Assessment of the tandem method using OSL dosimeters for ICRU 95 operational quantities

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Health Physics

Background:

• The International Commission on Radiation Units and Measurements (ICRU) introduced new operational quantities for radiation protection in Report 95, replacing those from Report 39/51.
• These new quantities, particularly Hp(10), have shown significant overestimation of photon doses, up to 5 times, for low-energy photons, impacting medical applications.
• Current dosimetry systems have not been proven capable of measuring these new ICRU 95 quantities.

Purpose of the Study:

• To investigate the feasibility of a novel all-optically stimulated luminescence (OSL) dosimetry system for measuring ICRU 95 operational quantities for photons.
• To evaluate a dosimetry system composed of magnesium tetraborate doped with cerium, lithium, and gadolinium (MgB4O7:Ce,Li,Gd) and beryllium oxide (BeO).

Main Methods:

• Development and testing of a tandem OSL dosimetry system using MgB4O7:Ce,Li,Gd and BeO.
• Analysis of tandem curves to assess energy discrimination capabilities.
• Evaluation of the system's ability to measure ICRU 95 operational quantities for photons across different energy ranges.

Main Results:

• The tandem OSL system demonstrated a useful range for energy discrimination starting at higher energies (83 keV).
• The applied tandem method using MgB4O7:Ce,Li,Gd and BeO is limited to distinguishing between low and high average photon energies.
• The system cannot correct for the observed low-energy dependence issues associated with the ICRU 95 operational quantities for photons.

Conclusions:

• The investigated tandem OSL dosimetry system is not suitable for accurately measuring ICRU 95 operational quantities for photons due to limitations in low-energy photon response.
• Further research is needed to develop dosimetry systems capable of accurately measuring the new ICRU 95 quantities and addressing the low-energy photon overestimation problem.