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Purpose Quantitative estimates of dopamine transporter availability, determined with [ 123 I]FP-CIT SPECT, depend on the SPECT equipment, including both hardware and (reconstruction) software, which limits their use in multicentre research and clinical routine. This study tested a dedicated reconstruction algorithm for its ability to reduce camera-specific intersubject variability in [ 123 I]FP-CIT SPECT. The secondary aim was to evaluate binding in whole brain (excluding striatum) as a reference for quantitative analysis. Methods Of 73 healthy subjects from the European Normal Control Database of [ 123 I]FP-CIT recruited at six centres, 70 aged between 20 and 82 years were included. SPECT images were reconstructed using the QSPECT software package which provides fully automated detection of the outer contour of the head, camera-specific correction for scatter and septal penetration by transmission-dependent convolution subtraction, iterative OSEM reconstruction including attenuation correction, and camera-specific “to kBq/ml” calibration. LINK and HERMES reconstruction were used for head-to-head comparison. The specific striatal [ 123 I]FP-CIT binding ratio (SBR) was computed using the Southampton method with binding in the whole brain, occipital cortex or cerebellum as the reference. The correlation between SBR and age was used as the primary quality measure. Results The fraction of SBR variability explained by age was highest (1) with QSPECT, independently of the reference region, and (2) with whole brain as the reference, independently of the reconstruction algorithm. Conclusion QSPECT reconstruction appears to be useful for reduction of camera-specific intersubject variability of [ 123 I]FP-CIT SPECT in multisite and single-site multicamera settings. Whole brain excluding striatal binding as the reference provides more stable quantitative estimates than occipital or cerebellar binding.

PurposeIodine-125 (125I) seeds can be used as landmarks to locate non-palpable breast lesions instead of implanting metal wires. This relatively new technique requires a nuclear probe usually used for technetium-99m (99mTc) sentinel node detection. This study aimed to compare the performances of different probes and valid the feasibility of this technique, especially in the case of simultaneous 125I-seed and 99mTc breast cancer surgery.MethodsThree probes with different features (SOE-3211, SOE-3214 and GammaSUP-II) were characterised according to the NEMA NU3-2004 standards for a 99mTc source and a 125I-seed. Several tests such as sensitivity, linearity or spatial resolution allowed an objective comparison of their performances. NEMA testing was extended to work on signals discrimination in case of simultaneous detection of two different sources (innovative figure of merit “Shift Index”) and to assess the 99mTc scatter fraction, a useful parameter for the improvement of the probes in terms of detector materials and electronic system.ResultsAlthough the GammaSUP-II probe saturated at a lower activity (1.6 MBq at 10 mm depth), it allowed better sensitivity and spatial resolution at the different NEMA tests performed with the 99mTc source (7865 cps/MBq and 15 mm FWHM at 10 mm depth). With the 125I-seed, the GammaSUP-II was the most sensitive probe (3106 cps/MBq at 10 mm depth) and the SOE-3211 probe had the best spatial resolution (FWHM 20 mm at 10 mm depth). The SOE-3214 probe was more efficient on discriminating 125I from 99mTc in case of simultaneous detection. The SOE probes were more efficient concerning 99mTc scatter fraction assessments. The SOE-3211 probe, with overall polyvalent performances, seemed to be an interesting trade-off for detection of both 125I and 99mTc.ConclusionThe three probes showed heterogeneous performances but were all suitable for simultaneous 99mTc sentinel node and 125I-seed detection. This study provides an objective and innovative methodology to compare probes performances and then choose the best trade-off regarding their expected use.

