Given the escalating number of cancer patients and the consequent rise in demand for radiation therapy in China, there is an urgent need to establish and improve a talent cultivation system for radiation dosimetrists. The United States, with an early-established cultivation system for radiation dosimetrists, boasts relatively mature and comprehensive systems of academic education and qualification certification. This study summarized and analyzed the educational and certification patterns for radiation dosimetrists in the United States based on public data from relevant institutions, related literature, and interviews with American radiation dosimetrists. Meanwhile, this study delved into and assessed the shortcomings in China′s radiation dosimetry education, examination, certification, and career advancement pathways. Furthermore, this study offered suggestions and recommendations for constructing a novel pattern tailored to the cultivation of radiation dosimetrists in China, in order to facilitate the high-quality development of the medical dosimetry discipline.

Medical physicists play an important role in radiodiagnosis, radiotherapy, and nuclear medicine practices. The International Atomic Energy Agency (IAEA) suggests that medical physicists should be trained and achieve professional certifications. Many developed countries/regions have established comprehensive examination and certification programs for medical physicists. However, these systems are yet to be improved in China. This leads to a lack of control over the professional competence and practice standards in the workforce, posing a negative impact on the quality and safety of China’s clinical services in radiation medicine. The International Medical Physics Certification Board (IMPCB) is aimed at accrediting national/regional medical physics certification programs and providing certification of individual medical physicists in countries/regions lacking such certification programs. This study introduces the procedures and specific method for China’s medical physicists to achieve professional certifications via IMPCB, aiming to help improve their professionalism.

Objective:To validate the effectiveness of the leaf position data of multi-leaf collimator (MLC) recorded in the Infinity medical linear accelerator log file (LF).Methods:In this study, the establishment of the film dose calibration curve involved two steps. Initially, the pixel values obtained from scanning the film were converted into net optical density values. Subsequently, a sixth-order polynomial fit was performed on the net optical density and dose data. The picket fence (PF) tests were performed on the electronic portal imaging device (EPID) and film, and the corresponding acquired PF test images were analyzed using the relative leaf travel distance, relative leaf position, relative leaf pair full-width half -maximum (FWHM), and relative leaf pair neighbor region width analysis index, and compared with the relevant results in LF. In addition, to investigate the effect of gravity on the recorded leaf position data by the Infinity medical linear accelerator LF, the above PF tests were executed at 0°, 90°, 180°, and 270° gantry angles, respectively. Intergroup differences were assessed with the Wilcoxon rank-sum test.Results:The film dose calibration curve demonstrated high goodness-of-fit, with a correlation coefficient ( R2) of 0.9994. Across all gantry angles, the dispersion of overall leaf position data for EBT3 film, EPID, and LF followed a consistent pattern based on four analysis metrics: EBT3 film > EPID > LF. Moreover, for each analysis metric, inter-tool differences in standard deviations of results were consistently below 0.1 mm, and this pattern was invariant to gantry angle. Conclusions:The leaf position data recorded in the Infinity medical linear accelerator LF have a high degree of accuracy, and can be used as reference for the actual position of the MLC leaf. Furthermore, gravitational forces exhibit negligible impact on leaf position data acquired via LF.

Given the escalating number of cancer patients and the consequent rise in demand for radiation therapy in China, there is an urgent need to establish and improve a talent cultivation system for radiation dosimetrists. The United States, with an early-established cultivation system for radiation dosimetrists, boasts relatively mature and comprehensive systems of academic education and qualification certification. This study summarized and analyzed the educational and certification patterns for radiation dosimetrists in the United States based on public data from relevant institutions, related literature, and interviews with American radiation dosimetrists. Meanwhile, this study delved into and assessed the shortcomings in China′s radiation dosimetry education, examination, certification, and career advancement pathways. Furthermore, this study offered suggestions and recommendations for constructing a novel pattern tailored to the cultivation of radiation dosimetrists in China, in order to facilitate the high-quality development of the medical dosimetry discipline.

Medical physicists play an important role in radiodiagnosis, radiotherapy, and nuclear medicine practices. The International Atomic Energy Agency (IAEA) suggests that medical physicists should be trained and achieve professional certifications. Many developed countries/regions have established comprehensive examination and certification programs for medical physicists. However, these systems are yet to be improved in China. This leads to a lack of control over the professional competence and practice standards in the workforce, posing a negative impact on the quality and safety of China’s clinical services in radiation medicine. The International Medical Physics Certification Board (IMPCB) is aimed at accrediting national/regional medical physics certification programs and providing certification of individual medical physicists in countries/regions lacking such certification programs. This study introduces the procedures and specific method for China’s medical physicists to achieve professional certifications via IMPCB, aiming to help improve their professionalism.

