other Radiation Biology Radiation Biology گزارش کوتاه Short Report <div style="text-align: justify;"><span style="font-size:10pt"><span style="text-justify:newspaper"><span style="text-kashida-space:50%"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:black"><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Background</span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-weight:bold"><span style="language:en-US">:</span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">External radiotherapy procedures as an important tool for curing nasopharyngeal carcinoma (NPC) are commonly performed with one of the well-known techniques, three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT). </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Materials and Methods: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">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. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Results: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">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. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Conclusion: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">Although the IMRT procedure is more effective than 3D-CRT in the dose delivery process, 3D-CRT with mixed photon-electron beams can create dose homogeneity.</span></span></span></span></span></span></span></span></span></div> Nasopharyngeal carcinoma, conformal radiotherapy, intensity-modulated radiotherapy, tumor control probability. 809 812 http://ijrr.com/browse.php?a_code=A-10-1-1399&slc_lang=other&sid=1 H. Ahmadpour 7900319475328460031973 7900319475328460031973 No Department of Medical Physics, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran A. Mohammadkarim mohammadkarim.medphys@gmail.com 7900319475328460031974 7900319475328460031974 Yes Radiation Sciences Research Center (RSRC), Aja University of Medical Sciences, Tehran, Iran A. Kazemian 7900319475328460031975 7900319475328460031975 No Radiation Oncology Research Center (RORC), Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran G. Geraily 7900319475328460031976 7900319475328460031976 No Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran P. Hejazi 7900319475328460031977 7900319475328460031977 No Department of Medical Physics, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran M. Yadollahi 7900319475328460031978 7900319475328460031978 No Department of Radiology Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran M. Najafi 7900319475328460031979 7900319475328460031979 No Department of Radiation Oncology, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran N. Gorjizadeh 7900319475328460031980 7900319475328460031980 No Department of Radiation Oncology, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran