FIRST CARDIAC COMPUTED TOMOGRAPHY TYPICAL RADIATION DOSE VALUES FROM A SINGLE CENTRE IN NIGERIA: A PILOT STUDY

Area of Science:

• Medical Imaging
• Radiology
• Radiation Dosimetry

Background:

• Radiation dose from cardiac computed tomography (CT) is a persistent concern.
• Diagnostic reference levels (DRLs) are essential for dose optimization in CT procedures.
• Variability in radiation doses necessitates establishing local or national DRLs.

Purpose of the Study:

• To establish typical median radiation doses for coronary artery calcium scoring (CACS) and cardiac CT angiography (CCTA).
• To assess the range and variability of radiation doses (CTDIvol and DLP) in cardiac CT examinations.
• To provide data for developing DRLs for CACS and CCTA procedures.

Main Methods:

• Retrospective analysis of radiation dose data from 58 adult patients undergoing cardiac CT.
• Dosimetry metrics collected included volume computed tomography dose index (CTDIvol) and dose length product (DLP).
• Statistical analysis to determine median doses and dose variability for CACS and CCTA.

Main Results:

• Typical median CACS doses: CTDIvol 5.9 mGy, DLP 86.6 mGy*cm.
• Typical median CCTA doses: CTDIvol 11.1 mGy, DLP 190.8 mGy*cm.
• Significant dose variability observed: CACS CTDIvol (2.7-15.9 mGy, 6-fold), CCTA CTDIvol (3.8-52.8 mGy, 14-fold), CACS DLP (33.2-344.2 mGy*cm, 10-fold), CCTA DLP (32.8-834.9 mGy*cm, 25-fold).

Conclusions:

• Established typical median doses for CACS and CCTA are lower than in some international comparisons.
• Wide intra-procedure radiation dose variability highlights the need for dose optimization strategies.
• The findings support the development and implementation of DRLs to reduce unnecessary radiation exposure in cardiac CT.