Objective:To investigate the relationship of the acute radiation reactions of totalbody irradiation before hematopoietic stem cell transplantation with the different total and fractionated doses of irradiation.Methods:The clinical data of 48 patients who underwent 6 MV X-ray total body irradiation pretreatment from May 2015 to December 2019 in Shijiazhuang Ping'an Hospital before undergoing hematopoietic stem cell transplantation were retrospectively analyzed. The patients were divided into 8 Gy group (12 cases), 10 Gy group (31 cases) and 12 Gy group (5 cases) according to the total radiation dose, and divided into 4 Gy/f group (17 cases) and 5 Gy/f group (31 cases) according to the fractionated radiation dose. Acute radiation reactions in the oral mucosa, pharynx, salivary glands, upper gastrointestinal tract, lower gastrointestinal tract and lung of patients in each group after radiotherapy were summarized and compared.Results:Acute pharyngeal reaction in the total radiation dose of 8 Gy group showed that 11 cases (91.7%) were grade 0 and 1 case (8.3%) was grade 1; in the total radiation dose of 10 Gy group, 10 cases (32.3%) were grade 0, 13 cases (41.9%) were grade 1, 4 cases (12.9%) were grade 2, 3 cases (9.7%) were grade 3, and 1 case (3.2%) was grade 4; in the total radiation dose of 12 Gy group, 2 cases (40.0%) were grade 0, 1 case (20.0%) was grade 1, 1 case (20.0%) was grade 2, and 1 case (20.0%) was grade 3. The severity of acute pharyngeal radiation reaction in the total radiation dose of 8 Gy group was better than that in the 10 Gy and 12 Gy groups, and the difference was statistically significant ( χ2 = 11.338, P = 0.003); there was no significant difference in the incidence of acute radiation reactions in other parts (all P > 0.05). Acute pharyngeal radiation reaction in the fractionated radiation dose of 4 Gy/f group showed that 13 cases (76.5%) were grade 0, 2 case (11.8%) was grade 1, 1 case (5.9%) was grade 2, and 1 case (5.9%) was grade 3; in the 5 Gy/f group, 10 cases (32.3%) were grade 0, 13 cases (41.9%) were grade 1, 4 cases (12.9%) were grade 2, 3 cases (9.7%) were grade 3, and 1 case (3.2%) was grade 4. The severity of acute pharyngeal radiation reaction in the fractionated radiation dose 4 Gy/f group was better than that in the 5 Gy/f group, and the difference was statistically significant ( Z = -2.606, P = 0.009); there was no significant difference in the incidence of acute radiation reactions in other parts (all P > 0.05). Conclusion:The total dose of 8 Gy and fractionated dose of 4 Gy/f in the total body irradiation before hematopoietic stem cell transplantation can alleviate the acute pharyngeal radiation reaction.

Objective:To study the set-up error of vertebral carcinoma radiotherapy guided by kV CBCT scans in our hospital.Methods:37 patients with vertebral carcinoma,were under IMRT(intensity-modulated radiation therapy).All patients were given CBCT scans before treatment by Varian Ⅸ linear accelerator airborne imaging system.The system reconstructed image automaticly and matched the CT image of treatment plan.We could achieve the set-up error of right-left (Ⅹ),anterior-posterior (Y),superior-interferior(Z) directions.Results:37 patients with vertebral carcinoma were underwent 114 times of CBCT scans.When only concerdered the error magnitude,the error at right-left (Ⅹ),anterior-posterior (Y),superior-interferior (Z) directions were (2.69-± 2.46) mm,(5.37 ± 4.57)mm,(4.02 ± 3.5) mm,respectly.Among which,the set-up error of thoracic vertebra cancer were (2.02 ± 2.07)mm,(4.80-± 4.59) mm and(4.00 ± 3.92) mm,lumbar vertebra cancer were (3.35 ± 2.65) mm,(5.83 ± 4.54)mm and(4.03 ± 3.08) mm.Conclusion:During the radiotherapy of vertebral carcinoma patinets,the set-up error of the lumbar vertebra is larger than that of the thoracic vertebra in the right-left(Ⅹ) direction,so attention should be paid to set-up so as to reduce the treatment error.

>加速器包括电子枪、波导管、微波功率源、真空系统、偏转系统等,工作中这些部件要散发一定热量,影响加速器工作。温控系统是通过循环水流消除这些部件散发的热量,使加速器内部保持恒定的工作温度。温控系统是整个加速器系统的重要组成部分之一,瓦里安iX加速器自动温控系统出现问题,加速器提示水流联锁。一、材料与方法1.瓦里安iX加速器自动恒温系统:由内循环水系统、外