Objective:To evaluate the clinical application value of the adaptive aperture by comparing intensity-modulated proton radiotherapy(IMPT) plans using and not using the aperture for brain tumors.Methods:A total of twenty patients treated with postoperative radiotherapy for brain tumors were enrolled in this study. IMPT plans were developed for each patient using and not using the adaptive aperture under the same optimization conditions. The target conformal index (CI) value, target homogeneity index (HI) value, and the dose to normal tissues of the two sets of plans were compared.Results:The IMPT plans designed using the adaptive aperture significantly increased the mean CI value from 0.58 to 0.66, while decreasing the mean 50% prescription dose volume from 797.70 cm 3 to 638.15 cm 3. These plans also reduced the irradiation doses to the cochlea, brainstem, optic chiasm, optic nerve, and lens ( t = 2.06, 3.02, 2.11, 2.58, 2.67, P < 0.05). Additionally, there was no significant difference in the HI value of the target volumes and the machine jumps (MU) between the two sets of plans ( P > 0.05). Conclusions:The adaptive aperture can significantly reduce the irradiation dose to normal tissues outside the target volumes, positively impacting the protection of organs at risk (OARs) around the target values. This demonstrates its great potential for clinical application.

Objective To present and discuss beam characteristics of the first Mevion S250i gantry-mounted accelerator pencil beam scanning proton therapy system in China.Methods The output dose was measured using a parallel-plate ionization chamber.The integrated depth dose was measured with a large-radius Bragg peak ionization chamber,covering 19 energy levels ranging from 227 MeV to 28 MeV,to analyze the proton beam characteristics.The spots in the air were measured with Phoenix flat panel detector on the beam central axis,and the precision of the delivery position was verified by measuring the multi-spot beam map.The interleaf leakage and penumbra reduction of adaptive aperture were measured to characterize its performance.Results The proton system was calibrated for a maximum energy of 227 MeV,with a(10×10)cm2uniform field delivering 1 Gy dose at a depth of 5 cm underwater.The system effectively modulated the proton beam range to the patient's surface,maintaining a constant 80%-80%Bragg peak width of 8.6 mm at all energy levels.The spot size of the highest energy beam at the isocenter was about 4 mm in the air,and the spot delivery position error was less than 1 mm.The interleaf leakage rate of the adaptive aperture for the highest energy beam was below 1.5%,and the penumbra was significantly reduced.Conclusion Mevion S250i proton therapy system demonstrates unique design and beam characteristics,which is reflected in the Bragg peak shape,spot size variation with energy,and penumbra sharpening of adaptive aperture;and these differences should be considered in treatment planning system modeling and planning for precision treatment.

With the proposal and development of new technologies, new methods, and new education theories, the research on medical education and teaching has been conducted extensively. The theories, methods, and management mode of the research on medical education and teaching are keeping pace with the times and thus promote the rapid improvement in teaching ability, medical talents, and the training level of medical humanities. However, current studies on medical education and teaching focus too much on the innovation of education theories, methods, and management and neglect the aspects such as educational ethics, student awareness, and assessment of potential benefits and risks. In addition, the lack of unified implementation and supervision standards in the whole process management of education research is also a problem that needs to be solved urgently, especially in empirical studies, which brings great challenges to the standardized implementation of education research. By performing an analogy with the clinical trial research system and summarizing education research and educational ethics, this study, for the first time, proposes a set of standardized and systematic medical education and research standards, including the paradigms of classification, staging and different stages. These standards provide a theoretical basis for implementing medical education research, improving the education compliance of target students, fully guaranteeing the benefits of target students, and avoiding the risks in education research, which provides a reference for standardized education research in other disciplines.

