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Cox CPW, Brabander T, Vegt E, de Lussanet de la Sablonière QG, Graven LH, Verburg FA, Segbers M. Reduction of [ 68Ga]Ga-DOTA-TATE injected activity for digital PET/MR in comparison with analogue PET/CT. EJNMMI Phys 2024; 11:27. [PMID: 38488989 PMCID: PMC11266332 DOI: 10.1186/s40658-024-00629-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 03/06/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND New digital detectors and block-sequential regularized expectation maximization (BSREM) reconstruction algorithm improve positron emission tomography (PET)/magnetic resonance (MR) image quality. The impact on image quality may differ from analogue PET/computed tomography (CT) protocol. The aim of this study is to determine the potential reduction of injected [68Ga]Ga-DOTA-TATE activity for digital PET/MR with BSREM reconstruction while maintaining at least equal image quality compared to the current analogue PET/CT protocol. METHODS NEMA IQ phantom data and 25 patients scheduled for a diagnostic PET/MR were included. According to our current protocol, 1.5 MBq [68Ga]Ga-DOTA-TATE per kilogram (kg) was injected. After 60 min, scans were acquired with 3 (≤ 70 kg) or 4 (> 70 kg) minutes per bedposition. PET/MR scans were reconstructed using BSREM and factors β 150, 300, 450 and 600. List mode data with reduced counts were reconstructed to simulate scans with 17%, 33%, 50% and 67% activity reduction. Image quality was measured quantitatively for PET/CT and PET/MR phantom and patient data. Experienced nuclear medicine physicians performed visual image quality scoring and lesion counting in the PET/MR patient data. RESULTS Phantom analysis resulted in a possible injected activity reduction of 50% with factor β = 600. Quantitative analysis of patient images revealed a possible injected activity reduction of 67% with factor β = 600. Both with equal or improved image quality as compared to PET/CT. However, based on visual scoring a maximum activity reduction of 33% with factor β = 450 was acceptable, which was further limited by lesion detectability analysis to an injected activity reduction of 17% with factor β = 450. CONCLUSION A digital [68Ga]Ga-DOTA-TATE PET/MR together with BSREM using factor β = 450 result in 17% injected activity reduction with quantitative values at least similar to analogue PET/CT, without compromising on PET/MR visual image quality and lesion detectability.
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Affiliation(s)
- Christina P W Cox
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Postbus 2040, 3000 CA, Rotterdam, The Netherlands.
| | - Tessa Brabander
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Postbus 2040, 3000 CA, Rotterdam, The Netherlands
| | - Erik Vegt
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Postbus 2040, 3000 CA, Rotterdam, The Netherlands
| | - Quido G de Lussanet de la Sablonière
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Postbus 2040, 3000 CA, Rotterdam, The Netherlands
| | - Laura H Graven
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Postbus 2040, 3000 CA, Rotterdam, The Netherlands
| | - Frederik A Verburg
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Postbus 2040, 3000 CA, Rotterdam, The Netherlands
| | - Marcel Segbers
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Postbus 2040, 3000 CA, Rotterdam, The Netherlands
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Maronnier Q, Robaine N, Chaltiel L, Dierickx LO, Cassou-Mounat T, Terroir M, Vija L, Vallot D, Brillouet S, Lamesa C, Filleron T, Caselles O, Courbon F. Insertion of synthetic lesions on patient data: a method for evaluating clinical performance differences between PET systems. EJNMMI Phys 2024; 11:9. [PMID: 38252388 PMCID: PMC10803700 DOI: 10.1186/s40658-023-00610-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
BACKGROUND Performance assessment of positron emission tomography (PET) scanners is crucial to guide clinical practice with efficiency. We have already introduced and experimentally evaluated a simulation method allowing the creation of a controlled ground truth for system performance assessment. In the current study, the goal was to validate the method using patient data and demonstrate its relevance to assess PET performances accuracy in clinical conditions. METHODS Twenty-four patients were recruited and sorted into two groups according to their body mass index (BMI). They were administered with a single dose of 2 MBq/kg 18F-FDG and scanned using clinical protocols consecutively on two PET systems: the Discovery-IQ (DIQ) and the Discovery-MI (DMI). For each BMI group, sixty synthetic lesions were dispatched in three subgroups and inserted at relevant anatomical locations. Insertion of synthetic lesions (ISL) was performed at the same location into the two consecutive exams. Two nuclear medicine physicians evaluated individually and blindly the images by qualitatively and semi-quantitatively reporting each detected lesion and agreed on a consensus. We assessed the inter-system detection rates of synthetic lesions and compared it to an initial estimate of at least 1.7 more targets detected on the DMI and the detection rates of natural lesions. We determined the inter-reader variability, evaluated according to the inter-observer agreement (IOA). Adequate inter-reader variability was found for IOA above 80%. Differences in standardized uptake value (SUV) metrics were also studied. RESULTS In the BMI ≤ 25 group, the relative true positive rate (RTPR) for synthetic and natural lesions was 1.79 and 1.83, respectively. In the BMI > 25 group, the RTPR for synthetic and natural lesions was 2.03 and 2.27, respectively. For each BMI group, the detection rate using ISL was consistent to our estimate and with the detection rate measured on natural lesions. IOA above 80% was verified for any scenario. SUV metrics showed a good agreement between synthetic and natural lesions. CONCLUSIONS ISL proved relevant to evaluate performance differences between PET scanners. Using these synthetically modified clinical images, we can produce a controlled ground truth in a realistic anatomical model and exploit the potential of PET scanner for clinical purposes.
