New probe for the improvement of the Spatial Resolution in total-body PET (PROScRiPT)

In recent decades, PET scanners have been widely used for diagnosis and treatment monitoring in nuclear medicine. The continuous effort of the scientific community has led to improvements in scanner performance. Total-body PET is one of the latest upgrades in PET scanners. These kinds of scanners are able to scan the whole body of the patient with a single bed position, since the scanner tube is long enough for the patient to fit inside. While these scanners show unprecedented efficiency and extended field-of-view, a drawback is their low spatial resolution compared to dedicated scanners. In order to improve the spatial resolution of specific areas when measuring with a total-body PET scanner, the IRIS group at IFIC-Valencia is developing a probe. The proposed setup of the probe contains a monolithic scintillation crystal and a SiPM. The signal of the probe is read out by a TOFPET2 ASIC from PETsys, which has shown good performance for PET in terms of spatial and time resolutions. Furthermore, the PETsys technology generates a trigger signal that will be used to time synchronise the probe and the scanner. The proof-of-concept of the probe will be tested in a Preclinical Super Argus PET/CT scanner for small animals located at IFIC. Preliminary simulations of the scanner and the probe under ideal conditions show a slight improvement in the position reconstruction compared to the data obtained with the scanner, therefore we expect a considerable improvement when using the probe in a total-body PET scanner. Characterisation tests of the probe have been performed with a 22Na point-like source, obtaining an energy resolution of 9.09% for the 511 keV energy peak and a temporal resolution of 619 ps after time walk correction. The next step of the project is to test the probe measuring in temporal coincidence with the scanner.

Download Full-text

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.

Download Full-text

Performance evaluation of the uEXPLORER Total-body PET/CT scanner based on NEMA NU 2-2018 with additional tests to characterize long axial field-of-view PET scanners

Journal of Nuclear Medicine ◽

10.2967/jnumed.120.250597 ◽

2020 ◽

pp. jnumed.120.250597 ◽

Cited By ~ 1

Author(s):

Benjamin A. Spencer ◽

Eric Berg ◽

Jeffrey P. Schmall ◽

Negar Omidvari ◽

Edwin K. Leung ◽

...

Keyword(s):

Performance Evaluation ◽

Field Of View ◽

Ct Scanner ◽

Axial Field ◽

Pet Ct ◽

Total Body ◽

Pet Scanners

Download Full-text

The role of activity, scan duration and patient's weight in the optimization of 18FDG imaging protocols on a TOF-PET/CT scanner

10.21203/rs.3.rs-17743/v1 ◽

2020 ◽

Author(s):

Roberta Matheoud ◽

Naema Al-Maymani ◽

Alessia Oldani ◽

Gian Mauro Sacchetti ◽

Marco Brambilla ◽

...

Keyword(s):

Image Quality ◽

Activity Concentration ◽

Whole Body ◽

Internal Diameter ◽

Ct Scanner ◽

Recovery Coefficient ◽

Pet Ct ◽

Bed Position ◽

Tof Pet

Abstract Background : Time-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality , in low counts acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on 18 F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment.Methods : The NEMA-IEC body phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR), and weight. The phantom was filled with 5.3 kBq/mL of FDG solution and the spheres with TBR of 21, 9, and 5 in 3 different sessions. Images were acquired at varying activity concentration from 5.1 to 1.3 kBq/mL and images were reconstructed for ESD of 30-151 seconds per bed position with and without Point Spread Function (PSF) correction. The parameters were all considered in simultaneous experiments and in a single analysis using multiple linear regression methods.Results : As expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and weight of the patient, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the weight of the patient and TBR of the lesion.Conclusions : Due to the interchangeable role of AC and ESD in modulating CRC, ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.

Download Full-text

Whole-body Cancer Screening Using 18F-FDG Novel Combined PET/CT Scanner

Health Evaluation and Promotion ◽

10.7143/jhep.32.370 ◽

2005 ◽

Vol 32 (4) ◽

pp. 370-375

Author(s):

Chieki WADA ◽

Tomoo SHIMADA ◽

Yasuko ADACHI

Keyword(s):

Cancer Screening ◽

Whole Body ◽

Ct Scanner ◽

Pet Ct ◽

18F Fdg

Download Full-text

The Role of Activity, Scan Duration and Patient's Body Mass Index in the Optimization of 18FDG Imaging Protocols on a TOF-PET/CT Scanner

10.21203/rs.3.rs-136005/v1 ◽

2020 ◽

Author(s):

Roberta Matheoud ◽

Naema Al-Maymani ◽

Alessia Oldani ◽

Gian Mauro Sacchetti ◽

Marco Brambilla ◽

...

