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Assessment and Comparison of Homogeneity and Conformity Indexes in Step-And-Shoot and Compensator-Based Intensity Modulated Radiation Therapy (Imrt) and Three-Dimensional Conformal Radiation Therapy (3D Crt) in Prostate Cancer Publisher



Salimi M1 ; Abi KST2 ; Nedaie HA3 ; Hassani H2 ; Gharaati H3 ; Samei M4 ; Shahi R5 ; Zarei H6
Authors
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Authors Affiliations
  1. 1. Medical Physics and Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
  2. 2. Department of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
  3. 3. Radiotherapy Oncology Department, Tehran University of Medical Sciences, Tehran, Iran
  4. 4. Radiotherapy Oncology Center, Karaj, Iran
  5. 5. Department of Energy Engineering, Sharif University of Technology, Tehran, Iran
  6. 6. Department of Radiology, Allied Medical Faculty, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Source: Journal of Medical Signals and Sensors Published:2017


Abstract

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. © 2017 Journal of Medical Signals & Sensors.