Assessment of Image Quality and Lesion Detectability With Digital PET/CT System

Purpose: The aim of this study was to assess image quality and lesion detectability acquired with a digital Positron Emission Tomography/Computed Tomography (PET/CT) Siemens Biograph Vision 600 system.Material and Methods: Consecutive patients who underwent a FDG PET/CT during the first week of use of a digital PET/CT (Siemens Biograph Vision 600) at the nuclear medicine department of the university hospital of Brest were analyzed. PET were realized using list mode acquisition. For all patients, 4 datasets were reconstructed. We determined, according to phantom measurements, an equivalent time acquisition/reconstruction parameters pair of the digital PET/CT corresponding to an analog PET/CT image quality (“analog-like”) as reference dataset. We compared the reference dataset with 3 others digital PET/CT reconstruction parameters, allowing a decrease of emission duration: 60, 90, and 120 s per bed position. Three nuclear medicine physicians evaluated independently, for each dataset, overall image quality [Maximal Intensity Projection (MIP), noise, sharpness] using a 4-point scale. Physicians assessed also lesion detection capability by reporting new visible lesions on each digital datasets with their confidence level in comparison with analog-like dataset.Results: Ninety-eight patients were analyzed. Image quality of MIP (IQMIP), sharpness (IQSHARPNESS), and noise (IQNOISE) of all digital datasets (60, 90, and 120 s) were better than those evaluated with analog-like reconstruction. Moreover, digital PET/CT system improved IQMIP, IQNOISE, and IQSHARPNESS whatever the BMI. Lesion detection capability and confidence level were higher for 60, 90, 120 s per bed position, respectively, than for analog-like images.Conclusion: Our study demonstrated an improvement of image quality and lesion detectability with a digital PET/CT system.

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Comparing lesion detection efficacy and image quality across different PET system generations to optimize the iodine-124 PET protocol for recurrent thyroid cancer

EJNMMI Physics ◽

10.1186/s40658-021-00361-y ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

David Kersting ◽

Walter Jentzen ◽

Miriam Sraieb ◽

Pedro Fragoso Costa ◽

Maurizio Conti ◽

...

Keyword(s):

Thyroid Cancer ◽

Image Quality ◽

Neck Region ◽

Lesion Detection ◽

Whole Body ◽

Acquisition Time ◽

Region Detection ◽

Pet Ct ◽

Bed Position ◽

New Generation

Abstract Background In recurrent differentiated thyroid cancer patients, detectability in 124I PET is limited for lesions with low radioiodine uptake. We assess the improvements in lesion detectability and image quality between three generations of PET scanners with different detector technologies. The results are used to suggest an optimized protocol. Methods Datasets of 10 patients with low increasing thyroglobulin or thyroglobulin antibody levels after total thyroidectomy and radioiodine therapies were included. PET data were acquired and reconstructed on a Biograph mCT PET/CT (whole-body, 4-min acquisition time per bed position; OSEM, OSEM-TOF, OSEM-TOF+PSF), a non-TOF Biograph mMR PET/MR (neck region, 4 min and 20 min; OSEM), and a new generation Biograph Vision PET/CT (whole-body, 4 min; OSEM, OSEM-TOF, OSEM-TOF+PSF). The 20-min image on the mMR was used as reference to calculate the detection efficacy in the neck region. Image quality was rated on a 5-point scale. Results All detected lesions were in the neck region. Detection efficacy was 8/9 (Vision OSEM-TOF and OSEM-TOF+PSF), 4/9 (Vision OSEM), 3/9 (mMR OSEM and mCT OSEM-TOF+PSF), and 2/9 (mCT OSEM and OSEM-TOF). Median image quality was 4 (Vision OSEM-TOF and OSEM-TOF+PSF), 3 (Vision OSEM, mCT OSEM-TOF+PSF, and mMR OSEM 20-min), 2 (mCT OSEM-TOF), 1.5 (mCT OSEM), and 1 (mMR OSEM 4 min). Conclusion At a clinical standard acquisition time of 4 min per bed position, the new generation Biograph Vision using a TOF-based image reconstruction demonstrated the highest detectability and image quality and should, if available, be preferably used for imaging of low-uptake lesions. A prolonged acquisition time for the mostly affected neck region can be useful.

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The Impact of Patient’s Body Habitus on PET Image Quality in Digital and Analogic PET/CT

10.21203/rs.3.rs-56118/v1 ◽

2020 ◽

Author(s):

Kathleen Weyts ◽

Elske Quak ◽

Idlir Licaj ◽

Charline Lasnon ◽

Renaud Ciappuccini ◽

...

