Ravi Akkamma, Lee Susan, Karsif Karen, Osian Adrian, Nori Dattatreyudu
Department of Radiation Oncology, New York Hospital Queens, Flushing, NY 11355, USA.
J Cancer Res Ther. 2011 Jan-Mar;7(1):64-8. doi: 10.4103/0973-1482.80469.
To explore the dosimetric advantages of the new MammoSite multilumen (ML) balloon for breast brachytherapy treatment compared to conventional single lumen (SL) device plan.
Patients deemed appropriate for accelerated partial breast irradiation (APBI) were implanted with the MammoSite ML balloon. Two plans were generated in each patient for the same target coverage (PTV_EVAL) and dose to normal structures were plotted. The first plan used only the central single lumen with single-dwell position (SL), and the second plan (ML) was generated using the other lumens of the device. Dose distributions of the SL and ML plans were compared.
For the same PTV_EVAL, the ML balloon improved dose coverage at the tip and base of the applicator compared to SL plan. The skin and rib doses were reduced using the ML plan versus SL plan for the same PTV_EVAL in-patient 2, where the skin-balloon distance was 7 mm and the rib-balloon distance was <1 cm. For patient 1, the skin and rib distances were greater than 1 cm and the ML plan did not further minimize the dose to normal structures.
In our initial experience, dosimetric goals can be better achieved using the ML MammoSite balloon when normal structures (skin and ribs) are close to PTV_EVAL with a distance of <7 mm and rib distance of <1 cm. The multiple lumen of ML balloon can optimize dose and reduce excessive dose to rib and skin and therefore minimize the long-term toxicities of rib discomfort, skin fibrosis and fat necrosis.
探讨新型MammoSite多腔（ML）球囊用于乳腺近距离放射治疗与传统单腔（SL）装置计划相比的剂量学优势。
将被认为适合加速部分乳腺照射（APBI）的患者植入MammoSite ML球囊。为每位患者生成两个针对相同靶区覆盖范围（PTV_EVAL）的计划，并绘制正常结构的剂量。第一个计划仅使用中央单腔及单驻留位置（SL），第二个计划（ML）则使用该装置的其他腔。比较SL和ML计划的剂量分布。
对于相同的PTV_EVAL，与SL计划相比，ML球囊改善了施源器尖端和底部的剂量覆盖。在患者2中，对于相同的PTV_EVAL，使用ML计划与SL计划相比，皮肤和肋骨剂量降低，该患者皮肤 - 球囊距离为7 mm，肋骨 - 球囊距离<1 cm。对于患者1，皮肤和肋骨距离大于1 cm，ML计划并未进一步使正常结构的剂量最小化。
在我们的初步经验中，当正常结构（皮肤和肋骨）与PTV_EVAL距离<7 mm且肋骨距离<1 cm时，使用ML MammoSite球囊可更好地实现剂量学目标。ML球囊的多个腔可优化剂量并减少对肋骨和皮肤的过量剂量，从而将肋骨不适、皮肤纤维化和脂肪坏死等长期毒性降至最低。
