Quantitative Assessment of Treatment Planning Dosimetric Parameters in 3D-Crt With the Mixed Photon-Electron Beams Versus Imrt for the Nasopharyngeal Carcinoma Publisher



Ahmadpour H ; Mohammadkarim A ; Kazemian A ; Geraily G ; Hejazi P ; Yadollahi M ; Najafi M ; Gorjizadeh N
Source: International Journal of Radiation Research Published:2025

Abstract

Background: External radiotherapy procedures as an important tool for curing nasopharyngeal carcinoma (NPC) are commonly performed with one of the wellknown techniques, three-dimensional conformal radiotherapy (3D-CRT) or intensitymodulated radiotherapy (IMRT). Materials and Methods: In this study, the therapeutically dosimetric parameters including conformity index (CI), homogeneity index (HI), and tumor control probability (TCP) were extracted from the dose volume histogram (DVH) curves of fifteen patients in two designed treatment plans including, 3D-CRT and IMRT. 3D-CRT plans were performed in three phases by considering the mixed photon-electron beams in the second phase with a total dose of 70 Gy in 35 fractions. The prescribed dose of IMRT plans was 70 Gy in 33 fractions by employing 9 fields of photon beams. Results: A significant statistical difference was observed in TCP and CI between 3D-CRT and IMRT plans. The average value of TCP in IMRT is 5.65 times that of 3D-CRT. Also, IMRT showed a 123% increase in the average value of CI compared with 3D-CRT.There were no significant statistical changes in HI between the two treatments. Conclusion: Although the IMRT procedure is more effective than 3DCRT in the dose delivery process, 3D-CRT with mixed photon-electron beams can create dose homogeneity. © 2025, Novin Medical Radiation Institute. All rights reserved.