Salimi Marzieh, Abi Kaveh Shirani Tak, Nedaie Hassan Ali, Hassani Hossein, Gharaati Hussain, Samei Mahmood, Shahi Rezgar, Zarei Hamed
PhD Candidate of Medical Physics, Medical Physics and Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.
MSc of Medical Radiation Engineering, Department of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
J Med Signals Sens. 2017 Apr-Jun;7(2):102-107.
Intensity modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D CRT) are two treatment modalities in prostate cancer, which provide acceptable dose distribution in tumor region with sparing the surrounding normal tissues. IMRT is based on inverse planning optimization; in which, intensity of beams is modified by using multileaf collimators and also compensators with optimum shapes in step and shoot (SAS) and compensator-based method, respectively. In the recent study, some important parameters were compared in two IMRT and 3D CRT methods. Prescribed dose was 80 Gy for both IMRT procedures and 70 Gy for 3D CRT. Treatment plans of 15 prostate cancer candidates were compared to target the minimum dose, maximum dose, V 76 Gy (for IMRT plans) V 66.5 Gy (for 3D CRT), mean dose, conformity index (CI), and homogeneity index (HI). Dose conformity in compensators-based IMRT was better than SAS and 3D CRT. The same outcome was also achieved for homogeneity index. The target coverage was achieved 95% of prescribed dose to 95% of planning target volume (PTV) in 3D CRT and 95% of prescribed dose to 98% of PTV in IMRT methods. IMRT increases maximum dose of tumor region, improves CI and HI of target volume, and also reduces dose of organs at risks.
调强放射治疗（IMRT）和三维适形放射治疗（3D CRT）是前列腺癌的两种治疗方式，它们在肿瘤区域能提供可接受的剂量分布，同时保护周围正常组织。IMRT基于逆向计划优化；在这种方法中，分别通过使用多叶准直器以及在步进和射击（SAS）方法和基于补偿器的方法中采用最佳形状的补偿器来调整射束强度。在最近的研究中，对两种IMRT和3D CRT方法中的一些重要参数进行了比较。两种IMRT程序的处方剂量均为80 Gy，3D CRT的处方剂量为70 Gy。比较了15例前列腺癌患者的治疗计划，以确定最小剂量、最大剂量、V76 Gy（针对IMRT计划）、V66.5 Gy（针对3D CRT）、平均剂量、适形指数（CI）和均匀性指数（HI）。基于补偿器的IMRT的剂量适形性优于SAS和3D CRT。均匀性指数也得到了相同的结果。在3D CRT中，95%的计划靶体积（PTV）达到了95%的处方剂量，在IMRT方法中，98%的PTV达到了95%的处方剂量。IMRT增加了肿瘤区域的最大剂量，改善了靶体积的CI和HI，同时也降低了危及器官的剂量。
