Late 124I PET/CT Uptake Measurement-Assessment of Appropriate Examination Protocol in Benign Thyroid Diseases.

Published on Jul 1, 2017in Clinical Nuclear Medicine7.794
· DOI :10.1097/RLU.0000000000001677
Martin Freesmeyer15
Estimated H-index: 15
Anja Sophie Gabler1
Estimated H-index: 1
+ 1 AuthorsThomas Winkens10
Estimated H-index: 10
PURPOSE: This study aimed at investigating the performance of late I PET/CT for radioiodine uptake (RAIU) measurement at 336 hours after administration in patients with benign thyroid diseases requiring radioiodine therapy. Special attention was paid to the comparability of I uptake (I-RAIU) to the clinical standard (I-RAIU, probe measurement). Considering cost aspects, we sought to establish an economically reasonable examination protocol based on scan duration and administered activity. METHODS: List-mode PET data sets of 40-minute acquisition time were acquired 336 hours after administration of 1 MBq I in 18 patients. Different scan durations were simulated by different reconstruction intervals (RIs) ranging from 5 seconds to 40 minutes, and total thyroid activity was measured. Mean I-RAIU levels of each RI were compared with mean I-RAIU levels (3 MBq). A hypothetical scan duration or hypothetical activity, respectively, was sought by means of a proportion equation, considering that the length of an RI is equitable to a hypothetical activity. RESULTS: After 336 hours, the mean total thyroid activity was 254 ± 7.7 kBq for I and 26.9 ± 8.7 kBq for I. The mean I-RAIU and I-RAIU showed high levels of agreement for RI from 2 minutes to 40 minutes. Reconstruction interval shorter than 2 minutes did not result in sufficient agreement. CONCLUSIONS: The present study confirmed the feasibility of late I PET/CT as alternative method for RAIU measurement in patients with benign thyroid diseases; 1 MBq I PET/CT scans as short as 2 minutes resulted in RAIU levels comparable to those of standard I-RAIU. The parameter "appropriate scan-duration activity product" is proposed to enable an economically reasonable examination protocol.
#1Anja Sophie Gabler (FSU: University of Jena)H-Index: 1
#2Christian Kühnel (FSU: University of Jena)H-Index: 5
Last. Martin Freesmeyer (FSU: University of Jena)H-Index: 15
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This study aimed to assess a hypothetical minimum administered activity of (124)I required to achieve comparability between pretherapeutic radioiodine uptake (RAIU) measurements by (124)I PET/CT and by (131)I RAIU probe, the clinical standard. In addition, the impact of different reconstruction algorithms on (124)I RAIU and the evaluation of pixel noise as a parameter for image quality were investigated.Different scan durations were simulated by different reconstruction intervals of 600-s list-m...
#1Hossein Gharib (Mayo Clinic)H-Index: 75
#2Enrico PapiniH-Index: 50
Last. AceH-Index: 1
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Abstract Thyroid nodules are detected in up to 50 to 60% of healthy subjects. Most nodules do not cause clinically significant symptoms, and as a result, the main challenge in their management is to rule out malignancy, with ultrasonography (US) and fine-needle aspiration (FNA) biopsy serving as diagnostic cornerstones. The key issues discussed in these guidelines are as follows: (1) US-based categorization of the malignancy risk and indications for US-guided FNA (henceforth, FNA), (2) cytologic...
Objective: Optimization of tracer dose regimes in positron emission tomography (PET) imaging is a trade-o between diagnostic image quality and radiation exposure. The challenge lies in dening minimal tracer doses that still result in sucien t diagnostic image quality. In order to nd such minimal doses, it would be useful to simulate tracer dose reduction as this would enable to study the eects of tracer dose reduction on image quality in single patients without repeated injections of dierent amo...