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Affiliation(s)
- Quentin Maronnier
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France.
| | - Nesrine Robaine
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Léonor Chaltiel
- Biostatistics Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Lawrence O Dierickx
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Thibaut Cassou-Mounat
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Marie Terroir
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Lavinia Vija
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Delphine Vallot
- Medical Physics Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Séverine Brillouet
- Radiopharmacy Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Chloé Lamesa
- Radiopharmacy Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Thomas Filleron
- Biostatistics Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Olivier Caselles
- Medical Physics Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Frédéric Courbon
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
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Chen X, Hu P, Yu H, Tan H, He Y, Cao S, Zhou Y, Shi H. Head-to-head intra-individual comparison of total-body 2-[ 18F]FDG PET/CT and digital PET/CT in patients with malignant tumor: how sensitive could it be? Eur Radiol 2023; 33:7890-7898. [PMID: 37338551 DOI: 10.1007/s00330-023-09825-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 03/14/2023] [Accepted: 03/26/2023] [Indexed: 06/21/2023]
Abstract
OBJECTIVES To comparatively evaluate the lesion-detecting ability of 2-[18F]FDG total-body PET/CT (TB PET/CT) and conventional digital PET/CT. METHODS This study enrolled 67 patients (median age, 65 years; 24 female and 43 male patients) who underwent a TB PET/CT scan and a conventional digital PET/CT scan after a single 2-[18F]FDG injection (3.7 MBq/kg). Raw PET data for TB PET/CT were acquired over the course of 5 min, and images were reconstructed using data from the first 1, 2, 3, and 4 min and the entire 5 min (G1, G2, G3, G4, and G5, respectively). The conventional digital PET/CT scan acquired in 2-3 min per bed (G0). Two nuclear medicine physicians independently assessed subjective image quality using a 5-point Likert scale and recorded the number of 2-[18F]FDG-avid lesions. RESULTS A total of 241 lesions (69 primary lesions; 32 liver, lung, and peritoneum metastases; and 140 regional lymph nodes) among 67 patients with various types of cancer were analyzed. The subjective image quality score and SNR (signal-to-noise ratio) increased gradually from G1 to G5, and these values were significantly higher than the values at G0 (all p < 0.05). Compared to conventional PET/CT, G4 and G5 of TB PET/CT detected an additional 15 lesions (2 primary lesions; 5 liver, lung, and peritoneum lesions; and 8 lymph node metastases). CONCLUSION TB PET/CT was more sensitive than conventional whole-body PET/CT in detecting small (4.3 mm, maximum standardized uptake value (SUVmax) of 1.0) or low-uptake (tumor-to-liver ratio of 1.6, SUVmax of 4.1) lesions. CLINICAL RELEVANCE STATEMENT This study explored the gain of the image quality and lesion detectability of TB PET/CT, compared to conventional PET/CT, and recommended the appropriate acquisition time for TB PET/CT in clinical practice with an ordinary 2-[18F] FDG dose. KEY POINTS • TB PET/CT increases the effective sensitivity to approximately 40 times that of conventional PET scanners. • The subjective image quality score and signal-to-noise ratio of TB PET/CT from G1 to G5 were better than those of conventional PET/CT. • 2-[18F]FDG TB PET/CT with a 4-min acquisition time at a regular tracer dose detected an additional 15 lesions compared to conventional PET/CT.
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Affiliation(s)
- Xueqi Chen
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China
- Nuclear Medicine Institute of Fudan University, Shanghai, 200032, China
- Shanghai Institute of Medical Imaging, Shanghai, 200032, China
| | - Pengcheng Hu
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China
- Nuclear Medicine Institute of Fudan University, Shanghai, 200032, China
- Shanghai Institute of Medical Imaging, Shanghai, 200032, China
| | - Haojun Yu
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China
- Nuclear Medicine Institute of Fudan University, Shanghai, 200032, China
- Shanghai Institute of Medical Imaging, Shanghai, 200032, China
| | - Hui Tan
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China
- Nuclear Medicine Institute of Fudan University, Shanghai, 200032, China
- Shanghai Institute of Medical Imaging, Shanghai, 200032, China
| | - Yibo He
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China
- Nuclear Medicine Institute of Fudan University, Shanghai, 200032, China
- Shanghai Institute of Medical Imaging, Shanghai, 200032, China
| | - Shuangliang Cao
- Central Research Institute, United Imaging Healthcare Group Co., Ltd., Shanghai, 201807, China
| | - Yun Zhou
- Central Research Institute, United Imaging Healthcare Group Co., Ltd., Shanghai, 201807, China
- School of Biomedical Engineering, Shanghai Tech University, Shanghai, China
| | - Hongcheng Shi
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.
