摘要
目的改进调强放射治疗的照射野布野方法,在提高靶区剂量的同时,尽量减少患侧晶体及其他正常组织的受照射剂量,提高患者长期生存质量。方法 5例患有泪腺腺样囊性癌患者(左侧),所有患者靶区均包括患侧眶左下壁和眶顶壁。布野方式采取以下三种:(1)常规共面均分9野;(2)非常规共面不均分5野;(3)非常规非共面不均分6野(以下分别简称为9野、5野和6野)。比较以上三种布野方式完成计划的剂量体积直方图(dose volume histogram,DVH)、剂量分布图及物理和生物学参数(最大、最小、平均剂量,适形指数(conformity indexes,CI)和等效均匀剂量(equivalent uniform dose,EUD)。结果 6野计划靶体积(planning target volume,PTV)的D98%、V95%分别比9野和5野增大1.3%、0.6%和11.4%、3.5%,D2%比5野小1%,CI及EUD无明显差别。对于危及器官(organ at risk,OAR),6野除了脑干的Dmin略差于5野以外,其余均优于9野和5野。结论从PTV和OARs所受剂量比对情况来看,非常规不均分6野明显具有剂量学优势,要优于其他两种方法。
Objective To improve the beam directions for the intensity -modulated radiotherapy, to minimize the irradiation dose for the affected side of crystal and cornea as well as other normal tissues while improving the target dose, so as to improve the quality of patient long -term survival. Methods Five patients with orbital adenoid cystic carcinoma （left） were recruited. All the target areas of irradiation included the left lower wall and top wall of the affected side of orbit. The beam directions were taken as the following three types： a） conventional eoplanar uniform division of 9 beams; b） unconventional coplanar non -uniform division of 5 beams ; c） unconventional non - coplanar non - uniform division of 6 beams （ hereinafter referred to respectively as 9 beams, 5 beams and 6 beams）. The proposed dose volume histogram （DVH） , the dose distributions as well as the physical and biological parameters （maximum, minimum and mean doses, conformity indexes （CI） and equivalent uniform dose （EUD）） of the above three plans were eomparod. Results The D98qo and V95~o of 6 beams PTV were 1.3% and 0.6% as well as 1 1.4% and 0.6% larger than those of 9 beams and 5 beams respectively, D2qo was 1% smaller than 5 beams, but CI and EUD had no obvious differences. For OARs, 6 fields were superior to 9 and 5 beams except that Dmin of brainstem was slightly worse than 5 beams. Conclusions In view of the compari- sons of the irradiated doses for the target and the organs at risk, the third method, i. e. , unconventional non - uniform division of 6 beams has the obvious advantage of dosimetry, which is superior to the other two methods.
出处
《武警医学》
CAS
2013年第12期1039-1042,共4页
Medical Journal of the Chinese People's Armed Police Force
关键词
腺样囊性癌
调强放射治疗
放射治疗计划
计算机辅助
adenoid cystic carcinoma
intensity modulated radiotherapy
planning, computer - assisted
