en Radiation Biology Radiation Biology تحقيق بديع Original Research <p><strong>Background:</strong> In radiation therapy, peripheral dose or the dose outside the radiotherapy field, is important when anatomical structures with very low dose tolerances are involved. One of these critical organs in pelvic irradiation is testis. The amount of radiation delivered to the testes in radiotherapy must be kept as small as possible, consistent with the limit dose of this organ. The threshold doses for temporary and permanent sterility are 0.15 Gy and 6-8 Gy, respectively. Therefore, in pelvic irradiation, protecting testis from these doses and also scattered radiation which could escalate testis dose should be considered. <strong>Materials and Methods:</strong> In order to determine the possibility of using testicular shield for high and low energies, TLD dosimetry was done on phantom and 27 patients involved with bladder, rectum and prostate cancers. <strong>Results:</strong> Dosimetric results showed that the ability of testicular shield in reducing testes absorbed dose is approximately the same (about 7 cGy) for low and high energy photon beams. <strong>Conclusion:</strong> a testicular shield with a fixed thickness of 1.27cm can be used as testis protection for either high and low energies.</p> Testicular shield, pelvic irradiation, peripheral dose 355 359 http://ijrr.com/browse.php?a_code=A-10-1-528&slc_lang=en&sid=1 N. Banaee 790031947532846009443 790031947532846009443 No Department of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran H.A. Nedaie Nedaieha@sina.tums.ac.ir 790031947532846009444 790031947532846009444 Yes Radiotherapy Oncology Department, Cancer research Centre, Tehran University of Medical Sciences, Tehran, Iran E. Esmati 790031947532846009445 790031947532846009445 No Radiotherapy Oncology Department, Cancer research Centre, Tehran University of Medical Sciences, Tehran, Iran H. Nosrati 790031947532846009446 790031947532846009446 No Shahid Beheshti University of Medical Sciences, Tehran, Iran M. Jamali 790031947532846009447 790031947532846009447 No Radiotherapy Oncology Department, Cancer research Centre, Tehran University of Medical Sciences, Tehran, Iran