Recent Advancements in CT Detectors: A Comprehensive Review

The Computed Tomography (CT) scanners are widely used in the diagnostic and therapeutic medical fields due to their quick scanning times, excellent spatial resolution and widespread availability. The X-ray detector is essential for creating images and has a significant impact on radiation dose and image quality. All current commercial scanners use solid-state detectors and are comparable to third-generation technology. Detector characteristics include efficiency, stability, response time and afterglow. CT scanners have been used since 1971, and in the intervening decades, the technology has advanced tremendously. Notable developments in detector technologies have improved image quality and decreased radiation doses. The EMI head scanner was first equipped with Sodium Iodide (NaI) detectors, which necessitated long scan periods and a water bath to control detector saturation. These designs were improved upon by later generations, which offered quicker scanning speeds and better image quality. While the fourth generation of scanners used a stationary ring of detectors to drastically reduce scan durations, the thirdgeneration scanners introduced fan beams and rotation-rotation action. The sixth generation, called dual-source CT, allowed for dual-energy imaging using two X-ray tubes. The fifth generation, called electron-beam CT, produced X-rays using an electron beam. The seventh generation replaced traditional X-ray film with Flat-panel Detectors (FPD), which improved imaging. CT detector advancements include gemstone, stellar, photon counting, and NanoPanel prism detectors. The gemstone scintillator material is produced by General Electric Healthcare (GEHC). The Photon-counting Detector (PCD) is a new CT detector technology that uses a direct conversion X-ray detector to record X-ray photon energies. The stellar detector is based on Siemens Healthineers, and the NanoPanel prism detector is based on Philips. The present article discusses the recent trends in CT detector technology.