A calibration method for a wireless real-time CMOS pixel medical dosimeter

This study introduces and validates a novel calibration function for wireless wearable dosimeters, crucial for real-time dosimetry in interventional radiology. Focusing on enhancing accuracy and safety, it compares data from threshold-based wireless dosimeters with a full-data-read detector. The research involves a central detector and four lateral wireless dosimeters, each equipped with an identically-typed CMOS Image Sensor (CIS), subjected to various photon dose rates and doses from a certified beam. Two key calibration functions were developed: one that correlates the pixel count over a threshold with the dose rate, and the other that links the cumulative pixel value above the threshold to the total absorbed dose. These functions are essential in converting raw CIS data into precise dosimetric information. The study findings reveal that the single-pixel sensitivity of wireless prototypes is approximately 8.5 +/- 0.8 ADC/nGy. Following the application of calibration functions, the responses of these prototypes align consistently with the TLD dosimeter measurements. In particular, for three of the prototypes, this calibration ensures that the measurement uncertainty remains within 6% for the dose rate and within 8% for the dose. This research confirms the effectiveness and feasibility of pixel-based wireless dosimeters in interventional radiology, highlighting the importance of integrating offline data processing for enhanced measurement precision.