(TG-51/TRS-398), was 0.999 and 0.997 for 6 and15 MV photon beams,whereas these ratios were 1.013,1.009, 1.003, and 1.000 for 6, 9, 12, and 15 MeV electron beams, respectively. This difference in the absorbed dosesto-water D_w ratio may be attributed mainly due to beam quality(K_Q) and ion recombination correction factor.
文摘Medical diagnostic X-rays are the largest manmade source of ionizing radiation received by the members of the general public. The aim of this study was to evaluate the radiographic reject/repeat rate and also to determine dose to the patients from radiographic rejects/repeats in radiology centers of Urmia University of Medical Sciences. During a 4 month period the most frequently examinations were chosen in three radiology centers. A form was designed as a reject/repeat analysis form for radiographers to complete each time a film was rejected by radiologists or repeated. The collected data were compiled at the end of each week and entered into a computer for analysis at the end of study. The results of this study showed that highest and lowest repetition rates were for pelvis, 14.01% and upper limb, 4.17%, respectively. The main reasons of repetition of radiographs were due to exposure (54%) and positioning (18%) errors. The average repeat rate in all three hospitals was 7.20%. It was found that human error has important role to repetition of radiographs. It is demonstrated that those patients having repeated radiographs received an average of 3.23 Gy·cm2. Based on the findings of this study it must be remembered that the highest repetition rate was for pelvis. Considering the radiosensitive organs related to pelvis especially in pediatric patients some special considerations must be applied for pelvis examinations.
文摘Background: Among medical technologies that use ionizing radiation, CT is currently the radio diagnostic technic that can deliver the highest radiation to the Patient compared with other conventional procedures. In developing countries, the uses and risks of CT have not been well characterized. Objective: To estimate the lifetime attributable risk (LAR) incidence and mortality for cancer for each procedure for adult’s patients who had Computed Tomography examinations in 10 imaging centers in the city of Douala-Cameroon so as to provide a reference data. Materials and Methods: We conducted a cross-sectional study describing radiation dose associated with the 8 most common types of diagnostic CT studies performed on 1287 consecutive adult patients at 10 Douala radiology department. We estimated lifetime attributable risks of cancer by study type from these measured doses. Estimation of LAR for cancer incidence and mortality was based on the effective dose, patient’s sex and age at exposure using the BIER VII preferred models. Results: Mean effective dose from CT scans examinations varied from: 0.30 and 8.81 mSv. The highest doses were observed for lumbar spine CT (8.81 mSv), followed by abdomen-pelvis procedure (6.46 mSv), chest-abdomen-pelvic CT (6.61 mSv), chest CT (3.90 mSv), cervical Spine CT (3.05 mSv), head CT (1.7 mSv) and lower for sinus CT (0.30 mSv). The LAR values of all cancer from patients’ CT scans obtained vary from 67.13 excess per 100,000 (about 1 in 1489) and 0.45 excess per 100,000 (about 1 in 222,222). All cancer risk was high for lumbar spine CT in women 20 years old (67.13 excess deaths in 100,000 scans) followed by chest-abdomen-pelvic CT (50.36 excess deaths in 100,000 scans) and abdomen-pelvic CT (49.22 excess deaths in 100,000 scans) for the same age group. The LAR of incidence and mortality values were higher from female’s patients than males and higher for younger than older patients. Conclusion: This study was set out to estimate the LAR values associated with adult common CT scans procedures. The data indicates, LAR risks related to induced cancer from CT exposures were estimated to be low. This risk can be relatively significant for younger age group compared to older age group. The LAR values obtained will help to better evaluate radiation exposure risk, before ordering a CT scans examinations.
文摘Every year there are new 1,600 cases of breast cancer in Bosnia and Herzegovina. The most effective method for early detection of breast cancer is mammography. To examine risks and benefits of this diagnostic method it is necessary to determine patient doses. Mainly, almost all published data about patient doses refer to two specific age groups: 40-49 and 50-64 years of age. Very little data about patient doses applied during a routine mammography for patients from 65-80 years of age are available. During the conducted research, one calculated doses for the complete mammographic examination of 42 patients from this age group. The calculated patient doses are related to the whole spectrum of technical, physical, clinical and diagnostic parameters which compose a complete mammographic examination.
