Munshi Anusheel, Pai Rajeshri H, Phurailatpam Reena, Budrukkar Ashwini, Jalali Rakesh, Sarin Rajiv, Deshpande D D, Shrivastava Shyam K, Dinshaw Ketayun A
Department of Radiation Oncology, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India.
Med Dosim. 2009 Summer;34(2):140-4. doi: 10.1016/j.meddos.2008.08.006. Epub 2008 Sep 24.
Evaluation of dose distribution in a single plane (i.e., 2-dimensional [2D] planning) is simple and less resource-intensive than CT-based 3-dimensional radiotherapy (3DCRT) planning or intensity modulated radiotherapy (IMRT). The aim of the study was to determine if 2D planning could be an appropriate treatment in a subgroup of breast cancer patients based on their breast size. Twenty consecutive patients who underwent breast conservation were planned for radiotherapy. The patients were grouped in 3 different categories based on their respective chest wall separation (CWS) and the thickness of breast, as "small," "medium," and "large." Two more contours were taken at locations 5 cm superior and 5 cm inferior to the isocenter plane. Maximum dose recorded at specified points was compared in superior/inferior slices as compared to the central slice. The mean difference for small breast size was 1.93 (standard deviation [SD] = 1.08). For medium breas size, the mean difference was 2.98 (SD = 2.40). For the large breasts, the mean difference was 4.28 (SD = 2.69). Based on our dosimetric study, breast planning only on the single isocentric contour is an appropriate technique for patients with small breasts. However, for large- and medium-size breasts, CT-based planning and 3D planning have a definite role. These results can be especially useful for rationalizing treatment in busy oncology centers.
在单个平面内评估剂量分布（即二维[2D]计划）很简单，且与基于CT的三维放射治疗（3DCRT）计划或调强放射治疗（IMRT）相比，资源消耗更少。本研究的目的是确定基于乳腺癌患者的乳房大小，2D计划是否可能是适合亚组患者的一种治疗方式。对连续20例行保乳手术的患者进行放射治疗计划。根据患者各自的胸壁间距（CWS）和乳房厚度，将患者分为3个不同类别，即“小”、“中”和“大”。在等中心平面上方5 cm和下方5 cm处再取两个轮廓。将在指定点记录的最大剂量在上下层面与中心层面进行比较。小乳房大小的平均差值为1.93（标准差[SD]=1.08）。中等乳房大小的平均差值为2.98（SD=2.40）。对于大乳房，平均差值为4.28（SD=2.69）。基于我们的剂量学研究，仅在单个等中心轮廓上进行乳房计划对小乳房患者是一种合适的技术。然而，对于大中型乳房，基于CT的计划和三维计划有明确的作用。这些结果对于繁忙的肿瘤中心合理安排治疗可能特别有用。
