Department of Radiation Oncology, UC San Diego, CA 92130, USA.
J Appl Clin Med Phys. 2009 Dec 3;11(1):3021. doi: 10.1120/jacmp.v11i1.3021.
This work compares two accelerated partial breast irradiation modalities, MammoSite brachytherapy and three dimensional conformal radiotherapy (3D-CRT), to a new method, SAVI brachytherapy, following NSABP B-39 guidelines. A total of 21 patients treated at UC San Diego with the SAVI device were evaluated in this comparison. 9 of the 21 patients were eligible for all three modalities and were dosimetrically compared evaluating V90, V150, V200, total target volume, maximum skin, lung, and chestwall/rib dose. The target volumes (PTV_EVAL) differed with SAVI having the least total volume at 59.9 cc vs. 71.5 cc and 351.6 cc for MammoSite and 3D-CRT, respectively. The median V90, V150 and V200 for the three modalities were 97.7%, 25.0 cc, 10.4 cc (SAVI) vs. 97.6%, 23.9 cc, 5.0 cc (MammoSite) vs. 100% (V90 3D-CRT). The maximum dose for SAVI, MammoSite, and 3D-CRT, respectively, relative to the prescribed dose, for the: lung was 80.0%, 150.0%, and 104.9%; for rib 108.8%, 225.0%, and 114.7%: for skin 75.0%, 135.0%, and 108.6%. Comparing modalities, PTV coverage varied between 97.6% - 100.0% with more breast tissue covered by 3D-CRT, as expected, given the differences between external beam and brachytherapy. The maximum lung, skin and rib doses were lowest for the SAVI, highlighting its ability to conform to exclude normal tissues. In offering partial breast radiation, the availability of a variety of techniques allows for maximal patient eligibility, and comparison of individual method pros and cons may guide the most appropriate choice for each patient.
本研究按照 NSABP B-39 指南，比较了两种加速部分乳腺照射方式（MammoSite 近距离放疗和三维适形放疗）与一种新方法（SAVI 近距离放疗）。共有 21 名在加州大学圣地亚哥分校接受 SAVI 治疗的患者参与了本项比较研究。其中 21 名患者中的 9 名符合所有三种治疗方式的条件，对他们进行了剂量学比较，评估了 V90、V150、V200、总靶区体积、最大皮肤、肺和胸壁/肋骨剂量。靶区体积（PTV_EVAL）因治疗方式而异，SAVI 的总容积最小，为 59.9cc，而 MammoSite 和 3D-CRT 的总容积分别为 71.5cc 和 351.6cc。三种治疗方式的中位 V90、V150 和 V200 分别为 97.7%、25.0cc、10.4cc（SAVI）、97.6%、23.9cc、5.0cc（MammoSite）、100%（3D-CRT）。SAVI、MammoSite 和 3D-CRT 的最大剂量与处方剂量的比值分别为：肺 80.0%、150.0%和 104.9%；肋骨 108.8%、225.0%和 114.7%；皮肤 75.0%、135.0%和 108.6%。比较不同治疗方式时，PTV 覆盖率在 97.6%到 100.0%之间，3D-CRT 覆盖的乳腺组织更多，这与外照射与近距离放疗之间的差异有关。SAVI 的最大肺、皮肤和肋骨剂量最低，这突出了它排除正常组织的能力。在提供部分乳腺放疗时，各种技术的可用性可使更多患者符合治疗条件，并且比较不同方法的优缺点可能有助于为每位患者选择最合适的治疗方法。
