How should brachytherapy sources be measured?

Brachytherapy sources should be measured in terms of Air Kerma Strength (AKS), which quantifies the amount of energy that a radiation source delivers to air. AKS is important as it accounts for both the activity of the source and its geometry, providing a standardized way to express the strength of the radioactive material in a brachytherapy implant.

This measurement is crucial for accurate dose calculations and treatment planning, allowing medical professionals to ensure that the correct dose is delivered to the targeted tumor area while minimizing exposure to surrounding healthy tissues. AKS reflects how effectively the source will contribute to the prescribed dose rate for a patient, aiding in the assessment of the treatment's efficacy.

While dose rate is also a relevant factor in brachytherapy, it is not the primary method for measuring the radiation source itself. Visual inspection does not provide quantifiable data necessary for treatment and would not typically guide clinical decision-making. Measuring in relation to field size does not account for the specific characteristics of the radiation source, making it insufficient for determining dosimetry in brachytherapy.