Optimization of image quality and target position accuracy for four-dimensional cone-beam computed tomography

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K16459
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Radiation science
• Research Institution: Kumamoto University
• Principal Investigator: Shimohigashi Yoshinobu 熊本大学, 病院, 主任診療放射線技師 (60771110)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: ４次元コーンビームCT / 体幹部定位放射線治療 / 画質改善 / 位置照合精度 / 最適化

Outline of Final Research Achievements

In this study, the image qualities of 4D cone-beam CT (CBCT) images obtained using various gantry rotation speeds (GRSs) for stereotactic body radiation therapy (SBRT) were quantitatively evaluated. Our findings suggest that GRSs of 67 and 85°/min are optimal selections in terms of image quality, acquisition time, and positional errors for 4D-CBCT-based image guidance. Moreover, the image quality of in-treatment 4D-CBCT (In-4D-CBCT) obtained with various prescription doses were quantitatively evaluated in volumetric modulated arc therapy (VMAT) for SBRT of the lungs and liver. We concluded that the image quality of In-4D-CBCT degraded compared with the reference image; however, it was sufficiently accurate for assessing the tumor position in VMAT for SBRT of the lungs and liver both in terms of the target volume similarity and accuracy of the fiducial marker position.

Free Research Field

放射線治療

Academic Significance and Societal Importance of the Research Achievements

本研究による高精度な腫瘍位置照合の実現は、体幹部定位放射線治療の局所制御率の向上と有害事象の低減に繋がり、患者に安全な放射線治療を提供する可能性がある。また本研究成果は、４次元コーンビームCTの短時間撮像を可能とし、患者体動の誘発や腫瘍位置および動きの変化を最小限にし、結果として位置照合精度の向上に繋がる。