en Radiation Biology Radiation Biology تحقيق بديع Original Research <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">Using cone-beam computed tomography (CBCT) in radiotherapy, the thorax or pelvis, which are both large areas, can be scanned by rotating the gantry 360&deg; using a half-fan (HF) bowtie filter (BF). The HF mode has a longer scan time than that of the full-fan (FF) mode, thus exposing the patient to an increased imaging dose. </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">To determine the applicability of FF to anatomically large areas, positioning error values and absorbed dose of organs at risk (OARs) were measured when HF and FF were employed in 22 patients who underwent pelvic intensity-modulated radiation therapy. </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">In a clinical experiment applying FFBF scan mode to anatomically large areas of a patient&rsquo;s body during CBCT, the positioning error values were measured for all target areas within the mean &plusmn; 3 mm in all three directions. The scanning time in the FF scan mode was reduced by 20 s, while the absorption dose was reduced by 7&ndash;52 times in the OARs. </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">The appropriate application of FF for treating large-size targets can reduce the CBCT scanning time, which, in turn, would markedly decrease the radiation exposure in patients by reducing random errors during procedures.</span></span></span></span></span></span></span></span></span></div> Bowtie filter, Full-fan, Half-fan, Positioning error values. 355 360 http://ijrr.com/browse.php?a_code=A-10-1-1182&slc_lang=en&sid=1 W.K. Choi 7900319475328460026964 7900319475328460026964 No Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea W. Park 7900319475328460026965 7900319475328460026965 No Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea S. Kim ksc@gachon.ac.kr 7900319475328460026966 7900319475328460026966 Yes