Objective:To validate the effectiveness of the leaf position data of multi-leaf collimator (MLC) recorded in the Infinity medical linear accelerator log file (LF).Methods:In this study, the establishment of the film dose calibration curve involved two steps. Initially, the pixel values obtained from scanning the film were converted into net optical density values. Subsequently, a sixth-order polynomial fit was performed on the net optical density and dose data. The picket fence (PF) tests were performed on the electronic portal imaging device (EPID) and film, and the corresponding acquired PF test images were analyzed using the relative leaf travel distance, relative leaf position, relative leaf pair full-width half -maximum (FWHM), and relative leaf pair neighbor region width analysis index, and compared with the relevant results in LF. In addition, to investigate the effect of gravity on the recorded leaf position data by the Infinity medical linear accelerator LF, the above PF tests were executed at 0°, 90°, 180°, and 270° gantry angles, respectively. Intergroup differences were assessed with the Wilcoxon rank-sum test.Results:The film dose calibration curve demonstrated high goodness-of-fit, with a correlation coefficient ( R2) of 0.9994. Across all gantry angles, the dispersion of overall leaf position data for EBT3 film, EPID, and LF followed a consistent pattern based on four analysis metrics: EBT3 film > EPID > LF. Moreover, for each analysis metric, inter-tool differences in standard deviations of results were consistently below 0.1 mm, and this pattern was invariant to gantry angle. Conclusions:The leaf position data recorded in the Infinity medical linear accelerator LF have a high degree of accuracy, and can be used as reference for the actual position of the MLC leaf. Furthermore, gravitational forces exhibit negligible impact on leaf position data acquired via LF.

Objective:To investigate the effect of phosphorylated HSP27 on the proliferation and metastasis of nasopharyngeal carcinoma and its molecular mechanism. Methods:①Western blot assay was used to detect the expression levels of HSP27 and p-HSP27 in CNE1 and CNE2 cells of nasopharyngeal carcinoma. Inhibited the phosphorylation of HSP27, Transwell assay detected the metastasis ability of nasopharyngeal carcinoma cells. ②Nasopharyngeal carcinoma cell lines（CNE2-OE1 and CNE2-OE2） overexpressing phosphorylated and dephosphorylated mutants of HSP27 were synthesized, empty vector transfected CNE2 cells（CNE2-NC） were used as controls. The proliferation ability of the three groups of cells was detected by CCK8, and the expression levels of CyclinD1, Bax and Bcl-2 were detected by Western blot. Transwell was used to detect the migration and invasion ability of cells, and Western blot was used to detect the expression levels of E-cadherin, Vimentin, MMP2 and MMP9. Results:The expression level of HSP27 in CNE2 was higher than that of CNE1 cells, while the expression level of p-HSP27 was opposite. After inhibition of HSP27 phosphorylation, the invasion and migration ability of CNE1 cells decreased significantly, with no significant change in CNE2 cells. Compared with CNE2-NC, the growth rate of CNE2-OE1 decreased, and the growth rate of CNE2-OE2 increased. The expression level of CyclinD1 was down-regulated in CNE2-OE1 and higher in CNE2-OE2. The expression level of Bax in CNE2-OE1 was increased, while the expression of Bcl-2 was decreased. There was no significant change in the expression of Bax and Bcl-2 in CNE2-OE2. Compared with CNE2-NC, the migration ability of CNE2-OE1 was enhanced and the invasion ability was weakened, while the migration ability of CNE2-OE2 was weakened and the invasion ability was enhanced. There was no significant difference in the expression levels of E-cadherin was decreased in CNE2-OE1 and increased in CNE2-OE2. There was no significant difference in the expression levels of Vimentin among the three groups. The expression levels of MMP2 and MMP9 were up-regulated in CNE2-OE2, and slightly down-regulated in CNE2-OE1. Conclusion:HSP27 and p-HSP27 were differentially expressed in different nasopharyngeal carcinoma cells, and the metastasis ability of nasopharyngeal carcinoma was not only related to the expression level of HSP27, but also related to the level of p-HSP27. The p-HSP27 inhibited CNE 2 cell proliferation and promoted their apoptosis. As p-HSP27 plays different roles in different stages of nasopharyngeal carcinoma metastasis, it can increase the migration ability of CNE2 cells and reduce its invasion ability. p-HSP27 may induce EMT changes in CNE2 by down-regulating E-cadherin, thus promoting CNE2 migration, and may inhibit CNE2 invasion by down-regulating MMPs expression.
Humans ; Cell Proliferation ; Cell Line, Tumor ; Nasopharyngeal Carcinoma/pathology* ; Nasopharyngeal Neoplasms/pathology* ; Cell Movement ; HSP27 Heat-Shock Proteins/metabolism* ; Phosphorylation ; Neoplasm Metastasis ; Matrix Metalloproteinase 9/metabolism* ; Neoplasm Invasiveness ; Matrix Metalloproteinase 2/metabolism* ; Heat-Shock Proteins/metabolism* ; Cyclin D1/metabolism* ; Molecular Chaperones/metabolism* ; Cadherins/metabolism*