Objective:To discuss the acceptance test of beam performance and mechanical precision of the first Mevion type S250i proton therapy system in China,and verify the stability and reliability of that in clinical treatment.Methods:According to the requirements of acceptance report of manufacturer,the output and range of machine unit(MU),the accuracy and stability of size and position of beam spot,the penumbra and position accuracy of adaptive aperture(AA)of Mevion type S250i proton therapy system,as well as the tests of mechanical properties and functions of the requirement of clinical use,were checked and tested for acceptance.Results:The maximum deviation of MU output was 1.3%,and the maximum deviation of the range was 0.037 g/cm2,and the maximum distal fall-off was 0.465 cm,and the minimum range of energy modulation was 0.21 g/cm2.The maximum deviations of the size of beam spot and the maximum deviation of the position were respectively 0.07 cm and 0.05 cm.The maximum AA penumbra was 0.007 cm,and the AA position accuracy was less than 0.1 cm.Conclusion:The acceptance test of the Mevion type S250i proton therapy system indicates that the parameters of the beam performance and mechanical precision can meet the requirements of the acceptance contract and AAPM-TG224 report of manufacturer,which has verified the machine has better favorable stability and reliability.

Objective:To measure and assess relevant radiation doses at the radiotherapy site of the first domestic single-vault proton therapy system.Methods:The radiation levels of the therapy system during and after beam irradiation were measured, and annual effective doses were assessed for personnel at the site.Results:During beam irradiation, the highest radiation dose was detected at the shielded door of the equipment floor, with a gamma radiation level of 2.140 μSv/h and a neutron radiation level of 0.850 μSv/h. Neutron radiation disappeared immediately once the beams stopped. In contrast, the radiation activated originated mostly from gamma rays. A longer time after beams stopped was associated with lower induced radiation intensity at the same location. Furthermore, a farther distance from the irradiated object corresponded to lower induced radiation intensity at the same time. The assessment result reveal that the annual effective doses to the personnel were at the safe level, with physicists exposed to the highest dose of 2.138 mSv.Conclusions:The radiation level at the studied proton therapy site meets the safety requirement, and the treatment can be performed safely at this site.

Objective:To verify and calibrate the CT modeling curves of three CT devices in RayStation proton treatment planning system (TPS).Methods:CT-mass density (CT-MD) curves were established by CT Hounsfield units of different tissue substitute materials obtained by scanning the model with CT equipment. CT-stopping power (CT-SP) curves were established by calculation based on the chemical composition of various human tissues. The equivalent water thickness of tissue substitute modules was calculated with different CT modeling curves in TPS. The actual equivalent water thickness of various modules was measured by a Bragg peak detector, and compared with the calculated values of TPS to verify the accuracy of different CT models.Results:The differences of CT modeling curves were significantly different under different tube voltage scanning protocols. Compared with CT-MD curves, CT-SP curves based on the stoichiometric calibration were more suitable for proton dose calculation. However, the values of stopping power corresponding to high CT values still needed to be optimized, and the calculation error after calibration was less than 3%.Conclusion:The method of verifying and calibrating CT unit curves of proton TPS is described, proving that the CT-SP curves after stoichiometric calculation are more suitable for proton dose calculation.

