Monte Carlo simulations are frequently utilized in radiation dose assessments.However,many researchers find the prevailing computing platforms to be intricate.This highlights a pressing need for a specialized framewor...Monte Carlo simulations are frequently utilized in radiation dose assessments.However,many researchers find the prevailing computing platforms to be intricate.This highlights a pressing need for a specialized framework for phantom dose evalua-tion.To address this gap,we developed a user-friendly radiation dose assessment platform using the Monte Carlo toolkit,Geant4.The Tsinghua University Phantom Dose(THUDosePD)augments the flexibility of Monte Carlo simulations in dosi-metric research.Originating from THUDose,a code with generic,functional,and application layers,THUDosePD focuses predominantly on anatomical phantom dose assessment.Additionally,it enables medical exposure simulation,intricate geometry creation,and supports both three-dimensional radiation dose analysis and phantom format transformations.The system operates on a multi-threaded parallel CPU architecture,with some modules enhanced for GPU parallel computing.Benchmark tests on the ICRP reference male illustrated the capabilities of THUDosePD in phantom dose assessment,covering the effective dose,three-dimensional dose distribution,and three-dimensional organ dose.We also conducted a voxelization conversion on the polygon mesh phantom,demonstrating the method’s efficiency and consistency.Extended applications based on THUDosePD further underline its broad adaptability.This intuitive,three-dimensional platform stands out as a valuable tool for phantom radiation dosimetry research.展开更多
Background:As mammography X-ray imaging technologies advance and provide elevated contrast in soft tissues,a need has developed for reliable imaging phantoms for use in system design and component calibration.In advan...Background:As mammography X-ray imaging technologies advance and provide elevated contrast in soft tissues,a need has developed for reliable imaging phantoms for use in system design and component calibration.In advanced imaging modalities such as refraction-based methods,it is critical that developed phantoms capture the biological details seen in clinical precancerous and cancerous cases while minimizing artifacts that may be caused due to phantom production.This work presents the fabrication of a breast tissue imaging phantom from cadaveric breast tissue suitable for use in both transmission and refraction-enhanced imaging systems.Methods:Human cancer cell tumors were grown orthotopically in nude athymic mice and implanted into the fixed tissue while maintaining the native tumor/adipose tissue interface.Results:The resulting human–murine tissue hybrid phantom was mounted on a clear acrylic housing for absorption and refraction X-ray imaging.Digital breast tomosynthesis was also performed.Conclusion:Both attenuation-based imaging and refraction-based imaging of the phantom are presented to confirm the suitability of this phantom's use in both imaging modalities.展开更多
Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstra...Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstrated, with ring speeds routinely behaving within 10% tolerances at speeds of approximately 10 - 70 cm/s, a form of real-time QA of the device at the time of imaging is needed to confirm correct function on demand in any environment. Methods: The technology described here achieves real-time QA, comprising a linear encoder, laser-photodiode array, and Doppler probe, measuring piston motion, ring speed and intra-ring velocity respectively. This instrumentation does not interfere with imaging system QA, but allows QA to be performed on both the ring vortex and the device in real-time. Results: The encoder reports the reliability of the piston velocity profile, whilst ring speed is measured by laser behaviour. Incorporation of a calibrated Doppler probe offers a consistency check that confirms behaviour of the central axial flow. For purposes of gold-standard measurement, all elements can be related to previous Laser PIV acquisitions with the same device settings. Conclusion: Consequently, ring vortex production within tolerances is confirmed by this instrumentation, delivering accurate QA in real-time. This implementation offers a phantom QA procedure that exceeds anything seen in the literature, providing the technology to enhance quantitative assessment of flow imaging modalities.展开更多
