WE-G-BRA-06: Calibrating an Ionisation Chamber: Gaining Experience Using a Dosimetry 'flight Simulator'

Area of Science:

• Medical Physics
• Radiotherapy
• Radiation Dosimetry

Background:

• Enhancing safety in radiotherapy practice is a key focus.
• Simulation training offers a promising avenue for improving safety protocols.
• The Virtual Environment for Radiotherapy Training (VERT) has been developed to facilitate this training.

Purpose of the Study:

• To simulate the calibration of an ionisation chamber for use in Linac photon beams using the VERT system.
• To validate the simulation's ability to replicate real-world calibration procedures following the UK 1990 Code of Practice.
• To assess the feasibility of using virtual environments for radiotherapy physics training.

Main Methods:

• The VERT system created a 3D virtual environment for simulating ionisation chamber calibration.
• Simulations included 6MV and 15 MV Linac photon beams, with configurable chamber correction factors.
• Realistic environmental conditions (temperature, pressure) and measurement errors were incorporated.
• A virtual water phantom was used to obtain Quality Indices (QI) and inter-compare chambers for calibration factor calculation.

Main Results:

• Virtual 6/15 MV beams yielded QI values of 0.668/0.761 and inter-comparison ratios of 0.4408/0.4402.
• Departmental chamber calibration factors were calculated within the simulation.
• The simulation allowed for confirmation of Linac output by applying calculated factors and environmental corrections.

Conclusions:

• The VERT system effectively demonstrates practical radiotherapy physics processes, reinforcing learning.
• The simulation can be adapted to various protocols beyond the UK Code of Practice.
• This research highlights the potential of virtual training environments in radiotherapy education and safety.