Keyword(s):

Image Quality ◽

Fdg Pet ◽

Pearson Correlation ◽

Linear Regression Analysis ◽

Acquisition Time ◽

Body Habitus ◽

Pet Ct ◽

Digital Pet ◽

Bed Position ◽

The Impact

Abstract Background: New digital versus analogic PET has higher temporal resolution and more stable count rate, potentially limiting the degradation of PET image quality in larger patients. We wanted to describe the influence of patient’s body habitus on [18F]FDG PET image quality primary in digital PET/CT and analogic PET/CT.Results:We studied retrospectively the relation between patient’s weight, BMI, fatty massand PET image quality, described by the coefficient of variance in the liver (CVliv) and visually.177 unique patient exams on digital PET/CT (weight 35-127 kg; BMI 15-44 kg/m2) were performed with 2 protocols (protocol 1: N=52: 3MBq (0,08mCi)/kg [18F]FDG; 2minutes/bed position; 2iterations10subsets; 2mm diameter voxels and protocol 2: N=125: 4MBq (0,11mCi) /kg [18F]FDG; 1min/bed position; 4iterations4subsets; 2mm voxels).74 unique patient exams were analyzed on analogic PET/CT (weight 38-130 kg; BMI 14-52 kg/m2; with one protocol: 4MBq (0,11mCi)/kg [18F]FDG; 2min40sec/bedposition for BMI<25 and 3min40sec for BMI ≥25; 3iterations21subsets; 4mm voxels).Uni-and multivariable linear regression analysis showed positive association of CVliv with weight, BMI, fatty mass (p£0.009) and male sex (p£0,03) for both camera’s, with good fit in CVliv versus weight model on digital PET/CT (R2 up to 0.62). 4MBq (0,11mCi) protocol on digital PET/CT versus analogic PET/CT obtained lower CVliv on digital PET/CT in patients <70kg, without a difference if 70-<90kg and in Pearson correlation coefficients (p=0,26) despite substantially longer acquisition time for analogic PET/CT. For digital PET/CT CVliv increased similarly with weight for both protocols, up to 26% [95% Confidence Interval 2-56%] for ³90 kg versus <70kg, but overall CVliv values were lower in 4MBq (0,11mCi) protocol 2.Also visually PET image quality decreased with habitus on each camera (p£0.001) and was lower in females on digital PET/CT only (p=0,04).Conclusions:[18F]FDG PET image quality decreases with weight and enlarging body habitus on digital and analogic PET/CT imposing further optimization and harmonization also in digital PET/CT. This is important for clinical routine, but also (multicentric) research and development of artificial intelligence software.

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Head-to-head comparison of a Si-photomultiplier-based and a conventional photomultiplier-based PET-CT system

EJNMMI Physics ◽

10.1186/s40658-021-00366-7 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Jenny Oddstig ◽

Gustav Brolin ◽

Elin Trägårdh ◽

David Minarik

Keyword(s):

Image Quality ◽

Acquisition Time ◽

Reconstruction Algorithms ◽

Ct Scanner ◽

Recovery Coefficient ◽

Reconstruction Methods ◽

Pet Ct ◽

Significant Difference ◽

Ct System ◽

Bed Position

Abstract Background A novel generation of PET scanners based on silicon (Si)-photomultiplier (PM) technology has recently been introduced. Concurrently, there has been development of new reconstruction methods aimed at increasing the detectability of small lesions without increasing image noise. The combination of new detector technologies and new reconstruction algorithms has been found to increase image quality. However, it is unknown to what extent the demonstrated improvement of image quality is due to scanner hardware development or improved reconstruction algorithms. To isolate the contribution of the hardware, this study aimed to compare the ability to detect small hotspots in phantoms using the latest generation SiPM-based PET/CT scanner (GE Discovery MI) relative to conventional PM-based PET/CT scanner (GE Discovery 690), using identical reconstruction protocols. Materials and methods Two different phantoms (NEMA body and Jasczcak) with fillable spheres (31 μl to 26.5 ml) and varying sphere-to-background-ratios (SBR) were scanned in one bed position for 15–600 s on both scanners. The data were reconstructed using identical reconstruction parameters on both scanners. The recovery-coefficient (RC), noise level, contrast (spherepeak/backgroundpeak-value), and detectability of each sphere were calculated and compared between the scanners at each acquisition time. Results The RC-curves for the NEMA phantom were near-identical for both scanners at SBR 10:1. For smaller spheres in the Jaszczak phantom, the contrast was 1.22 higher for the DMI scanner at SBR 15:1. The ratio decreased for lower SBR, with a ratio of 1.03 at SBR 3.85:1. Regarding the detectability of spheres, the sensitivity was 98% and 88% for the DMI and D690, respectively, for SBR 15:1. For SBR 7.5, the sensitivity was 75% and 83% for the DMI and D690, respectively. For SBR 3.85:1, the sensitivity was 43% and 30% for the DMI and D690, respectively. Conclusion Marginally higher contrast in small spheres was seen for the SiPM-based scanner but there was no significant difference in detectability between the scanners. It was difficult to detect differences between the scanners, suggesting that the SiPM-based detectors are not the primary reason for improved image quality.