Keyword(s):

Body Mass Index ◽

Image Quality ◽

Body Mass ◽

Activity Concentration ◽

Background Activity ◽

Whole Body ◽

Internal Diameter ◽

Ct Scanner ◽

Pet Ct ◽

Tof Pet

Abstract BackgroundTime-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality in low counts acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on 18F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment. MethodsThe NEMA-IQ phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR), and body mass index (BMI). The phantom was filled with an average concentration of 5.3 kBq/mL of FDG solution and the spheres with TBR of 21.2, 8.8, and 5.0 in 3 different sessions. Images were acquired at varying background activity concentration from 5.1 to 1.3 kBq/mL and images were reconstructed for ESD of 30-151 seconds per bed position with and without Point Spread Function (PSF) correction. The parameters were all considered in a single analysis using multiple linear regression methods. ResultsAs expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and BMI of the phantom, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the weight of the patient and TBR of the lesion. ConclusionsAC and ESD proved to be effective tools in modulating CNR. ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.

Download Full-text

Impact of target-to-background ratio, target size, emission scan duration, and activity on physical figures of merit for a 3D LSO-based whole body PET/CT scanner

Medical Physics ◽

10.1118/1.2776242 ◽

2007 ◽

Vol 34 (10) ◽

pp. 3854-3865 ◽

Cited By ~ 20

Author(s):

M. Brambilla ◽

R. Matheoud ◽

C. Secco ◽

G. Sacchetti ◽

S. Comi ◽

...

Keyword(s):

Target Size ◽

Whole Body ◽

Ct Scanner ◽

Background Ratio ◽

Figures Of Merit ◽

Pet Ct

Download Full-text

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.

Download Full-text

SUV variability in EARL-accredited conventional and digital PET

EJNMMI Research ◽

10.1186/s13550-019-0569-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Daniëlle Koopman ◽

Pieter L. Jager ◽

Cornelis H. Slump ◽

Siert Knollema ◽

Jorn A. van Dalen

Keyword(s):

Confidence Interval ◽

Prospective Study ◽

Relative Difference ◽

Whole Body ◽

Pet Scanning ◽

Pet Ct ◽

Digital Pet ◽

Average Size ◽

Pet Scanners ◽

Pet Scans

Abstract Background A high SUV-reproducibility is crucial when different PET scanners are in use. We evaluated the SUV variability in whole-body FDG-PET scans of patients with suspected or proven cancer using an EARL-accredited conventional and digital PET scanner. In a head-to-head comparison we studied images of 50 patients acquired on a conventional scanner (cPET, Ingenuity TF PET/CT, Philips) and compared them with images acquired on a digital scanner (dPET, Vereos PET/CT, Philips). The PET scanning order was randomised and EARL-compatible reconstructions were applied. We measured SUVmean, SUVpeak, SUVmax and lesion diameter in up to 5 FDG-positive lesions per patient. The relative difference ΔSUV between cPET and dPET was calculated for each SUV-parameter. Furthermore, we calculated repeatability coefficients, reflecting the 95% confidence interval of ΔSUV. Results We included 128 lesions with an average size of 19 ± 14 mm. Average ΔSUVs were 6-8% with dPET values being higher for all three SUV-parameters (p < 0.001). ΔSUVmax was significantly higher than ΔSUVmean (8% vs. 6%, p = 0.002) and than ΔSUVpeak (8% vs. 7%, p = 0.03). Repeatability coefficients across individual lesions were 27% (ΔSUVmean and ΔSUVpeak) and 33% (ΔSUVmax) (p < 0.001). Conclusions With EARL-accredited conventional and digital PET, we found a limited SUV variability with average differences up to 8%. Furthermore, only a limited number of lesions showed a SUV difference of more than 30%. These findings indicate that EARL standardisation works. Trial registration This prospective study was registered on the 31th of October 2017 at ClinicalTrials.cov. URL: https://clinicaltrials.gov/ct2/show/NCT03457506?id=03457506&rank=1.