The fabrication of multi-material medical phantoms with both patient-specificity and realistic mechanical properties is of great importance for the development of surgical planning and medical training.In this work,a ...The fabrication of multi-material medical phantoms with both patient-specificity and realistic mechanical properties is of great importance for the development of surgical planning and medical training.In this work,a 3D multi-material printing system for medical phantom manufacturing was developed.Rigid and elastomeric materials are firstly combined in such application for an accurate tactile feedback.The phantom is designed with multiple layers,where silicone ink,Thermoplastic Polyurethane(TPU),and Acrylonitrile Butadiene Styrene(ABS)were chosen as printing materials for skin,soft tissue,and bone,respectively.Then,the printed phantoms were utilized for the investigation of needle-phantom interaction by needle insertion experiments.The mechanical needle-phantom interaction was characterized by skin-soft tissue interfacial puncture force,puncture depth,and number of insertion force peaks.The experiments demonstrated that the manufacturing conditions,i.e.the silicone grease ratio,interfacial thickness and the infill rate,played effective roles in regulating mechanical needle-phantom interaction.Moreover,the influences of material properties,including interfacial thickness and ultimate stress,on needle-phantom interaction were studied by finite element simulation.Also,a patient-specific forearm phantom was printed,where the anatomical features were acquired from Computed Tomography(CT)data.This study provided a potential manufacturing method for multi-material medical phantoms with tunable mechanical properties and offered guidelines for better phantom design.展开更多
Phantom limb pain is a chronic pain syndrome that is difficult to cope with.Despite neurostimulation treatment is indicated for refractory neuropathic pain,there is scant evidence from randomized controlled trials to ...Phantom limb pain is a chronic pain syndrome that is difficult to cope with.Despite neurostimulation treatment is indicated for refractory neuropathic pain,there is scant evidence from randomized controlled trials to recommend it as the treatment choice.Thus,a systematic review was performed to analyze the efficacy of central nervous system stimulation therapies as a strategy for pain management in patients with phantom limb pain.A literature search for studies conducted between 1970 and September 2020 was carried out using the MEDLINE and Embase databases.Principles of The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline were followed.There were a total of 10 full-text articles retrieved and included in this review.Deep brain stimulation,repetitive transcranial magnetic stimulation,transcranial direct current stimulation,and motor cortex stimulation were the treatment strategies used in the selected clinical trials.Repetitive transcranial magnetic stimulation and transcranial direct current stimulation were effective therapies to reduce pain perception,as well as to relieve anxiety and depression symptoms in phantom limb pain patients.Conversely,invasive approaches were considered the last treatment option as evidence in deep brain stimulation and motor cortex stimulation suggests that the value of phantom limb pain treatment remains controversial.However,the findings on use of these treatment strategies in other forms of neuropathic pain suggest that these invasive approaches could be a potential option for phantom limb pain patients.展开更多
在新型Phantom 4K摄影机中有很多技术创新。最重要的方面是图像质量的提高。噪波控制也非常好,动态范围至少提高了2档,增加了电源输入输出(I/O)选项和辅助接口使摄影机更加满足电影现场拍摄的需要。在摄影机右侧面的智能屏显中呈现更多...在新型Phantom 4K摄影机中有很多技术创新。最重要的方面是图像质量的提高。噪波控制也非常好,动态范围至少提高了2档,增加了电源输入输出(I/O)选项和辅助接口使摄影机更加满足电影现场拍摄的需要。在摄影机右侧面的智能屏显中呈现更多的摄影机控制。围绕菜单和控制部分,摄影机功能也作了改善。摄影机在4K(4096 X 2160)分辨率下拍摄速度1000帧/秒,实时拍摄时长4.展开更多
Incorporation of the Monte Carlo(MC)algorithm in optimizing CyberKnife(CK)plans is cumbersome,and early models unconfigured MC calculations,therefore,this study investigated algorithm-based dose calculation discrepanc...Incorporation of the Monte Carlo(MC)algorithm in optimizing CyberKnife(CK)plans is cumbersome,and early models unconfigured MC calculations,therefore,this study investigated algorithm-based dose calculation discrepancies by selecting different prescription isodose lines(PIDLs)in head and lung CK plans.CK plans were based on anthropomorphic phantoms.Four shells were set at 2-60 mm from the target,and the constraint doses were adjusted according to the design stratcgy.After optimization,30%-90%PIDL plans were generated by ray tracing(RT).In