A method for describing the doses delivered by transmission x-ray computed tomography

Area of Science:

• Medical Physics
• Radiological Imaging
• Radiation Dosimetry

Background:

• Computed tomography (CT) procedures involve multiple adjacent scans, complicating accurate absorbed dose assessment.
• Existing methods for dose calculation in CT may not fully capture the complexities of multi-scan procedures.

Purpose of the Study:

• To propose and evaluate a novel method for describing the absorbed dose delivered by x-ray transmission CT procedures.
• To characterize the dose resulting from CT procedures consisting of a series of adjacent scans.

Main Methods:

• The proposed dose descriptor is the average dose at several locations within the central scan of a series.
• This average dose is derived from the integral of the dose profile perpendicular to the scan plane of a single scan.
• The method was evaluated using single scan dose profiles from five different CT systems across various scan numbers and phantom locations.

Main Results:

• The proposed method accurately estimates the average dose for multiple adjacent CT scans.
• For higher dose regions, the dose descriptor derived from single scan profiles overestimates the multiple scan average dose by no more than 10% for procedures with at least eight scans.

Conclusions:

• The developed method provides a reliable means to characterize absorbed dose from CT procedures involving multiple adjacent scans.
• This approach simplifies dose assessment for complex CT examinations, particularly in critical dose regions.