PATIENT-SPECIFIC DOSIMETRY USING IN-HOUSE DEVELOPED OSL DISC DOSEMETERS

Area of Science:

• Medical Physics
• Radiotherapy Dosimetry
• Luminescent Materials

Background:

• Accurate dosimetry is crucial for effective radiotherapy and patient safety.
• Existing dosimetry methods have limitations in specific clinical applications.
• Development of novel dosimeters is essential for advancing radiotherapy techniques.

Purpose of the Study:

• To evaluate the dosimetric characteristics of indigenously developed optically stimulated luminescent (OSL) phosphors in disc form.
• To assess the suitability of these OSL discs for machine and patient-specific dosimetry in radiotherapy.
• To compare OSL disc measurements with established dosimetry methods and treatment planning system calculations.

Main Methods:

• Circular OSL phosphor discs (5 mm diameter) were fabricated from three indigenous materials.
• Dosimetric properties, including absorbed dose measurement and uncertainty, were characterized.
• Patient-specific dosimetry was performed for five radiotherapy cases, comparing OSL discs with ionization chambers and Gafchromic EBT3 film.

Main Results:

• The combined standard uncertainty in absorbed dose measurement using OSL discs was determined to be 3.34%.
• OSL discs demonstrated suitability for dosimetric applications in radiotherapy.
• Measurements from OSL discs were comparable to ionization chambers, Gafchromic EBT3 film, and radiotherapy treatment planning system (TPS) calculated doses across all evaluated cases.

Conclusions:

• Indigenously developed OSL discs are suitable for accurate dosimetry in radiotherapy.
• These OSL discs provide reliable patient-specific dose measurements comparable to conventional methods.
• The observed variations between TPS calculations and OSL disc measurements fall within acceptable uncertainty limits.