BackgroundDiagnostic value of 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine ([18F]FDOPA) PET in patients with suspected recurrent gliomas is recognised. We conducted a multicentre prospective study to assess its added value in the practical management of patients suspected of recurrence of high grade gliomas (HGG).MethodsPatients with a proven HGG (WHO grade III and IV) were referred to the multidisciplinary neuro-oncology board (MNOB) during their follow-up after initial standard of care treatment and when MRI findings were not fully conclusive. Each case was discussed in 2 steps. For step 1, a diagnosis and a management proposal were made only based on the clinical and the MRI data. For step 2, the same process was repeated taking the [18F]FDOPA PET results into consideration. A level of confidence for the decisions was assigned to each step. Changes in diagnosis and management induced by [18F]FDOPA PET information were measured. When unchanged, the difference in the confidence of the decisions were assessed. The diagnostic performances of each step were measured.Results107 patients underwent a total of 138 MNOB assessments. The proposed diagnosis changed between step 1 and step 2 in 37 cases (26.8%) and the proposed management changed in 31 cases (22.5%). When the management did not change, the confidence in the MNOB final decision was increased in 87 cases (81.3%). Step 1 had a sensitivity, specificity and accuracy of 83%, 58% and 66% and step 2, 86%, 64% and 71% respectively.Conclusion[18F]FDOPA PET adds significant information for the follow-up of HGG patients in clinical practice. When MRI findings are not straightforward, it can change the management for more than 20% of the patients and increases the confidence level of the multidisciplinary board decisions.

Purpose Dopamine transporter (DAT) imaging with [ 123 I]FP-CIT (DaTSCAN) is an established diagnostic tool in parkinsonism and dementia. Although qualitative assessment criteria are available, DAT quantification is important for research and for completion of a diagnostic evaluation. One critical aspect of quantification is the availability of normative data, considering possible age and gender effects on DAT availability. The aim of the European Normal Control Database of DaTSCAN (ENC-DAT) study was to generate a large database of [ 123 I]FP-CIT SPECT scans in healthy controls. Methods SPECT data from 139 healthy controls (74 men, 65 women; age range 20 – 83 years, mean 53 years) acquired in 13 different centres were included. Images were reconstructed using the ordered-subset expectation-maximization algorithm without correction (NOACSC), with attenuation correction (AC), and with both attenuation and scatter correction using the triple-energy window method (ACSC). Region-of-interest analysis was performed using the BRASS software (caudate and putamen), and the Southampton method (striatum). The outcome measure was the specific binding ratio ( SBR ). Results A significant effect of age on SBR was found for all data. Gender had a significant effect on SBR in the caudate and putamen for the NOACSC and AC data, and only in the left caudate for the ACSC data (BRASS method). Significant effects of age and gender on striatal SBR were observed for all data analysed with the Southampton method. Overall, there was a significant age-related decline in SBR of between 4 % and 6.7 % per decade. Conclusion This study provides a large database of [ 123 I]FP-CIT SPECT scans in healthy controls across a wide age range and with balanced gender representation. Higher DAT availability was found in women than in men. An average age-related decline in DAT availability of 5.5 % per decade was found for both genders, in agreement with previous reports. The data collected in this study may serve as a reference database for nuclear medicine centres and for clinical trials using [ 123 I]FP-CIT SPECT as the imaging marker.

