Improved estimates of effective dose equivalent using two optimal anisotropic responding dosimeters.

Area of Science:

• Medical Physics
• Radiation Detection and Measurement
• Dosimetry

Background:

• Traditional two-dosimeter approaches for photon beam measurements face significant overestimation issues for lateral, overhead, and underfoot incidence.
• Isotropic-responding dosimeters exhibit substantial errors when radiation beams deviate from normal incidence.
• A need exists for dosimeters that accurately measure effective dose equivalent (H(E)) across all beam directions.

Purpose of the Study:

• To develop a novel dosimeter that minimizes overestimation of effective dose equivalent (H(E)) for non-anterior-posterior beam directions.
• To maintain accurate performance for anterior and posterior beam directions.
• To investigate dosimeter geometries using aluminum oxide (Al2O3) for optimal anisotropic response.

Main Methods:

• Monte Carlo simulations were employed to investigate various dosimeter geometries.
• Aluminum oxide (Al2O3) was used as the attenuator material.
• The developed Optimal Anisotropic Responding dosimeters were tested with 0.08, 0.30, and 1.00 MeV photon beams at multiple angles.

Main Results:

• The developed dosimeters showed a maximum overestimation of 80% for effective dose equivalent (H(E)) across all energies and directions.
• This is a significant improvement compared to the 202% overestimation seen with isotropic-responding dosimeters.
• Performance for anterior and posterior beam directions remained comparable to isotropic dosimeters.

Conclusions:

• The developed Optimal Anisotropic Responding dosimeters effectively mitigate overestimation issues for non-anterior-posterior radiation beams.
• These dosimeters offer improved accuracy in radiation protection assessments across diverse beam geometries.
• Further application to effective dose (E) measurements confirmed the dosimeter's utility and provided comparative data with H(E).