Su M, Ayzenberg V, Li W
Mount Sinai School of Medicine, Elmhurst, NY.
Med Phys. 2012 Jun;39(6Part16):3806. doi: 10.1118/1.4735529.
To compare an advantage/disadvantage between Field-in-Field (FIF) technique and conventional physical wedge (PW) technique for a whole breast (WB) tangential field irradiation.
Total 86 patients were included in this study. 46 of them were left breast cancer cases. FIF/PW plans were created by Eclipse (V7.3, Varian) with 6MV or 6MV mixed with 18MV. Plans had a same ioscenter location, beam setup and normalized isodose line selection for each case. Varian 21EX Linac with 120 MLC was used for beam delivery. Two plans were compared by PTV encompassed by 95% isodose line (V95), dose inhomogeneity (DI), dose received by 10% volume of lung (D10), mean lung dose (MLD), dose received by 5% volume of heart (D5), Mean heart dose (MHD), total MU, maximum dose in the plan and the number of field needed for each fraction.
Comparing with PW plan, FIF plan showed an average percentage improvement of V95 was 0.1±1.6, DI was 0.6±5.0, MLD was 1.5±4.2, D5 was 2.0±8.8, MHD was 3.2±4.6. However, D10 increased by 1.4%±0.050. FIF lowered an average daily MU by 28.5%±0.080, maximum dose by 0.5%±0.018, and increased number of treatment field by 1.50±0.356. There were 12 cases treated with mixed beam in PW technique vs 10 in FIF technique.
The advantages of FIF technique included: (1) Reduce radiation contamination to contra lateral breast and Linac room induced activity by remove the PW, lower MU and diminish a higher energy. (2) Time saving was not only from less MU but also from not need go into the treatment room for a wedge adjustment. (3) Reduced the therapist work load. (4) Regular MU 2nd check was applied because there was not FIF merge involved in the treatment field. With a MLC to shape the field and treatment record/verification system to control the treatment, increasing number of treatment field didn't show as a problem.
比较全场中野（FIF）技术与传统物理楔形板（PW）技术在全乳切线野照射中的优缺点。
本研究共纳入86例患者。其中46例为左乳腺癌病例。FIF/PW计划由Eclipse（V7.3，Varian）使用6MV或6MV与18MV混合射线制定。每个病例的计划具有相同的等中心位置、射野设置和归一化等剂量线选择。使用配备120 MLC的Varian 21EX直线加速器进行射线输出。通过95%等剂量线所包含的计划靶体积（V95）、剂量不均匀性（DI）、10%肺体积所接受的剂量（D10）、平均肺剂量（MLD）、5%心脏体积所接受的剂量（D5）、平均心脏剂量（MHD）、总跳数（MU）、计划中的最大剂量以及每个分次所需的射野数来比较两种计划。
与PW计划相比，FIF计划显示V95平均改善百分比为0.1±1.6，DI为0.6±5.0，MLD为1.5±4.2，D5为2.0±8.8，MHD为3.2±4.6。然而，D10增加了1.4%±0.050。FIF使平均每日MU降低了28.5%±0.080，最大剂量降低了0.5%±0.018，治疗射野数增加了1.50±0.356。PW技术中有12例采用混合射线治疗，而FIF技术中有10例。
FIF技术的优点包括：（1）通过去除PW减少对侧乳腺的辐射污染和直线加速器机房的感生放射性，降低MU并减少高能射线。（2）节省时间不仅在于MU减少，还在于无需进入治疗室进行楔形板调整。（3）减轻了治疗师的工作量。（4）由于治疗野中不涉及FIF合并，因此应用常规的MU二次检查。通过使用MLC来塑形射野和治疗记录/验证系统来控制治疗，增加的治疗野数并未成为问题。
