Physicians utilize nuclear medicine scans, such as Single Photon Emission Computed Tomography (SPECT) scans, to monitor cardiac activity, trace blood flow, and identify diseases concealed within the body. Currently, these scanners require costly detectors that are challenging to manufacture.
Advancements in Detector Technology
Recent research led by scientists from Northwestern University and Soochow University in China has resulted in the development of the first perovskite-based detector capable of capturing individual gamma rays for SPECT imaging with unprecedented precision. This innovative tool promises to enhance the quality, speed, affordability, and safety of commonly used nuclear medicine imaging techniques.
Benefits for Patients
For patients, this advancement could lead to shorter scan durations, improved image clarity, and reduced radiation exposure. The findings of this study were published on August 30 in the journal Nature Communications.
Perovskite Materials in Nuclear Medicine
“Perovskites are a class of crystals primarily recognized for their contributions to solar energy technology,” stated Mercouri Kanatzidis, the senior author of the study from Northwestern University. “Now, they are positioned to revolutionize nuclear medicine. This is the first definitive proof that perovskite detectors can produce the sharp, reliable images essential for optimal patient care.”
Co-corresponding author Yihui He, a professor at Soochow University, added, “Our approach not only enhances the performance of detectors but also has the potential to reduce costs, making advanced imaging technologies accessible to more hospitals and clinics.”
Current Limitations of Traditional Detectors
Nuclear medicine, including SPECT imaging, functions similarly to an invisible camera. A small, safe, short-lived radiotracer is introduced into a patient’s body, emitting gamma rays that traverse tissues and strike a detector positioned externally. Each gamma ray acts as a pixel of light. By aggregating millions of these pixels, computers can construct three-dimensional images of active organs.
Presently, detectors utilizing cadmium zinc telluride (CZT) or sodium iodide (NaI) present multiple drawbacks. CZT detectors are prohibitively expensive, often costing between hundreds of thousands to millions of dollars for a complete system, and are prone to brittleness and cracking during manufacturing. Although NaI detectors are less costly, they are unwieldy and yield less clear images, akin to photographs taken through a foggy lens.
Innovative Use of Perovskite Crystals
To address these challenges, the research team explored perovskite crystals, a material that Kanatzidis has investigated for over a decade. His group first developed solid-film solar cells using perovskites in 2012 and discovered their potential for detecting X-rays and gamma rays shortly thereafter. This discovery catalyzed a global surge in research focused on hard radiation detection materials.
“This work demonstrates the vast capabilities of perovskite detectors beyond laboratory settings,” Kanatzidis remarked. “Upon discovering their efficacy in detecting X-rays and gamma rays in 2013, we envisioned their potential. Now, we have demonstrated that perovskite-based detectors can achieve the resolution and sensitivity required for demanding applications such as nuclear medicine imaging, marking a significant stride towards real-world applications.”
Details of the New Detector
Kanatzidis and He spearheaded the crystal growth, surface engineering, and device design for this latest study. By meticulously growing and shaping these crystals, the researchers created a pixelated sensor akin to smartphone camera pixels, which delivers exceptional clarity and stability.
He, responsible for the design and development of the prototype gamma-ray detector, optimized the camera’s pixelated architecture and advanced multi-channel readout electronics. The team demonstrated that perovskite-based detectors achieve record energy resolutions and exceptional single-photon imaging performance, setting the stage for practical integration into next-generation nuclear medicine imaging systems.
Future Directions and Commercialization
In experimental setups, the detector was able to discern gamma rays of varying energies with the highest resolution recorded to date. It effectively detected extremely faint signals from the commonly used medical radiotracer technetium-99m, producing sharp images that could differentiate tiny radioactive sources spaced merely a few millimeters apart. The device exhibited remarkable stability, capturing nearly all of the tracer’s signal without distortion or loss. Consequently, patients might experience shorter scan durations or reduced radiation doses.
Northwestern’s spinout company, Actinia Inc., is working to commercialize this technology in collaboration with partners in the medical device sector to transition it from the laboratory to clinical environments. Due to their simplified growth process and reduced component complexity, perovskites present a more affordable alternative to both CZT and NaI detectors while maintaining high-quality imaging capabilities. This advancement also offers a feasible path to utilizing lower doses of radiotracers compared to those viable with NaI detectors, thereby ensuring broader patient access.
Conclusion
“The demonstration that perovskites can facilitate single-photon gamma-ray imaging is a vital milestone,” He noted. “It confirms these materials are prepared to transition from laboratory research to practical applications that directly enhance human health. Moving forward, we envision opportunities to refine these detectors further, increase production scalability, and explore entirely new avenues in medical imaging.”
Kanatzidis emphasized, “High-quality nuclear medicine should not be exclusive to hospitals with the most expensive equipment. Perovskites can help pave the way for clearer, quicker, and safer scans for a broader patient population. The ultimate objective is enhanced scans, improved diagnoses, and superior patient care.”
The study, titled “Single photon γ-ray imaging with high energy and spatial resolution perovskite semiconductor for nuclear medicine,” was supported by various agencies, including the Defense Threat Reduction Agency and the National Natural Science Foundation of China.
Key Health Takeaway
The advancement in perovskite-based detectors for nuclear medicine imaging may significantly enhance diagnostic capabilities and patient safety, allowing for clearer images, faster scan times, and reduced radiation exposure.