Objective:To analyze the current adoption of palliative care by patients with unresectable metastatic colorectal cancer (mCRC) in China.Methods:From 1 March 2023 to 30 June 2023, a questionnaire survey was conducted by random sampling. An exclusive research platform for the Blue Book on Clinical Diagnosis and Treatment of Metastatic Colorectal Cancer. An online questionnaire was sent to medical oncologists (including chief physicians, associate chief physicians, attending physicians and residents) in general hospitals and oncology hospitals in four major regions of East, Central, South and Northeast China. The questionnaire contained 28 questions requesting basic information about doctors, the number of patients with mCRC, the status of treatment from first to fourth line and beyond, points concerning treatment of pain in patients with mCRC, and expectations for the future. A medical team was responsible for the quality control of data collected, whereas statisticians performed the data cleaning and sorting and statistical analysis.Results:A total of 300 clinical questionnaires were collected, including 217 (72%) from doctors in general hospitals and 83 (28%) from doctors in oncology hospitals. Senior physicians (including associate chief physicians and chief physicians) accounted for 65% of the respondents, attending physicians 30%, and residents 5%. Within 3 months (average for each month), 46.4±26.6% patients were diagnosed with recurrent or unresectable mCRC by each physician, 51.6±26.8% of the patients being in cancer hospitals and 44.4±26.3% in general hospitals. One hundred percent of patients receiving first-line treatment received palliative care, as did 80.3% of those receiving second-line treatment, 58.2% of those receiving third-line treatment, and 35.1% of those receiving ≥fourth-line treatment. The primary factor governing selection of first-line treatment was guideline recommendations, whereas comorbidities and the patients' physical status dictated second line to fourth line treatment. Standard first-line treatment was administered to 93.8% of eligible patients, standard second-line treatment to 94.3%; and standard third-line treatment to 73.5%. First-line therapy included targeted therapy in 63.6% of patients and immunotherapy in 2.8%; second-line therapy included targeted therapy in 63.0% of patients and immunotherapy in 2.0%; third-line therapy included targeted therapy in 59.2% of patients and immunotherapy in 2.2%; and fourth-line therapy included targeted therapy in 48.7% of patients and immunotherapy in 3.1%. First-line treatment lasted an average of 9.6 months, second-line treatment 6.7 months, third-line treatment 4.9 months, and fourth-line treatment 3.7 months. More than 70% of the patients maintained a good quality of life after receiving first and second-line treatment and more than 60% of them had ECOG performance scores of 0–1. After receiving third- and fourth-line treatment, 50%–60% of patients maintained a good quality of life and 40%–50% of them maintained ECOG performance scores of 0–1. The survey also revealed that the main deficiencies in treatment were limited effectiveness of third-line treatment, insufficient availability and opportunity for clinical research, popularity of new drugs or new drug combination strategies, and limited channels for participation in multidisciplinary diagnosis and treatment. Clinicians reported looking forward to participating in more clinical research on new drugs, hearing about the experience of experts in the field, and discovery of new targets and new drugs that increased the options for posterior line treatment of colorectal cancer.Conclusions:This report objectively summarizes the current situation, treatment difficulties, and expectations of frontline physicians concerning management of mCRC, thus providing a basis for decision-making and future direction for the diagnosis and research on treatment of mCRC.

Objective:To analyze the current adoption of palliative care by patients with unresectable metastatic colorectal cancer (mCRC) in China.Methods:From 1 March 2023 to 30 June 2023, a questionnaire survey was conducted by random sampling. An exclusive research platform for the Blue Book on Clinical Diagnosis and Treatment of Metastatic Colorectal Cancer. An online questionnaire was sent to medical oncologists (including chief physicians, associate chief physicians, attending physicians and residents) in general hospitals and oncology hospitals in four major regions of East, Central, South and Northeast China. The questionnaire contained 28 questions requesting basic information about doctors, the number of patients with mCRC, the status of treatment from first to fourth line and beyond, points concerning treatment of pain in patients with mCRC, and expectations for the future. A medical team was responsible for the quality control of data collected, whereas statisticians performed the data cleaning and sorting and statistical analysis.Results:A total of 300 clinical questionnaires were collected, including 217 (72%) from doctors in general hospitals and 83 (28%) from doctors in oncology hospitals. Senior physicians (including associate chief physicians and chief physicians) accounted for 65% of the respondents, attending physicians 30%, and residents 5%. Within 3 months (average for each month), 46.4±26.6% patients were diagnosed with recurrent or unresectable mCRC by each physician, 51.6±26.8% of the patients being in cancer hospitals and 44.4±26.3% in general hospitals. One hundred percent of patients receiving first-line treatment received palliative care, as did 80.3% of those receiving second-line treatment, 58.2% of those receiving third-line treatment, and 35.1% of those receiving ≥fourth-line treatment. The primary factor governing selection of first-line treatment was guideline recommendations, whereas comorbidities and the patients' physical status dictated second line to fourth line treatment. Standard first-line treatment was administered to 93.8% of eligible patients, standard second-line treatment to 94.3%; and standard third-line treatment to 73.5%. First-line therapy included targeted therapy in 63.6% of patients and immunotherapy in 2.8%; second-line therapy included targeted therapy in 63.0% of patients and immunotherapy in 2.0%; third-line therapy included targeted therapy in 59.2% of patients and immunotherapy in 2.2%; and fourth-line therapy included targeted therapy in 48.7% of patients and immunotherapy in 3.1%. First-line treatment lasted an average of 9.6 months, second-line treatment 6.7 months, third-line treatment 4.9 months, and fourth-line treatment 3.7 months. More than 70% of the patients maintained a good quality of life after receiving first and second-line treatment and more than 60% of them had ECOG performance scores of 0–1. After receiving third- and fourth-line treatment, 50%–60% of patients maintained a good quality of life and 40%–50% of them maintained ECOG performance scores of 0–1. The survey also revealed that the main deficiencies in treatment were limited effectiveness of third-line treatment, insufficient availability and opportunity for clinical research, popularity of new drugs or new drug combination strategies, and limited channels for participation in multidisciplinary diagnosis and treatment. Clinicians reported looking forward to participating in more clinical research on new drugs, hearing about the experience of experts in the field, and discovery of new targets and new drugs that increased the options for posterior line treatment of colorectal cancer.Conclusions:This report objectively summarizes the current situation, treatment difficulties, and expectations of frontline physicians concerning management of mCRC, thus providing a basis for decision-making and future direction for the diagnosis and research on treatment of mCRC.