基金supported by a fund from the Key Project of Natural Science Foundation of Tianjin [16JCZDJC36100]Medical and Health Technology Innovation Project of the Chinese Academy of Medical Sciences [2017-I2M-1-016]+2 种基金Fundamental Research Funds for the Central Universities [3332018116]PUMC Youth Fund [3332015101]Fundamental Research Funds for CAMS&PUMC [2016ZX310074]
文摘Hyperthyroidism refers to a clinical state that results from inappropriately hight hyroid hormone levels in the tissues;.Ⅰ-131 therapy plays a critical role and provides a remarkable curative effect in targeting thyroid diseases. Thyroid cells can take up isotope I-131, which emits not only beta rays but also
文摘Information about the peak skin dose and Dose Area product (DAP) from percutaneous transluminal coronary angioplasty (PTCA) and coronary angiography (CA) was collected from three catheter application rooms. The range of maximum photon energy was 50 - 125 kVp and the fluoroscopy time was 0.6 - 52 seconds. Values of up to 143 Gy·cm2 for DAP and 0.752 mGy for cumulative dose (CD) were found in CA procedures. Otherwise the DAP and CD for PTCA were found to be 143 Gy·cm2 and 2.287 mGy respectively in 3rd Quartile. The relation between the fluoroscopy time and the DAP is also considered. Objectives: The objective of this study is to obtain information about patient peak skin doses (PSD), dose area product (DAP), Fluoroscopy Time (FT) and Cumulative Dose (CD) from PTCA and CA which is the most predominant with respect to high skin doses in addition to other procedures. The aim of this study is also to assess the radiation dose received by patients undergoing interventional radiology procedures, by identifying the procedures that deliver the highest doses. This study is also helpful to establish the reference dose level for adult patients undergoing interventional procedure, and to provide recommendations on how to reduce dose on selected procedures that have been identified to deliver patient dose values near the ICRP (International Commission on Radiological Protection) threshold values.
文摘AIM To determine the clinical characteristics of elderly patients of hemorrhagic gastroduodenal ulcer on low-dose aspirin(LDA)therapy.METHODS A total of 1105 patients with hemorrhagic gastroduodenal ulcer treated in our hospital between January 2000 and March 2016 were grouped by age and drugs used,and these groups were compared in several factors.These groups were compared in terms of length of hospital stay,presence/absence of hemoglobin(Hb)decrease,presence/absence of blood transfusion,Forrest Ⅰ,percentage of Helicobacter pylori infection,presence/absence of underlying disease,and percentage of severe cases.RESULTS The percentage of blood transfusion(62.6%vs 47.7%,P<0.001),Hb decrease(53.8% vs 40.8%,P<0.001),and the length of hospital stay(23.5 d vs 16.7 d,P<0.001)were significantly greater in those on drug therapy.The percentage of blood transfusion(65.3%vs 47.8%,P<0.001),Hb decrease(54.2%vs 42.1%,P<0.001),and length of hospital stay(23.3 d vs 17.5 d,P<0.001)were significantly greater in the elderly.In comparison with the LDA monotherapy group,the percentage of severe cases was significantly higher in the LDA combination therapy group when elderly patients were concerned(16.1%vs34.0%,P=0.030).Meanwhile,among those on LDA monotherapy,there was no significant difference between elderly and non-elderly(16.1%vs 16.0%,P=0.985).CONCLUSION A combination of LDA with antithrombotic drugs or nonsteroidal anti-inflammatory drugs(NSAIDs)contributes to aggravation.And advanced age is not an aggravating factor when LDA monotherapy is used.
文摘We use a nuclear technique based on the determination of the detection efficiencies of solid state nuclear track detectors CR-39 and LR-115 type II (SSNTDs) for alpha particles emitted from the series of uranium-238 and thorium-232 in a phytotherapeutic sample and the measurement of alpha track densities registered on these detectors to assess alpha activities due to uranium-238;thorium-232;radon and thoron in samples of phytotherapeutic preparations consumed by Moroccan adult patients. For modern preparations, the alpha activities due to <sup>238</sup>U, <sup>232</sup>Th and <sup>222</sup>Rn range from 14.27 mBq/kg to 22.02 mBq/kg, from 6.27 mBq/kg to 9.64 mBq/kg and from 14.27 Bq/kg to 22.02 Bq/kg respectively. For classical preparations, the alpha activities due to <sup>238</sup>U, <sup>232</sup>Th and <sup>222</sup>Rn range from 16.73 mBq/kg to 24 mBq/kg, from 7.34 mBq/kg to 10.82 mBq/kg and from 16.73 Bq/kg to 24.72 Bq/kg respectively. A dosimetric model for ingestion has been highlighted to determine committed equivalent dose to different compartments of human gastrointestinal system due to the ingestion of phytotherapeutic preparations by Moroccan adult patients. The maximum overall effective dose due to <sup>238</sup>U, <sup>232</sup>Th, and <sup>222</sup>Rn after the ingestion of the studied phytotherapeutic preparations, was found equal to 38 × 10<sup>-8</sup> S·vy<sup>-1</sup> which is less than the dose limit given by the international commission for radiological protection in it publication 56.
文摘Objectives: Patients undergoing 18F-FDG PET/CT imaging are considered external radiation sources. Accurate dose rate estimates are important for conducting realistic risk assessments and performing dose reconstruction in cases of accidental exposures. The patient radiation self-attenuation factor is assumed to be a function of the patient’s body size metrics, but we can use these metrics to predict the dose rate around the patients with accuracy. The objective of this work was first to measure the patient attenuation factor by performing direct dose rate measurements from patients undergoing PET/CT imaging studies using 18F-FDG. The second objective was to study the possible correlation between the measured dose rate constant per unit activity from the patients and their body size metrics;five metrics were tested in this work. The last objective was to measure the patients’ voiding factor. Methods: We have measured dose rates at one meter from 57 patients and noted the patient’s height (H), weight (W) and calculated patient size metrics namely: Equivalent Cylindrical Diameter (ECD), Equivalent Spherical Diameter (ESD) and the Body Mass Index (BMI). Results: The measured average dose rate was 92.2 ± 14 μSv·h-1·GBq-1 measured at one meter. Therefore, the dose rate constant of 92 μSv·h-1·GBq-1 proposed by the AAPM, TG-108 report is adequate for radiation protection purposes. There was no statistically significant correlation between the dose rate constant per unit activity and the patient body size metrics. We have measured a patient voiding factor of 0.89 ± 0.06 in comparison with 0.85 recommended by the AAPM. Conclusions: The presented data can be used by medical physicist working in nuclear medicine in formulating more accurate risk estimations resulting from radiation exposure from patients undergoing 18F-FDG PET/CT imaging.