Download Full-text

Direct comparison of brain [18F]FDG images acquired by SiPM-based and PMT-based PET/CT: phantom and clinical studies

EJNMMI Physics ◽

10.1186/s40658-020-00337-4 ◽

2020 ◽

Vol 7 (1) ◽

Author(s):

Kei Wagatsuma ◽

Muneyuki Sakata ◽

Kenji Ishibashi ◽

Akira Hirayama ◽

Hirofumi Kawakami ◽

...

Keyword(s):

Spatial Resolution ◽

Clinical Studies ◽

Image Noise ◽

Image Contrast ◽

Silicon Photomultiplier ◽

Timing Resolution ◽

Standardized Uptake Values ◽

Positron Emission ◽

Pet Ct ◽

Pet Scanners

Abstract Background Silicon photomultiplier-positron emission tomography (SiPM-PET) has better sensitivity, spatial resolution, and timing resolution than photomultiplier tube (PMT)-PET. The present study aimed to clarify the advantages of SiPM-PET in 18F-fluoro-2-deoxy-D-glucose ([18F]FDG) brain imaging in a head-to-head comparison with PMT-PET in phantom and clinical studies. Methods Contrast was calculated from images acquired from a Hoffman 3D brain phantom, and image noise and uniformity were calculated from images acquired from a pool phantom using SiPM- and PMT-PET. Sequential PMT-PET and SiPM-PET [18F]FDG images were acquired over a period of 10 min from 22 controls and 10 patients. All images were separately normalized to a standard [18F]FDG PET template, then the mean standardized uptake values (SUVmean) and Z-score were calculated using MIMneuro and CortexID Suite, respectively. Results Image contrast, image noise, and uniformity in SiPM-PET changed 19.2, 3.5, and − 40.0% from PMT-PET, respectively. These physical indices of both PET scanners satisfied the criteria for acceptable image quality published by the Japanese Society of Nuclear Medicine of contrast > 55%, CV ≤ 15%, and SD ≤ 0.0249, respectively. Contrast was 70.0% for SiPM-PET without TOF and 59.5% for PMT-PET without TOF. The TOF improved contrast by 3.5% in SiPM-PET. The SUVmean using SiPM-PET was significantly higher than PMT-PET and did not correlate with a time delay. Z-scores were also significantly higher in images acquired from SiPM-PET (except for the bilateral posterior cingulate) than PMT-PET because the peak signal that was extracted by the calculation of Z-score in CortexID Suite was increased. The hypometabolic area in statistical maps was reduced and localized using SiPM-PET. The trend was independent of whether the images were derived from controls or patients. Conclusions The improved spatial resolution and sensitivity of SiPM-PET contributed to better image contrast and uniformity in brain [18F]FDG images. The SiPM-PET offers better quality and more accurate quantitation of brain PET images. The SUVmean and Z-scores were higher in SiPM-PET than PMT-PET due to improved PVE. [18F]FDG images acquired using SiPM-PET will help to improve diagnostic outcomes based on statistical image analysis because SiPM-PET would localize the distribution of glucose metabolism on Z-score maps.

Download Full-text

Perspectives of brain imaging with PET systems

Bio-Algorithms and Med-Systems ◽

10.1515/bams-2021-0178 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Stan Majewski

Keyword(s):

Whole Body ◽

Compton Imaging ◽

High Performing ◽

Development Path ◽

Brain Pet ◽

Moderate Resolution ◽

Total Body ◽

Body Scanner ◽

Pet Scanners ◽

Very High

Abstract In this partial review and partial attempt at vision of what may be the future of dedicated brain PET scanners, the key implementations of the PET technique, we postulate that we are still on a development path and there is still a lot to be done in order to develop optimal brain imagers. Optimized for particular imaging tasks and protocols, and also mobile, that can be used outside the PET center, in addition to the expected improvements in sensitivity and resolution. For this multi-application concept to be more practical, flexible, adaptable designs are preferred. This task is greatly facilitated by the improved TOF performance that allows for more open, adjustable, limited angular coverage geometries without creating image artifacts. As achieving uniform very high resolution in the whole body is not practical due to technological limits and high costs, hybrid systems using a moderate-resolution total body scanner (such as J-PET) combined with a very high performing brain imager could be a very attractive approach. As well, as using magnification inserts in the total body or long-axial length imagers to visualize selected targets with higher resolution. In addition, multigamma imagers combining PET with Compton imaging should be developed to enable multitracer imaging.

Download Full-text