Boosting central target dose by optimizing embedded dose hot spots for gamma knife radiosurgery

Aims: To develop a boost technique for Gamma Knife radiosurgery by embedding and optimizing dose hot spots inside a conventional Gamma Knife plan.

Methods: An optimization algorithm was developed to automatically arrange the pattern and adjust the intensities of the embedded dose hot spots. We compared the treatment plans of the optimized boost technique with the conventional Gamma Knife treatment plans, where dose hot spots were scattered randomly within the target volume.

Results: We found the embedded boost plans significantly increased the maximum dose of the target (on average 31% or 5-6 Gy). The mean dose to the target was increased by an averaged 7.1% (1.5-2 Gy). In contrast, the dose to the adjacent normal brain was strictly maintained with the dose volume histograms differing less than 0.5% between the boost treatment plans and the conventional treatment plans. The planning effort and treatment time was comparable between the two techniques.

Conclusion: We have demonstrated a simple and an effective technique for increasing the central target dose without affecting the normal brain sparing for Gamma Knife radiosurgery.