文摘目的应用序贯法探讨丙泊酚或不同剂量瑞马唑仑对舒芬太尼抑制老年患者气管插管反应的半数有效剂量(50%effective dose,ED_(50))的影响。方法选择2022年10至12月在气管插管全身麻醉下接受择期手术的老年患者,美国麻醉医师协会(American Society of Anesthesiologists,ASA)分级Ⅰ、Ⅱ级,年龄65~80岁,将患者采用随机数字表法分为4组:丙泊酚组(P组,诱导时给予丙泊酚2mg/kg)和瑞马唑仑组(R1、R2、R3组,诱导时分别静脉注射瑞马唑仑0.2、0.3、0.4mg/kg)。麻醉诱导时给予Dixon序贯法设定剂量的舒芬太尼后,静脉注射丙泊酚或相应剂量瑞马唑仑及顺式阿曲库铵0.15mg/kg,待4个成串刺激(train of four,TOF)计数为0时行气管插管。若气管插管反应阳性,则下一例患者舒芬太尼剂量提高1个浓度梯度,否则降低1个浓度梯度,各相邻浓度之间的比为1∶1.1,直至出现7个转折点终止研究。采用Probit回归分析计算舒芬太尼抑制老年患者气管插管反应ED_(50)和95%有效剂量(95%effective dose,ED_(95))以及相应的95%置信区间(confidenceinterval,CI)。记录所有患者低血压、心动过缓、注射痛等不良反应的发生情况。结果本研究共纳入老年患者113例,P、R1、R2、R3组分别24、28、30、31例。丙泊酚2mg/kg或0.2、0.3、0.4mg/kg瑞马唑仑时舒芬太尼抑制老年患者气管插管反应的ED_(50)和ED_(95)及相应95%CI分别为:P组ED_(50)为0.236μg/kg(95%CI:0.218~0.256),ED_(95)为0.266μg/kg(95%CI:0.250~0.398);R1组ED_(50)为0.284μg/kg(95%CI:0.265~0.309),ED_(95)为0.329μg/kg(95%CI:0.306~0.478);R2组ED_(50)为0.239μg/kg(95%CI:0.221~0.260),ED_(95)为0.282μg/kg(95%CI:0.261~0.415);R3组ED_(50)为0.198μg/kg(95%CI:0.182~0.211),ED_(95)为0.231μg/kg(95%CI:0.216~0.303)。与P组相比,R1、R2、R3组低血压、心动过缓、注射痛发生率较低(P<0.05)。R2组舒芬太尼ED_(50)与P组相类似,但低血压、注射痛发生率与P组相比较低。结论随着瑞马唑仑剂量的增加,舒芬太尼抑制老年患者气管插管反应的ED_(50)逐渐降低;在ED_(50)相近的情况下,瑞马唑仑相较于丙泊酚诱导的低血压、心动过缓、注射痛发生率更低,因而在老年患者气管插管全身麻醉中,使用瑞马唑仑诱导更具有优势。
文摘This study designed to evaluate the entrance surface air kerma (ESAK) to the patient during X-ray examination to the skull antero-posterior (AP), skull Lateral (LAT), chest postero-anterior (PA), Lumber spine AP/LAT and Pelvis AP. Totally, 408 patients were included in this study using computed radiography (CR) in different three hospitals in Khartoum;five X-ray machines were covered. The entrance surface air kerma (ESAK) was calculated for each patient from the exposure parameters using different peak tube voltages. Patient’s data such as (age and weight) and exposure parameters (kVp) and (mAs) were recorded. The result obtained showed that, the entrance surface air kerma ranged from 0.88 to 3.30 mGy for Skull (AP), 0.588 to 1.87 mGy for skull (LAT), 0.03 to 2 mGy for chest PA, 1.50 to 3.40 mGy Lumbar spine AP, 2.60 to 5.15 mGy for Lumbar spine (LAT), and 1.05 to 4.40 mGy for Pelvis. This study provides additional data that can help the regulatory authority to establish reference dose level for diagnostic radiology in Sudan. This study recommends that the CR operator must be used to optimize the patient dose by using the best strategies available for reducing radiation dose. Computed radiography must be used with high level training for medical staff to reduce the dose;each radiology department should implement a patient dose measurement quality assurance programme. Doses to the patients should be regularly monitored and the proposed national DRLs should be taken as guidance for optimization.