Patient skin dose assessment during CT-guided interventional procedures

Area of Science:

• Radiology
• Medical Physics
• Interventional Radiology

Background:

• Patient skin dose is a critical consideration in interventional radiology procedures.
• Computed tomography (CT) guided interventions are increasingly common.
• Accurate dosimetry is essential for patient safety during these procedures.

Purpose of the Study:

• To investigate patient skin doses during common CT-guided interventional radiology procedures.
• To compare doses between abdominal biopsies and radiofrequency (RF) ablations.
• To identify factors influencing patient skin dose in these procedures.

Main Methods:

• Assessed patient skin dose using slow verification films.
• Recorded technical factors: kilovoltage (kVp), tube load (mAs), slice thickness, and total number of slices (S).
• Analyzed data from 14 abdominal biopsies and 15 RF ablations.

Main Results:

• Median maximum entrance skin dose (ESD(M)) for biopsies was 108 mGy (range: 9.5-282 mGy) with a significant correlation between slice count and dose (r=0.80).
• Median ESD(M) for RF ablations was 238 mGy (range: 104-500 mGy), with no significant correlation found between slice count and dose.
• RF ablation doses occasionally exceeded 1.2 Gy, the limit for slow verification films.

Conclusions:

• CT-guided biopsies involve relatively low patient skin doses.
• CT-guided RF ablations can deliver high patient skin doses, necessitating alternative dosimetry methods.
• Further research is warranted due to the wide range of observed doses.