Reduction of Collimator Correction Artefacts with  Bayesian Reconstruction in Spect

Kangasmaa, Tuija; Sohlberg, Antti; Kuikka, Jyrki T.

doi:10.1155/2011/630813

Cited by 22 publications

(28 citation statements)

References 17 publications

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“…This somewhat compensates for the generally higher SUVs of PET, which may partly result in the smallest difference in SUV peak . The SPECT SUV peak , and SUV max as well, may have also been slightly overestimated due to collimator response correction artifact [29]. These same factors increasing SPECT SUVs peak may also cause SPECT SUVRs peak to be higher than PET SUVRs peak resulting in the largest systematic difference among our SUVR measures.…”

Section: Discussionmentioning

confidence: 99%

Comparison of standardized uptake values between 99mTc-HDP SPECT/CT and 18F-NaF PET/CT in bone metastases of breast and prostate cancer

et al. 2019

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BackgroundDespite recent technological advances allowing for quantitative single-photon emission computed tomography (SPECT), quantitative SPECT has not been widely used in the clinical practice. The aim of this study is to evaluate the feasibility of quantitative SPECT for measuring metastatic bone uptake in breast and prostate cancer by comparing standard uptake values (SUVs) measured with 99mTc-HDP SPECT/CT and 18F-NaF PET/CT.MethodsTwenty-six breast and 27 prostate cancer patients at high risk of bone metastases underwent both 99mTc-HDP SPECT/CT and 18F-NaF PET/CT within 14 days of each other. The SPECT and PET data were reconstructed using ordered-subset expectation-maximization algorithms achieving quantitative images. Metastatic and benign skeletal lesions visible in both data sets were identified, and their maximum, peak, and mean SUVs (SUVmax, SUVpeak, and SUVmean) were determined. SUV ratios (SUVRs) between the lesions and adjacent normal appearing bone were also calculated. Linear regression was used to evaluate the correlations between the SUVs of SPECT and PET and Bland-Altman plots to evaluate the differences between the SUVs and SUVRs of SPECT and PET.ResultsA total of 231 skeletal lesions, 129 metastatic and 102 benign, were analyzed. All three SUV measures correlated very strongly between SPECT and PET (R2 ≥ 0.80, p < 0.001) when all lesions were included, and the PET SUVs were significantly higher than SPECT SUVs (p < 0.001). The median differences were 21%, 12%, and 19% for SUVmax, SUVpeak, and SUVmean, respectively. On the other hand, the SUVRs were similar between SPECT and PET with median differences of 2%, − 9%, and 2% for SUVRmax, SUVRpeak, and SUVRmean, respectively.ConclusionThe strong correlation between SUVs and similar SUVRs of 99mTc-HDP SPECT/CT and 18F-NaF PET/CT demonstrate that SPECT is an applicable tool for clinical quantification of bone metabolism in osseous metastases in breast and prostate cancer patients.

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Section: Discussionmentioning

confidence: 99%

Comparison of standardized uptake values between 99mTc-HDP SPECT/CT and 18F-NaF PET/CT in bone metastases of breast and prostate cancer

et al. 2019

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“…With the smoothing prior, it is hypothesized that the pancreas activity is more homogeneously distributed in the images. The MAP MRP preserves edges and hotspots more than the smoothing prior but also assumes a locally monotonic image [13]. Scatter, CT map-based attenuation and collimator correction were applied as available in the reconstruction software.…”

Section: Methodsmentioning

confidence: 99%

A 3D-printed anatomical pancreas and kidney phantom for optimizing SPECT/CT reconstruction settings in beta cell imaging using 111In-exendin

Weg¹,

Deden²,

Meeuwis³

et al. 2016

EJNMMI Phys

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BackgroundQuantitative single photon emission computed tomography (SPECT) is challenging, especially for pancreatic beta cell imaging with 111In-exendin due to high uptake in the kidneys versus much lower uptake in the nearby pancreas. Therefore, we designed a three-dimensionally (3D) printed phantom representing the pancreas and kidneys to mimic the human situation in beta cell imaging. The phantom was used to assess the effect of different reconstruction settings on the quantification of the pancreas uptake for two different, commercially available software packages.Methods3D-printed, hollow pancreas and kidney compartments were inserted into the National Electrical Manufacturers Association (NEMA) NU2 image quality phantom casing. These organs and the background compartment were filled with activities simulating relatively high and low pancreatic 111In-exendin uptake for, respectively, healthy humans and type 1 diabetes patients. Images were reconstructed using Siemens Flash 3D and Hermes Hybrid Recon, with varying numbers of iterations and subsets and corrections. Images were visually assessed on homogeneity and artefacts, and quantitatively by the pancreas-to-kidney activity concentration ratio.ResultsPhantom images were similar to clinical images and showed comparable artefacts. All corrections were required to clearly visualize the pancreas. Increased numbers of subsets and iterations improved the quantitative performance but decreased homogeneity both in the pancreas and the background. Based on the phantom analyses, the Hybrid Recon reconstruction with 6 iterations and 16 subsets was found to be most suitable for clinical use.ConclusionsThis work strongly contributed to quantification of pancreatic 111In-exendin uptake. It showed how clinical images of 111In-exendin can be interpreted and enabled selection of the most appropriate protocol for clinical use.

