The impact of varying number of OSEM iterations on Standardized Uptake Value (SUV) and image quality of PET/CT Scan

Background: In PET imaging both quantitative and qualitative interpretations are used. Qualitative and quantitative interpretations depend upon PET/CT image quality that along with many biologic factors strongly depends upon image reconstruction parameters. Aim: The objective of this experimental work was to study the impact of one of the key reconstruction parameter, i.e., number of reconstruction iteration, on standardized uptake value and image quality of PET/CT scan. Methods: Images of NEMA IEC Image Quality Phantom were acquired in list mode for 10 mins on Discovery STE PET/CT scanner, using tumor to background ratio of 4:1 and 18F-FDG as radiotracer. List mode data were further transformed into data sets of varying acquisition time (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 mins) per bed position. Transformed data set of 5.0 mins were used to study the impact of varying number of iterations (2, 3, 4, 5, 7, 10, 15, 20) using OSEM approach of iterative reconstruction. Standardized uptake value (SUV) and underestimation in SUV were calculated as quantitative measures, while hot lesion contrast, cold lesion contrast and background variability were calculated as qualitative measures. Results: Standardized uptake value, hot and cold lesion contrast, image spatial resolution and background variability showed increasing trend with increase in reconstruction iterations. Maximum increase of 20.25%, 16.33%, 9.79% and 6.88% was observed in SUV for 10 mm, 13 mm, 17 mm and 22 mm lesions as number of iteration change from 2 to 3. Smallest and the largest diameter lesions showed maximum underestimations of 54.67% and 8.20% at 2 iterations respectively. Percentage hot lesion contrast showed rapid increase as the number of iteration change from 2 to 7 and increased slowly afterward. Background variability range from 4.4% to 6.4%, 4.1%–5.7%, 3.6%–4.6%, 3%–3.8%, 2.7%–3.2%, 2.4%–2.7% for 10.0 mm, 13.0 mm, 17.0 mm, 22.0 mm, 28.0 mm and 37.0 mm sphere respectively. Conclusion: Optimized reconstruction parameters for routine clinical studies 3 iterations with image matrix size of 128 × 128 with filters FWHM of 6 mm and for high resolution studies 3 iterations image matrix size of 256×256 with filters FWHM of 6 mm.

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Impact of total variation regularized expectation maximization reconstruction on the image quality of 68Ga-PSMA PET: a phantom and patient study

British Journal of Radiology ◽

10.1259/bjr.20201356 ◽

2021 ◽

pp. 20201356

Author(s):

Feng-Jiao Yang ◽

Shu-Yue Ai ◽

Runze Wu ◽

Yang Lv ◽

Hui-Fang Xie ◽

...

Keyword(s):

Prostate Cancer ◽

Image Quality ◽

Total Variation ◽

Expectation Maximization ◽

Image Noise ◽

Psma Pet ◽

Pet Ct ◽

Digital Pet ◽

The Impact

Objectives: To investigate the impact of total variation regularized expectation maximization (TVREM) reconstruction on the image quality of 68Ga-PSMA-11 PET/CT using phantom and patient data. Methods: Images of a phantom with small hot sphere inserts and 20 prostate cancer patients were acquired with a digital PET/CT using list-mode and reconstructed with ordered subset expectation maximization (OSEM) and TVREM with seven penalisation factors between 0.01 and 0.42 for 2 and 3 minutes-per-bed (m/b) acquisition. The contrast recovery (CR) and background variability (BV) of the phantom, image noise of the liver, and SUVmax of the lesions were measured. Qualitative image quality was scored by two radiologists using a 5-point scale (1-poor, 5-excellent). Results: The performance of CR, BV, and image noise, and the gain of SUVmax was higher for TVREM 2 m/b groups with the penalization of 0.07 to 0.28 compared to OSEM 3 m/b group (all p < 0.05). The image noise of OSEM 3 m/b group was equivalent to TVREM 2 and 3 m/b groups with a penalization of 0.14 and 0.07, while lesions’ SUVmax increased 15 and 20%. The highest qualitative score was attained at the penalization of 0.21 (3.30 ± 0.66) for TVREM 2 m/b groups and the penalization 0.14 (3.80 ± 0.41) for 3 m/b group that equal to or greater than OSEM 3 m/b group (2.90 ± 0.45, p = 0.2 and p < 0.001). Conclusions: TVREM improves lesion contrast and reduces image noise, which allows shorter acquisition with preserved image quality for PSMA PET/CT. Advances in knowledge: TVREM reconstruction with optimized penalization factors can generate higher quality PSMA-PET images for prostate cancer diagnosis.

