Abstract No. 34 Planar scintigraphy overestimates hepatopulmonary shunt fractions compared with quantitative SPECT/CT

Radioimmunoscintigraphy (RIS) with 111ln- and 131 I-labelled monoclonal anti bodies (MAbs) against CEA and/or CA 19-9 was performed in 83 patients with various gastrointestinal carcinomas. A total of 276 body regions could be examined. The results of planar scintigraphy and SPECT were compared intraindividually. Using 111 In-labelled MAbs the sensitivity of RIS was significantly improved by SPECT (88.9 vs. 52.4% with planar scintigraphy, p <0.01). For131 l-labelled MAbs the effect was smaller (83.9 vs. 65.6% with planar scintigraphy, n.s.). This finding can be explained by different kinetics and biodistribution of the used MAb preparations.111 In-labelled MAbs with long whole-body retention and rapid blood clearance reveal ideal qualities for SPECT; on the other hand, the short whole-body retention of131 l-labelled MAbs leads to small count rates and therefore long counting times that make delayed SPECT unsuitable in clinical practice

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Absolute SPECT/CT quantification of cerebral uptake of 99mTc-HMPAO for patients with neurocognitive disorders

Nuklearmedizin ◽

10.3413/nukmed-0765-15-09 ◽

2016 ◽

Vol 55 (04) ◽

pp. 158-165 ◽

Cited By ~ 3

Author(s):

Friedrich Welz ◽

James Sanders ◽

Torsten Kuwert ◽

Juan Maler ◽

Johannes Kornhuber ◽

...

Keyword(s):

Tissue Concentration ◽

Tracer Uptake ◽

Planar Imaging ◽

Quantitative Spect ◽

Dementia Patients ◽

Hmpao Spect ◽

Patient Groups ◽

The Absolute ◽

99Mtc Hmpao

SummaryIt was reported from planar imaging studies that the cerebral uptake of injected 99mTc-HMPAO activity is about 4–7% in humans. Recent work has shown that modern SPECT/ CT devices are able to quantify the tissue concentration of radioactivity in vivo in absolute units (Bq/ml), while avoiding the limitations of planar techniques. The aims of this study were (a) to determine the cerebral uptake of 99mTc-HMPAO in absolute units in SPECT/CT, (b) to investigate potential differences in absolute tracer uptake for patients suspected of dementia. Patients, methods: We performed 99mTc-HMPAO SPECT/CT in 65 patients with suspected dementia. 99mTc-HMPAO uptake was determined using a previously published quantitative SPECT/CT protocol. The absolute HMPAO uptake and the results of a regionalized analysis were compared for MMSE and NINCDS-ADRDA based patient groups. Results: The mean absolute uptake of 99mTc-HMPAO for our patient population was 4.3 ± 0.8% of the injected dose. The uptake, as well as the regionalized analysis yielded significantly different results for low ( 23) and high (>23) MMSE groups and also for some of the NINCDS-ADRDA groups. Conclusion: Our results show that the absolute cerebral uptake of 99mTc-HMPAO is in the range of previously reported results, obtained by planar techniques. Absolute uptake is significantly different between the patient groups.

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Comprehensive SPECT/CT system characterization and calibration for 177Lu quantitative SPECT (QSPECT) with dead-time correction

EJNMMI Physics ◽

10.1186/s40658-020-0275-6 ◽

2020 ◽

Vol 7 (1) ◽

Cited By ~ 2

Author(s):

Andrea Frezza ◽

Corentin Desport ◽

Carlos Uribe ◽

Wei Zhao ◽

Anna Celler ◽

...

Keyword(s):

Dead Time ◽

Dead Time Correction ◽

Quantitative Spect ◽

System Characterization ◽

Time Correction ◽

Ct System

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Optimization of SPECT/CT imaging protocols for quantitative and qualitative 99mTc SPECT

EJNMMI Physics ◽

10.1186/s40658-021-00405-3 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Dennis Kupitz ◽

Heiko Wissel ◽

Jan Wuestemann ◽

Stephanie Bluemel ◽

Maciej Pech ◽

...

