CZT in Advanced Medical Imaging

Kromek’s CZT-based detectors are supplied to OEMs to incorporate into their advanced imaging technology, improving patient outcomes globally

What is Advanced Medical Imaging?  

Advanced medical imaging refers to the current technologies used in modern diagnostic procedures, such as MRI, SPECT, PET and CT scans. 

By constantly developing the standard of the diagnostic equipment used today, patient outcomes can be significantly improved, saving more lives. 

From Unsplash - A computer-assisted tomographic (CAT) scanner, with a Caucasian female technician working at a screen and behind a glass wall. A patient is on a table and being tested by the CAT scanner. The lighting is very subdued. This new technology revolutionized detection of brain tumors

Kromek’s role in Advanced Imaging 

Cadmium Zinc Telluride (CZT) crystals are at the heart of Kromek’s contributions to the field of Advanced Medical Imaging, which occur primarily at our facility in Pennsylvania in the U.S. Kromek manufactures and supplies CZT gamma detectors to global OEMs (Original Equipment Manufacturers) to incorporate into their medical imaging equipment.  

The CZT detectors supplied to OEMs come in the form of scalable modules, each made up of a 22mm x 22mm CZT crystal and supporting electronics, such as the Kromek-designed ASIC: the brain of the system.  

The signals are aggregated from the modules that make up the SPECT system’s gamma camera, and the data transferred via the ethernet for real-time image outputs. 

CZT gamma detector for medical imaging

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Why CZT?

Incorporating CZT detectors into advanced imaging technology comes with many benefits for OEMs

CZT vs Scintillators 

The resolution and more flexible engineering capabilities of CZT outperforms other commercially available scintillators such as NaI (Sodium Iodide). This is because CZT records signals directly from X-ray or gamma photons. Due to this, the position of the signal conversion can be recorded more accurately. NaI, on the other hand, converts this signal into light first, which then requires the use of photomultipliers or SiPMs to get a current pulse. Photomultipliers with their larger size reduce the inherent spatial resolution of the system. 

CZT-cadmium zinc telluride detectors

Anodes and Cathodes 

The anodes and cathodes built into the modules inform both the position and time of the signals. The signals from the anodes and cathodes are correlated, so it is possible to calculate where the gamma interaction occurred within the CZT crystal.  As a result, Depth of Interaction (DoI) corrections can be performed on an event-by-event basis.   

Other commercially available modules and scintillators only give data on position. This is because they rely on the readout from the anode only, which causes a loss of the depth of interaction data. 

Kromek modules also have a readout mode that gives the nearest neighbor signals and negative energies in addition to the primary anode (the anode that observed the biggest positive signal). This gives the users the ability to enable more complex charge sharing correction algorithms. 

CZT vs other semiconductors 

As well as a high resolution, CZT is also able to operate at room temperature without active cooling, and has a high efficiency for detecting gamma photons. This can ensure that the detection requirements are met while keeping the radiation dose to patients lower. 

As a result, CZT is a highly portable, efficient and cost-effective detector solution for OEMs in the field of advanced imaging. 


Kromek’s modules are optimised for use in SPECT (Single-Photon Emission Computerised Tomography) systems and applications, which involves taking scans of different organs, tissues and bones in the patient’s body. Different detector configurations allow for different organs to be imaged effectively. For example, Kromek’s Low Dose MBI project aims to use a 4 x 6 detector segment configuration to significantly improve early breast cancer detection in women with dense breast tissue.  

Overall, these gamma detector modules can be configured to almost any size. Along with the universal software compatibility of the ASIC, this makes them adaptable for any OEM needs. For instance, the CZT modules can allow super resolution calculations to be made to inspect and identify very small tumours. Even as the size of the detector changes, the pixel pitch of 2mm is maintained across detector arrays, maintaining a high resolution. This flexibility allows the modules to be integrated into any existing OEM gantry.  

The small form factor of the modules allows the gamma camera to be positioned closer to the area of interest, important for the more in-depth examination of target tissues, organs or bones. For example, in breast imaging, a smaller form factor would make it easier to image tumours nearer to the chest wall. Having smaller gamma detectors would also allow OEMs to build smaller systems with smaller gantries, producing more cost-effective solutions. 

A doctor examines mammograms on a view box.

Find out more


The Product

Let us introduce you to the D-Matrix: a fully integrated, photon-counting, pixilated, 12-bit energy discriminating CZT detector/imager, ready to help you with your CZT research or detector development

CZT gamma detectors for medical OEMs

The World of SPECT

CZT brings many advantages to the development of medical imaging technologies for SPECT applications



Superpowers of CZT

Dive more into the depths of CZT physics, and find out what exactly makes it such a ‘cool’ piece of technology

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