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A study on the effects of an extended CT field of view (FOV) on the standardized uptake value (SUV) in a PET/CT scan using 18F-fluoro-2deoxy-D-glucose

Journal of the Korean Physical Society ◽

10.3938/jkps.61.2091 ◽

2012 ◽

Vol 61 (12) ◽

pp. 2091-2095 ◽

Cited By ~ 1

Author(s):

Soon-Ki Park ◽

Ki-Pyo Nam ◽

Woo-Young Jung ◽

Kyeong-Sik Kim ◽

Sang-Ki Shin ◽

...

Keyword(s):

Ct Scan ◽

Standardized Uptake Value ◽

Field Of View ◽

Pet Ct ◽

Pet Ct Scan

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EFFECT OF STANDARDIZED UPTAKE VALUE DISCRETIZATION ON RADIOMICS FEATURES OF LIVER TUMORS USING 18FDG-PET/CT SCAN

Russian Electronic Journal of Radiology ◽

10.21569/2222-7415-2021-11-3-132-137 ◽

2021 ◽

Vol 11 (3) ◽

pp. 132-137

Author(s):

M.A. Mahmoud ◽

◽

M. Shihab ◽

SS. Saad ◽

F. Elhussiny ◽

...

Keyword(s):

Ct Scan ◽

Liver Tumors ◽

Standardized Uptake Value ◽

18Fdg Pet ◽

Pet Ct ◽

Pet Ct Scan

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Bone marrow examination (BMex) in staging of SCLC after implementation of PET/CT scan.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.e20014 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. e20014-e20014

Author(s):

Karin Holmskov Hansen ◽

Mette Boes Eriksen ◽

Tine Schytte ◽

Olfred Hansen

Keyword(s):

Decision Making ◽

Ct Scan ◽

Bone Metastases ◽

Bone Lesions ◽

Therapeutic Decision ◽

Therapeutic Decisions ◽

Pet Ct ◽

Therapeutic Decision Making ◽

The Impact ◽

Pet Ct Scan

e20014 Background: Correct staging of small cell lung cancer (SCLC) in limited disease (LD) or extensive disease (ED) is crucial as it has an impact on the therapeutic decision-making. The staging procedures in SCLC in the late 1990s included chest X-ray, blood samples, abdominal ultrasonography (UL), and iliac crest BMex. The aim of this study was to evaluate the continued eligibility of performing BMex in patients (ptt) with SCLC as a routine staging procedure, and to see how often therapeutic decisions were influenced by a positive BM before and after the PET/CT scan era. Methods: All diagnostic and staging procedures were registered in ptt with SCLC referred to our department from 1995 to 1999 in cohort 1 (C1). Cohort 2 (C2) included SCLC patients referred from 2009 to 2013. In C2 results of PET/CT in terms of bone metastases were related to results of BMex. Results: In C1 194 ptt was referred with 136 (70%) having ED. BMex was omitted in 32 (17%) fragile ptt having known ED while all LD ptt underwent BMex. BM involvement was seen in 37 (23%) of all 162 BMex and 36% of the 104 ED ptt examined. When BM was negative the staging of ED was due to other imaging. The BM had an impact on therapeutic decision-making in 5 (4%) of 136 having ED and 5 (3%) of 162 BMex. In C2 211 ptt of 292 (72%) had ED and 203 (70%) of all ptt underwent BMex. BM biopsy was done in 137 (65 %) ED and in 66 (69 %) LD. Of 137 ED ptt BM involvement was found in 31 (23 %) cases. A PET/CT scan was performed in 13 (42 %) of these ptt of which bone metastases was found in 12 (92 %). One patient (8%) had a PET/CT without bone lesions. Bone metastases were seen at PET/CT scan in 61 ptt in C2, of these 22 (36%) had negative BM, whereas 12 (20%) had BM involvement and in 3 ptt (5%) BMex were inconclusive. No BMex was performed in 24 ptt (39%). BMex had an impact on therapeutic decision-making in 3 (1.4%) of 211 having ED and 5 (2.5%) of 203 BMex. Conclusions: Due to staging by PET/CT and CT scan in SCLC ptt the impact of BMex in the therapeutic decision-making has decreased and fewer ptt are undergoing BMex. Though a negative PET/CT cannot exclude BM involvement BMex may be considered omitted.