Purpose For the first time, three currently available 360° CZT-SPECT/CT cameras were compared under clinical conditions using phantom-based measurements. Methods A 99m Tc- and a 177 Lu-customized NEMA IEC body phantom were imaged with three different cameras, StarGuide (GE Healthcare), VERITON-CT versions 200 (V200) and 400 (V400) (Spectrum Dynamics Medical) under the same clinical conditions. Energy resolution and volumetric sensitivity were evaluated from energy spectra. Vendors provided the best reconstruction parameters dedicated to visualization and/or quantification, based on their respective software developments. For both 99m Tc- and 177 Lu-phantoms, noise level, quantification accuracy, and recovery coefficient (RC) were performed with 3DSlicer. Image quality metrics from an approach called “task-based” were computed with iQMetrix-CT on 99m Tc visual reconstructions to assess, through spatial frequencies, noise texture in the background (NPS) and contrast restitution of a hot insert (TTF). Spatial resolution indices were calculated from frequencies corresponding to TTF 10% and TTF 50% . Results Despite the higher sensitivity of VERITON cameras and the enhanced energy resolution of the V400 (3.2% at 140 keV, 5.2% at 113 keV, and 3.6% at 208 keV), StarGuide presents comparable image quality. This highlights the need to differentiate sensitivity from count quality, which is influenced by hardware design (collimator, detector block) and conditions image quality as well as the reconstruction process (algorithms, scatter correction, noise regulation). For 99m Tc imaging, the quantitative image optimization approach based on RC mean for StarGuide versus RC max for V200 and V400 systems (RC mean /RC max : 0.9/1.8; 0.5/0.9; 0.5/0.9 respectively—Ø37 mm). SR TB10/50 showed nearly equivalent spatial resolution performances across the different reconstructed images. For 177 Lu imaging, the 113 keV imaging of the V200 and V400 systems demonstrated strong performances in both image quality and quantification, while StarGuide and V400 systems offer even better potential due to their ability to exploit signals from both the 113 and 208 keV peaks. 177 Lu quantification was optimized according to RC max for all cameras and reconstructions (1.07 ± 0.09—Ø37 mm). Conclusions The three cameras have equivalent potential for 99m Tc imaging, while StarGuide and V400 have demonstrated higher potential for 177 Lu. Dedicated visual or quantitative reconstructions offer better specific performances compared to the unified visual/quantitative reconstruction. The task-based approach appears to be promising for in-depth comparison of images in the context of system characterization/comparison and protocol optimization.

For the first time, three currently available 360° CZT-SPECT/CT cameras were compared under clinical conditions using phantom-based measurements. A Tc- and a Lu-customized NEMA IEC body phantom were imaged with three different cameras, StarGuide (GE Healthcare), VERITON-CT versions 200 (V200) and 400 (V400) (Spectrum Dynamics Medical) under the same clinical conditions. Energy resolution and volumetric sensitivity were evaluated from energy spectra. Vendors provided the best reconstruction parameters dedicated to visualization and/or quantification, based on their respective software developments. For both Tc- and Lu-phantoms, noise level, quantification accuracy, and recovery coefficient (RC) were performed with 3DSlicer. Image quality metrics from an approach called \"task-based\" were computed with iQMetrix-CT on Tc visual reconstructions to assess, through spatial frequencies, noise texture in the background (NPS) and contrast restitution of a hot insert (TTF). Spatial resolution indices were calculated from frequencies corresponding to TTF and TTF . Despite the higher sensitivity of VERITON cameras and the enhanced energy resolution of the V400 (3.2% at 140 keV, 5.2% at 113 keV, and 3.6% at 208 keV), StarGuide presents comparable image quality. This highlights the need to differentiate sensitivity from count quality, which is influenced by hardware design (collimator, detector block) and conditions image quality as well as the reconstruction process (algorithms, scatter correction, noise regulation). For Tc imaging, the quantitative image optimization approach based on RC for StarGuide versus RC for V200 and V400 systems (RC /RC : 0.9/1.8; 0.5/0.9; 0.5/0.9 respectively-Ø37 mm). SR showed nearly equivalent spatial resolution performances across the different reconstructed images. For Lu imaging, the 113 keV imaging of the V200 and V400 systems demonstrated strong performances in both image quality and quantification, while StarGuide and V400 systems offer even better potential due to their ability to exploit signals from both the 113 and 208 keV peaks. Lu quantification was optimized according to RC for all cameras and reconstructions (1.07 ± 0.09-Ø37 mm). The three cameras have equivalent potential for Tc imaging, while StarGuide and V400 have demonstrated higher potential for Lu. Dedicated visual or quantitative reconstructions offer better specific performances compared to the unified visual/quantitative reconstruction. The task-based approach appears to be promising for in-depth comparison of images in the context of system characterization/comparison and protocol optimization.