the evaluation module,CK plans were recalculated using the MC algorithm.Therefore,the dosimetric parameters of different PIDL plans based on the RT and MC algorithms were obtained and analyzed.The discrepancies(mean+SD)were 3.72%+0.31%,3.40%+0.11%,3.47%+0.32%,0.17%+0.11%,0.64%+3.60%,7.73%+1.60%,14.62%+3.21%and 10.10%+1.57%for Djs,Dmeam),Dys,and coverage of the PTV,DGI,V,,V;and V,in the head plans and-6.32%+1.15%,-13.46%+0.98%,-20.63%+2.25%,-34.78%+25.03%,12248%+175.60%,-12.92%+5.41%,3.19%+4.67%and 7.13%+1.56%in the lung plans,respectively.The following parameters were significantly correlated with PIDL:dp98%at the 0.05 level and dpal,dys and dv3 at the 0.01 level for the head plans;dp98e%at the 0.05 level and do1e%,dpmeam,Ccoweange,dool,dvs and dv;at the 0.01 level for the lung plans.RT may be used to calculate the dose in CK head plans,but when the dose of organs at risk is close to the limit,it is necessary to refer to the MC results or to further optimize the CK plan to reduce the dose.For lung plans,the MC algorithm is recommended.For early models without the MC algorithm,a lower PIDL plan is recommended;otherwise,a large PIDL plan risks serious underdosage in the target area.展开更多
Phantom bite syndrome(PBS),also called occlusal dysesthesia,is characterized by persistent non-verifiable occlusal discrepancies.Such erroneous and unshakable belief of a“wrong bite”might impel patients to visit mul...Phantom bite syndrome(PBS),also called occlusal dysesthesia,is characterized by persistent non-verifiable occlusal discrepancies.Such erroneous and unshakable belief of a“wrong bite”might impel patients to visit multiple dental clinics to meet their requirements to their satisfaction.Subsequently,it takes a toll on their quality of life causing,career disruption,financial loss and suicidal thoughts.In general,patients with PBS are quite rare but distinguishable if ever encountered.Since Marbach reported the first two cases in 1976,there have been dozens of published cases regarding this phenomenon,but only a few original studies were conducted.Despite the lack of official classification and guidelines,many authors agreed on the existence of a PBS“consistent pattern”that clinicians should be made aware.Nevertheless,the treatment approach has been solely based on incomplete knowledge of etiology,in which none of the proposed theories are fully explained in all the available cases.In this review,we have discussed the critical role of enhancing dental professionals’awareness of this phenomenon and suggested a comprehensive approach for PBS,provided by a multidisciplinary team of dentists,psychiatrists and exclusive psychotherapists.展开更多
基金This work was supported by the National Natural Science Foundation of China(General Program)(Nos.12175114,U2167209)the Foundation of Key Laboratory of Metrology and Calibration Technology(No.JLKG2022001C001)+2 种基金the Platform Development foundation of China Institute for Radiation Protection(No.YP21030101)the National Key R&D Program of China(No.2021YFF0603600)the Tsinghua University Initiative Scientific Research Program(No.20211080081).
文摘Monte Carlo simulations are frequently utilized in radiation dose assessments.However,many researchers find the prevailing computing platforms to be intricate.This highlights a pressing need for a specialized framework for phantom dose evalua-tion.To address this gap,we developed a user-friendly radiation dose assessment platform using the Monte Carlo toolkit,Geant4.The Tsinghua University Phantom Dose(THUDosePD)augments the flexibility of Monte Carlo simulations in dosi-metric research.Originating from THUDose,a code with generic,functional,and application layers,THUDosePD focuses predominantly on anatomical phantom dose assessment.Additionally,it enables medical exposure simulation,intricate geometry creation,and supports both three-dimensional radiation dose analysis and phantom format transformations.The system operates on a multi-threaded parallel CPU architecture,with some modules enhanced for GPU parallel computing.Benchmark tests on the ICRP reference male illustrated the capabilities of THUDosePD in phantom dose assessment,covering the effective dose,three-dimensional dose distribution,and three-dimensional organ dose.We also conducted a voxelization conversion on the polygon mesh phantom,demonstrating the method’s efficiency and consistency.Extended applications based on THUDosePD further underline its broad adaptability.This intuitive,three-dimensional platform stands out as a valuable tool for phantom radiation dosimetry research.
