Advancing Nuclear Medicine Through Innovation (2007) / Chapter Skim
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7 Instrumentation and Computational Sciences
7 Instrumentation and Computational Sciences
Pages 104-117
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From page 104... ...
. 7.1 BACKGROUND As discussed in other chapters of this report, the use of nuclear medicine technology for both diagnostic and therapeutic applications is central to the goal of personalized medicine.
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From page 105... ...
Once the data are acquired, image reconstruction algorithms are required to generate tomographic image sets of the spatial distribution of radiotracer within the body. Recent developments involve modeling the physical characteristics of the camera into the iterative reconstruction process to improve image quality and radionuclide quantification.
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From page 106... ...
To meet these goals, the development of imaging instruments and computational tools requires collaborative teams of investigators in physics, engineering, and mathematics who understand the entire process of nuclear medicine image generation. This ranges from understanding radionuclide decay (from simple single photon and positron emitters such as technetium99m and fluorine-18 to complex isotope decays such as iodine-124 with positrons and prompt gamma emissions, which complicate signal acquisition in the 511-keV window)
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From page 107... ...
, SPECT, PET, cyclotron targetry and radionuclide generator systems, basic image reconstruction algorithms, and kinetic modeling applied to PET and SPECT studies. The state-of-the-art SPECT and PET scanners used today in the clinic illustrate how critical it is to have the infrastructure and funding to support the flow of technology from the nuclear and high-energy laboratories that develop new detectors and electronics to the nuclear medicine instrumentation laboratories that develop new imaging tools.
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From page 108... ...
and a microPET scanner (right) illustrates the improvement in spatial resolution possible with a dedicated small animal scanner.
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From page 109... ...
7-3 impact of PET/CT in clinical oncology and the commercial sector rapidly developed these imaging instruments for clinical practice. In fact, all PET scanners today are marketed as PET/CT scanners because the combination of anatomic information (CT)
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From page 110... ...
Its advantage in cancer detection and staging has been demonstrated in terms of superior image quality (higher contrast with lower noise for the same number of events detected) and better detection of lesions compared to conventional PET (see Figure 7.5)
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From page 111... ...
7.3 CURRENT STATE OF THE FIELD AND EMERGING PRIORITIES Emerging goals for nuclear medicine include early detection, which will require improvements in equipment sensitivity; the accurate quantification of biomarker uptake in disease for the evaluation of treatment response; and the quantification of radiotracer heterogeneity, which may be of potential utility for dose-painting applications of intensity-modulated radiotherapy. These limits may be tested in preclinical equipment such as microSPECT and microPET scanners, which operate at the cutting edge of the technology, with volumetric resolutions that are approximately 10-fold higher than their counterpart systems in the clinic.
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From page 112... ...
Detector designs utilizing nonradioactive crystalline materials are advantageous because the high background signal associated with the current LSO crystals places limits on the detection of micrometastatic disease. Furthermore, improved algorithms that can stably reconstruct the activity distribution from low-count statistics will be important.
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From page 113... ...
, but it is currently difficult to fund this type of research at universities or national laboratories. Hand-in-hand with the development of detectors, electronics, and imaging instruments goes the development of image reconstruction algorithms,
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From page 114... ...
The ability to perform this task in practice has benefited from the increased availability of powerful computing resources. For example, an iterative image reconstruction algorithm with data corrections built into the system model was considered to be impractical a decade ago.
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From page 115... ...
as well as committee members' own experiences, the committee concluded that improvements in instrumentation and computation are necessary to lead to advances in quantitative imaging and, in turn, nuclear medicine. These improvements depend on the following: • better spatial resolution; • higher sensitivity; • further integration of instruments to provide multimodality (multisignal)
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From page 116... ...
Three examples of these upcoming technologies include TOF PET, combined PET/MR machines, and SPECT/CT with the potential to allow quantification of single photon radiotracers for the first time; these three technologies will directly impact future patient management in the following ways: • TOF PET allows significant improvements in clinical image
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From page 117... ...
Software is under development to co-register serial SPECT/ CT exams and generate dosimetric maps for the radionuclide, of sig nificant importance for patient-specific targeted therapy planning. The extensive portfolio of SPECT agents approved by the Food and Drug Administration coupled with the unique ability of SPECT to perform simultaneous multienergy window exams widens previously untapped opportunities in single photon nuclear medicine imaging, through ad vances in quantitative SPECT imaging.
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