Rechner Laura A, Eley John G, Howell Rebecca M, Zhang Rui, Mirkovic Dragan, Newhauser Wayne D
The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, TX 77030, USA. Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA. Department of Oncology, Section of Radiotherapy, Rigshospitalet, Blegdamsvej 9, 2100 København Ø, Denmark.
Phys Med Biol. 2015 May 21;60(10):3999-4013. doi: 10.1088/0031-9155/60/10/3999. Epub 2015 Apr 28.
Proton therapy confers substantially lower predicted risk of second cancer compared with photon therapy. However, no previous studies have used an algorithmic approach to optimize beam angle or fluence-modulation for proton therapy to minimize those risks. The objectives of this study were to demonstrate the feasibility of risk-optimized proton therapy and to determine the combination of beam angles and fluence weights that minimizes the risk of second cancer in the bladder and rectum for a prostate cancer patient. We used 6 risk models to predict excess relative risk of second cancer. Treatment planning utilized a combination of a commercial treatment planning system and an in-house risk-optimization algorithm. When normal-tissue dose constraints were incorporated in treatment planning, the risk model that incorporated the effects of fractionation, initiation, inactivation, repopulation and promotion selected a combination of anterior and lateral beams, which lowered the relative risk by 21% for the bladder and 30% for the rectum compared to the lateral-opposed beam arrangement. Other results were found for other risk models.
与光子治疗相比，质子治疗带来的二次癌症预测风险要低得多。然而，此前尚无研究采用算法方法来优化质子治疗的射束角度或通量调制，以将这些风险降至最低。本研究的目的是证明风险优化质子治疗的可行性，并确定能将前列腺癌患者膀胱和直肠的二次癌症风险降至最低的射束角度和通量权重组合。我们使用了6种风险模型来预测二次癌症的超额相对风险。治疗计划采用了商业治疗计划系统和内部风险优化算法相结合的方式。当在治疗计划中纳入正常组织剂量限制时，考虑了分次、起始、失活、再增殖和促进作用的风险模型选择了前后和侧向射束的组合，与对侧侧向射束排列相比，这使得膀胱的相对风险降低了21%，直肠的相对风险降低了30%。其他风险模型也得出了其他结果。
