Enhanced Dosimetric Accuracy Using Quality Factor Compensation Method for In Vivo Electron Paramagnetic Resonance...

Area of Science:

• Medical Physics
• Dosimetry
• Biophysics

Background:

• In vivo EPR tooth dosimetry offers a method for assessing radiation doses.
• Quality factors (Q factors) can vary significantly, impacting dose assessment accuracy.
• A pseudo-in-vivo phantom was developed to simulate in vivo conditions for Q factor measurement.

Purpose of the Study:

• To develop and validate a dose assessment method for in vivo EPR tooth dosimetry that compensates for quality factors (Q factors).
• To improve the dosimetric accuracy by mitigating uncertainties arising from Q factor variations.
• To evaluate the performance of the Q factor compensation method using phantom and human data.

Main Methods:

• A pseudo-in-vivo phantom with human central incisors was used to measure Q factors at various tooth depths.
• In vivo Q factors were measured from human volunteers and post-radiotherapy patients.
• Teeth were irradiated at different doses (0-10 Gy) and signals measured using an in vivo EPR tooth dosimetry system.
• Dose-response data were analyzed with and without Q factor compensation to assess dosimetric accuracy.

Main Results:

• The pseudo-in-vivo phantom accurately represented in vivo Q factor distributions.
• Dosimetric sensitivity and background signals decreased with increasing tooth depth due to lower Q factors.
• Q factor compensation converged diverged dose-response data, significantly improving dosimetric accuracy (reduced SEIP).
• Assessed doses for patients and volunteers showed improved accuracy after Q factor compensation.

Conclusions:

• The developed Q factor compensation method effectively mitigates uncertainty in in vivo EPR tooth dosimetry.
• This approach enhances the reliability and accuracy of radiation dose assessment using teeth.
• The findings support the clinical application of EPR tooth dosimetry with improved precision.