Purpose A joint initiative of the European Association of Nuclear Medicine (EANM) Neuroimaging Committee and EANM Research Ltd. aimed to generate a European database of [ 123 I]FP-CIT single photon emission computed tomography (SPECT) scans of healthy controls. This study describes the characterization and harmonization of the imaging equipment of the institutions involved. Methods 123 I SPECT images of a striatal phantom filled with striatal to background ratios between 10:1 and 1:1 were acquired on all the gamma cameras with absolute ratios measured from aliquots. The images were reconstructed by a core lab using ordered subset expectation maximization (OSEM) without corrections (NC), with attenuation correction only (AC) and additional scatter and septal penetration correction (ACSC) using the triple energy window method. A quantitative parameter, the simulated specific binding ratio (sSBR), was measured using the “Southampton” methodology that accounts for the partial volume effect and compared against the actual values obtained from the aliquots. Camera-specific recovery coefficients were derived from linear regression and the error of the measurements was evaluated using the coefficient of variation (COV). Results The relationship between measured and actual sSBRs was linear across all systems. Variability was observed between different manufacturers and, to a lesser extent, between cameras of the same type. The NC and AC measurements were found to underestimate systematically the actual sSBRs, while the ACSC measurements resulted in recovery coefficients close to 100% for all cameras (AC range 69–89%, ACSC range 87–116%). The COV improved from 46% (NC) to 32% (AC) and to 14% (ACSC) ( p  < 0.001). Conclusion A satisfactory linear response was observed across all cameras. Quantitative measurements depend upon the characteristics of the SPECT systems and their calibration is a necessary prerequisite for data pooling. Together with accounting for partial volume, the correction for scatter and septal penetration is essential for accurate quantification.

Technetium-99m hexamethylpropylene amine oxime (HMPAO) and (99m)Tc- N, N\"-1,2-ethylene diylbis- l-cysteine diethyl ester dihydrochloride (ECD) yield significantly different images of cerebral perfusion owing to their particular pharmacokinetics. The aim of this study was to assess the topography, extension and statistical significance of these differences in Alzheimer's disease (AD). Sixty-four patients with mild to moderate AD were retrospectively selected by two European centres. Two series of patients, including 32 studied with (99m)Tc-HMPAO single-photon emission tomography (SPET) and 32 studied with (99m)Tc-ECD SPET, were matched for sex, age (+/-3 years) and severity of cognitive impairment as assessed by the Mini-Mental State Examination (MMSE) (+/-2 points), following a case-control procedure. SPET data were processed using SPM99 software (uncorrected height threshold: P=0.001). (99m)Tc-ECD SPET gave significantly higher uptake ratio values than (99m)Tc-HMPAO SPET in several symmetrical clusters, including the right and left occipital cuneus, the left occipital and parietal precuneus, and the left superior and middle temporal gyri. (99m)Tc-HMPAO SPET gave significantly higher uptake ratio values than ECD in two smaller clusters, including the hippocampus in both hemispheres. In AD, relative brain uptake of (99m)Tc-HMPAO and (99m)Tc-ECD is different in several brain regions, some of which are typically involved in AD, such as the precuneus and the hippocampus. These differences confirm the need for specific normal databases, but their impact on routine SPET reports in AD is not known and deserves an ad hoc investigation.

123I-Labeled radiotracers are suitable for in vivo imaging of the dopaminergic system by SPECT. However, precise measurement of striatal uptake is limited by scatter, attenuation, and the finite spatial resolution of the camera. We studied the quantitative accuracy that can be achieved with (123)I SPECT of the dopaminergic neurotransmission system. Using a Monte Carlo simulation and brain phantom experiments, we studied the biases in brain and striatal absolute uptake estimates and in binding potential (BP) values for different processing schemes with corrections for attenuation, scatter, and the partial-volume effect. Without any correction, brain activity was underestimated by at least 65%, and absolute striatal activity measured in regions corresponding to the anatomic contours of the striata was underestimated by about 90%. With scatter and attenuation corrections only, estimated brain activity was accurate within 10%; however, striatal activity remained underestimated by about 50%, and BP values were underestimated by more than 50%. When combined with attenuation and scatter corrections, anatomically guided partial-volume effect correction (PVC) reduced the biases in striatal activity estimates and in BP values to about 10%. PVC reliability was affected by errors in registering SPECT with anatomic images, in segmenting anatomic images, and in estimating the spatial resolution. With registration errors of 1 voxel (2.1 x 2.1 x 3.6 mm(3)) in all directions and of 15 degrees around the axial direction, PVC still improved the accuracy of striatal activity and BP estimates compared with scatter and attenuation corrections alone, the errors being within 25%. A 50% overestimation of the striatal volume yielded an approximate 30% change in striatal activity estimates with respect to no overestimation but still provided striatal activity estimates that were more accurate than those obtained without PVC (average errors +/- 1 SD were -22.5% +/- 1.0% with PVC and -49.0% +/- 5.5% without PVC). A 2-mm error in the spatial resolution estimate changed the striatal activity and BP estimates by no more than 10%. Accurate estimates of striatal uptake and BP in (123)I brain SPECT are feasible with PVC, even with small errors in registering SPECT with anatomic data or in segmenting the striata.

