How is bone marrow dose measured?

Bone marrow dose is typically measured as an estimate from the entrance skin exposure (ESE) because the ESE provides a measure of the radiation dose that enters the body. While ESE does not directly measure the dose received by the bone marrow, it is a useful estimate because it reflects the radiation that reaches the tissues within the body, including the bone marrow.

The relationship between ESE and the dose received by various tissues, including bone marrow, can often be established through dosimetric calculations and models, allowing practitioners to estimate the deeper doses based on external measurements. This method combines practical considerations—such as the difficulty of measuring doses directly from bone marrow—with established radiation safety protocols that ensure patient safety and dose management.

In contrast, measuring directly from the bone marrow is not feasible due to the invasive nature of such an approach. Estimates based on gonadal doses and direct beam measurements do not accurately reflect the specific exposure to bone marrow, making the use of ESE the most appropriate method for estimating bone marrow dose in practice.