Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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Comparative Study Clinical Trial
Correction of photon attenuation and collimator response for a body-contouring SPECT/CT imaging system.
(111)In-Capromab pendetide imaging is indicated for postprostatectomy patients at risk for residual or recurrent disease. However, this study is complicated by relatively long times for tumor uptake and background washout that require imaging to be performed several days after radiopharmaceutical administration. In addition, (111)In-capromab pendetide demonstrates uptake in normal structures that produce images that are interpreted best using correlation with anatomic imaging. Finally, the visual quality of radionuclide imaging can be improved with corrections for photon attenuation and for the geometric response of the radionuclide collimator. Therefore, we have evaluated the advantages of using a commercially available dual-modality SPECT/CT system. In this article, we evaluate a novel iterative reconstruction algorithm using the SPECT/CT data obtained from phantoms and (111)In-capromab pendetide patient studies. ⋯ A priori anatomic data can be used to enhance the quality of the SPECT image when reconstructed using iterative techniques (e.g., MLEM) that use the CT data to produce a patient-specific attenuation map and a collimator response model based on the body contour produced during the SPECT acquisition.
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Clinical Trial Controlled Clinical Trial
Correction methods for random coincidences in fully 3D whole-body PET: impact on data and image quality.
With the advantages of the increased sensitivity of fully 3-dimensional (3D) PET for whole-body imaging come the challenges of more complicated quantitative corrections and, in particular, an increase in the number of random coincidences. The most common method of correcting for random coincidences is the real-time subtraction of a delayed coincidence channel, which does not add bias but increases noise. An alternative approach is the postacquisition subtraction of a low-noise random coincidence estimate, which can be obtained either from a smoothed delayed coincidence sinogram or from a calibration scan or directly estimated. Each method makes different trade-offs between noise amplification, bias, and data-processing requirements. These trade-offs are dependent on activity injected, the local imaging environment (e.g., near the bladder), and the reconstruction algorithm. ⋯ A 15% improvement in image SNR arises from a 32% increase in the NEC rate. Thus, scan duration can be reduced by 25% while still maintaining a constant total acquired NEC.
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Clinical Trial
Automatic detection and size quantification of infarcts by myocardial perfusion SPECT: clinical validation by delayed-enhancement MRI.
We aimed to validate the accuracy of a new automated myocardial perfusion SPECT quantification based on normal limits for detection and sizing of infarcts, using delayed-enhancement MRI (DE-MRI) as a gold standard. ⋯ Automated quantification of the EXT on myocardial perfusion SPECT images can reliably detect infarcts and measure infarct sizes.
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Precise PET/CT localization of focal (18)F-FDG uptake in the gastrointestinal tract (GIT) may exclude malignancy in sites of physiologic activity but may also induce false-negative reports for malignant or premalignant lesions. The purpose of the present study was to retrospectively evaluate the nature and significance of unexpected focal (18)F-FDG uptake localized by PET/CT within the GIT. ⋯ Incidental focal (18)F-FDG uptake localized by PET/CT within the GIT is of clinical significance in most patients. These findings should be followed up with appropriate invasive procedures guided by hybrid imaging results.