Spot-Scanning Confocal Photon Beams for Hypofractionated Brain Radiosurgery.

Area of Science:

• Medical Physics
• Radiation Oncology
• Neurosurgery

Background:

• Stereotactic radiosurgery (SRS) is a standard treatment for brain tumors.
• Hypofractionated SRS aims to deliver higher doses in fewer fractions.
• Existing SRS delivery methods may have limitations in achieving optimal dose conformity.

Purpose of the Study:

• To develop and implement a novel dose kernel-based spot scanning (DKSC) treatment delivery technique for hypofractionated brain SRS.
• To evaluate the feasibility and advantages of DKSC compared to conventional SRS methods.
• To report on the clinical implementation workflow and planning considerations for DKSC on the Leksell Gamma Knife (LGK) system.

Main Methods:

• DKSC employs hundreds of confocal photon dose kernels placed along a continuous scanning path within the 3D target volume.
• Dose kernels of variable sizes, shapes, and beam weights were optimized to achieve conformal dose distributions.
• The DKSC technique was implemented and tested using the Leksell Gamma Knife (LGK) system.

Main Results:

• DKSC was successfully implemented for the first clinical patient treatment.
• The study reports the general methodology, specific workflow, and treatment planning considerations for DKSC on the LGK.
• A comparison highlighted the novelty and potential advantages of DKSC over conventional LGK-SRS treatments.

Conclusions:

• DKSC is technically feasible and clinically implementable for hypofractionated brain SRS.
• DKSC offers unique advantages for achieving conformal dose distributions in brain SRS.
• Further research is needed to explore DKSC for various SRS modalities and disease sites, including extra-cranial lesions.