Objective To analyze the daily quality assurance(QA)measurement results of IBA Sphinx Compact device on the Mevion compact pencil beam scanning proton therapy system for evaluating its clinical application value in proton therapy.Methods The daily QA measurement of Mevion S250i proton therapy system was carried out with Sphinx Compact device for 30 consecutive days,and the measurement results were analyzed.Results The average deviation between the positioning laser and the image center was(0.42±0.27)mm in 30 days.All of the proximal and distal depth errors of the high-and low-energy pencil beams were within 0.50 mm.The position deviation of all the spots measured did not exceed 1.00 mm,and the size deviation was less than 7.5%.The deviation between the image center and the beam center was not more than 0.75 mm.The relative deviation of the flatness of the rectangular field was about 0.5%.The deviation of the output dose of the square field was within 1.0%.Conclusion The proton system daily QA measurement items recommended by AAPM TG-224 report can be accurately and rapidly measured with Sphinx Compact device.The device is a practical and efficient daily QA tool with high practical value in clinic.

Tbx18,Wt1,and Tcf21 have been identified as epicardial markers during the early embryonic stage.However,the gene markers of mature epicardial cells remain unclear.Single-cell transcriptomic analysis was performed with the Seurat,Monocle,and CellphoneDB packages in R software with standard pro-cedures.Spatial transcriptomics was performed on chilled Visium Tissue Optimization Slides(10x Genomics)and Visium Spatial Gene Expression Slides(10x Genomics).Spatial transcriptomics analysis was performed with Space Ranger software and R software.Immunofluorescence,whole-mount RNA in situ hybridization and X-gal staining were performed to validate the analysis results.Spatial transcriptomics analysis revealed distinct transcriptional profiles and functions between epicardial tissue and non-epicardial tissue.Several gene markers specific to postnatal epicardial tissue were identified,including Msln,C3,Efemp1,and Upk3b.Single-cell transcriptomic analysis revealed that cardiac cells from wildtype mouse hearts(from embryonic day 9.5 to postnatal day 9)could be categorized into six major cell types,which included epicardial cells.Throughout epicardial development,Wt1,Tbx18,and Upk3b were consistently expressed,whereas genes including Msln,C3,and Efemp1 exhibited increased expression during the mature stages of development.Pseudotime analysis further revealed two epicardial cell fates during maturation.Moreover,Upk3b,Msln,Efemp1,and C3 positive epicardial cells were enriched in extracellular matrix signaling.Our results suggested Upk3b,Efemp1,Msln,C3,and other genes were mature epicardium markers.Extracellular matrix signaling was found to play a critical role in the mature epicardium,thus suggesting potential therapeutic targets for heart regeneration in future clinical practice.