Research in Focus: Ensuring accurate reference doses in radiation therapy
Radiation therapy uses a controlled dose of radiation to kill cancer cells, or damage them so they cannot grow, multiply or spread. The therapy is targeted to ensure that the cancer cells receive the full dose of radiation, while as little radiation as possible reaches the normal body tissue near the cancer.
For specialists to know they are delivering the correct clinical dose of radiation to the correct site in the body, it is vital that they first calibrate the radiation against a standard reference dose. Calculation of a reference dose is performed under strict conditions set by international codes of practice, however there may be specific limitations in different reference systems that users must take into account when calibrating doses.
This research, conducted by Sadia Aftab of Barwon Health at Calvary Mater Hospital, set out to test the impact of a metal rail found in the SNC 3D scanner water tank reference system, on the delivery of a reference dose of radiation.
By setting up an experimental system and varying factors such as radiation type and the location of the metal rail, the researchers found that:
- For low energy radiation, which tends to be used to treat superficial cancers, the metal rail did obstruct the dose of radiation in some conditions.
- This effect was not observed when high energy radiation, which is used to treat cancers deeper within the body, was tested.
These results provide a warning that in some cases, adjustments need to be considered to the reference dose calculation to ensure that the correct clinical dose of low energy radiation is delivered to the patient. Findings such as these are vital contributors to the safe and effective delivery of radiation therapy.
Authors: Sadia Aftab, Michael P. Barnes, Marcus Doebrich & Joerg Lehmann
Citation: The Journal of Applied Clinical Medical Volume 21(4): 95-101, April 2020
Department: Radiation Oncology Research, Andrew Love Cancer Centre, Barwon Health