Clustering of time activity curves for uptake pattern assessment in dynamic nuclear medicine imaging

Nuclear medicine could provide an accurate estimate of the biochemical composition, metabolism, and capability of the kidney. Using nuclear medicine imaging to scan the organ, we can find the time-activity curve, called a renogram, by the intensity of the image. The activity curve can be employed to describe organ capability. Traditional methods of observing the activity curve of the whole kidney can obscure some small details. This paper proposes an improved renogram based on blood vessel distribution to estimate the kidney capability automatically. Every patient must acquire 180 renal dynamic images from the renal scan. First, acquiring region of the kidney in the No. 68 kidney image and correcting the background of this sample image, the sample image will be applied to the rest of the images to find the region of the kidney. The kidney image is then divided into several sub-regions according to the paths of the blood vessels from No. 50 kidney image. For each sub-region, we find the time–intensity curve, called the sub-renogram. Then, we observe the activity curves of the sub-region and the whole kidney separately to assist the diagnosis. The results of the automatic analysis are similar to the traditional methods used on the whole kidney, which ignores any abnormal sub-region activity. The proposed method can improve the accuracy of the doctor’s diagnosis.

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Patients with fever of unknown origin (FUO): diagnosis by nuclear medicine imaging

Nuklearmedizin ◽

10.1055/s-0038-1623872 ◽

2001 ◽

Vol 40 (03) ◽

pp. 59-70 ◽

Cited By ~ 13

Author(s):

W. Becker ◽

J. Meiler

Keyword(s):

Nuclear Medicine ◽

Fever Of Unknown Origin ◽

Tumor Imaging ◽

White Blood Cells ◽

Unknown Origin ◽

Final Diagnosis ◽

Recurrent Fever ◽

Nuclear Medicine Imaging

SummaryFever of unknown origin (FUO) in immunocompetent and non neutropenic patients is defined as recurrent fever of 38,3° C or greater, lasting 2-3 weeks or longer, and undiagnosed after 1 week of appropriate evaluation. The underlying diseases of FUO are numerous and infection accounts for only 20-40% of them. The majority of FUO-patients have autoimmunity and collagen vascular disease and neoplasm, which are responsible for about 50-60% of all cases. In this respect FOU in its classical definition is clearly separated from postoperative and neutropenic fever where inflammation and infection are more common. Although methods that use in-vitro or in-vivo labeled white blood cells (WBCs) have a high diagnostic accuracy in the detection and exclusion of granulocytic pathology, they are only of limited value in FUO-patients in establishing the final diagnosis due to the low prevalence of purulent processes in this collective. WBCs are more suited in evaluation of the focus in occult sepsis. Ga-67 citrate is the only commercially available gamma emitter which images acute, chronic, granulomatous and autoimmune inflammation and also various malignant diseases. Therefore Ga-67 citrate is currently considered to be the tracer of choice in the diagnostic work-up of FUO. The number of Ga-67-scans contributing to the final diagnosis was found to be higher outside Germany than it has been reported for labeled WBCs. F-l 8-2’-deoxy-2-fluoro-D-glucose (FDG) has been used extensively for tumor imaging with PET. Inflammatory processes accumulate the tracer by similar mechanisms. First results of FDG imaging demonstrated, that FDG may be superior to other nuclear medicine imaging modalities which may be explained by the preferable tracer kinetics of the small F-l 8-FDG molecule and by a better spatial resolution of coincidence imaging in comparison to a conventional gamma camera.

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Nuclear medicine imaging of neuroendocrine tumours

Endocrine Abstracts ◽

10.1530/endoabs.32.s5.2 ◽

2013 ◽

Author(s):

Anders Sundin

Keyword(s):

Nuclear Medicine ◽

Neuroendocrine Tumours ◽

Nuclear Medicine Imaging

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Correction for the Partial Volume Effects (PVE) in Nuclear Medicine Imaging: A Post-Reconstruction Analytic Method

Applied Sciences ◽

10.3390/app11146460 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6460

Author(s):

Fabio Di Martino ◽

Patrizio Barca ◽

Eleonora Bortoli ◽

Alessia Giuliano ◽

Duccio Volterrani

Keyword(s):

Nuclear Medicine ◽

Imaging System ◽

Tomographic Reconstruction ◽

Mathematical Expression ◽

Reconstruction Algorithm ◽

Volume Effect ◽

Nuclear Medicine Imaging ◽

Theoretical Derivation ◽

Reconstruction Process ◽

Partial Volume

Quantitative analyses in nuclear medicine are increasingly used, both for diagnostic and therapeutic purposes. The Partial Volume Effect (PVE) is the most important factor of loss of quantification in Nuclear Medicine, especially for evaluation in Region of Interest (ROI) smaller than the Full Width at Half Maximum (FWHM) of the PSF. The aim of this work is to present a new approach for the correction of PVE, using a post-reconstruction process starting from a mathematical expression, which only requires the knowledge of the FWHM of the final PSF of the imaging system used. After the presentation of the theoretical derivation, the experimental evaluation of this method is performed using a PET/CT hybrid system and acquiring the IEC NEMA phantom with six spherical “hot” ROIs (with diameters of 10, 13, 17, 22, 28, and 37 mm) and a homogeneous “colder” background. In order to evaluate the recovery of quantitative data, the effect of statistical noise (different acquisition times), tomographic reconstruction algorithm with and without time-of-flight (TOF) and different signal-to-background activity concentration ratio (3:1 and 10:1) was studied. The application of the corrective method allows recovering the loss of quantification due to PVE for all sizes of spheres acquired, with a final accuracy less than 17%, for lesion dimensions larger than two FWHM and for acquisition times equal to or greater than two minutes.

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