PDF(Pubmed)
Abstract：
OBJECTIVE: To investigate the effect of various frequencies of bolus use on the superficial dose of volumetric modulated arc therapy after modified radical mastectomy for breast cancer.
METHODS: Based on the computed tomography images of a female anthropomorphic breast phantom, a 0.5 cm silicone-based 3D-printed bolus was created. Nine points evenly distributed on the breast skin were selected for assessing the skin dose, and a volume of subcutaneous lymphatic drainage of the breast (noted as ROI2-3) was delineated for assessing the chest wall dose. The treatment plans with and without bolus (plan_wb and plan_nb) were separately designed using the prescription of 50 Gy in 25 fractions following the standard dose constraints of the adjacent organ at risk. To characterize the accuracy of treatment planning system (TPS) dose calculations, the doses of the nine points were measured five times by thermoluminescence dosimeters (TLDs) and then were compared with the TPS calculated dose.
RESULTS: Compared with Plan_nb (144.46 ± 10.32 cGy), the breast skin dose for plan_wb (208.75 ± 4.55 cGy) was significantly increased (t = -18.56, P < 0.001). The deviation of skin dose was smaller for Plan_wb, and the uniformity was significantly improved. The calculated value of TPS was in good agreement with the measured value of TLD, and the maximum deviation was within 5%. Skin and ROI2-3 doses were significantly increased with increasing frequencies of bolus applications. The mean dose of the breast skin and ROI2-3 for 15 and 23 times bolus applications were 45.33 Gy, 50.88 Gy and 50.36 Gy, 52.39 Gy, respectively.
CONCLUSIONS: 3D printing bolus can improve the radiation dose and the accuracy of the planned dose. Setting Plan_wb to 15 times for T1-3N+ breast cancer patients and 23 times for T4N+ breast cancer patients can meet the clinical need. Quantitative analysis of the bolus application frequency for different tumor stages can provide a reference for clinical practice.
METHODS: Based on the computed tomography images of a female anthropomorphic breast phantom, a 0.5 cm silicone-based 3D-printed bolus was created. Nine points evenly distributed on the breast skin were selected for assessing the skin dose, and a volume of subcutaneous lymphatic drainage of the breast (noted as ROI2-3) was delineated for assessing the chest wall dose. The treatment plans with and without bolus (plan_wb and plan_nb) were separately designed using the prescription of 50 Gy in 25 fractions following the standard dose constraints of the adjacent organ at risk. To characterize the accuracy of treatment planning system (TPS) dose calculations, the doses of the nine points were measured five times by thermoluminescence dosimeters (TLDs) and then were compared with the TPS calculated dose.
RESULTS: Compared with Plan_nb (144.46 ± 10.32 cGy), the breast skin dose for plan_wb (208.75 ± 4.55 cGy) was significantly increased (t = -18.56, P < 0.001). The deviation of skin dose was smaller for Plan_wb, and the uniformity was significantly improved. The calculated value of TPS was in good agreement with the measured value of TLD, and the maximum deviation was within 5%. Skin and ROI2-3 doses were significantly increased with increasing frequencies of bolus applications. The mean dose of the breast skin and ROI2-3 for 15 and 23 times bolus applications were 45.33 Gy, 50.88 Gy and 50.36 Gy, 52.39 Gy, respectively.
CONCLUSIONS: 3D printing bolus can improve the radiation dose and the accuracy of the planned dose. Setting Plan_wb to 15 times for T1-3N+ breast cancer patients and 23 times for T4N+ breast cancer patients can meet the clinical need. Quantitative analysis of the bolus application frequency for different tumor stages can provide a reference for clinical practice.
摘要：
目的：探讨不同频率的推注使用对乳腺癌改良根治术后体积调节电弧治疗浅表剂量的影响。
方法：基于女性拟人化乳房体模的计算机断层扫描图像，创建了一个0.5厘米的基于硅胶的3D打印团块。选择9个均匀分布在乳房皮肤上的点用于评估皮肤剂量，描绘了乳房皮下淋巴引流的体积（记录为ROI2-3）以评估胸壁剂量。有和没有推注的治疗计划（plan_wb和plan_nb）是使用50Gy的处方在25个分数中按照相邻器官的标准剂量约束分别设计的。为了表征治疗计划系统（TPS）剂量计算的准确性，通过热释光剂量计（TLD）测量9点的剂量五次，然后与TPS计算的剂量进行比较。
结果：与Plan_nb（144.46±10.32cGy）相比，计划wb的乳房皮肤剂量（208.75±4.55cGy）显着增加（t=-18.56，P<0.001）。Plan_wb的皮肤剂量偏差较小，均匀性明显提高。TPS的计算值与TLD的测量值吻合良好，最大偏差在5%以内。皮肤和ROI2-3剂量随着推注应用频率的增加而显著增加。15和23次推注应用的乳房皮肤和ROI2-3的平均剂量为45.33Gy，50.88Gy和50.36Gy，52.39Gy,分别。
结论：3D打印推注可以提高辐射剂量和计划剂量的准确性。T1-3N+乳腺癌患者设定Plan_wb为15次,T4N+乳腺癌患者设定23次,可以满足临床需要。定量分析不同肿瘤分期的推注应用频率可为临床实践提供参考。
方法：基于女性拟人化乳房体模的计算机断层扫描图像，创建了一个0.5厘米的基于硅胶的3D打印团块。选择9个均匀分布在乳房皮肤上的点用于评估皮肤剂量，描绘了乳房皮下淋巴引流的体积（记录为ROI2-3）以评估胸壁剂量。有和没有推注的治疗计划（plan_wb和plan_nb）是使用50Gy的处方在25个分数中按照相邻器官的标准剂量约束分别设计的。为了表征治疗计划系统（TPS）剂量计算的准确性，通过热释光剂量计（TLD）测量9点的剂量五次，然后与TPS计算的剂量进行比较。
结果：与Plan_nb（144.46±10.32cGy）相比，计划wb的乳房皮肤剂量（208.75±4.55cGy）显着增加（t=-18.56，P<0.001）。Plan_wb的皮肤剂量偏差较小，均匀性明显提高。TPS的计算值与TLD的测量值吻合良好，最大偏差在5%以内。皮肤和ROI2-3剂量随着推注应用频率的增加而显著增加。15和23次推注应用的乳房皮肤和ROI2-3的平均剂量为45.33Gy，50.88Gy和50.36Gy，52.39Gy,分别。
结论：3D打印推注可以提高辐射剂量和计划剂量的准确性。T1-3N+乳腺癌患者设定Plan_wb为15次,T4N+乳腺癌患者设定23次,可以满足临床需要。定量分析不同肿瘤分期的推注应用频率可为临床实践提供参考。
