MI-3 Plus

Lead Research Organisation: University of Sheffield
Department Name: Electronic and Electrical Engineering

Abstract

CMOS Active Pixel Sensors (APS) are revolutionising many aspects of imaging with their superior performance, flexibility and close integration with the acquisition and processing requirements. Their progress is, in no small part, due to advances in mainstream CMOS technology. Industry is focussed on developing CMOS imagers for the mass markets such as digital cameras and mobile phones. Within MI-3, we brought together sufficient technology expertise and users to exploit APS technology for a broad range of science. This project, MI-3 Plus, will take forward one aspect of this technology - namely, the realisation of radiation-hard, wafer-scale imagers, approximately 12 cm square, specially designed for scientific and clinical use. In doing so, we directly address one of the challenges set out in the EPSRC Grand Challenges in Silicon Technology (2008) - Large imaging arrays for use in medical applications and imaging of explosives and weapons. Such large imagers will be able to cope with an accumulated radiation dose in excess of 10 MRad, be approximately 12 cm x 12 cm and incorporate programmable intra-frame resets and binning to cope with the wide dynamics of image intensity found in many medical/scientific applications. It would be possible to tile these imagers, with a minimum bonding gap, to produce torso-wide lensless systems for radiography, etc. The imagers, and the supporting acquisition systems, will be trialled in number of key application areas, namely:* Bone/breast radiography using laboratory and synchrotron sources * Structural crystallography on laboratory and synchrotron sources* High resolution and discriminatory baggage screening * Digital mammography, in particular tomosynthesis (3D imaging) * Radiation-hard very large area sensors for radiotherapy (x-ray and proton) The more general capabilities of CMOS technology can be exploited in miniature analytical instruments for medicine, life sciences, etc - the so-called Lab-on-a-chip concept. This is another topic that forms one of the EPSRC Grand Challenges. Through selective etching of our APS devices we will demonstrate the advantages of very efficient imaging - at high sensitivity and resolution - using this new approach.Overall, comparisons with existing methods will be rigorously undertaken; and the resulting systems will be widely demonstrated to their respective user communities and associated commercial system providers.

Publications

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Esposito M (2011) DynAMITe: a wafer scale sensor for biomedical applications in Journal of Instrumentation

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Esposito M (2013) 14 C autoradiography with a novel wafer scale CMOS Active Pixel Sensor in Journal of Instrumentation

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Konstantinidis A (2010) Optical characterisation of a CMOS active pixel sensor using periodic noise reduction techniques in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

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Konstantinidis A (2012) The Dexela 2923 CMOS X-ray detector: A flat panel detector based on CMOS active pixel sensors for medical imaging applications in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Related Projects

Project Reference Relationship Related To Start End Award Value
EP/G037671/1 01/08/2009 01/01/2011 £1,195,473
EP/G037671/2 Transfer EP/G037671/1 01/01/2011 31/01/2013 £989,110
 
Description MI-3 Plus, building upon previous work on CMOS Active Pixel Sensors, designed and realised a single imager on an industry standard 8" (200 mm) wafer. The imager, called Dynamite, is not only one of the largest imagers made but is the World's first radiation-hard wafer-scale imager. It is intended to meet demanding applications in x-ray medical imaging and other branches of biological/medical science. In producing this unique device, MI-3 Plus fully met one of EPSRC's Grand Challenges in Silicon Technology (2008).



Dynamite is not only one of the largest CMOS imagers built that can withstand the harsh environment of imaging high energy x-rays, but is also one of the most complex. It is four independent cameras in one array, with differing spatial resolutions. This means that it meets the needs not only of x-ray computer tomography (CT) but also the higher resolutions needed for mammography. It possesses less noise and faster readout than conventional silicon flat-panel detectors, so exposing the patient to less radiation and also due to its fast readout can operate unaffected by movements of the patient.



The active imaging part of the array is very close to two sides of the device, so mosaics of devices can be butted together to produce "body-sized" imagers.



Dynamite has been demonstrated by members of the MI-3 Plus consortium for direction-enhanced mammography (which will allow elemental analysis of mammograms to indicate which tissue is cancerous and which is benign), replacement of photographic emulsions in contact imaging for a variety of biological analysis techniques including auto-radiography and Western Blotting (its sensitivity means that images can be captured up to 30 times faster), and for initial imaging of protons in proton therapy facilities (it can provide accurate imaging and dose information for this rapidly expanding treatment in radiotherapy)
Exploitation Route The most significant market for very large area CMOS imagers will be in medical diagnosis (and to a lesser extent in therapy). The current technology for "digital" radiography is flat-panels using amorphous silicon thin film transistors (as in LCD televisions) - they suffer from high noise, slow readout and high cost. Now that we have shown the ability to make, with high yield, very large area CMOS imagers that can tolerant the high radiation exposure to x-rays, CMOS will almost certainly become the dominant technology of the future.



It is not only medical uses that would benefit from very large area CMOS imagers but many procedures in biochemistry where either film is still used or cameras that use conventional lenses (which are always inefficient) and defence/monitoring systems for measuring radioactivity. The technology underlying the development of Dynamite has, in part, been protected by patents and has directly led to the formation of a new company, ISDI Ltd, dedicated to the provision of large scale CMOS imagers to healthcare and other sectors: several wafer-scale designs have been fabricated by ISDI Ltd for an international healthcare company and will appear in products in 2013. Two patents have been secured which offer protection to critical IP used in the design of Dynamite.
Sectors Electronics,Healthcare

 
Description PRaVDA (Proton Radiotherapy Verification and Dosimetry Applications)
Amount £1,850,000 (GBP)
Funding ID 098285 
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 01/2011 
End 07/2017
 
Title Dynamite - World's First Radiation-hard Wafer-scale CMOS Imager 
Description A monolithic silicon CMOS Active Pixel Sensor, designed in 0.18 um process, which measures approx. 13 cm square and is fully radiation-hard. It consisting of 4 independent cameras in one array with two different spatial resolutions (50 um and 100 um). It is also, for the first time, possible to undertake true binning in CMOS imagers (common in CCD images) which permits much lower noise floors. Very flexible readout - multiple regions of interest and non-destructive readout. It is two sides buttable allowing the construction of arrays up to 26 cm square. Fully characterised with visible light, soft and hard x-rays, high-energy electrons and protons (up to 190 MeV). Awarded IET Innovation Prize for Electronics (2012) It fully meets one of the grand challenges set out by EPSRC in its Grand Challenges in Silicon Technology (2008). The device has been exploited by other members of MI3 Plus, used for initial studies on proton imaging which led to award of £1.6m Wellcome Trust Translation grant, and formed the underlying IP for the foundation of ISDI Ltd. 
Type Of Technology Physical Model/Kit 
 
Title Standalone Imaging System for Dynamite 
Description Full support system for Dynamite - flexible hardware, with optional device cooling, and robust user-interface for control and analysis of images (or sequences). 
Type Of Technology Physical Model/Kit 
 
Company Name ISDI Ltd 
Description ISDI Ltd (Company Reg. No. 07314677) was founded to exploit IP developed under MI-3 Plus (and related grants and activities) and maintain the accumulated skill base. 
Year Established 2010 
Impact ISDI Ltd formed to exploit the extensive know-how and IP on CMOS sensors gained through this grant and others. ISDI Ltd received no assistance from Host institutions or other organisations. The IP has been transferred to the Company.
Website http://www.isdicmos.com
 
Description APS in Pre-Clinical Science: Next Generation Disruptive Technology for Multi-Modality Imaging 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact talk at Nuclear Science Symposium and Medical Imaging Anaheim, California.
Year(s) Of Engagement Activity 2012