Major Tibor, Niehoff Peter, Kovács György, Fodor János, Polgár Csaba
National Institute of Oncology, Radiotherapy Department, Budapest, Hungary.
Radiother Oncol. 2006 Jun;79(3):321-8. doi: 10.1016/j.radonc.2006.05.005. Epub 2006 May 26.
To make a quantitative dosimetric comparison between treatment plans of multicatheter-based interstitial brachytherapy (IB) and MammoSite brachytherapy (MSB) for breast cancer.
Seventeen patients treated with IB and twenty-four with MSB were selected for the study. The irradiations for IB patients were planned using conventional two-film reconstruction technique. Following the implantation each patient was CT scanned, then the planning target volume (PTV) was retrospectively defined on the CT data set, and the original plan was reconstructed (CONV plans). Furthermore, conformal plans were also created by dose optimization on target (CONF plans). The planning for MammoSite applicator was based on CT imaging. The dose distributions were evaluated with dose-volume histograms. The following parameters were calculated and compared: volume of the PTV and its percentage receiving 90, 100, 150 and 200% of the prescribed dose (V90, V100, V150 and V200, respectively), percentage dose covering 90% of the PTV (D90), minimum dose in the PTV (D(min)), maximum dose in the PTV (D(max)) for MSB only, dose homogeneity index (DHI), and conformal index (COIN). To assess the dose to organs at risk maximum point dose to skin, lung and heart was used.
The median number of implanted catheters for IB was 11 (range: 6-13), the average balloon volume for MSB was 59.1cm(3) (range: 43.4-75.3 cm(3)). The average volume of PTV was 63.4 and 109.6 cm(3) for IB and MSB patients, respectively. The average V90, V100, V150, V200 were 76, 70, 26 and 9% for IB(CONV); 92, 87, 55 and 32% for IB(CONF) and 96, 88, 27 and 3% for MSB, respectively. The average D90 was 72, 94 and 99%, the D(min) was 47, 58 and 67%, respectively. The mean D(max) was 258% for MSB. The average DHI was 0.63, 0.37 and 0.70 for IB(CONV), IB(CONF) and MSB, respectively. D(max) to skin, lung and heart were 45, 54 and 31% for IB(CONV), 50, 55 and 29% for IB(CONF,) 97, 66 and 27% for MSB, respectively.
Target volume coverage was better for MSB than conventional IB, and it was comparable to conformal IB. The suboptimal coverage for IB patients is due to radiography based planning, which is unable to provide 3D information of the target. Dose homogeneity was somewhat better for MSB than IB(CONV), but the dose to skin and lung was higher for MSB. The MSB provides dosimetrically acceptable dose plans. The quality of interstitial implants can be improved with image-guided catheter insertions regarding both homogeneity and conformality.
对基于多导管的间质近距离放射治疗（IB）和 MammoSite 近距离放射治疗（MSB）用于乳腺癌的治疗计划进行定量剂量学比较。
选取 17 例接受 IB 治疗的患者和 24 例接受 MSB 治疗的患者进行研究。IB 患者的照射计划采用传统双胶片重建技术制定。植入后对每位患者进行 CT 扫描，然后在 CT 数据集上回顾性定义计划靶体积（PTV），并重建原始计划（CONV 计划）。此外，还通过对靶区进行剂量优化创建适形计划（CONF 计划）。MammoSite 施源器的计划基于 CT 成像。用剂量体积直方图评估剂量分布。计算并比较以下参数：PTV 的体积及其接受规定剂量 90%、100%、150%和 200%的百分比（分别为 V90、V100、V150 和 V200）、覆盖 90%PTV 的剂量百分比（D90）、PTV 中的最小剂量（D(min)）、仅针对 MSB 的 PTV 中的最大剂量（D(max)）、剂量均匀性指数（DHI）和适形指数（COIN）。为评估危及器官的剂量，采用皮肤、肺和心脏的最大点剂量。
IB 的植入导管中位数为 11（范围：6 - 13），MSB 的平均球囊体积为 59.1cm³（范围：43.4 - 75.3cm³）。IB 和 MSB 患者的 PTV 平均体积分别为 63.4 和 109.6cm³。IB（CONV）的平均 V90、V100、V150、V200 分别为 76%、70%、26%和 9%；IB（CONF）分别为 92%、87%、55%和 32%；MSB 分别为 96%、88%、27%和 3%。平均 D90 分别为 72%、94%和 99%，D(min)分别为
