Quantitative Imaging of Yttrium-86 PET with the ECAT EXACT HR&lt;SUP&gt;+&lt;/SUP&gt; in 2D Mode

Kull, Thomas; Ruckgaber, Jochen; Weller, Rolf; Reske, Sven N.; Glatting, Gerhard

doi:10.1089/1084978041979599

Cited by 6 publications

(3 citation statements)

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“…Mixing both effects, PV and PGC effects, to one correction step by measuring a combined correction factor expressed as an effective RC for a particular phantom setup is probably valid only for this phantom geometry. Normally, the PGC-correction has to be performed in a separate step before image reconstruction such as the published sinogram-based methods (Lubberink et al 2002, Beattie et al 2003, Walrand et al 2003, Kull et al 2004. As a matter of fact, the application of the resolution and isovolume RCs yielded satisfactory results with absolute percentage deviations <20% for true ACs >2.2 kBq ml −1 .…”

Section: Study Limitationsmentioning

confidence: 99%

“…A number of sinogram-correction methods have been proposed to correct for the prompt gamma coincidence (PGC) effect, which occur not only for 124 I but also for other relevant PET radionuclides such as 86 Y. For example, a method has been developed whereby a correction is performed by background subtraction in the emission sinograms before image reconstruction (Lubberink et al 2002, Kull et al 2004. More accurate methods have been suggested involving a convolution subtraction using empirically or analytically determined cascade coincidence kernels (Walrand et al 2003, Beattie et al 2003.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of factors affecting the absolute recovery coefficients in iodine-124 PET lesion imaging

Jentzen¹

2010

Phys. Med. Biol.

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The use of recovery coefficients (RCs) in (124)I PET lesion imaging is a simple method to correct the imaged activity concentration (AC) primarily for the partial-volume effect and, to a minor extent, for the prompt gamma coincidence effect. The aim of this phantom study was to experimentally investigate a number of various factors affecting the (124)I RCs. Three RC-based correction approaches were considered. These approaches differ with respect to the volume of interest (VOI) drawn, which determines the imaged AC and the RCs: a single voxel VOI containing the maximum value (maximum RC), a spherical VOI with a diameter of the scanner resolution (resolution RC) and a VOI equaling the physical object volume (isovolume RC). Measurements were performed using mainly a stand-alone PET scanner (EXACT HR(+)) and a latest-generation PET/CT scanner (BIOGRAPH mCT). The RCs were determined using a cylindrical phantom containing spheres or rotational ellipsoids and were derived from images acquired with a reference acquisition protocol. For each type of RC, the influence of the following factors on the RC was assessed: object shape, background activity spill in and iterative image reconstruction parameters. To evaluate the robustness of the RC-based correction approaches, the percentage deviation between RC-corrected and true ACs was determined from images acquired with a clinical acquisition protocol of different AC regimes. The observed results of the shape and spill-in effects were compared with simulation data derived from a convolution-based model. The study demonstrated that the shape effect was negligible and, therefore, was in agreement with theoretical expectations. In contradiction to the simulation results, the observed spill-in effect was unexpectedly small. To avoid variations in the determination of RCs due to reconstruction parameter changes, image reconstruction with a pixel length of about one-third or less of the scanner resolution and an OSEM 1 x 32 algorithm or one with somewhat higher number of effective iterations are recommended. Using the clinical acquisition protocol, the phantom study indicated that the resolution- or isovolume-based recovery-correction approaches appeared to be more appropriate to recover the ACs from patient data; however, the application of the three RC-based correction approaches to small lesions containing low ACs was, in particular, associated with large underestimations. The phantom study had several limitations, which were discussed in detail.

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Section: Study Limitationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental investigation of factors affecting the absolute recovery coefficients in iodine-124 PET lesion imaging

Jentzen¹

2010

Phys. Med. Biol.

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“…However, in addition to positron emission and electron capture (EC), these radionuclides also emit prompt gamma rays that are in cascades with a positron or other gamma rays, which causes spurious activity in the images. Correction methods of spurious activity have been an area of active research recently (Beattie et al 2003, Walrand et al 2003, Pentlow et al 2000, Lubberink et al 2002, Buchholz et al 2003, Kull et al 2004, Bockisch et al 2006. In addition, cascade gamma rays also yield increased singles rates, which increase detector dead time and random coincidence rates.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo modeling of cascade gamma rays in⁸⁶Y PET imaging: preliminary results

Zhu¹,

Fakhri²

2009

Phys. Med. Biol.

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86Y is a PET agent that could be used as an ideal surrogate to allow personalized dosimetry in 90Y radionuclide therapy. However, 86Y also emits cascade gamma rays. We have developed a Monte Carlo program based on SimSET to model cascade gamma rays in PET imaging. The new simulation was validated with the GATE simulation package. Agreements within 15% were found in spatial resolution, apparent scatter fraction (ratio of coincidences outside peak regions in line source sinograms), singles and coincidences statistics and detected photons energy distribution within the PET energy window. A 20% discrepancy was observed in the absolute scatter fraction, likely caused by differences in the tracking of higher-energy cascade gamma photons. On average the new simulation is 6 times faster than GATE, and the computing time can be further improved by using variance reduction techniques currently available in SimSET. Comparison with phantom acquisitions showed agreements in spatial resolutions and the general shape of projection profiles; however, the standard scatter correction method on the scanner is not directly applicable for 86Y PET as it leads to incorrect scatter fractions. The new simulation was used to characterize 86Y PET. Compared with conventional 18F PET, in which major contamination at low count rates comes from scattered events, cascade gamma-involved events are more important in 86Y PET. The two types of contaminations have completely different distribution patterns, which should be considered for the corrections of their effects. Our approach will be further improved in the future in the modeling of random coincidences and tracking of high energy photons, and simulation results will be used for the development of correction methods in 86Y PET.

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Impact of prompt gamma emission of 44Sc on quantification in preclinical and clinical PET systems

Rosar

Bohnenberger

Moon³

et al. 2021

Applied Radiation and Isotopes

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Quantitative Imaging of Yttrium-86 PET with the ECAT EXACT HR<SUP>+</SUP> in 2D Mode

Cited by 6 publications

References 0 publications

Experimental investigation of factors affecting the absolute recovery coefficients in iodine-124 PET lesion imaging

Experimental investigation of factors affecting the absolute recovery coefficients in iodine-124 PET lesion imaging

Monte Carlo modeling of cascade gamma rays in⁸⁶Y PET imaging: preliminary results

Impact of prompt gamma emission of 44Sc on quantification in preclinical and clinical PET systems

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Quantitative Imaging of Yttrium-86 PET with the ECAT EXACT HR<SUP>+</SUP> in 2D Mode

Cited by 6 publications

References 0 publications

Experimental investigation of factors affecting the absolute recovery coefficients in iodine-124 PET lesion imaging

Experimental investigation of factors affecting the absolute recovery coefficients in iodine-124 PET lesion imaging

Monte Carlo modeling of cascade gamma rays in86Y PET imaging: preliminary results

Impact of prompt gamma emission of 44Sc on quantification in preclinical and clinical PET systems

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Monte Carlo modeling of cascade gamma rays in⁸⁶Y PET imaging: preliminary results