Inanc Berrin, Inanc Kubilay, Okten Begum, Mermut Ozlem
Department of Radiation Oncology, University of Health Sciences, Istanbul Training and Research Hospital, Istanbul, Turkey.
Department of Radiation Oncology, University of Health Sciences Turkey, Sisli Hamidiye Etfal Teaching and Research Hospital, Istanbul, Turkey.
Sisli Etfal Hastan Tip Bul. 2021 Mar 17;55(1):81-85. doi: 10.14744/SEMB.2020.25986. eCollection 2021.
Determining boost volume (BV) during breast radiotherapy can be challenging at times. Therefore, surgical clips are now being widely used. At times, when surgical clips are inadequate in determining the BV, other additional imaging methods are required. In the present study, we aimed to demonstrate that pre-operative positron emission tomography/computed tomography (PET-CT) can be used to determine the BV after a breast-conversing surgery.
We selected thirty patients who underwent breast-conserving surgery with surgical clips and had preoperative Fluorine-18-Fluorodeoxyglucose PET (18 FDG PET/CT). The BV in planning tomography (CT) and primary tumor volume (TV) in pre-operative F-18 FDG PET/CT was contoured by a radiation oncologist. These two volumes were superposed using rigid image fusion. In every patient, two BVs were measured. The mean shift between the two volumes by the calculation of the center of mass and percentage of the PET-CT TV (PET-CT TV) in planning the BV (planning target volume [PTV]-BV) was calculated.
The median age was 52 years (range 25-72 years). The pre-operative PET-CT TV median was 8.89 cm (range 1.00-64.30 cm). The median PTV-BV was 62.92 cm (12.57-123.07 cm). The median shifts between the center of volumes were 1.76 cm (range 0.90-3.50) in X(coronal), 1.73 cm (range 0.60-3.60) in the Y(axial), and 1.20 cm (0.40-2.80) in the Z(sagittal) directions, respectively. The shifts in these three planes were determined to be statistically significant (p<0.001). The percent volume of PET-CT TV included PTV TV, ranging from 35% to 100% (mean 54%, standard deviation 29.53) and 100% in two out of 31 patients.
Our study has shown that pre-operative PET-CT cannot be used to determine the BV in patients who replaced surgical clips and had undergone breast-conserving surgery. To define a more accurate BV, surgical clips should be placed in four planes, and more PTV margins should be given in treatment planning.
在乳腺癌放疗期间确定瘤床补量体积（BV）有时具有挑战性。因此，手术夹现在被广泛使用。有时，当手术夹不足以确定BV时，需要其他额外的成像方法。在本研究中，我们旨在证明术前正电子发射断层扫描/计算机断层扫描（PET-CT）可用于确定保乳手术后的BV。
我们选择了30例接受了带手术夹的保乳手术且术前行氟-18-氟脱氧葡萄糖PET（18F-FDG PET/CT）检查的患者。放疗肿瘤学家在计划断层扫描（CT）中勾勒出BV，在术前F-18 FDG PET/CT中勾勒出原发肿瘤体积（TV）。使用刚性图像融合将这两个体积叠加。在每位患者中，测量了两个BV。通过计算质心以及PET-CT TV在计划BV（计划靶体积[PTV]-BV）中的百分比，计算了两个体积之间的平均偏移。
中位年龄为52岁（范围25 - 72岁）。术前PET-CT TV中位数为8.89 cm（范围1.00 - 64.30 cm）。中位PTV-BV为62.92 cm（12.57 - 123.07 cm）。体积中心之间的中位偏移在X轴（冠状面）为1.76 cm（范围0.90 - 3.50），在Y轴（矢状面）为1.73 cm（范围0.60 - 3.60），在Z轴（横断面）为1.20 cm（0.40 - 2.80）。这三个平面中的偏移在统计学上具有显著意义（p<0.001）。PET-CT TV包含PTV TV的体积百分比范围为35%至100%（平均54%，标准差29.53），31例患者中有2例为100%。
我们的研究表明，术前PET-CT不能用于确定放置了手术夹且接受了保乳手术的患者的BV。为了定义更准确的BV，手术夹应放置在四个平面，并且在治疗计划中应给予更多的PTV边界。
