Inverse Compton scattering X-rays are commonly generated by the collision of the incident relativistic high-energy electrons with the low-energy photons of laser pulses. Compared with the X-rays from bremsstrahlung radiation, which are often used in clinical settings, inverse Compton X-rays have unique advantages in radiological diagnosis and treatment due to their distinctive physical properties. In these years, the demand of precision radiotherapy technology has been increasingly emphasized. Inverse Compton X-rays may provide such a promising path for the development of precision radiotherapy. However, only a few facilities worldwide can achieve the generation of inverse Compton X-rays, and relevant studies in the field of radiation therapy are also in the exploratory stage. In this article, recent research progress at home and abroad were reviewed to introduce the ways of inverse Compton X-rays generation as well as their characteristics and advantages in radiation physics, aiming to provide reference for evaluating their application values and prospects in radiation therapy.

Objective:To compare the uncertainty of dose calibration systems between EBT4 and EBT3 films, and to evaluate the effectiveness and accuracy of EBT4 films in radiotherapy dose measurements.Methods:EBT4 and EBT3 films were irradiated with clinical 6 MV photon beams at doses ranging from 0 to 1,600 MU. Films were scanned after resting for 0 and 24 h to establish dose calibration functions based on net optical density. The dose uncertainties introduced by function fitting, dose resolution, film non-uniformity, scan repeatability, and scanner non-uniformity during calibration of the two films were obtained through experimental tests and mathematical calculations. Independent-sample t-tests were used to compare differences in fitting uncertainty and dose resolution between the two films, while homogeneity of variance tests were used to compare differences in film non-uniformity and scan repeatability. The combined total uncertainty was then calculated and compared. Finally, the total combined uncertainty was calculated by integrating all individual sources of uncertainty and compared between the two films. Results:Within the absorbed dose range of 1-12 Gy, EBT4 films exhibited significantly lower dose uncertainties from function fitting and dose resolution than EBT3 films at the same standing time ( P<0.01). No significant differences were observed between the two films in terms of non-uniformity and scan repeatability ( P>0.05). The total dose uncertainties of EBT4 and EBT3 films at 0 h standing were 5.65% and 7.87%, respectively, while the total uncertainties at 24 h standing were 4.73% and 6.33%, respectively. Overall, the dose calibration system of EBT4 films demonstrated consistently lower total uncertainty. Conclusion:Under identical conditions, EBT4 films demonstrate superior and more stable dose uncertainty compared with EBT3 films, thereby meeting the clinical requirements for radiation dose measurements with higher precision.

Inverse Compton scattering X-rays are commonly generated by the collision of the incident relativistic high-energy electrons with the low-energy photons of laser pulses. Compared with the X-rays from bremsstrahlung radiation, which are often used in clinical settings, inverse Compton X-rays have unique advantages in radiological diagnosis and treatment due to their distinctive physical properties. In these years, the demand of precision radiotherapy technology has been increasingly emphasized. Inverse Compton X-rays may provide such a promising path for the development of precision radiotherapy. However, only a few facilities worldwide can achieve the generation of inverse Compton X-rays, and relevant studies in the field of radiation therapy are also in the exploratory stage. In this article, recent research progress at home and abroad were reviewed to introduce the ways of inverse Compton X-rays generation as well as their characteristics and advantages in radiation physics, aiming to provide reference for evaluating their application values and prospects in radiation therapy.