- Nuclear Medicine Institute of Fudan University, Shanghai, 200032, China.
- Shanghai Institute of Medical Imaging, Shanghai, 200032, China.
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Pu Y, Li L, Peng H, Liu L, Heymann D, Robert C, Vallette F, Shen S. Drug-tolerant persister cells in cancer: the cutting edges and future directions. Nat Rev Clin Oncol 2023; 20:799-813. [PMID: 37749382 DOI: 10.1038/s41571-023-00815-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2023] [Indexed: 09/27/2023]
Abstract
Drug-tolerant persister (DTP) cell populations were originally discovered in antibiotic-resistant bacterial biofilms. Similar populations with comparable features have since been identified among cancer cells and have been linked with treatment resistance that lacks an underlying genomic alteration. Research over the past decade has improved our understanding of the biological roles of DTP cells in cancer, although clinical knowledge of the role of these cells in treatment resistance remains limited. Nonetheless, targeting this population is anticipated to provide new treatment opportunities. In this Perspective, we aim to provide a clear definition of the DTP phenotype, discuss the underlying characteristics of these cells, their biomarkers and vulnerabilities, and encourage further research on DTP cells that might improve our understanding and enable the development of more effective anticancer therapies.
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Affiliation(s)
- Yi Pu
- Department of Thoracic Surgery and Institute of Thoracic Oncology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
- Department of Burn Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Lu Li
- Lung Cancer Centre, West China Hospital, Sichuan University, Chengdu, China
| | - Haoning Peng
- Department of Thoracic Surgery and Institute of Thoracic Oncology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Lunxu Liu
- Department of Thoracic Surgery and Institute of Thoracic Oncology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Dominique Heymann
- Nantes Université, CNRS, UMR6286, US2B, Nantes, France
- Institut de Cancérologie de l'Ouest, Saint-Herblain, France
| | - Caroline Robert
- INSERM U981, Gustave Roussy Cancer Campus, Villejuif, France
- Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - François Vallette
- Institut de Cancérologie de l'Ouest, Saint-Herblain, France.
- Nantes Université, INSERM, U1307, CRCI2NA, Nantes, France.
| | - Shensi Shen
- Department of Thoracic Surgery and Institute of Thoracic Oncology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.
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Fragoso Costa P, Jentzen W, SÜßELBECK F, Fendler WP, Rischpler C, Herrmann K, Conti M, Kersting D, Weber M. Reduction of emission time for [68Ga]Ga-PSMA PET/CT using the digital biograph vision: a phantom study. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF... 2023; 67:57-68. [PMID: 34309334 DOI: 10.23736/s1824-4785.21.03300-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The aim of this phantom study was to optimize the [68Ga]Ga-PSMA PET/CT examination in terms of scan time duration and image reconstruction parameters, in combination with PSF and TOF modelling, in a digital Biograph Vision PET/CT scanner. METHODS Three types of phantoms were used: 1) soft-tissue tumor phantom consisting of six spheres mounted in a torso phantom; 2) bone-lung tumor phantom; 3) resolution phantom. Phantom inserts were filled with activity concentrations (ACs) that were derived from clinical data. Phantom data were acquired in list-mode at one bed position. Images with emission data ranging from 30 to 210 s in 30-s increments were reconstructed from a reference image acquired with 3.5-min emission. Iterative image reconstruction (OSEM), point-spread-function (PSF) and time-of-flight (TOF) options were applied using different iterations, Gaussian filters, and voxel sizes. The criteria for image quality was lesion detectability and lesion quantification, evaluated as contrast-to-noise ratio (CNR) and maximum AC (peak AC), respectively. A threshold value of CNR above 6 and percentage maximum AC (peak AC) deviation range of ±20% of the reference image were considered acceptable. The proposed single-bed scan time reduction was projected to a whole-body examination (patient validation scan) using the continuous-bed-motion mode. RESULTS Sphere and background ACs of 20 kBq/mL and 1 kBq/mL were selected, respectively. The optimized single-bed scan time was approximately 60 s using OSEM-TOF or OSEM-TOF+PSF (four iterations, 4.0-mm Gaussian filter and almost isotropic voxel size of 3.0-mm side length), resulting in a PET spatial resolution of 6.3 mm for OSEM-TOF and 5.5 mm for OSEM-TOF+PSF. In the patient validation, the maximum percentage difference in lesion quantification between standard and optimized protocol (whole-body scan time of 15 vs. 5 min) was below 19%. CONCLUSIONS A reduction of single-bed and whole-body scan time for [68Ga]Ga-PSMA PET/CT compared to current recommended clinical acquisition protocols is postulated. Clinical studies are warranted to validate the applicability of this protocol.
