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Title: Evaluation of On-Board kV Cone Beam Computed Tomography–Based Dose Calculation With Deformable Image Registration Using Hounsfield Unit Modifications

Purpose: The purpose of this study was to estimate the accuracy of the dose calculation of On-Board Imager (Varian, Palo Alto, CA) cone beam computed tomography (CBCT) with deformable image registration (DIR), using the multilevel-threshold (MLT) algorithm and histogram matching (HM) algorithm in pelvic radiation therapy. Methods and Materials: One pelvis phantom and 10 patients with prostate cancer treated with intensity modulated radiation therapy were studied. To minimize the effect of organ deformation and different Hounsfield unit values between planning CT (PCT) and CBCT, we modified CBCT (mCBCT) with DIR by using the MLT (mCBCT{sub MLT}) and HM (mCBCT{sub HM}) algorithms. To evaluate the accuracy of the dose calculation, we compared dose differences in dosimetric parameters (mean dose [D{sub mean}], minimum dose [D{sub min}], and maximum dose [D{sub max}]) for planning target volume, rectum, and bladder between PCT (reference) and CBCTs or mCBCTs. Furthermore, we investigated the effect of organ deformation compared with DIR and rigid registration (RR). We determined whether dose differences between PCT and mCBCTs were significantly lower than in CBCT by using Student t test. Results: For patients, the average dose differences in all dosimetric parameters of CBCT with DIR were smaller than those of CBCT withmore » RR (eg, rectum; 0.54% for DIR vs 1.24% for RR). For the mCBCTs with DIR, the average dose differences in all dosimetric parameters were less than 1.0%. Conclusions: We evaluated the accuracy of the dose calculation in CBCT, mCBCT{sub MLT}, and mCBCT{sub HM} with DIR for 10 patients. The results showed that dose differences in D{sub mean}, D{sub min}, and D{sub max} in mCBCTs were within 1%, which were significantly better than those in CBCT, especially for the rectum (P<.05). Our results indicate that the mCBCT{sub MLT} and mCBCT{sub HM} can be useful for improving the dose calculation for adaptive radiation therapy.« less
Authors:
 [1] ;  [1] ; ;  [1] ; ;  [2] ;  [3] ; ; ;  [1]
  1. Department of Radiation Oncology, Tohoku University School of Medicine, Sendai (Japan)
  2. Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Tohoku University, Sendai (Japan)
  3. Radiation Technology, Tohoku University Hospital, Sendai (Japan)
Publication Date:
OSTI Identifier:
22416590
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 89; Journal Issue: 2; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ACCURACY; ALGORITHMS; BLADDER; COMPARATIVE EVALUATIONS; COMPUTERIZED TOMOGRAPHY; DEFORMATION; IMAGE PROCESSING; NEOPLASMS; PATIENTS; PELVIS; PHANTOMS; PLANNING; PROSTATE; RADIATION DOSES; RADIOTHERAPY; RECTUM