基金National Institutes of Health,Grant/Award Number:EB023969 and HL154687。
文摘Background:As mammography X-ray imaging technologies advance and provide elevated contrast in soft tissues,a need has developed for reliable imaging phantoms for use in system design and component calibration.In advanced imaging modalities such as refraction-based methods,it is critical that developed phantoms capture the biological details seen in clinical precancerous and cancerous cases while minimizing artifacts that may be caused due to phantom production.This work presents the fabrication of a breast tissue imaging phantom from cadaveric breast tissue suitable for use in both transmission and refraction-enhanced imaging systems.Methods:Human cancer cell tumors were grown orthotopically in nude athymic mice and implanted into the fixed tissue while maintaining the native tumor/adipose tissue interface.Results:The resulting human–murine tissue hybrid phantom was mounted on a clear acrylic housing for absorption and refraction X-ray imaging.Digital breast tomosynthesis was also performed.Conclusion:Both attenuation-based imaging and refraction-based imaging of the phantom are presented to confirm the suitability of this phantom's use in both imaging modalities.
文摘Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstrated, with ring speeds routinely behaving within 10% tolerances at speeds of approximately 10 - 70 cm/s, a form of real-time QA of the device at the time of imaging is needed to confirm correct function on demand in any environment. Methods: The technology described here achieves real-time QA, comprising a linear encoder, laser-photodiode array, and Doppler probe, measuring piston motion, ring speed and intra-ring velocity respectively. This instrumentation does not interfere with imaging system QA, but allows QA to be performed on both the ring vortex and the device in real-time. Results: The encoder reports the reliability of the piston velocity profile, whilst ring speed is measured by laser behaviour. Incorporation of a calibrated Doppler probe offers a consistency check that confirms behaviour of the central axial flow. For purposes of gold-standard measurement, all elements can be related to previous Laser PIV acquisitions with the same device settings. Conclusion: Consequently, ring vortex production within tolerances is confirmed by this instrumentation, delivering accurate QA in real-time. This implementation offers a phantom QA procedure that exceeds anything seen in the literature, providing the technology to enhance quantitative assessment of flow imaging modalities.
基金This study was partially supported by the National Key Research and Development Program of China(Grant No.2018YFA0703000)the National Natural Science Foundation of China(Grant No.52075482)+1 种基金the Key Research and Development Program of Zhejiang Province(Grant No.2017CO1063)the National Natural Science Foundation of China(Grant No.51875518).
文摘The fabrication of multi-material medical phantoms with both patient-specificity and realistic mechanical properties is of great importance for the development of surgical planning and medical training.In this work,a 3D multi-material printing system for medical phantom manufacturing was developed.Rigid and elastomeric materials are firstly combined in such application for an accurate tactile feedback.The phantom is designed with multiple layers,where silicone ink,Thermoplastic Polyurethane(TPU),and Acrylonitrile Butadiene Styrene(ABS)were chosen as printing materials for skin,soft tissue,and bone,respectively.Then,the printed phantoms were utilized for the investigation of needle-phantom interaction by needle insertion experiments.The mechanical needle-phantom interaction was characterized by skin-soft tissue interfacial puncture force,puncture depth,and number of insertion force peaks.The experiments demonstrated that the manufacturing conditions,i.e.the silicone grease ratio,interfacial thickness and the infill rate,played effective roles in regulating mechanical needle-phantom interaction.Moreover,the influences of material properties,including interfacial thickness and ultimate stress,on needle-phantom interaction were studied by finite element simulation.Also,a patient-specific forearm phantom was printed,where the anatomical features were acquired from Computed Tomography(CT)data.This study provided a potential manufacturing method for multi-material medical phantoms with tunable mechanical properties and offered guidelines for better phantom design.
文摘Phantom limb pain is a chronic pain syndrome that is difficult to cope with.Despite neurostimulation treatment is indicated for refractory neuropathic pain,there is scant evidence from randomized controlled trials to recommend it as the treatment choice.Thus,a systematic review was performed to analyze the efficacy of central nervous system stimulation therapies as a strategy for pain management in patients with phantom limb pain.A literature search for studies conducted between 1970 and September 2020 was carried out using the MEDLINE and Embase databases.Principles of The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline were followed.There were a total of 10 full-text articles retrieved and included in this review.Deep brain stimulation,repetitive transcranial magnetic stimulation,transcranial direct current stimulation,and motor cortex stimulation were the treatment strategies used in the selected clinical trials.Repetitive transcranial magnetic stimulation and transcranial direct current stimulation were effective therapies to reduce pain perception,as well as to relieve anxiety and depression symptoms in phantom limb pain patients.Conversely,invasive approaches were considered the last treatment option as evidence in deep brain stimulation and motor cortex stimulation suggests that the value of phantom limb pain treatment remains controversial.However,the findings on use of these treatment strategies in other forms of neuropathic pain suggest that these invasive approaches could be a potential option for phantom limb pain patients.