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Affiliation(s)
- Pedro Fragoso Costa
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany -
| | - Walter Jentzen
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Finja SÜßELBECK
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Wolfgang P Fendler
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | | | - David Kersting
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
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Itagaki K, Mitsumoto K, Kajisako M, Shioji M, Kawase S. Effect of Tumor-Pixel Positioning on the Variability of SUV Measurements in PET Images. ASIA OCEANIA JOURNAL OF NUCLEAR MEDICINE & BIOLOGY 2023; 11:71-81. [PMID: 36619185 PMCID: PMC9803621 DOI: 10.22038/aojnmb.2022.61623.1434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/04/2022] [Accepted: 02/19/2022] [Indexed: 01/10/2023]
Abstract
Objectives The aim of this study was to investigate the effect on standardized uptake value (SUV) measurement variability of the positional relationship between objects of different sizes and the pixel of a positron emission tomography (PET) image. Methods We used a NEMA IEC body phantom comprising six spheres with diameters of 10, 13, 17, 22, 28, and 37 mm. The phantom was filled with 18F solution and contained target-to-background ratios (TBRs) of 2, 4, and 8. The PET data were acquired for 30 min using a SIGNA PET/MR scanner. The PET images were reconstructed with the ordered subsets expectation maximization (OSEM) algorithm with and without point-spread function (PSF) correction (OSEM + PSF + Filter and OSEM + Filter, respectively). A Gaussian filter of 4 mm full width at half maximum was applied in all reconstructions, except for one model (OSEM + PSF + no Filter). The matrix sizes were 128×128, 192×192, 256×256 and 384×384. Reconstruction was performed by shifting the reconstruction center position by 1 mm in the range 0 to 3 mm in the upward or rightward direction for each parameter. For all reconstructed images, the SUVmax of each hot sphere was measured. To investigate the resulting variation in the SUVmax, the coefficient of variation (CV) of each SUVmax was calculated. Results The CV of the SUVmax increased as the matrix size and the diameter of the hot sphere decreased in all reconstruction settings. With PSF correction, the CV of SUVmax increased as the TBR increased except when the TBR was 2. The CV of the SUVmax measured in the OSEM + PSF + no Filter images were larger than those measured in the OSEM + PSF + Filter images. The amount of this increase was higher for smaller spheres and larger matrix sizes and was independent of TBR. Conclusions Shifting the reconstruction center position of the PET image causes variability in SUVmax measurements. To reduce the variability of SUV measurements, it is necessary to use sufficient matrix sizes to satisfy sampling criterion and appropriate filters.
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Affiliation(s)
- Koji Itagaki
- Corresponding author: Koji Itagaki. Kyoto University Hospital, Division of Clinical Radiology Service, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Tel: 075-751-3522;
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Silosky M, Xing F, Wehrend J, Litwiller DV, Metzler SD, Chin BB. Modeling contrast-to-noise ratio from list mode reconstructions of 68Ga DOTATATE PET/CT: predicting detectability of hepatic metastases in shorter acquisition PET reconstructions. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2023; 13:33-42. [PMID: 36923602 PMCID: PMC10009466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/15/2022] [Indexed: 03/18/2023]
Abstract
BACKGROUND Deep learning (DL) algorithms have shown promise in identifying and quantifying lesions in PET/CT. However, the accuracy and generalizability of these algorithms relies on large, diverse datasets which are time and labor intensive to curate. Modern PET/CT scanners may acquire data in list mode, allowing for multiple reconstructions of the same datasets with different parameters and imaging times. These reconstructions may provide a wide range of image characteristics to increase the size and diversity of datasets. Training algorithms with shorter imaging times and higher noise properties requires that lesions remain detectable. The purpose of this study is to model and predict the contrast-to-noise ratio (CNR) for shorter imaging times based on CNR from longer duration, lower noise images for 68Ga DOTATATE PET hepatic lesions and identify a threshold above which lesions remain detectable. METHODS 68Ga DOTATATE subjects (n=20) with hepatic lesions were divided into two subgroups. The "Model" group (n=4 subjects; n=9 lesions; n=36 datapoints) was used to identify the relationship between CNR and imaging time. The "Test" group (n=16 subjects; n=44 lesions; n=176 datapoints) was used to evaluate the prediction provided by the model. RESULTS CNR plotted as a function of imaging time for a subset of identified subjects was very well fit with a quadratic model. For the remaining subjects, the measured CNR showed a very high linear correlation with the predicted CNR for these lesions (R2 > 0.97) for all imaging durations. From the model, a threshold CNR=6.9 at 5-minutes predicted CNR > 5 at 2-minutes. Visual inspection of lesions in 2-minute images with CNR above the threshold in 5-minute images were assessed and rated as a 4 or 5 (probably positive or definitely positive) confirming 100% lesion detectability on the shorter 2-minute PET images. CONCLUSIONS CNR for shorter DOTATATE PET imaging times may be accurately predicted using list mode reconstructions of longer acquisitions. A threshold CNR may be applied to longer duration images to ensure lesion detectability of shorter duration reconstructions. This method can aid in the selection of lesions to include in novel data augmentation techniques for deep learning.
