Feasibility of CBCT-based proton dose calculation using a histogram-matching algorithm in proton beam therapy

Kazuhiro Arai; Noriyuki Kadoya; Takahiro Kato; Hiromitsu Endo; Shinya Komori; Yoshitomo Abe; Tatsuya Nakamura; Hitoshi Wada; Yasuhiro Kikuchi; Yoshihiro Takai; Keiichi Jingu

doi:10.1016/j.ejmp.2016.12.006

Feasibility of CBCT-based proton dose calculation using a histogram-matching algorithm in proton beam therapy

Phys Med. 2017 Jan:33:68-76. doi: 10.1016/j.ejmp.2016.12.006. Epub 2016 Dec 18.

Authors

Affiliations

¹ Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Koriyama, Japan.
² Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan. Electronic address: kadoya.n@rad.med.tohoku.ac.jp.
³ Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Koriyama, Japan.
⁴ Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, Koriyama, Japan.
⁵ Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan.

PMID: 27998666
DOI: 10.1016/j.ejmp.2016.12.006

Abstract

The aim of this study was to confirm On-Board Imager cone-beam computed tomography (CBCT) using the histogram-matching algorithm as a useful method for proton dose calculation. We studied one head and neck phantom, one pelvic phantom, and ten patients with head and neck cancer treated using intensity-modulated radiation therapy (IMRT) and proton beam therapy. We modified Hounsfield unit (HU) values of CBCT and generated two modified CBCTs (mCBCT-RR, mCBCT-DIR) using the histogram-matching algorithm: modified CBCT with rigid registration (mCBCT-RR) and that with deformable image registration (mCBCT-DIR). Rigid and deformable image registration were applied to match the CBCT to planning CT. To evaluate the accuracy of the proton dose calculation, we compared dose differences in the dosimetric parameters (D2% and D98%) for clinical target volume (CTV) and planning target volume (PTV). We also evaluated the accuracy of the dosimetric parameters (D_mean and D2%) for some organs at risk, and compared the proton ranges (PR) between planning CT (reference) and CBCT or mCBCTs, and the gamma passing rates of CBCT and mCBCTs. For patients, the average dose and PR differences of mCBCTs were smaller than those of CBCT. Additionally, the average gamma passing rates of mCBCTs were larger than those of CBCT (e.g., 94.1±3.5% in mCBCT-DIR vs. 87.8±7.4% in CBCT). We evaluated the accuracy of the proton dose calculation in CBCT and mCBCTs for two phantoms and ten patients. Our results showed that HU modification using the histogram-matching algorithm could improve the accuracy of the proton dose calculation.

Keywords: Adaptive radiotherapy; CBCT; Deformable image registration; Head and neck cancer; Proton therapy.

MeSH terms

Algorithms*
Cone-Beam Computed Tomography*
Feasibility Studies
Head and Neck Neoplasms / diagnostic imaging
Head and Neck Neoplasms / radiotherapy
Humans
Phantoms, Imaging
Proton Therapy / methods*
Radiation Dosage*
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted / methods*
Radiotherapy, Image-Guided*
Radiotherapy, Intensity-Modulated