摘要
背景与目的:调强适形放射治疗(intensity-modulatedradiotherapy,IMRT)在乳腺癌保留乳房治疗中显示了较好的剂量学优势和发展前景,其中靶区的确定是IMRT最关键的环节,决定了放射治疗计划和实施的准确性,但目前仍缺乏乳腺癌全乳临床靶体积(clinicaltargetvolume,CTV)确定与勾画的规范。本研究分析不同医师勾画全乳CTV的差异,以合理地确定乳腺癌IMRT中的全乳CTV。方法:由4名放射治疗医师与1名放射诊断医师分别在6例患者中勾画全乳CTV及相应的参考CTV,分析其体积差异,计算共有体积与最大体积之比R值,测量各医师勾画CTVs在不同方向与参考CTV比较的最大边距差异,以各医师勾画CTV为基础设计切线野并测量其射野中心肺厚度(centrallungdistance,CLD)。结果:2例乳腺腺体密度较低的患者体积差异最大,其R值仅为0.660和0.651,其余4例患者的R值分别是0.735、0.752及0.799、0.769,又以有乳腺边界体表标记患者的R值较大;与参考CTV相比,6例患者中各放疗医师勾画的CTVs在前界、后界、上界、下界和内界、外界最大边距的差异分别是0、(1.2±3.4)mm、(1.5±2.1)mm、(0.7±4.1)mm、(0.6±3.3)mm、(0.8±0.8)mm,各患者中差异部位以乳腺腋尾组织边界与无银夹标记的瘤床边界最为明显;以各医师勾画CTVs设计切线野的CLD平均值在4例患者中均超过2cm。结论:不同医师勾画全乳CTV差异的主要来源是患者本身乳腺腺体密度的个体化差异以及各医师对乳腺腋尾腺体边界、瘤床范围和保护肺组织限度的认识不一。
BACKGROUND ＆ OBJECTIVE： In patients with breast cancer who underwent breast conservation treatment, intensity-modulated radiotherapy （IMRT） has been approved to hold better dosimetric advantages and improvable future. Target delineation is the most important process, which determines the accuracy of planning and application of IMRT. However, there is no consensus criterion for the delineation of clinical target volume （CTV） of intact breast. This study was to investigate the factors influencing the delineation of CTV of intact breast in IMRT for breast cancer. METHODS： The CTV of intact breast in 6 patients was delineated by 4 radiation oncologists and 1 radiologist individually, and reference CTV was determined by group consensus. The extent of variation in CTV delineation was quantified by the ratio of common volumes （Vco） of all CTVs to the maximum volume encompassing all CTVs （Vmax）. The deviation in the extent of CTV from the extent of reference CTV was quantified in each orthogonal direction to find the origins of variations. In addition, all central lung distances （CLD） in tangential fields, which were designed based on CTVs, were measured. RESULTS. The ratios of Vco to Vmax were low （0.660 and 0.651, respectively） in 2 patients with low glandular density. Among the other 4 patients with high glandular density, the ratio was relatively higher in 2 patients with radio-opaque marks than in the other 2 patients with no marks （0.799, 0.769 vs. 0.735, 0.752, respectively）. Compared with reference CTVs, the patients＇ average deviations of the extent of CTVs were 0 in anterior direction, （1.2±3.4） mm in posterior direction, （1.5±2.1） mm in cranial direction, （0.7±4.1） mm in caudal direction, （0.6±3.3） mm in medial direction, and （0.8±0.8） mm in lateral direction. The most obvious variations were observed in the area of breast axillary part and primary tumor bed after surgery. The mean CLD in 4 patients exceeded over the conventional limitation of 2 cm. CONCLUSION： The variability between CTVs of intact breast delineated by different radiation oncologists is strongly related to individual glandular density, the extent of breast axillary part, the primary tumor bed after surgery, and the different understanding for lung sparing limitations.
出处
《癌症》
SCIE
CAS
CSCD
北大核心
2006年第1期62-65,共4页
Chinese Journal of Cancer
关键词
乳腺肿瘤/放射疗法
调强适形放射治疗
临床靶
体积
Breast neoplasms/radiotherapy
Intensity-modulated radiotherapy
Clinical target volume
