Establishing local diagnostic reference levels for computed tomography examinations using size-specific dose...

Area of Science:

• Radiology and Medical Imaging
• Radiation Protection
• Medical Physics

Background:

• Diagnostic reference levels (DRLs) are crucial for limiting patient radiation exposure during computed tomography (CT).
• Traditional DRLs do not account for variations in patient size, potentially leading to inaccurate dose assessments.
• Size-specific dose estimates (SSDEs) offer a more personalized approach to radiation dose evaluation.

Purpose of the Study:

• To establish local DRLs (LDRLs) for common CT examinations in Saudi Arabia.
• To evaluate the utility of SSDEs in determining more accurate and patient-size-specific radiation dose levels.
• To compare established LDRLs with international DRLs and assess the correlation between SSDEs and CTDIvol.

Main Methods:

• Data from adult CT examinations at Madinah General Hospital were collected between January and March 2023.
• Size-specific dose estimates (SSDEs) were calculated for each patient using the effective diameter (Deff).
• Local DRLs were determined for brain, cervical spine, chest, thoracic spine, and KUB examinations.

Main Results:

• Established LDRLs for brain, cervical spine, chest, thoracic spine, and KUB were 118 mGy, 12 mGy, 8 mGy, 17 mGy, and 7 mGy, respectively.
• A strong correlation was found between SSDEs and CTDIvol for most examinations (p<0.05).
• SSDEs were higher than CTDIvol, particularly for smaller patients, highlighting the importance of size-adjusted dosimetry.

Conclusions:

• The established LDRLs fall within international DRL ranges, validating the methodology.
• SSDEs provide more accurate and relevant data for radiation safety practices in CT.
• Widespread adoption of SSDEs in new CT scanners is recommended for consistency and standardization in radiation dose management.