Compensation techniques in NIRS proton beam radiotherapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Biomedical Engineering

Background:

• Proton beam therapy offers superior dose distribution compared to conventional radiation.
• Its sharp dose fall-off allows for precise targeting of tumors.
• Optimizing dose delivery requires effective techniques to conform the dose to the target volume.

Purpose of the Study:

• To describe and evaluate bolus techniques used in NIRS (National Institute for Radiological Sciences) proton beam radiation therapy planning.
• To detail the process of patient-specific bolus construction for proton therapy.
• To explore the use of alginate as a bolus material in this context.

Main Methods:

• Initial CT scanning to delineate target volumes and plan radiation parameters.
• Custom bolus fabrication using dental paraffin and resin.
• Utilizing alginate as the primary bolus material due to its physical density and skin contact properties.
• Repeat CT scanning with the bolus and fixation device for verification before treatment.

Main Results:

• The described bolus technique allows for precise conformity of the radiation dose to the target volume.
• Alginate demonstrates favorable physical density and skin surface contact for bolus applications.
• The individualized construction and verification process ensures suitability of the bolus and fixation devices.

Conclusions:

• Current bolus techniques, including the use of alginate, are effective in leveraging the dose distribution advantages of proton beam therapy.
• Further research is needed to identify improved bolus materials and streamline construction methods for enhanced patient care.