Author: Petr Bruza, Eric R. Fossum, Alexander Geiersbach, David J. Gladstone, Karthik Raj Venkatesan 👨🔬
Affiliation: Dartmouth College, Thayer School of Engineering, Dartmouth College 🌍
Purpose: Current Cherenkov imaging sensors rely on image intensifiers to generate sufficient signal for photon detection. While image intensifiers (IIs) exhibit good Cherenkov photon signal response, they lack scalability, are sensitive to background light, and are more susceptible to spectral variations which make dosimetry difficult. To overcome these hurdles, we propose construction of a custom CMOS sensor capable of Cherenkov photon detection without II use.
Methods: Cherenkov images were taken with standard external beam treatment conditions to determine the current spatial resolution and noise response of Cherenkov cameras with IIs. Complete characterization of Cherenkov camera response was performed at the bench with measurement of the modulation transfer function and the photon transfer curve using a Siemens star phantom and a CW LED light source respectively.
Results: Modulation transfer function (MTF) and photon transfer curves (PTC) were determined. MTF width at 50% was 0.76 cycles/mm and read noise of the iCMOS system was 0.49 electrons. These metrics informed CMOS sensor design goals for an II free Cherenkov imaging sensor.
Conclusion: Image Intensified Cherenkov cameras were characterized and converted to conventional CMOS sensor specifications, enabling development of a novel Cherenkov sensor without and II. This work lays the foundation for a scalable solution to enhanced Cherenkov signal detection.