Modern possibilities of cardiovascular imaging using gamma cameras with cadmium–zinc–telluride-detectors

<p>Myocardial perfusion imaging is considered one of the leading non-invasive diagnostic tools for the assessment of patients with known or suspected coronary artery disease and other cardiac pathologies. The technical improvement of the currently used gamma-tomographic devices has increased the diagnostic capability of this technique. In recent years, the use of dedicated cardiac SPECT cameras with solid-state cadmium–zinc–telluride (CZT) technology has increased in nuclear imaging. These new CZT technologies have several advantages over existing scanner models. The development of new CZT detectors and their collimator configuration has increased scanning sensitivity and spatial resolution values. Also, due to the significantly higher sensitivity of new CZT detectors and new methods of data processing, radiologists have already introduced new scanning protocols and methods for radionuclide assessment of myocardial blood flow, reserve and non-invasive visualisation of the functioning of the sympathetic nervous system into clinical practice. The purpose of this review is to provide data on the main technical characteristics of gamma cameras equipped CZT detectors as well as the current possibilities of using CZT cameras for examining patients with various cardiovascular diseases.</p><p>Received 1 April 2020. Revised 22 April 2020. Accepted 30 April 2019.</p><p><strong>Funding:</strong> The work is supported by a grant of the Russian Science Foundation No. 17-75-20118.</p><p><strong>Conflict of interest:</strong> Authors declare no conflict of interest.</p><p><strong>Author contributions</strong><br />Conception and study design: S.M. Minin, K.V. Zavadovky, A.B. Romanov<br />Drafting the article: S.M. Minin, K.V. Zavadovky, N.A. Nikitin, A.V. Mochula, A.B. Romanov<br />Critical revision of the article: S.M. Minin, K.V. Zavadovky<br />Final approval of the version to be published: S.M. Minin, K.V. Zavadovky, N.A. Nikitin, A.V. Mochula, A.B. Romanov</p>

Sensors for Positron Emission Tomography Applications

Positron emission tomography (PET) imaging is an essential tool in clinical applications for the diagnosis of diseases due to its ability to acquire functional images to help differentiate between metabolic and biological activities at the molecular level. One key limiting factor in the development of efficient and accurate PET systems is the sensor technology in the PET detector. There are generally four types of sensor technologies employed: photomultiplier tubes (PMTs), avalanche photodiodes (APDs), silicon photomultipliers (SiPMs), and cadmium zinc telluride (CZT) detectors. PMTs were widely used for PET applications in the early days due to their excellent performance metrics of high gain, low noise, and fast timing. However, the fragility and bulkiness of the PMT glass tubes, high operating voltage, and sensitivity to magnetic fields ultimately limit this technology for future cost-effective and multi-modal systems. As a result, solid-state photodetectors like the APD, SiPM, and CZT detectors, and their applications for PET systems, have attracted lots of research interest, especially owing to the continual advancements in the semiconductor fabrication process. In this review, we study and discuss the operating principles, key performance parameters, and PET applications for each type of sensor technology with an emphasis on SiPM and CZT detectors—the two most promising types of sensors for future PET systems. We also present the sensor technologies used in commercially available state-of-the-art PET systems. Finally, the strengths and weaknesses of these four types of sensors are compared and the research challenges of SiPM and CZT detectors are discussed and summarized.