Medical Imaging

A Short Introduction

Medical imaging, being non-invasive, fast, and accurate, provides scientific and intuitive evidence for the diagnosis and treatment of various diseases. It plays an irreplaceable role in disease screening, diagnosis, treatment, and prognosis evaluation. It has become the "eyes" of clinical doctors in diagnosing and treating diseases.

Medical imaging involves a wide range of imaging equipment, each based on different technical principles. Among these, the X-ray Computed Tomography (CT) system plays a crucial role in routine imaging diagnostics, assisting doctors in diagnosing a variety of conditions, such as neurological disorders, cardiovascular diseases, pulmonary lesions, and more.

The evolution of CT technology has been slow since the first CT scanner was introduced in 1972. Despite numerous efforts to advance CT technology, such as changes in motion structures and an increase in the number of detector rows, which have improved CT performance to some extent, the core component—the detector, primarily based on scintillators, has been a limiting factor due to the material performance limitations. The introduction of the photon-counting imaging technology CT by Siemens in 2021 revolutionized the market landscape for advanced detectors, significantly enhancing CT performance. It is considered the most significant technological advancement in the CT field in decades. Photon-counting technology has become the core direction for the development of the next generation of CT, making photon-counting detectors the hottest topic in CT research.

CZT, as one of the best materials for preparing photon-counting detectors, has been widely recognized within the industry. Compared to scintillators, its superior spatial resolution, energy resolution, and high sensitivity characteristics make CT images clearer, enhance the ability to differentiate between materials, reduce imaging time, and decrease X-ray dose intake.


Single Photon Emission Computed Tomography (SPECT) is a medical imaging technique that images the radiation emitted from within a patient's body, used for diagnosing diseases with biological activities at the organ, cellular, and molecular levels. SPECT imaging requires the patient to ingest a radiopharmaceutical with an appropriate half-life. After the drug reaches the targeted imaging site, it emits photons due to radioactive decay. SPECT can be widely applied in various clinical fields such as bone imaging, myocardial perfusion imaging, thyroid imaging, and more.

The detector is the core component of SPECT, with typical SPECT equipment usually including two imaging detector panels. The performance of the detector directly determines the imaging resolution, sensitivity (which is related to dosage), and imaging time, among other parameters. The application of CZT detectors in SPECT can significantly reduce the amount of radiopharmaceuticals and test time, lower the dosage of medication for patients, increase detection efficiency, and enable dynamic imaging and multi-nuclide scanning.

Key Performance




Medication Dosage(99Tc)



A reduction in dosage by 1/5, enabling the D-SPECT system to handle 2-3 times the number of patients per day.

Imaging Time



A 10-fold reduction in imaging time, optimizing workflow and patient comfort

Dynamic Imaging



Coronary Flow Reserve (CFR) Measurement

Synchronized Multi-Nuclide Scanning



99Tc and 201TI Imaging

Dose Considerations



A significant reduction (75%) in radiation dose compared to conventional nuclear medicine dual-head SPECT.

Dose Measurement and Coronary Flow Reserve (CFR)

Cannot (PET was used as the gold standard in the past)


CFR (Coronary Flow Reserve) can integrate the hemodynamic effects of blood flow through the heart's three main arteries, providing a comprehensive assessment of the coronary arteries and myocardium. This capability is crucial for pre-operative clinical evaluations and post-operative monitoring. By measuring the difference in blood flow through the coronary arteries at rest and under stress, CFR offers valuable insights into the functional capacity of these arteries, helping to identify significant coronary artery disease.


A bone densitometer is a medical device used to measure the bone mineral density (BMD), commonly utilized to assess bone health issues such as osteoporosis. Within bone densitometers, cadmium zinc telluride (CZT) detectors can effectively detect changes in the X-ray energy spectrum, which can reflect the distribution and density of minerals in the bones. By analyzing the signals received by the detector, the bone densitometer can generate images of the bones and calculate the numerical value of bone density.

Due to the high sensitivity and high resolution characteristics of cadmium zinc telluride (CZT) detectors, they can rapidly and accurately capture changes in the X-ray energy spectrum. Therefore, they can provide more accurate bone density measurement results, helping doctors to assess the patient's bone health condition more accurately.


Due to its excellent energy resolution capabilities and the characteristic of operating at room temperature, CZT makes bone density measurement devices more convenient to operate, while also enhancing the accuracy of the measurement results. Furthermore, the application of CZT material in medical imaging technology, especially in the field of bone density measurement, contributes to improving diagnostic quality and patient safety.

The handheld medical gamma camera is a portable medical imaging device designed to detect and map the distribution of radioactive isotopes. These devices are commonly used in oncology and nuclear medicine, for example, in identifying the spread of cancer during sentinel lymph node biopsies (SLNB). The compact design of handheld gamma cameras allows for greater flexibility and efficiency during surgical and diagnostic procedures. They are already in use in Germany and are expected to expand into other applications in the future, such as Digital Radiography (DR), Mammography, C-arm X-ray machines, Digital Subtraction Angiography (DSA), Dental X-ray machines, Gamma Knife, PET scans (Positron Emission Tomography), and other gamma cameras.

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