Introduction
Residual distal parametrial involvement after radiochemotherapy is a true challenge for brachytherapists since the width and asymmetry of high-risk clinical target volume (HR-CTV) are difficult to cover properly with a standard implant.

Material and methods
Dosimetric plans of five patients treated with Venezia advanced gynecological applicator at our institution were reviewed. For each patient, we compared the original plan with a new plan where oblique needles were removed and re-optimized manually. Optimization process was halted when EQD210 D90 HR-CTV reached 90 Gy, when one hard constraint to organs at risk (OARs) was reached according to the EMBRACE II protocol, or when dose-rate of one of OARs exceeded 0.6 Gy/h.

Results
Tumors were large; median HR-CTV volume was 64 cc and median distance between tandem and outer contour of HR-CTV was 40 mm. For the five patients, HR-CTV EQD210 D90 was superior in the plan using oblique needles, with a median difference of 6.5 Gy (range, 1.7-8.5 Gy). Median D90 HR-CTV and intermediate-risk CTV (IR-CTV) were significantly increased with oblique needles: 85.9 Gy (range, 83.2-90.3 Gy) vs. 81.5 Gy (range, 77.4-84 Gy), and 68.7 Gy (range, 66.3-72.3 Gy) vs. 67 Gy (range, 64.3-69.1 Gy), p = 0.006 for both. There were no significant differences in the dose to OARs. Plans with only parallel needles had less favorable dose distribution, with cold spots on the outer parametria and higher vaginal activation to compensate parametrial coverage in its inferior part.

Conclusions
VeneziaTM applicator permits reproducible application to increase CTV coverage in patients with distal parametrial tumor residue during brachytherapy, while maintaining acceptable dose to OARs.



中文翻译：

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与仅平行针相比，带斜针的Venezia涂抹器可改善远端子宫旁子宫肿瘤残留物中的临床目标体积覆盖率

前言
放射化学疗法后残留的远端子宫旁肌受累对于近距离放射治疗师是一个真正的挑战，因为高风险临床目标体积（HR-CTV）的宽度和不对称性很难用标准植入物正确覆盖。

材料和方法
回顾了我院接受Venezia高级妇科应用治疗的5例患者的剂量计划。对于每位患者，我们将原始计划与新计划进行了比较，在新计划中，移除了斜针并手动对其进行了优化。当EQD210 D90 HR-CTV达到90 Gy，根据EMBRACE II协议达到对危险器官（OAR）的一种硬约束或当一种OAR的剂量率超过0.6 Gy / h时，优化过程就停止了。

结果
肿瘤很大；HR-CTV的中位数为64 cc，纵列与HR-CTV的轮廓之间的中位数距离为40 mm。对于5例患者，使用斜针的HR-CTV EQD210 D90在计划中更好，中位差为6.5 Gy（范围为1.7-8.5 Gy）。斜针的中位D90 HR-CTV和中危CTV（IR-CTV）显着增加：85.9 Gy（范围，83.2-90.3 Gy）与81.5 Gy（范围，77.4-84 Gy）和68.7 Gy（范围，66.3-72.3 Gy）对比67 Gy（范围64.3-69.1 Gy），两者的p = 0.006。OARs的剂量没有显着差异。仅使用平行针的计划的剂量分布较差，在子宫旁膜上有冷点，而阴道活化较高，以补偿其下半部分的膜下覆盖。

结论
VeneziaTM涂药器可重复使用，以在近距离放疗期间增加远端子宫旁子宫肿瘤残留患者的CTV覆盖率，同时保持可接受的OAR剂量。