A motorized solid-state phantom for patient-specific dose verification in ion beam radiotherapy

Area of Science:

• Medical Physics
• Radiotherapy Technology

Background:

• Ion beam radiotherapy requires precise dose verification, especially at non-horizontal gantry angles.
• Existing methods for quality assurance at oblique angles present challenges.

Purpose of the Study:

• To develop and validate a motorized solid-state phantom for 3D dosimetry at oblique gantry angles in ion beam radiotherapy.
• To ensure accurate quality assurance and patient-specific dose verification.

Main Methods:

• A motorized solid-state phantom with 24 ionization chambers was developed.
• Mechanical and dosimetric accuracy were assessed, and corrections for uncertainties were derived.
• Coordinate transformation from cylindrical to Cartesian systems was determined.

Main Results:

• The phantom allows for 3D dosimetry at oblique gantry angles.
• Dose deviations averaged within 1.5% when compared to water phantom and horizontal beam measurements.
• The phantom integrates with existing treatment plan verification workflows.

Conclusions:

• The developed phantom is suitable for quality assurance and 3D dose verification in proton and carbon ion therapy at oblique gantry angles.
• This technology enhances patient safety for treatments delivered at gantry beam lines.