Phantom-derived estimation of effective dose equivalent from X rays with and without a lead apron

Area of Science:

• Medical Physics
• Radiological Protection
• Diagnostic Imaging

Background:

• Accurate dosimetry is crucial for monitoring radiation exposure in healthcare professionals.
• Estimating effective dose (E) and effective dose equivalent (H(E)) during fluoroscopy presents challenges due to partial shielding.
• Lead aprons alter dose distribution, complicating accurate personal dosimetry.

Purpose of the Study:

• To measure organ dose equivalents in a humanoid phantom to estimate effective dose (E) and effective dose equivalent (H(E)) from low-energy X-rays.
• To evaluate the accuracy of personal monitors in estimating dose under the conditions of fluoroscopy, with and without lead apron shielding.
• To compare experimental dosimetry data with existing algorithms for effective dose estimation.

Main Methods:

• Organ dose equivalents were measured using a humanoid phantom exposed to 76 and 104 kVp X-ray beams.
• Dosimetry data were adjusted to simulate fluoroscopy settings under plane-parallel irradiation.
• Personal monitor readings (waist and neck) were compared to phantom-measured H(E) and E, and to established "two-monitor" algorithms.

Main Results:

• Dose estimates without a lead apron were within 0.2-20% of expected values.
• Monitors worn under a lead apron underestimated H(E) or E; monitors worn above the apron overestimated both.
• Experimentally determined H(E) and E were 1.4 to 3.3 times greater than estimates from "two-monitor" algorithms.

Conclusions:

• Accurate estimation of effective dose (E) and effective dose equivalent (H(E)) using single personal monitors under partial body exposure conditions is problematic.
• Current personal dosimetry methods may not adequately represent actual radiation doses received by healthcare professionals during fluoroscopy.
• The use of multiple personal monitors is likely necessary for reliable dose assessment in complex exposure scenarios.