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QA procedures for brachytherapy

Introduction

A treatment protocol has to be established for each individual tumour site to be treated by brachytherapy, which should include information on the applicators and specific equipment needed for the procedure. Before a brachytherapy treatment starts a number of checks have to be performed, which concern the treatment plan, the sources and the delivery equipment used for that particular patient treatment. The mechanical integrity of the system should also be checked regularly.

Important Principles

After creating the treatment plan the radiation oncologist has to check that the correct source-applicator combination has been chosen, and that the dose distribution is in accordance with the prescription. The total irradiation time should also be checked to ensure that it is reasonable for the proposed insertion. Subsequent to transfer of the planning data to the brachytherapy unit, they have to be checked for consistency and validity. Following the connection of the applicators to the afterloading unit, the correspondence of the applicators with the treatment plan has to be verified. It is especially important to ensure that the actual source to be loaded (type, strength) has the correct parameters in the treatment planning system. The dose per fraction and the step length have to be verified and the correct values of dwell locations and dwell times have to be checked for each channel.

Introduction to References

Many patient-related QA aspects of brachytherapy are described in reports of national and international organizations as reviewed in the ESTRO Booklet. More general information can be found in the IAEA Radiation Oncology Physics Handbook.