Application Requirements
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Imaging Technology Group has developed a detailed understanding
of the radiation detection and measurement requirements
and required imaging operations of a diverse range of
straightforward to complex applications and devices.
Using this awareness and understanding of individual
applications and devices, our group designs scintillators
and photodetectors appropriately and optimally matched
to the particular needs of specific applications/devices
and to each other.
Applications that figure prominently
in our group's research and development activities include:
Medical imaging is a key focus
of our group's efforts, as the largest single market
requiring radiation imaging. From single-exposure planar
X-ray and nuclear imaging to multi-slice X-ray CT (Computed
Tomography), PET (Positron Emission Tomography), SPECT
(Single-Photon Computed Tomography), mammography, tomosynthesis
(a CT-like form of mammography) and other modalities,
medical imaging imposes the most consistently stringent
individual and overall requirements upon radiation detectors
of any application. Detector spatial resolution, sensitivity
and energy resolution must be high - often as high as
is technologically possible - and other aspects of detector
operation, such as device operational speed and response
linearity and consistency, must meet exceptionally high
minimum requirements.
Pharmaceutical research and development
is as demanding as medical imaging in certain key respects.
Clearly, imaging small animals used in drug and treatment
testing requires exceptionally high spatial resolution
to resolve tiny structures and accurately identify and
size tumors and other lesions. In addition, in order
to minimize the stress placed on animals during imaging,
the sensitivity of the detector must be as high as possible,
so as to minimize scan time. High detector sensitivity
also allows the same animal (and thus a smaller number
of animals overall) to be used throughout a longitudinal
study, by reducing the radiation dose that must be administered
to a subject in order to obtain the required image quality.
In many cases computed tomography and volumetric imaging
of test subjects is required, with both transmission
(X-ray) and emission (injected radionuclide) imaging
performed in order to obtain combined anatomical and
functional imaging, which places the greatest demands
possible on detectors and imaging systems.
Homeland security and defense applications
today demand the highest affordable performance in imaging
systems. Airport security X-rays every passenger's carry-on
and checked articles, and is even beginning to use low-level
radiation for screening passengers themselves. Cargo
and items of every type (mail, parcels, freight containers
and even entire vehicles) on every type of transport
(air, sea, land) and at fixed locations (e.g., building
entrances) are increasingly being subjected to radiation-based
screening methods to detect dangerous items and substances,
radioactive materials, contraband and even hidden human
beings. The military, homeland security, disaster site
first responders and industry now require systems and
devices capable of detecting low-level radioactive and
other hazardous substances at very low concentrations
and often at a significant distance. Our group is developing
scintillators, detectors and device concepts to serve
the growing, changing and often unusual demands of each
of these areas.
Nondestructive testing (NDT) utilizing
X-rays, radionuclides and neutrons for analysis and
quality control is being applied in a growing number
and variety of industries and in the military. Such
NDT offers the ability to image machined, stamped, injection
molded, sintered, sealed and other assemblies and such
during manufacturing, and to image parts or entire structures
without disassembly during inspection, maintenance and
repairs. Radiation-based NDT can reveal hidden microscopic
flaws in materials that could otherwise not be detected
except through destructive testing. Neutron-based NDT,
for instance, can detect the presence or absence of
low-density substances (such as certain plastics, composites
and liquids) surrounded by high-Z materials, a difficult
or impossible task using other NDT methods of any type.
Further, advanced detectors, scintillators and imaging
techniques now offer the ability to visualize high-speed
and/or detailed devices in operation and liquids in
motion.
Synchrotron particle accelerators,
with over 1000 beamlines operating worldwide, perform
important X-ray diffraction (XRD) and scattering studies
and time-resolved small angle X-ray scattering (SAXS)
studies of biological materials, and are a limited but
challenging and growing market for advanced detectors
and scintillators. Time-resolved XRD of muscle has historically
been a driving force in synchrotron instrumentation
development, while other applications of time-resolved
XRD such as the studies of scattering from macromolecules
in solution, the kinetics of protein folding, and of
phase transitions in model membrane systems, have significant
and expanding biotechnological relevance. X-ray beamlines
at third generation synchrotron sources such as the
Advanced Photon Source (APS; Argonne, IL), have proven
to be outstanding tools for XRD and scattering studies
of non-crystalline biological materials, while the availability
of SAXS instruments on these sources has been invaluable
for static and time-resolved studies of various non-crystalline
biological systems. A major problem, however, has been
the difficulty of finding a detector that can provide
multiple frames of detailed structural information on
the required millisecond time scale at the extremely
high count rates available at synchrotron sources such
as the APS. RMD is working to develop such detectors
and associated suitable scintillators, both of which
are critical to fully exploiting the abilities of these
new radiation sources.
Nuclear physics and other research
depend heavily on radiation detection and measurement,
and our group is particularly well suited to understand
and respond to the requirements of such areas.
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