Objective:To explore the differences in the spatial distributions of brain metastases (BMs) from adenocarcinoma and non-adenocarcinoma among non-small cell lung cancer (NSCLS), aiming to provide a reference for developing optimal treatment protocols.Methods:A retrospective analysis was performed on data from 283 patients with NSCLC who underwent radiotherapy at the Zhejiang Cancer Hospital from January 2020 to July 2023. These patients included 191 adenocarcinoma cases with an average age of 62.04 years and 92 non-adenocarcinoma cases with an average age of 63.85 years. CT images with detected BMs of these patients were synchronously deformed and registered into a standard brain template to determine the distribution of BMs in the template. The Dice coefficient was employed to analyze the similarity in the distribution of BMs from adenocarcinoma and non-adenocarcinoma, and two-sample t-test was performed respectively using SPM and Dpabi software to ensure the consistency of the result. For brain regions with the number of BMs greater than or equal to 4, the voxels with a size 2 mm × 2 mm × 2 mm were counted. Results:Non-adenocarcinoma tended to invade the posterior lobe of the cerebellum, precuneus, anterior lobe of the cerebellum, cuneus, middle occipital gyrus, and middle temporal gyrus, with corresponding voxel counts of 2 577, 2 291, 1 947, 1 550, 1 200, and 600, respectively. In contrast, adenocarcinoma was more commonly metastasized to the inferior parietal lobule, posterior lobe of the cerebellum, central frontal gyrus, precentral gyrus, middle temporal gyrus, and precuneus, with the corresponding voxel counts of 211, 201, 194, 186, 137, and 84, respectively.Conclusion:Brain metastases exhibit different distributions between adenocarcinoma and non-adenocarcinoma, and both subtypes prefer to invade specific brain regions.

Objective:To develop and evaluate an unsupervised intensity-modulated radiation therapy (IMRT) automated planning scheme for the Eclipse commercial treatment planning system (TPS), aiming to simulate the manual operation during the whole optimization process.Methods:A retrospective analysis was performed on 25 gastric cancer patients aged 40-60 years who had completed radiotherapy in Zhejiang Cancer Hospital from March 2022 to March 2023. All patients were divided into the training ( n=7) and test sets ( n=18). All patients were treated with the same clinically prescribed dose standard: 45 Gy/25 times. Abdominal CT scan was performed using Philips simulator with a thickness of 5 mm. Based on the deep reinforcement learning (DRL) framework, a multi-agent optimization policy network (MOPN) was proposed to simulate the process of clinical manual planning design and obtain high quality automatic planning according to adjusting multiple optimization objectives. The automatic plan for all cases was generated by code programming using the eclipse scripting application program interface (ESAPI). Wilcoxon signed rank test was used to investigate the significance of the difference between automatic planning and clinical manual planning. Results:After the initial optimization objectives were adjusted by MOPN, the average plan score of all automatic plans was increased from 576.1±221.2 to 1852.8±294.9. Compared with clinical manual plans, the average D max of the spinal cord, the average D mean and V 5 Gy of the liver in the MOPN plans were reduced by 21.4%, 9.8% and 11.5%, respectively. Conclusions:With the help of ESAPI tool, MOPN can realize data interaction with TPS and the automation of IMRT treatment plan for gastric cancer. The trained MOPN can mimic the manual operation of the planner to adjust multiple optimization objectives and gradually improve the plan quality.

Based on the education and work experience in the radiotherapy and radiation protection industries in China and the United States, combined with comprehensive surveys into relevant websites and public materials of American health physics, this review introduces the education system of health physics and the certification system for health physicists in the United States. Furthermore, this paper provides a summary of the current status of academic education in radiation protection, the practical operations of radiation protection in medical institutions, and the staffing related to radiation safety in China. Accordingly, this study offers opinions and suggestions for further improving the disciplinary system of radiation protection in China.