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Affiliation(s)
- Michael Silosky
- Department of Radiology, University of Colorado School of Medicine, Anschutz Medical Campus Aurora, CO, USA
| | - Fuyong Xing
- Department of Biostatistics and Informatics, University of Colorado School of Medicine, Anschutz Medical Campus Aurora, CO, USA
| | - John Wehrend
- Department of Radiology, University of Colorado School of Medicine, Anschutz Medical Campus Aurora, CO, USA
| | | | - Scott D Metzler
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Bennett B Chin
- Department of Radiology, University of Colorado School of Medicine, Anschutz Medical Campus Aurora, CO, USA
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Muthukumar S, Darden J, Crowley J, Witcher M, Kiser J. A Comparison of PET Tracers in Recurrent High-Grade Gliomas: A Systematic Review. Int J Mol Sci 2022; 24:ijms24010408. [PMID: 36613852 PMCID: PMC9820099 DOI: 10.3390/ijms24010408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022] Open
Abstract
Humans with high-grade gliomas have a poor prognosis, with a mean survival time of just 12-18 months for patients who undergo standard-of-care tumor resection and adjuvant therapy. Currently, surgery and chemoradiotherapy serve as standard treatments for this condition, yet these can be complicated by the tumor location, growth rate and recurrence. Currently, gadolinium-based, contrast-enhanced magnetic resonance imaging (CE-MRI) serves as the predominant imaging modality for recurrent high-grade gliomas, but it faces several drawbacks, including its inability to distinguish tumor recurrence from treatment-related changes and its failure to reveal the entirety of tumor burden (de novo or recurrent) due to limitations inherent to gadolinium contrast. As such, alternative imaging modalities that can address these limitations, including positron emission tomography (PET), are worth pursuing. To this end, the identification of PET-based markers for use in imaging of recurrent high-grade gliomas is paramount. This review will highlight several PET radiotracers that have been implemented in clinical practice and provide a comparison between them to assess the efficacy of these tracers.
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Affiliation(s)
| | - Jordan Darden
- Carilion Clinic Neurosurgery, Roanoke, VA 24016, USA
| | | | - Mark Witcher
- Carilion Clinic Neurosurgery, Roanoke, VA 24016, USA
| | - Jackson Kiser
- Carilion Clinic Radiology, Roanoke, VA 24016, USA
- Correspondence:
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Fragoso Costa P, Jentzen W, Brahmer A, Mavroeidi IA, Zarrad F, Umutlu L, Fendler WP, Rischpler C, Herrmann K, Conti M, Seifert R, Sraieb M, Weber M, Kersting D. Phantom-based acquisition time and image reconstruction parameter optimisation for oncologic FDG PET/CT examinations using a digital system. BMC Cancer 2022; 22:899. [PMID: 35978274 PMCID: PMC9387080 DOI: 10.1186/s12885-022-09993-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 08/08/2022] [Indexed: 11/18/2022] Open
Abstract
Background New-generation silicon-photomultiplier (SiPM)-based PET/CT systems exhibit an improved lesion detectability and image quality due to a higher detector sensitivity. Consequently, the acquisition time can be reduced while maintaining diagnostic quality. The aim of this study was to determine the lowest 18F-FDG PET acquisition time without loss of diagnostic information and to optimise image reconstruction parameters (image reconstruction algorithm, number of iterations, voxel size, Gaussian filter) by phantom imaging. Moreover, patient data are evaluated to confirm the phantom results. Methods Three phantoms were used: a soft-tissue tumour phantom, a bone-lung tumour phantom, and a resolution phantom. Phantom conditions (lesion sizes from 6.5 mm to 28.8 mm in diameter, lesion activity concentration of 15 kBq/mL, and signal-to-background ratio of 5:1) were derived from patient data. PET data were acquired on an SiPM-based Biograph Vision PET/CT system for 10 min in list-mode format and resampled into time frames from 30 to 300 s in 30-s increments to simulate different acquisition times. Different image reconstructions with varying iterations, voxel sizes, and Gaussian filters were probed. Contrast-to-noise-ratio (CNR), maximum, and peak signal were evaluated using the 10-min acquisition time image as reference. A threshold CNR value ≥ 5 and a maximum (peak) deviation of ± 20% were considered acceptable. 20 patient data sets were evaluated regarding lesion quantification as well as agreement and correlation between reduced and full acquisition time standard uptake values (assessed by Pearson correlation coefficient, intraclass correlation coefficient, Bland–Altman analyses, and Krippendorff’s alpha). Results An acquisition time of 60 s per bed position yielded acceptable detectability and quantification results for clinically relevant phantom lesions ≥ 9.7 mm in diameter using OSEM-TOF or OSEM-TOF+PSF image reconstruction, a 4-mm Gaussian filter, and a 1.65 × 1.65 x 2.00-mm3 or 3.30 × 3.30 x 3.00-mm3 voxel size. Correlation and agreement of patient lesion quantification between full and reduced acquisition times were excellent. Conclusion A threefold reduction in acquisition time is possible. Patients might benefit from more comfortable examinations or reduced radiation exposure, if instead of the acquisition time the applied activity is reduced. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-022-09993-4.
