摘要
目的 探讨呼吸运动对肺癌SBRT显微病灶的不经意照射及靶区外扩边界的影响。方法 根据放疗照射过程中肺部肿瘤随呼吸运动的规律,建立肿瘤周围显微病灶进入或移出ITV概率模型,并结合4DCT的静态剂量分布,得到显微病灶理论计算值。运用模拟呼吸运动模体和光释光实测运动状态下显微病灶剂量分布,与显微病灶理论计算值比较,以验证模型的准确性。结果 周期运动靶区的显微病灶理论计算值与光释光实测值差值在5%内,距离ITV 10 mm以内区域接受的生物剂量〉80 Gy。结论 剂量模型可准确预测周期运动靶区显微病灶受量,呼吸运动使显微病灶接受的不经意照射剂量增加不需外扩CTV。
Objective To investigate the effect of respiratory motion on inadvertent irradiation dose （ⅡD） to the microscopic disease （MD） and expanding margin of target volume in stereotactic body radiotherapy for lung cancer. Methods Based on the pattern of respiration-induced tumor motion during lung radiotherapy, a probability model of MD entry into or exit from internal target volume （ITV） was established and the theoretical dose to MD was calculated according to the static dose distribution by four-dimensional computed tomography. The experimental dose to MD during respiratory motion was measured using a respiration simulation phantom and optically stimulated luminescence （OSL） and then compared with the theoretical value for model validation. Results For the target volume in periodic motion, the deviation of the theoretical dose to MD from the experimental value measured by OSL was less than 5%. A 10-mm margin around ITV received a biological dose higher than 80 Gy. Conclusions The dose model established in this study can accurately predict the irradiation dose to MD in the target volume in periodic motion. Respiratory motion increases ⅡD to MD and there is no need to expand clinical target volume.
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2017年第12期1426-1429,共4页
Chinese Journal of Radiation Oncology
基金
国家自然基金（81372436）
河南省与卫生部共建项目（201201009）
郑州市科技创新团队（121PCXTD524）
关键词
肺肿瘤
放射治疗剂量
呼吸生理现象
显微病灶
不经意照射
Lung neoplasms
Radiotherapy dosage
Respiratory physiological phenomena
Microscopic disease
Inadvertent irradiation dose
