نتایج جستجو برای: scatter correction
تعداد نتایج: 176847 فیلتر نتایج به سال:
PURPOSE Clinical performance studies of an extremity cone-beam CT (CBCT) system indicate excellent bone visualization, but point to the need for improvement of soft-tissue image quality. To this end, a rapid Monte Carlo (MC) scatter correction is proposed, and Penalized Likelihood (PL) reconstruction is evaluated for noise management. METHODS The accelerated MC scatter correction involved fas...
OBJECTIVE 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) and 99mTc-tetrofosmin (TET) are widely used for evaluation of myocardial fatty acid metabolism and perfusion, respectively. ECG-gated TET SPECT is also used for evaluation of myocardial wall motion. These tests are often performed on the same day to minimize both the time required and inconvenience to patients and medical...
Kilovoltage cone-beam CT (kV CBCT) can be acquired during the delivery of volumetric modulated arc therapy (VMAT), in order to obtain an image of the patient during treatment. However, the quality of such CBCTs is degraded by megavoltage (MV) scatter from the treatment beam onto the imaging panel. The objective of this paper is to introduce a novel MV scatter correction method for simultaneous ...
The purpose of this study was to assess the influence of different reconstruction factors in N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-I-123 iodophenyl)nortropane (I-123 FP-CIT) single-photon emission computed tomography (SPECT) images for the diagnosis of dopaminergic system neurodegeneration (DSND).Seventy-three patients (38 females, 35 males) suspected of DSND were included in this study. The p...
Excessive imaging dose from repeated scans and poor image quality mainly due to scatter contamination are the two bottlenecks of cone-beam CT (CBCT) imaging. Compressed sensing (CS) reconstruction algorithms show promises in recovering faithful signals from low-dose projection data but do not serve well the needs of accurate CBCT imaging if effective scatter correction is not in place. Scatter ...
UNLABELLED Heart to mediastinum count ratio (H/M) has been commonly utilized as an indicator of myocardial I-123 MIBG uptake. However, normal ranges of H/M were markedly different among various gamma camera systems. The purpose of this study was to clarify whether scatter correction by two-window method standardizes H/M among various gamma camera systems. METHODS Scatter uncorrected and corre...
PURPOSE Scatter is a very important artifact causing factor in dental cone-beam CT (CBCT), which has a major influence on the detectability of details within images. This work aimed to improve the image quality of dental CBCT through scatter correction. METHODS Scatter was estimated in the projection domain from the low frequency component of the difference between the raw CBCT projection and...
Accurate attenuation correction is a prerequisite for the determination of precise regional radioactivity concentrations in positron tomography. Attenuation correction can be performed using an external source of radiation and two measurements: a blank scan performed with no subject in the tomograph, and a transmission scan performed with the subject in the field of view. The ratio of blank to ...
We read with interest the recent paper by Shiga et al. published in the European Journal of Nuclear Medicine [1]. The authors report some interesting results concerning the effect of triple-energy window-based scatter correction on brain perfusion SPET using statistical para-metric mapping (SPM) analysis. The research performed is worthwhile and contributes significantly to our understanding of...
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