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Affiliation(s)
- Pedro Fragoso Costa
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Walter Jentzen
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Alissa Brahmer
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Ilektra-Antonia Mavroeidi
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany.,Department of Medical Oncology, University Hospital Essen, West German Cancer Center (WTZ), University Duisburg-Essen, 45147, Essen, Germany
| | - Fadi Zarrad
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Lale Umutlu
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany.,Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany
| | - Wolfgang P Fendler
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | | | - Robert Seifert
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - David Kersting
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany. .,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany.
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Image reconstruction using small-voxel size improves small lesion detection for positron emission tomography. Radiol Oncol 2022; 56:142-149. [PMID: 35417108 PMCID: PMC9122293 DOI: 10.2478/raon-2022-0015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/16/2022] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND PET/CT imaging is widely used in oncology and provides both metabolic and anatomic information. Because of the relatively poor spatial resolution of PET, the detection of small lesions is limited. The low spatial resolution introduces the partial-volume effect (PVE) which negatively affects images both qualitatively and quantitatively. The aim of the study was to investigate the effect of small-voxel (2 mm in-line pixel size) vs. standard-voxel (4 mm in-line pixel size) reconstruction on lesion detection and image quality in a range of activity ratios. MATERIALS AND METHODS The National Electrical Manufacturers Association (NEMA) body phantom and the Micro Hollow-Sphere phantom spheres were filled with a solution of [18F]fluorodeoxyglucose ([18F]FDG) in sphere-to-background ratios of 2:1, 3:1, 4:1 and 8:1. In all images reconstructed with 2 mm and 4 mm in-line pixel size the visual lesion delineation, contrast recovery coefficient (CRC) and contrast-to-noise ratio (CNR) were evaluated. RESULTS For smaller (≤ 13 mm) phantom spheres, significantly higher CRC and CNR using small-voxel reconstructions were found, also improving visual lesion delineation. CRC did not differ significantly for larger (≥ 17 mm) spheres using 2 mm and 4 mm in-line pixel size, but CNR was significantly lower; however, lower CNR did not affect visual lesion delineation. CONCLUSIONS Small-voxel reconstruction consistently improves precise small lesion delineation, lesion contrast and image quality.
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11
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Ichikawa H. [[Nuclear Medicine] 4. Phantom Studies in Oncology]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2022; 78:637-645. [PMID: 35718453 DOI: 10.6009/jjrt.2022-2038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Affiliation(s)
- Hajime Ichikawa
- Department of Radiology, Toyohashi Municipal Hospital
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
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12
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López-Mora DA, Carrió I, Flotats A. Digital PET vs Analog PET: Clinical Implications? Semin Nucl Med 2021; 52:302-311. [PMID: 34836617 DOI: 10.1053/j.semnuclmed.2021.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 10/19/2021] [Indexed: 12/17/2022]
Abstract
Positron emission tomography (PET) is a functional imaging technique introduced in 1970s. Over the years, PET was used alone but is in 2000 when the first hybrid PET/CT device was clinically introduced. Since then, PET has continuously been marked by technological developments, being the most recent one the introduction of silicon photomultipliers (SiPMs) as an alternative to standard photomultiplier tubes used in analog PET/CT systems. SiPMs, the basis for the so called digital PET/CT systems, are smaller than standard photomultiplier tubes (enabling higher spatial resolution) and provide up to 100% coverage of the crystal area, as well as high sensitivity, low noise, and fast timing resolution. SiPMs in combination with optimized acquisition and reconstruction parameters improve the localization of the annihilation events, provide high definition PET images, and offer higher sensitivity and higher diagnostic performance. This article summarizes the evidence about the superior performance of the state of the art digital PET and highlights its potential clinical implications. Digital PET opens new perspectives in the quantification and characterization of small lesions, which are mostly undetectable using analog PET systems, potentially changing patient management and improving outcomes in oncological and non-oncological diseases. Moreover, digital PET offers the possibility to reduce radiation dose and scan times which may facilitate the implementation of PET to address unmet clinical needs.