Objective:To compare the uncertainty of dose calibration systems between EBT4 and EBT3 films, and to evaluate the effectiveness and accuracy of EBT4 films in radiotherapy dose measurements.Methods:EBT4 and EBT3 films were irradiated with clinical 6 MV photon beams at doses ranging from 0 to 1,600 MU. Films were scanned after resting for 0 and 24 h to establish dose calibration functions based on net optical density. The dose uncertainties introduced by function fitting, dose resolution, film non-uniformity, scan repeatability, and scanner non-uniformity during calibration of the two films were obtained through experimental tests and mathematical calculations. Independent-sample t-tests were used to compare differences in fitting uncertainty and dose resolution between the two films, while homogeneity of variance tests were used to compare differences in film non-uniformity and scan repeatability. The combined total uncertainty was then calculated and compared. Finally, the total combined uncertainty was calculated by integrating all individual sources of uncertainty and compared between the two films. Results:Within the absorbed dose range of 1-12 Gy, EBT4 films exhibited significantly lower dose uncertainties from function fitting and dose resolution than EBT3 films at the same standing time ( P<0.01). No significant differences were observed between the two films in terms of non-uniformity and scan repeatability ( P>0.05). The total dose uncertainties of EBT4 and EBT3 films at 0 h standing were 5.65% and 7.87%, respectively, while the total uncertainties at 24 h standing were 4.73% and 6.33%, respectively. Overall, the dose calibration system of EBT4 films demonstrated consistently lower total uncertainty. Conclusion:Under identical conditions, EBT4 films demonstrate superior and more stable dose uncertainty compared with EBT3 films, thereby meeting the clinical requirements for radiation dose measurements with higher precision.

Objective:To improve the dosimetric accuracy of cell irradiation experiments by developing a method of accurately measuring the absorbed dose of ultra-thin solution in culture dishes under 200 kV medium-energy X-rays using EBT3 films.Methods:EBT3 film dose calibration was performed under Cyberknife 6 MV beam, and the beam quality (half-value layer) and effective energy of the 200 kV beam used in this study generated from Small Animal Radiation Research Platform through measurements and calculations were obtained to determine the EBT3 energy response correction factor. The 200 kV beam was utilized to irradiate three commonly used culture dishes filled with ultra-thin liquid placed on EBT3 films and the corrected EBT3 doses were taken as the liquid absorbed doses. The dose linearity of immersed films was also measured and analyzed. In addition, after modeling the irradiation environment, the independent Monte Carlo calculations of the liquid absorbed dose were performed by MCNP5 program. The calculation results were compared with the film measurement results to verify the accuracy of the measured doses.Results:The 200 kV beam had a half-value layer of 8.77 mm aluminum and effective energy of 57.4 keV, corresponding to an energy response correction factor of 0.889. The average liquid absorbed doses of large, medium and small culture dishes measured by EBT3 films under the specified parameters of 200 kV beam were (1.434±0.004) Gy, (1.467±0.011) Gy and (1.469±0.027) Gy after correction, respectively. The percentage errors from the corresponding Monte Carlo calculation doses were 0.07%, -0.70%, and 0.47%, respectively, where the relatively consistent results could be found. In addition, the dose linearity of immersed EBT3 films was also good, with coefficient of determination R2=0.9972. Conclusion:The method of measuring the dose of ultra-thin cell solution using EBT3 films proposed in this study is feasible, and the dose results obtained yield high accuracy under 200 kV beam.

ViewRay magnetic resonance (MR) guided radiotherapy system not only solves the problem of imaging dose,but also can set up accurately,online adaptive radiotherapy and gated irradiation according to magnetic resonance imaging (MRI).The development of this system provides a new technical means of accurate radiotherapy.This review describes the main structure of the ViewRay system,and summarizes quality assurance (QA),dosimetric comparison,respiratory motion management,online adaptive radiotherapy,and preliminary treatment effect.

Objective To study the effect of recombinant interlukin-2 plus chemotherapy in treatment of multiple myeloma. Methods We divided into two groups: chemotherapy plus rIL-2 group and simple chemotherapy group. The patients were given at dose of rIL-2 1×l06 IU/d, iH, qd, for 4 weeks and 4cycles. After 4 cycles the changes of T-cell subsets of their peripheral blood were determined. Response was evaluated according to Blad criteria. Adverse events were graded according to the National Cancer Institute Common Toxicity Criteria,version 3.0. Results The positive percentages of CD_3, CD_4 NK, CD_(69) and CD_4/CD_8ratio after chemotherapy in chemotherapy plus rIL-2 group were significantly higher than those before chemotherapy in the same group and those after chemotherapy in the other group. The overall response rate and complete response rate were 66.7 % and 25.0 % vs 50.0 % and 8.3 % respectively. The side effects of rIL-2 were predictable and manageable. Conclusion Recombinant interlukin-2 plus chemotherapy could increase immune function of patients with multiple myeloma and has a higher response rate as compared with simple chemotherapy.