Linear accelerator calibration monitor with a memory

Area of Science:

• Medical Physics
• Radiation Oncology
• Instrumentation

Background:

• Maintaining consistent radiation output from linear accelerators and cobalt units is crucial for accurate patient dosimetry.
• Current calibration checks can be time-consuming and require complex procedures, especially for remote facilities.

Purpose of the Study:

• To design and evaluate a portable, battery-operated calibration monitor for assessing the constancy of radiation output from linear accelerators and cobalt units.
• To provide a simple, rapid, and precise method for quality assurance checks between full calibrations.

Main Methods:

• The calibration monitor was designed to be lightweight and easily attachable to standard radiation therapy equipment.
• It features a digital readout for immediate dose verification and a CMOS digital counter for data retention.
• Precision was assessed through cobalt-60 irradiations over a 2.5-year period.

Main Results:

• The monitor demonstrated high precision, with a standard deviation of +/- 0.6% in cobalt-60 irradiations.
• Consistency checks can be completed in under two minutes.
• The device allows for remote calibration checks, similar to mailed thermoluminescent dosimeters, but with simplified readout procedures.

Conclusions:

• The developed calibration monitor offers a reliable, efficient, and user-friendly solution for ensuring the constancy of radiation output in clinical settings.
• Its portability and ease of use facilitate routine quality assurance and can be employed for blind checks at remote facilities.