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Image quality and lesion detectability in low-dose pediatric 18F-FDG scans using total-body PET/CT

European Journal of Nuclear Medicine and Molecular Imaging ◽

10.1007/s00259-021-05304-4 ◽

2021 ◽

Author(s):

Yu-Mo Zhao ◽

Ying-He Li ◽

Tao Chen ◽

Wei-Guang Zhang ◽

Lin-Hao Wang ◽

...

Keyword(s):

Image Quality ◽

Low Dose ◽

Lesion Detectability ◽

Pet Ct ◽

18F Fdg ◽

Total Body

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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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Comparison of Image Quality and Semi-quantitative Measurements with Digital PET/CT and Standard PET/CT from Different Vendors

Nuclear Medicine and Molecular Imaging ◽

10.1007/s13139-020-00661-8 ◽

2020 ◽

Vol 54 (5) ◽

pp. 233-240

Author(s):

Sung Hoon Kim ◽

Bong-Il Song ◽

Hae Won Kim ◽

Kyoung Sook Won

Keyword(s):

Image Quality ◽

Quantitative Measurements ◽

Pet Ct ◽

Digital Pet

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Impact of a Bayesian penalized likelihood reconstruction algorithm on image quality in novel digital PET/CT: clinical implications for the assessment of lung tumors

EJNMMI Physics ◽

10.1186/s40658-018-0223-x ◽

2018 ◽

Vol 5 (1) ◽

Cited By ~ 18

Author(s):

Michael Messerli ◽

Paul Stolzmann ◽

Michèle Egger-Sigg ◽

Josephine Trinckauf ◽

Stefano D’Aguanno ◽

...

Keyword(s):

Image Quality ◽

Penalized Likelihood ◽

Reconstruction Algorithm ◽

Lung Tumors ◽

Clinical Implications ◽

Pet Ct ◽

Digital Pet

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The effect of modern PET technology and techniques on the EANM paediatric dosage card

European Journal of Nuclear Medicine and Molecular Imaging ◽

10.1007/s00259-021-05635-2 ◽

2021 ◽

Author(s):

John Dickson ◽

Uta Eberlein ◽

Michael Lassmann

Keyword(s):

Image Quality ◽

Field Of View ◽

Published Data ◽

Axial Field ◽

Short Article ◽

Pet Ct ◽

Class B ◽

Total Body ◽

Bed Position ◽

Pet Scanners

Abstract Aim Recent advancements in PET technology have brought with it significant improvements in PET performance and image quality. In particular, the extension of the axial field of view of PET systems, and the introduction of semiconductor technology into the PET detector, initially for PET/MR, and more recently available long-field-of-view PET/CT systems (≥ 25 cm) have brought a step change improvement in the sensitivity of PET scanners. Given the requirement to limit paediatric doses, this increase in sensitivity is extremely welcome for the imaging of children and young people. This is even more relevant with PET/MR, where the lack of CT exposures brings further dose reduction benefits to this population. In this short article, we give some details around the benefits around new PET technology including PET/MR and its implications on the EANM paediatric dosage card. Material and methods Reflecting on EANM adult guidance on injected activities, and making reference to bed overlap and the concept of MBq.min bed−1 kg−1, we use published data on image quality from PET/MR systems to update the paediatric dosage card for PET/MR and extended axial field of view (≥ 25 cm) PET/CT systems. However, this communication does not cover the expansion of paediatric dosing for the half-body and total-body scanners that have recently come to market. Results In analogy to the existing EANM dosage card, new parameters for the EANM paediatric dosage card were developed (class B, baseline value: 10.7 MBq, minimum recommended activity 10 MBq). The recommended administered activities for the systems considered in this communication range from 11 MBq [18F]FDG for a child with a weight of 3 kg to 149 MBq [18F]FDG for a paediatric patient weight of 68 kg, assuming a scan of 3 min per bed position. The mean effective dose over all ages (1 year and older) is 2.85 mSv. Conclusion With this, recommendations for paediatric dosing are given for systems that have not been considered previously.

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