#1Yiqiang Jian (Yale University)H-Index: 6
#2Beata Planeta (Yale University)H-Index: 11
Last. Richard E. Carson (Yale University)H-Index: 96
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Statistical algorithms have been widely used in PET image reconstruction. The maximum likelihood expectation maximization reconstruction has been shown to produce bias in applications where images are reconstructed from a relatively small number of counts. In this study, image bias and variability in low-count OSEM reconstruction are investigated on images reconstructed with MOLAR (motion-compensation OSEM list-mode algorithm for resolution-recovery reconstruction) platform. A human brain ([11C]...
Background Benign thyroid diseases are widely common in western societies. However, the volumetry of the thyroid gland, especially when enlarged or abnormally formed, proves to be a challenge in clinical routine. The aim of this study was to develop a simple and rapid threshold-based isocontour extraction method for thyroid volumetry from 124I-PET/CT data in patients scheduled for radioactive iodine therapy.
#1Thomas Carlier (French Institute of Health and Medical Research)H-Index: 12
#2Ludovic Ferrer (French Institute of Health and Medical Research)H-Index: 24
Last. Françoise Kraeber-Bodéré (French Institute of Health and Medical Research)H-Index: 43
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The injected activity and the acquisition time per bed position for 18F-FDG PET scans are usually optimized by using metrics obtained from phantom experiments. However, optimal activity and time duration can significantly vary from a phantom set-up and from patient to patient. An approach using a patient-specific noise equivalent count rate (NECR) modelling has been previously proposed for optimizing clinical scanning protocols. We propose using the clinical NECR on a large population as a funct...
Abstract A precise estimate of thyroid volume is necessary for making adequate therapeutic decisions and planning, as well as for monitoring therapy response. The goal of this study was to compare the precision of different volumetry methods. Thyroid-shaped phantoms were subjected to volumetry via 2-D and 3-D ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). The 3-D US scans were performed using sensor navigation and mechanical sweeping methods. Volumetry calcu...
#1Flavia Molina-Duran (Heidelberg University)H-Index: 3
#2Dietmar Dinter (Heidelberg University)H-Index: 24
Last. Gerhard Glatting (Heidelberg University)H-Index: 18
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Abstract The impact of acquisition time on reconstructed PET image quality is analyzed for different acquisition times (1, 2, 3 and 4 min). Image quality was tested according to the National Electrical Manufacturers Association (NEMA) NU 2-2007, the evaluation for the signal to noise ratio (SNR) and the reconstructed activity ratio (RAR) for three algorithms, i.e. OSEM, TrueX and TOF applying different effective iteration numbers. The present work shows that the image quality of 3 and 4 min acqu...
Context: Radioiodine therapy of benign thyroid diseases requires pretherapy assessment of radioactive iodine uptake (RAIU) for reliable therapy planning. Objective: Our objective was to assess RAIU by low-activity 124I-positron emission tomography/low-dose computed tomography (124I-PET/CT) in comparison with standard 131I probe measurements. Design/Setting: This prospective comparative study was conducted at the Jena University Hospital, Jena, Germany, in a referral center setting. Patients: A t...
#1Andreas M. DarrH-Index: 2
#2Thomas OpfermannH-Index: 12
Last. Martin FreesmeyerH-Index: 15
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Purpose of the ReportThe standard thyroid functional imaging method, 99mTc-pertechnetate (99mTc-PT) planar scintigraphy, has technical drawbacks decreasing its sensitivity in detecting nodules or anatomical pathology. 124I-PET, lacking these disadvantages and allowing simultaneous CT, may have great
Cited By1
#1Simone SchenkeH-Index: 7
#2Rainer GörgesH-Index: 24
Last. Michael C. Kreissl (Otto-von-Guericke University Magdeburg)H-Index: 6
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Both, ultrasonography but also radionuclide imaging using [99mTc]Pertechnetate or radioactive iodine isotopes are essential tools used during the diagnostic workup of hyperthyroidism with or without structural alterations of the thyroid. Colour duplex sonography and ultrasound elastography may add important information in order to find the cause of the hormone excess. During the last years, also hybrid imaging using SPECT/-(CT) or PET-based methods, such as [124]Iodine-PET/CT or [124]Iodine-PET/...
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