Correction for distortion in a beam outline transfer device in radiotherapy CT-based simulation

Area of Science:

• Medical Physics
• Radiation Oncology
• Medical Imaging

Background:

• Accurate simulation is crucial for effective radiation therapy planning.
• Transferring planned radiation beam geometry to patient skin ensures precise targeting.
• Existing methods may lack efficiency or accuracy in beam outline transfer.

Purpose of the Study:

• To develop and evaluate a device for accurate beam outline transfer from CT simulations to patient skin.
• To integrate this device into a CT scanner for improved workflow and cost-effectiveness.
• To achieve high positioning accuracy for radiation therapy planning.

Main Methods:

• Construction and integration of a beam outline transfer device onto a Siemens DRH CT scanner gantry.
• Utilizing 3-D computerized simulation and planning systems for treatment beam geometry.
• Development of an empirically derived calibration procedure for accurate projection.
• Evaluation of positioning accuracy over a defined field size.

Main Results:

• The device accurately and efficiently projects planned treatment beam geometry onto the patient's skin.
• Achieved positioning accuracy is within +/- 0.1 cm over a 20 cm x 20 cm field.
• Integration into the CT scanner simplifies the device and reduces costs compared to external mounts.

Conclusions:

• The integrated beam outline transfer device offers a precise and efficient solution for radiation therapy simulation.
• The empirically derived calibration procedure is key to achieving high accuracy.
• This technology enhances the accuracy and workflow of radiation therapy planning.