Quantitative estimates of dopamine transporter availability, determined with [(123)I]FP-CIT SPECT, depend on the SPECT equipment, including both hardware and (reconstruction) software, which limits their use in multicentre research and clinical routine. This study tested a dedicated reconstruction algorithm for its ability to reduce camera-specific intersubject variability in [(123)I]FP-CIT SPECT. The secondary aim was to evaluate binding in whole brain (excluding striatum) as a reference for quantitative analysis.PURPOSEQuantitative estimates of dopamine transporter availability, determined with [(123)I]FP-CIT SPECT, depend on the SPECT equipment, including both hardware and (reconstruction) software, which limits their use in multicentre research and clinical routine. This study tested a dedicated reconstruction algorithm for its ability to reduce camera-specific intersubject variability in [(123)I]FP-CIT SPECT. The secondary aim was to evaluate binding in whole brain (excluding striatum) as a reference for quantitative analysis.Of 73 healthy subjects from the European Normal Control Database of [(123)I]FP-CIT recruited at six centres, 70 aged between 20 and 82 years were included. SPECT images were reconstructed using the QSPECT software package which provides fully automated detection of the outer contour of the head, camera-specific correction for scatter and septal penetration by transmission-dependent convolution subtraction, iterative OSEM reconstruction including attenuation correction, and camera-specific \"to kBq/ml\" calibration. LINK and HERMES reconstruction were used for head-to-head comparison. The specific striatal [(123)I]FP-CIT binding ratio (SBR) was computed using the Southampton method with binding in the whole brain, occipital cortex or cerebellum as the reference. The correlation between SBR and age was used as the primary quality measure.METHODSOf 73 healthy subjects from the European Normal Control Database of [(123)I]FP-CIT recruited at six centres, 70 aged between 20 and 82 years were included. SPECT images were reconstructed using the QSPECT software package which provides fully automated detection of the outer contour of the head, camera-specific correction for scatter and septal penetration by transmission-dependent convolution subtraction, iterative OSEM reconstruction including attenuation correction, and camera-specific \"to kBq/ml\" calibration. LINK and HERMES reconstruction were used for head-to-head comparison. The specific striatal [(123)I]FP-CIT binding ratio (SBR) was computed using the Southampton method with binding in the whole brain, occipital cortex or cerebellum as the reference. The correlation between SBR and age was used as the primary quality measure.The fraction of SBR variability explained by age was highest (1) with QSPECT, independently of the reference region, and (2) with whole brain as the reference, independently of the reconstruction algorithm.RESULTSThe fraction of SBR variability explained by age was highest (1) with QSPECT, independently of the reference region, and (2) with whole brain as the reference, independently of the reconstruction algorithm.QSPECT reconstruction appears to be useful for reduction of camera-specific intersubject variability of [(123)I]FP-CIT SPECT in multisite and single-site multicamera settings. Whole brain excluding striatal binding as the reference provides more stable quantitative estimates than occipital or cerebellar binding.CONCLUSIONQSPECT reconstruction appears to be useful for reduction of camera-specific intersubject variability of [(123)I]FP-CIT SPECT in multisite and single-site multicamera settings. Whole brain excluding striatal binding as the reference provides more stable quantitative estimates than occipital or cerebellar binding.