%0 Journal Article %A Sharbo, Gh. %A Hashemi, B. %A Bakhshandeh, M. %A Rakhsha, A. %T Assessment of developed IMRT and 3D-CRT planning protocols for treating nasopharyngeal cancer patients based on the target and organs at risks common volumes %J International Journal of Radiation Research %V 20 %N 2 %U http://ijrr.com/article-1-4259-en.html %R 10.52547/ijrr.20.2.8 %D 2022 %K Nasopharyngeal carcinoma, intensity modulated radiation therapy, 3D radiation therapy, treatment planning, radiobiological models., %X Background: Various developed intensity modulated radiation therapy (IMRT) and a three dimensional conformal radiation therapy (3D-CRT) protocols were assessed for treating nasopharyngeal cancer (NPC) based on radiobiological parameters. Materials and Methods: Treatment plans were made for 30 NPC patients using 15 developed IMRT and 3D-CRT protocols. The IMRT protocols comprised of three 7-fields with various collimator (0°, 5°, and 10°) and couch (0°, 4°, 8°, 12°) angles. The 3D-CRT technique included two phases. In the 1st phase a dose of 60 Gy was prescribed to the total PTV, but in the 2nd phase a dose of 10 Gy was prescribed to the PTV-70. The tumour control probability (TCP), normal tissues complication probability (NTCP), and complication-free tumor control probability (P+) parameters were estimated for assessing the IMRT protocols. Then, the ideal protocol (s) were proposed through comparing the IMRT protocols with each other and 3D-CRT protocol based on TCP, NTCP, and P+ values. Results: The IMRT protocol with 10° collimator and 8° couch angles had the lowest NTCP mean values. Significant differences were observed among the mean NTCP values for the brainstem and parotid glands, and P+ of the developed IMRT and 3D-CRT protocols. However, no significant differences were observed among the mean NTCP values for the spinal cord, optic chiasm and optic nerves among the protocols. Conclusions: The 3D-CRT protocol had a good outcome for the NPC patients having a lower common volume between their total planning target volume and OARs, while the results of the IMRT showed the opposite. %> http://ijrr.com/article-1-4259-en.pdf %P 307-315 %& 307 %! IMRT & 3D-CRT in nasopharyngeal cancer %9 Original Research %L A-10-1-909 %+ Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran %G eng %@ 2322-3243 %[ 2022