Dose verification of eye plaque brachytherapy using spectroscopic dosimetry

Area of Science:

• Medical Physics
• Radiation Oncology
• Ophthalmology

Background:

• Eye plaque brachytherapy is an established treatment for ocular malignancies.
• Current dosimetry methods (TLD, film) are time-consuming and not suitable for pre-treatment sterile environments.
• Accurate pre-treatment dose verification is crucial to prevent treatment errors and improve outcomes.

Purpose of the Study:

• To investigate spectroscopic dosimetry for real-time quality assurance of iodine-125 (I-125) eye plaques.
• To assess the feasibility of determining dose distribution prior to plaque insertion.
• To evaluate a novel silicon detector-based probe for this application.

Main Methods:

• Developed a silicon detector-based probe operating in spectroscopy mode.
• Encapsulated the probe in a ceramic holder and rubber sheath for protection.
• Tested the probe to determine the depth dose distribution of an I-125 eye plaque.

Main Results:

• The prototype probe determined depth dose distribution with deviations from AAPM Task Group 43 recommendations (6% at 3mm, 7% at 5mm, 1% at 10mm, 13% at 20mm).
• Deviations were attributed to the probe's construction.
• The concept of spectroscopic dosimetry shows promise for clinical application.

Conclusions:

• Spectroscopic dosimetry is a promising technique for real-time quality assurance in eye plaque brachytherapy.
• Further refinement of probe design is needed to minimize discrepancies.
• This method could enhance treatment accuracy and patient outcomes in ocular oncology.