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Affiliation(s)
- Diego Alfonso López-Mora
- Nuclear Medicine Department, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - Ignasi Carrió
- Nuclear Medicine Department, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Albert Flotats
- Nuclear Medicine Department, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
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13
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Lu S, Zhang P, Li C, Sun J, Liu W, Zhang P. A NIM PET/CT phantom for evaluating the PET image quality of micro-lesions and the performance parameters of CT. BMC Med Imaging 2021; 21:165. [PMID: 34749660 PMCID: PMC8576981 DOI: 10.1186/s12880-021-00683-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 10/07/2021] [Indexed: 11/10/2022] Open
Abstract
Background The commonly used NEMA IEC Body phantom has a number of defects, hindering its application for detecting micro-lesions and measuring the performance parameters of computed tomography (CT). This study aimed to propose a PET/CT phantom designed by National Institute of Metrology (NIM), China, which is capable of simultaneously testing the performance of PET and CT systems, and to evaluate the quality of imaging. Methods The phantom developed in the present study, the NIM PET/CT phantom, is composed of a PET imaging module and a CT imaging module, and these modules are connected together through bolts, which can simultaneously measure the imaging performance of PET and CT systems. Hot spheres were filled with 4:1 sphere-to-background activity concentration using 18F-fluorodeoxyglucose (18F-FDG), and cold spheres were filled with non-radioactive water. We compared the results of imaging obtained from the NIM PET/CT phantom and the NEMA IEC Body phantom to assess their diagnostic efficacy. In order to evaluate the generalization ability of the NIM PET/CT phantom, three different PET/CT systems were used to scan on the same scanning protocol. To evaluate the effects of image reconstruction algorithms on image quality assessment, ordered subset expectation maximization (OSEM), OSEM-point-spread function (PSF), OSEM-TOF, and OSEM-PSF-TOF algorithms were employed. Results The imaging quality of the NIM PET/CT phantom and the NEMA IEC Body phantom was relatively consistent. The NIM PET/CT phantom could detect 7 mm spheres without influencing the imaging quality. It was found that PSF reconstruction exhibited to reduce the speed of convergence, the contrast and background variability of spheres (13–28 mm) were significantly improved after two iterations. In addition to improve the image contrast and background variability, TOF could markedly improve the overall image quality and instrument detection limit. TOF-PSF could noticeably reduce noise level, enhance imaging details, and improve quality of imaging. Conclusions The results showed that in comparison with the NEMA IEC Body phantom, the NIM PET/CT phantom outperformed in evaluating the PET image quality of micro-lesions and the performance parameters of CT.
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Affiliation(s)
- Shujie Lu
- Center for Medical Metrology, National Institute of Metrology, Beijing, China
| | - Peng Zhang
- Center for Medical Metrology, National Institute of Metrology, Beijing, China
| | - Chengwei Li
- Center for Medical Metrology, National Institute of Metrology, Beijing, China
| | - Jie Sun
- Center for Medical Metrology, National Institute of Metrology, Beijing, China
| | - Wenli Liu
- Center for Medical Metrology, National Institute of Metrology, Beijing, China
| | - Pu Zhang
- Center for Medical Metrology, National Institute of Metrology, Beijing, China.
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14
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Can Q.Clear reconstruction be used to improve [68 Ga]Ga-DOTANOC PET/CT image quality in overweight NEN patients? Eur J Nucl Med Mol Imaging 2021; 49:1607-1612. [PMID: 34693467 DOI: 10.1007/s00259-021-05592-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/11/2021] [Indexed: 12/17/2022]
Abstract
AIM/INTRODUCTION Digital PET/CT allows Q.Clear image reconstruction with different Beta (β) levels. However, no definitive standard β level for [68 Ga]Ga-DOTANOC PET/CT has been established yet. As patient's body mass index (BMI) can affect image quality, the aim of the study was to visually and semi-quantitatively assess different β levels compared to standard OSEM in overweight patients. MATERIALS AND METHODS Inclusion criteria: (1) patients with NEN included in a prospective CE-approved electronic archive; (2) [68 Ga]Ga-DOTANOC PET/CT performed on a digital tomograph between September2019/March2021; (3) BMI ≥ 25. Images were acquired following EANM guidelines and reconstructed with OSEM and Q.Clear with three β levels (800, 1000, 1600). Scans were independently reviewed by three expert readers, unaware of clinical data, who independently chose the preferred β level reconstruction for visual overall image quality. Semi-quantitative analysis was performed on each scan: SUVmax of the highest uptake lesion (SUVmax-T), liver background SUVmean (SUVmean-L), SUVmax-T/SUVmean-L, Signal-to-noise ratio for both liver (LSNR) and the highest uptake lesion (SNR-T), Contrast-to-noise ratio (CNR). RESULTS Overall, 75 patients (median age: 63 years old [23-87]) were included: pre-obesity sub-group (25 ≤ BMI < 30, n = 50) and obesity sub-group (BMI ≥ 30, n = 25). PET/CT was positive for disease in 45/75 (60.0%) cases (14 obese and 31 pre-obese patients). Agreement among readers' visual rating was high (Fleiss κ = 0.88) and the β1600 was preferred in most cases (in 96% of obese patients and in 53.3% of pre-obese cases). OSEM was considered visually equal to β1600 in 44.7% of pre-obese cases and in 4% of obese patients. In a minority of pre-obese cases, OSEM was preferred (2%). In the whole population, CNR, SNR-T and LSNR were significantly different (p < 0.001) between OSEM and β1600, conversely to SUVmean-L (not significant). These results were also confirmed when calculated separately for the pre-obesity and obesity sub-groups β800 and β1000 were always rated inferior. CONCLUSIONS Q.Clear is a new technology for PET/CT image reconstruction that can be used to increase CNR and SNR-T, to subsequently optimise overall image quality as compared to standard OSEM. Our preliminary data on [68 Ga]Ga-DOTANOC PET/CT demonstrate that in overweight NEN patients, β1600 is preferable over β800 and β1000. Further studies are warranted to validate these results in lesions of different anatomical region and size; moreover, currently employed interpretative PET positivity criteria should be adjusted to the new reconstruction method.
