Evaluation of Dose Calculation Based on Cone-Beam CT Using Different Measuring Correction Methods for Head and Neck Cancer Patients

• Published in: Technology in cancer research & treatment 2023-01, Vol.22, p.15330338221148317-15330338221148317
• Main Authors: Gong, Hanshun, Liu, Bo, Zhang, Gaolong, Dai, Xiangkun, Qu, Baolin, Cai, Boning, Xie, Chuanbin, Xu, Shouping
• Format: Article
• Language: English
• Subjects: Computed tomography; Cone-Beam Computed Tomography - methods; Developments in the use of multiple imaging modalities for radiotherapy; Dosimetry; Head & neck cancer; Head and Neck Neoplasms - diagnostic imaging; Head and Neck Neoplasms - radiotherapy; Humans; Image Processing, Computer-Assisted - methods; Methods; Oral cavity; Phantoms, Imaging; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy, Intensity-Modulated - methods; Retrospective Studies; Statistical analysis
• ISSN: 1533-0346; 1533-0338
• DOI: 10.1177/15330338221148317

Purpose: To investigate and compare 2 cone-beam computed tomography (CBCT) correction methods for CBCT-based dose calculation. Materials and Methods: Routine CBCT image sets of 12 head and neck cancer patients who received volumetric modulated arc therapy (VMAT) treatment were retrospectively analyzed. The CBCT images obtained using an on-board imager (OBI) at the first treatment fraction were firstly deformable registered and padded with the kVCT images to provide enough anatomical information about the tissues for dose calculation. Then, 2 CBCT correction methods were developed and applied to correct CBCT Hounsfield unit (HU) values. One method (HD method) is based on protocol-specific CBCT HU to physical density (HD) curve, and the other method (HM method) is based on histogram matching (HM) of HU value. The corrected CBCT images (CBCTHD and CBCTHM for HD and HM methods) were imported into the original planning system for dose calculation based on the HD curve of kVCT (the planning CT). The dose computation result was analyzed and discussed to compare these 2 CBCT-correction methods. Results: Dosimetric parameters, such as the Dmean, Dmax and D5% of the target volume in CBCT plan doses, were higher than those in the kVCT plan doses; however, the deviations were less than 2%. The D2%, in parallel organs such as the parotid glands, the deviations from the CBCTHM plan dose were less than those of the CBCTHD plan dose. The differences were statistically significant (P