In brachytherapy treatment for skin cancer, how far are the sources typically kept from the skin?

In brachytherapy for skin cancer, the sources—often radioactive seeds or wires—are typically positioned 5 mm to 1 cm away from the skin surface. This distance is crucial for several reasons.

First, maintaining an appropriate distance helps to minimize skin toxicity. Brachytherapy involves placing radioactive sources close to the tumor site, allowing for a high dose of radiation to the tumor while sparing surrounding healthy tissue. If the sources are placed too close to the skin, it could result in excessive radiation exposure to the epidermis and dermis, leading to potential radiation burns or ulcers.

Second, a 5 mm to 1 cm distance allows for adequate dose distribution while ensuring that the treatment is effective in targeting the tumor. The positioning is often a balance between delivering a sufficient dose to the cancerous tissue and protecting the normal tissue from unwanted radiation exposure.

Finally, this range aligns with clinical practice guidelines that have been established based on research and outcomes. These guidelines aim to optimize treatment efficacy and patient safety, making the distance from the skin a critical component in planning and executing brachytherapy for skin cancer.