Assessing the delivery error detection sensitivity of a new 2D detector prototype for carbon ion PSQA measurements

Particle therapy requires stringent patient-specific quality assurance (PSQA) to validate dose distributions delivered by the system.

This study presents preliminary results on the performance evaluation of the MatriXX AiR 2D ionization-chamber array for patient-specific QA (PSQA) in carbon-ion therapy, comparing measured and planned dose distributions.

A series of 10 test cases, including a treatment plan for a box-shaped target (6-cm side length), uniformly covered by the dose and nine patient-specific treatment plans, were assessed. Measurements were conducted at two water equivalent depths using RW3 phantoms: beam entrance and within the Spread-Out Bragg Peak (SOBP). The study examined the detector's ability to detect deviations by systematically modifying treatment plans, comparing the measured and planned dose utilizing gamma index analysis.

Passing rate analysis revealed depth-dependent sensitivity to treatment plan delivery modifications. Measurements at the entrance depth showed better sensitivity to delivery changes than those taken within the SOBP CONCLUSIONS: The MatriXX AiR detector demonstrated strong potential for PSQA in carbon ion therapy. These findings support its application in clinical workflows to enhance treatment verification and accuracy.