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Comparison of Image Quality and Spatial Resolution Between 18F, 68Ga and 64Cu Phantom Measurements Using a Digital Biograph Vision PET/CT

10.21203/rs.3.rs-1159557/v1 ◽

2022 ◽

Author(s):

Anja Braune ◽

Liane Oehme ◽

Robert Freudenberg ◽

Frank Hofheinz ◽

Jörg van den Hoff ◽

...

Keyword(s):

Image Quality ◽

Spatial Resolution ◽

Ct Scans ◽

Reconstruction Method ◽

Recovery Coefficient ◽

Positron Energy ◽

Pet Ct ◽

The Individual ◽

The Impact

Abstract Background: The PET nuclide and reconstruction method can have a considerable influence on spatial resolution and image quality of PET/CT scans, which can, for example, influence the diagnosis in oncology. The individual impact of the positron energy of 18F, 68Ga and 64Cu on spatial resolution and image quality of PET/CT scans acquired using a clinical, digital scanner was compared. Furthermore, the impact of different reconstruction parameters on image quality and spatial resolution was evaluated for 18F-FDG PET/CT scans acquired with a scanner of the newest generation. Methods: PET/CT scans of a Jaszczak phantom and a NEMA PET body phantom, filled with 18F-FDG, 68Ga-HCl and 64Cu-HCl, respectively, were performed on a Siemens Biograph Vision. Images were assessed using spatial resolution and image quality (Recovery Coefficients (RC), coefficient of variation within the background, Contrast Recovery Coefficient (CRC), Contrast-Noise-Ratio (CNR), and relative count error in lung insert). In a subsequent analysis, the scan of the NEMA PET body phantom filled with 18F-FDG was reconstructed applying different parameters (with/without the application of Point Spread Function (PSF), Time of Flight (ToF) or post-filtering; matrix size). Spatial resolution and quantitative image quality were compared between reconstructions. Results: We found that image quality was comparable between 18F-FDG and 64Cu-HCl PET/CT measurements featuring similar maximal endpoint energy. In comparison, RC, CRC and CNR were worse in 68Ga-HCl data, despite similar count rates. Spatial resolution was up to 18 % worse in 68Ga-HCl compared to 18F-FDG images. Post-filtering of 18F-FDG acquisitions changed image quality the most and reduced spatial resolution by 52 % if a Gaussian filter with 5 mm FWHM was applied. ToF measurements especially improved the recovery of the smallest lesion (RCmean = 1.07 compared to 0.65 without ToF) and improved spatial resolution by 29 %.Conclusions: The positron energy of PET nuclides influences spatial resolution and image quality of digital PET/CT scans. Image quality of 68Ga-HCl PET/CT images was worse compared to 18F-FDG and 64Cu-HCl, respectively, despite similar count rates. Reconstruction parameters have a high impact on image quality and spatial resolution and should be considered when comparing images of different scanners or centers.

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