文摘在新型Phantom 4K摄影机中有很多技术创新。最重要的方面是图像质量的提高。噪波控制也非常好,动态范围至少提高了2档,增加了电源输入输出(I/O)选项和辅助接口使摄影机更加满足电影现场拍摄的需要。在摄影机右侧面的智能屏显中呈现更多的摄影机控制。围绕菜单和控制部分,摄影机功能也作了改善。摄影机在4K(4096 X 2160)分辨率下拍摄速度1000帧/秒,实时拍摄时长4.
基金This study was supported by grants from National Key Research and Development Plan for Digital Diagnostic Equipment Research and Development(No.2016YFC0106700)the Natural Science Foundation of Union Hospital,Tongji Medical College,Huazhong University of Science and Technology(No.02.03.2018-131).
文摘Incorporation of the Monte Carlo(MC)algorithm in optimizing CyberKnife(CK)plans is cumbersome,and early models unconfigured MC calculations,therefore,this study investigated algorithm-based dose calculation discrepancies by selecting different prescription isodose lines(PIDLs)in head and lung CK plans.CK plans were based on anthropomorphic phantoms.Four shells were set at 2-60 mm from the target,and the constraint doses were adjusted according to the design stratcgy.After optimization,30%-90%PIDL plans were generated by ray tracing(RT).In the evaluation module,CK plans were recalculated using the MC algorithm.Therefore,the dosimetric parameters of different PIDL plans based on the RT and MC algorithms were obtained and analyzed.The discrepancies(mean+SD)were 3.72%+0.31%,3.40%+0.11%,3.47%+0.32%,0.17%+0.11%,0.64%+3.60%,7.73%+1.60%,14.62%+3.21%and 10.10%+1.57%for Djs,Dmeam),Dys,and coverage of the PTV,DGI,V,,V;and V,in the head plans and-6.32%+1.15%,-13.46%+0.98%,-20.63%+2.25%,-34.78%+25.03%,12248%+175.60%,-12.92%+5.41%,3.19%+4.67%and 7.13%+1.56%in the lung plans,respectively.The following parameters were significantly correlated with PIDL:dp98%at the 0.05 level and dpal,dys and dv3 at the 0.01 level for the head plans;dp98e%at the 0.05 level and do1e%,dpmeam,Ccoweange,dool,dvs and dv;at the 0.01 level for the lung plans.RT may be used to calculate the dose in CK head plans,but when the dose of organs at risk is close to the limit,it is necessary to refer to the MC results or to further optimize the CK plan to reduce the dose.For lung plans,the MC algorithm is recommended.For early models without the MC algorithm,a lower PIDL plan is recommended;otherwise,a large PIDL plan risks serious underdosage in the target area.
基金Supported by JSPS KAKENHI Grant,No.19K10328(to Professor Toyofuku A).
文摘Phantom bite syndrome(PBS),also called occlusal dysesthesia,is characterized by persistent non-verifiable occlusal discrepancies.Such erroneous and unshakable belief of a“wrong bite”might impel patients to visit multiple dental clinics to meet their requirements to their satisfaction.Subsequently,it takes a toll on their quality of life causing,career disruption,financial loss and suicidal thoughts.In general,patients with PBS are quite rare but distinguishable if ever encountered.Since Marbach reported the first two cases in 1976,there have been dozens of published cases regarding this phenomenon,but only a few original studies were conducted.Despite the lack of official classification and guidelines,many authors agreed on the existence of a PBS“consistent pattern”that clinicians should be made aware.Nevertheless,the treatment approach has been solely based on incomplete knowledge of etiology,in which none of the proposed theories are fully explained in all the available cases.In this review,we have discussed the critical role of enhancing dental professionals’awareness of this phenomenon and suggested a comprehensive approach for PBS,provided by a multidisciplinary team of dentists,psychiatrists and exclusive psychotherapists.
