FLASH radiotherapy (FLASH-RT) is a treatment modality that delivers ultra-high dose rate and ultra-fast radiation for cancer treatment. Compared to conventional dose rate radiotherapy, FLASH-RT can yield similar efficacy for tumors and achieve normal tissue protection, translating to an increased therapeutic window. Due to this unique feature, FLASH-RT is attracting increasing attention from the radiotherapy community, both academia and industry. Due to its unique Bragg peak as well as intrinsic high dose rate, application of FLASH has more value and profound significance in proton therapy while achieving highly conformal dose deposition simultaneously. This article reviews research progress on FLASH-RT, relevant cell and animal studies, experimental conditions and results. Moreover, this article also investigates the potential biological mechanisms, technical challenges for implementation and potential clinical applications of FLASH-RT.

ObjectiveTo understand the human immunodeficiency virus（HIV） infection status and related factors by using the HIV/AIDS sentinel surveillance data of men who have sex with men（MSM） in Jinhua City， Zhejiang Province. MethodsSnowball sampling method was used to recruit MSM receiving HIV sentinel surveillance from 2016 to 2021.The inclusion criteria were aged 18 years old and above， reported having anal sex with man in recent 6 months. Questionnaire-based interviews were conducted on a one-on-one basis. Data including the characteristics of demography and ethology were collected. Five milliliter of blood samples were taken after the questionnaire. HIV and syphilis was screened. The time trend was analyzed with χ² test. Multivariate logistic regression model was used to analyze the factors associated with HIV infection status among MSM. ResultsThe positive rate of HIV was 8.0% （127/1 597）， with an increasing trend （P=0.002）， but the linear correlation was weak（r=0.075）. The positive rate of syphilis was 5.2% （83/1 597）， with no significant difference （P=0.661）.The constituent ratios showed an increasing trend （P<0.05） in using condoms consistently， finding male sexual partners through Internet or dating software， having anal sex in the past week， using condoms every time during anal sex in the past 6 months， accepting prevention services of AIDS in the last year， and the overall awareness of AIDS related knowledge. Multivariate logistic regression analysis showed that who was from national minority （OR=2.27， 95%CI： 1.08‒4.73） and from other provinces （OR=1.68， 95%CI： 1.08‒2.62）， who failed to consistently use condoms every time during anal sex in the past six months （OR=3.03， 95%CI： 2.02‒4.54）， who never accepted prevention services of AIDS in the last year （OR=2.17，95%CI：1.44‒3.27）， who don’t know the knowledge of AIDS （OR=1.86， 95%CI： 1.12‒3.07）， and who was infected with syphilis （OR=2.35， 95%CI： 1.20‒4.61） were at higher risk for HIV infection among MSM. ConclusionThe positive rate of HIV remains at a certain level among MSM in Jinhua. High-risk groups such as the patients with syphilis infections and floating population from other provinces need to be paid close attention. It is suggested to further strengthen the promotion of the use of condoms， awareness of AIDS and syphilis， warning education and comprehensive intervention services.

ObjectiveTo analyze the epidemiological characteristics of patients with hepatitis C in Jinhua City, Zhejiang Province from 2005 to 2023, so as to provide a scientific basis for the prevention and control of hepatitis C. MethodsThe data on patients with hepatitis C, as well as whose current address is in Jinhua City, from 2005 to 2023 were collected from the infectious disease surveillance system of the China Disease Control and Prevention Information Management System. Descriptive epidemiological methods were used to analyze the temporal, spatial and demographic distribution characteristics of hepatitis C. ResultsA total of 2 326 cases of hepatitis C were reported in Jinhua from 2005 to 2023, including 2 death cases, with an average annual incidence rate of 2.19/100 000, showing a trend which rose first and then declined and then rose again. Hepatitis C was reported all the year round without significant seasonal pattern. In terms of the number of reported cases and the average annual incidence rate, Yiwu City ranked the first place. From 2005 to 2023, a total of 1 438 (61.82%) male cases and 888 (38.18%) female cases were reported, and the reported incidence rate was higher for males (2.62/100 000) than that for females (1.74/100 000), showing a statistically significant difference (χ²=92.937, P<0.001). Most cases aged between 30 to <50 years old (1 175, 50.52%), and the incidence rate of hepatitis C among the age group of 40‒<50, 50‒<60, 60‒<70 years old was showing an upward trend, with farmers (1 024, 44.02%) as the main occupation . ConclusionThe prevalence of hepatitis C in Jinhua City is generally at a low level, with an incidence rate of increasing and then decreasing, but rise up again after 2019. Therefore, epidemic surveillance and health education among the male, middle-aged and elderly people and farmers, as well as the key regions where the migrant workers flows in should be enhanced.