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“…The imaging energy window was centered at the energy of the upper photo peak of Lu-177 at 208 keV (width 15 %). Quantitative SPECT reconstruction was performed with collimator-specific depth-dependent detector response modelling, corrections for photon attenuation and scattering and using a system-specific calibration factor (16 MAP iterations, 8 subsets, Bayesian weight 0.01, Hermes Hybrid Recon v.2.1.1, HERMES Medical Solutions, Sweden) (14,15).…”

Section: Image Acquisition and Reconstructionmentioning

confidence: 99%

Influence of dosimetry method on bone lesion absorbed dose estimates in PSMA therapy: application to mCRPC patients receiving Lu-177-PSMA-I&T

Brosch-Lenz

Uribe

Gosewisch

et al. 2020

Preprint

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Background Patients with metastatic, castration-resistant prostate cancer (mCRPC) present with an increased tumor burden in the skeleton. For these patients, Lutetium-177 (Lu-177) radioligand therapy targeting the prostate-specific membrane antigen (PSMA) has gained increasing interest with promising outcome data. Patient-individualized dosimetry enables quantification of therapy success with the aim of minimizing absorbed dose to organs at risk while maximizing absorbed dose to tumors. Different dosimetric approaches with varying complexity and accuracy exist for this purpose. The relatively simple OLINDA method applied to tumors assumes a homogeneous activity distribution in a sphere with unit density. Voxel S value (VSV) approaches can account for heterogeneous activities but are simulated for a specific tissue. Full patient-individual Monte Carlo (MC) dose simulation addresses both, heterogeneous activity and density distributions. Subsequent CT-based density correction has the potential to overcome the assumption of homogeneous density in OLINDA and VSV methods, which could be a major limitation for the application in bone metastases with heterogeneous density. The aim of this investigation is a comparison of these methods for bone lesion dosimetry in mCRPC patients receiving Lu-177-PSMA therapy. Results In total, 289 bone lesions in 15 mCRPC patients were analyzed. Percentage deviation (PD) of absorbed lesion doses compared to full MC was + 7 ± 13% (min: -60%; max: +47%) for the OLINDA unit density sphere model. With an applied CT-based density weighting to account for density differences in bone lesions, PD was − 15 ± 6% (min: -54%; max: -2%). For a soft tissue VSV approach, large PDs of + 16 ± 13% (min: -56%; max: +57%) were found; after voxel-wise density correction this was reduced to -5 ± 2% (min: -15%; max: -2%). The use of a combination of standard soft tissue and cortical bone VSVs showed deviations of -35 ± 8% (min: -76%; max: +5%). With additional voxel-wise density weighting, the PD was − 3 ± 2% (min: -13%; max: 0%). Conclusion Based on our bone lesion dosimetry results, a VSV approach with subsequent CT-based, voxel-wise density correction enabled dose estimates, that closely replicate computationally-demanding gold-standard full MC dose simulations.

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Reduction of Collimator Correction Artefacts with Bayesian Reconstruction in Spect

Cited by 22 publications

References 17 publications

Comparison of standardized uptake values between 99mTc-HDP SPECT/CT and 18F-NaF PET/CT in bone metastases of breast and prostate cancer

Comparison of standardized uptake values between 99mTc-HDP SPECT/CT and 18F-NaF PET/CT in bone metastases of breast and prostate cancer

A 3D-printed anatomical pancreas and kidney phantom for optimizing SPECT/CT reconstruction settings in beta cell imaging using 111In-exendin

Influence of dosimetry method on bone lesion absorbed dose estimates in PSMA therapy: application to mCRPC patients receiving Lu-177-PSMA-I&T

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Reduction of Collimator Correction Artefacts with Bayesian Reconstruction in Spect

Cited by 22 publications

References 17 publications

Comparison of standardized uptake values between 99mTc-HDP SPECT/CT and 18F-NaF PET/CT in bone metastases of breast and prostate cancer

Comparison of standardized uptake values between 99mTc-HDP SPECT/CT and 18F-NaF PET/CT in bone metastases of breast and prostate cancer

A 3D-printed anatomical pancreas and kidney phantom for optimizing SPECT/CT reconstruction settings in beta cell imaging using 111In-exendin

Influence of dosimetry method on bone lesion absorbed dose estimates in PSMA therapy: application to mCRPC patients receiving Lu-177-PSMA-I&amp;T

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Influence of dosimetry method on bone lesion absorbed dose estimates in PSMA therapy: application to mCRPC patients receiving Lu-177-PSMA-I&T