en 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="language:en-US">The aim of this study was to determine the radiation dose to the thyroid and spinal cord using different gantry angles for the supraclavicular field in breast cancer patients. </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">Fifty patients treated with opposing tangential fields for chest wall and ipsilateral supraclavicular (SCV) field were enrolled. On the planning computed tomography (CT) scans of patients receiving 50 Gray (Gy) of radiation in daily fractions of 2 Gy, the volumes of the thyroid, spinal cord, and supraclavicular (SCV) nodes were contoured. A comparison of the dosimetric parameters between three different gantry angles (0&deg;, 5&deg;, and 10&deg;) of the SCV field was performed. Moreover, the percentage volumes of absorbed dose by the thyroid at low (V15) and high (V45) doses were compared. The maximum dose to the spinal cord was also compared between the angles. </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">Differences between mean dose (Dmean) of thyroid, spinal cord, V15, and V45 values using different gantry angles were statistically significant (p <0.05). When the gantry angle increased, the Dmean of the thyroid and spinal cord significantly decreased. </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">Conclusions: </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">Gantry angle adjustment can reduce the dose to the thyroid. Therefore, contouring the thyroid as an organ at risk and utilizing an appropriate gantry angle during radiation is beneficial in minimizing the dose received by the thyroid. Nevertheless, the dose distribution of SCV lymph nodes and SCV field should be considered.</span></span></span></span></span></span></span></span></span></div> Breast neoplasms, radiotherapy, thyroid gland. 819 822 http://ijrr.com/browse.php?a_code=A-10-1-1401&slc_lang=en&sid=1 M. Bahador 7900319475328460031992 7900319475328460031992 No Department of Radiation Oncology, Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran S. Soltani Nejad 7900319475328460031993 7900319475328460031993 No Department of Radiation Oncology, Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran S. Yazdani yazdani_ph70@yahoo.com 7900319475328460031994 7900319475328460031994 Yes Department of Medical Physics, Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran