Method to plan, administer, and verify supine craniospinal irradiation.

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment

Background:

• Craniospinal irradiation is crucial for central nervous system malignancies but technically challenging.
• Inaccurate field matching can lead to dosimetric heterogeneity, impacting treatment efficacy.
• A reliable method for simulating and verifying the three-field junction is needed.

Purpose of the Study:

• To describe and validate a method for accurate simulation and verification of the three-field junction in craniospinal irradiation.
• To assess the feasibility and accuracy of using a supine position and mini-verification films for this technique.

Main Methods:

• Utilized virtual simulation with computed tomography (CT) for multiplanar reconstructions to confirm three-field matching.
• Determined isocenter placement, table position, and collimator angles, accounting for beam divergence.
• Employed mini-verification films and radio-opaque markers for direct junction verification during treatment.

Main Results:

• The supine position facilitated patient comfort and airway access.
• Virtual simulation and digital couch settings ensured efficient and accurate field placement.
• Mini-verification films effectively identified field placement errors exceeding 1 mm, allowing for correction.

Conclusions:

• The described method provides simple, quantitative evaluation of the three-field junction in craniospinal irradiation.
• Virtual simulation combined with mini-verification films enhances accuracy and reduces dosimetric heterogeneity.
• The supine position is a viable and effective setup for craniospinal irradiation field matching and verification.