A study on monitoring and assessment of leakage and scattering radiation in a helical tomotherapy room
10.3760/cma.j.issn.0254-5098.2013.04.028
- VernacularTitle:螺旋断层放射治疗室内泄漏辐射与散射辐射监测与评价研究
- Author:
Yongzhong MA
;
Ling WAN
;
Yun LOU
;
Zechen FENG
;
Hong ZHANG
;
Bo YANG
- Publication Type:Journal Article
- Keywords:
Helical tomotherapy;
Leakage radiation;
Scattering radiation;
Radiation protection
- From:
Chinese Journal of Radiological Medicine and Protection
2013;33(4):431-435
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study the radiation dose level and dose distribution of leakage and scattering radiation in a helical tomotherapy (TOMO) room,and to identify the dose distribution characteristic which is different from the conventional radiotherapy so as to provide scientific data for the radiation protection of TOMO.Methods A helical tomotherapy facility typed Tomotherapy Hi-Art was employed as the radiotherapy device.The air kerma from leakage radiation and scattering radiation distributed on the couch plane and in TOMO room were detected mainly by GR-200A TLDs of LiF(Mg,Cu,P),while 100 Gy were being accumulated under the condition of simulation radiation treatment.Then,the leakage radiation ratio and scattering-leakage radiation ratio (the ratio of site radiation dose to isocenter standard output dose) were calculated.Results The radiation level and dose distribution of leakage radiation and scattering radiation in the TOMO treatment room were in bilateral symmetry to the rotation isocenter and the treatment couch longitudinal axis,and the radiation level in front of the radiotherapy device was significantly higher than that of the rear of the TOMO equipment.In the plane of treatment couch,the maximum leakage radiation ratio at the position 100 cm away from the isocenter was only 1.3 × 10-4,and the mean value of the leakage radiation ratio at the position 300 cm away from the isocenter was lower than 2.0 × 10-5.The scattering radiation at 200-300 cm away from the isocenter was accounted for 25％-30％ of the leakage radiation from the responding sites,and the indoor scattering radiation decreased faster than leakage radiation with the distance from the isocenter.Conclusions The radiation level of leakage and scattering in a TOMO room is significantly lower than that in a conventional radiotherapy room.
