Radiological imaging protection: a study on imaging dose used while planning computed tomography for external...

Area of Science:

• Medical Physics
• Radiotherapy
• Diagnostic Imaging

Background:

• Limited data exists on imaging doses in radiotherapy planning computed tomography (RTCT).
• Previous research focused on image quality, not radiation dose, in RTCT.
• Establishing national diagnostic reference levels (DRLs) requires baseline dose data.

Purpose of the Study:

• To investigate imaging doses in RTCT across various Japanese institutions.
• To collect baseline data for establishing national DRLs for RTCT.
• To identify factors influencing RTCT imaging doses.

Main Methods:

• A nationwide survey of Japanese radiotherapy institutions was conducted.
• Questionnaires collected data on CTDIvol, DLP, and acquisition parameters for specific RTCT protocols.
• Data was analyzed for brain stereotactic irradiation, head and neck IMRT, lung SBRT, breast RT, and prostate IMRT.

Main Results:

• The 75th percentiles of CTDIvol and DLP were determined for five RTCT protocols.
• Institutions using auto exposure control (AEC) or image-improving reconstruction options (IIRO) showed lower doses.
• Dose-length product (DLP) varied based on motion management techniques in lung SBRT.

Conclusions:

• The collected data provides essential baseline information for establishing DRLs in Japan.
• Implementing AEC and IIRO may help reduce RTCT imaging doses.
• Establishing DRLs can guide efforts to optimize and reduce radiation exposure in RTCT.