Keyword(s):

Signal To Noise Ratio ◽

Quantitative Imaging ◽

Scatter Correction ◽

Reconstruction Algorithm ◽

Weighting Factor ◽

Quantitative Spect ◽

Pet Ct ◽

Spect Acquisition ◽

The Mean ◽

A Minor

Abstract Background The introduction of hybrid SPECT/CT devices enables quantitative imaging in SPECT, providing a methodological setup for quantitation using SPECT tracers comparable to PET/CT. We evaluated a specific quantitative reconstruction algorithm for SPECT data using a 99mTc-filled NEMA phantom. Quantitative and qualitative image parameters were evaluated for different parametrizations of the acquisition and reconstruction protocol to identify an optimized quantitative protocol. Results The reconstructed activity concentration (ACrec) and the signal-to-noise ratio (SNR) of all examined protocols (n = 16) were significantly affected by the parametrization of the weighting factor k used in scatter correction, the total number of iterations and the sphere volume (all, p < 0.0001). The two examined SPECT acquisition protocols (with 60 or 120 projections) had a minor impact on the ACrec and no significant impact on the SNR. In comparison to the known AC, the use of default scatter correction (k = 0.47) or object-specific scatter correction (k = 0.18) resulted in an underestimation of ACrec in the largest sphere volume (26.5 ml) by − 13.9 kBq/ml (− 16.3%) and − 7.1 kBq/ml (− 8.4%), respectively. An increase in total iterations leads to an increase in estimated AC and a decrease in SNR. The mean difference between ACrec and known AC decreased with an increasing number of total iterations (e.g., for 20 iterations (2 iterations/10 subsets) = − 14.6 kBq/ml (− 17.1%), 240 iterations (24i/10s) = − 8.0 kBq/ml (− 9.4%), p < 0.0001). In parallel, the mean SNR decreased significantly from 2i/10s to 24i/10s by 76% (p < 0.0001). Conclusion Quantitative SPECT imaging is feasible with the used reconstruction algorithm and hybrid SPECT/CT, and its consistent implementation in diagnostics may provide perspectives for quantification in routine clinical practice (e.g., assessment of bone metabolism). When combining quantitative analysis and diagnostic imaging, we recommend using two different reconstruction protocols with task-specific optimized setups (quantitative vs. qualitative reconstruction). Furthermore, individual scatter correction significantly improves both quantitative and qualitative results.

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Assessment of cardiac amyloidosis with 99mTc-pyrophosphate (PYP) quantitative SPECT

EJNMMI Physics ◽

10.1186/s40658-020-00342-7 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Chao Ren ◽

Jingyun Ren ◽

Zhuang Tian ◽

Yanrong Du ◽

Zhixin Hao ◽

...

Keyword(s):

Cardiac Amyloidosis ◽

Activity Concentration ◽

Standardized Uptake Value ◽

Blood Pool ◽

Systematic Difference ◽

Repeated Measurements ◽

Quantitative Spect ◽

Phantom Studies ◽

Grade 3 ◽

Operator Reproducibility

Abstract Background 99mTc-PYP scintigraphy provides differential diagnosis of ATTR cardiomyopathy (ATTR-CM) from light chain cardiac amyloidosis and other myocardial disorders without biopsy. This study was aimed to assess the diagnostic feasibility and the operator reproducibility of 99mTc-PYP quantitative SPECT. Method Thirty-seven consecutive patients who underwent a 99mTc-PYP thorax planar scan followed by SPECT and CT scans to diagnose suspected ATTR-CM were enrolled. For the quantitative SPECT, phantom studies were initially performed to determine the image conversion factor (ICF) and partial volume correction (PVC) factor to recover 99mTc-PYP activity concentration in the myocardium for calculating the standardized uptake value (SUV) (unit: g/ml). SUVmax was compared among groups of ATTR-CM, AL cardiac amyloidosis, and other pathogens (others) and among categories of Perugini visual scores (grades 0–3). The intra- and inter-operator reproducibility of quantitative SPECT was verified, and the corresponded repeatability coefficient (RPC) was calculated. Results The ICF was 79,327 Bq/ml to convert count rate in pixel to 99mTc activity concentration. PVC factor as a function of the measured activity concentration ratio in the myocardium and blood-pool was [y = 1.424 × (1 − exp(− 0.759 × x)) + 0.104]. SUVmax of ATTR-CM (7.50 ± 2.68) was significantly higher than those of AL (1.96 ± 0.35) and others (2.00 ± 0.74) (all p < 0.05). SUVmax of grade 3 (8.95 ± 1.89) and grade 2 (4.71 ± 0.23) were also significantly higher than those of grade 1 (1.92 ± 0.31) and grade 0 (1.59 ± 0.39) (all p < 0.05). Correlation coefficient (R2) of SUVmax reached 0.966 to 0.978 with only small systematic difference (intra = − 0.14; inter = − 0.23) between two repeated measurements. Intra- and inter-operator RPCs were 0.688 and 0.877. Conclusions 99mTc-PYP quantitative SPECT integrated with adjustable PVC factors is feasible to quantitatively and objectively assess the burden of cardiac amyloidosis for diagnosis of ATTR-CM.

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