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15
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Kersting D, Jentzen W, Fragoso Costa P, Sraieb M, Sandach P, Umutlu L, Conti M, Zarrad F, Rischpler C, Fendler WP, Herrmann K, Weber M. Silicon-photomultiplier-based PET/CT reduces the minimum detectable activity of iodine-124. Sci Rep 2021; 11:17477. [PMID: 34471170 PMCID: PMC8410931 DOI: 10.1038/s41598-021-95719-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/29/2021] [Indexed: 02/03/2023] Open
Abstract
The radioiodine isotope pair 124I/131I is used in a theranostic approach for patient-specific treatment of differentiated thyroid cancer. Lesion detectability is notably higher for 124I PET (positron emission tomography) than for 131I gamma camera imaging but can be limited for small and low uptake lesions. The recently introduced silicon-photomultiplier-based (SiPM-based) PET/CT (computed tomography) systems outperform previous-generation systems in detector sensitivity, coincidence time resolution, and spatial resolution. Hence, SiPM-based PET/CT shows an improved detectability, particularly for small lesions. In this study, we compare the size-dependant minimum detectable 124I activity (MDA) between the SiPM-based Biograph Vision and the previous-generation Biograph mCT PET/CT systems and we attempt to predict the response to 131I radioiodine therapy of lesions additionally identified on the SiPM-based system. A tumour phantom mimicking challenging conditions (derived from published patient data) was used; i.e., 6 small spheres (diameter of 3.7-9.7 mm), 9 low activity concentrations (0.25-25 kBq/mL), and a very low signal-to-background ratio (20:1). List-mode emission data (single-bed position) were divided into frames of 4, 8, 16, and 30 min. Images were reconstructed with ordinary Poisson ordered-subsets expectation maximization (OSEM), additional time-of-flight (OSEM-TOF) or TOF and point spread function modelling (OSEM-TOF+PSF). The signal-to-noise ratio and the MDA were determined. Absorbed dose estimations were performed to assess possible treatment response to high-activity 131I radioiodine therapy. The signal-to-noise ratio and the MDA were improved from the mCT to the Vision, from OSEM to OSEM-TOF and from OSEM-TOF to OSEM-TOF+PSF reconstructed images, and from shorter to longer emission times. The overall mean MDA ratio of the Vision to the mCT was 0.52 ± 0.18. The absorbed dose estimations indicate that lesions ≥ 6.5 mm with expected response to radioiodine therapy would be detectable on both systems at 4-min emission time. Additional smaller lesions of therapeutic relevance could be detected when using a SiPM-based PET system at clinically reasonable emission times. This study demonstrates that additional lesions with predicted response to 131I radioiodine therapy can be detected. Further clinical evaluation is warranted to evaluate if negative 124I PET scans on a SiPM-based system can be sufficient to preclude patients from blind radioiodine therapy.
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Affiliation(s)
- David Kersting
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany.
| | - Walter Jentzen
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Pedro Fragoso Costa
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Patrick Sandach
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | | | - Fadi Zarrad
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Wolfgang Peter Fendler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
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16
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Silosky MS, Patten LW, Chin BB. Small target repeatability of 68Ga and 18F: effects of target concentration and imaging time on SUV measurements in clinically relevant phantoms. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2021; 11:280-289. [PMID: 34513281 PMCID: PMC8414403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
Quantification of tumor uptake using PET imaging is important for the evaluation of therapy response. For 18F FDG PET scans, a change in uptake of 25% is commonly considered significant. For scans using novel radiopharmaceuticals, the threshold of significance is unclear. Factors including imaging time, tumor size, activity concentration, and radiopharmaceutical may affect the repeatablity of uptake metrics. This work evaluates the effect of these parameters on the repeatablity of maximum SUV (SUVmax) and mean SUV (SUVmean) in phantoms using 18F and 68Ga. An Esser PET phantom (Data Spectrum, Durham NC) was scanned on a Biograph Horizon PET/CT scanner (Siemens Medical Solutions, Malvern PA) using 18F and 68Ga. Data were acquired for 5 minutes with reconstructions between 0.5-5 minutes. The background activity mimicked clinical scans with target-to-background (T/B) ratios from 1.7-19.8. The SUVmax and SUVmean were measured for 5 slices. The mean, standard deviation, and coefficient of variation (COV) were calculated. The effects of radionuclide, imaging time, activity concentration, and target size on COV were evaluated using multivariate gamma regressions. COV for 68Ga was 40% higher and 54% higher on average than for 18F for SUVmax and SUVmean, respectively. Decreased lesion size, imaging time, and activity concentration were significantly associated with increased COV for both metrics (P < 0.001). COV was substantially reduced at high T/B for 68Ga. At the highest T/B the COV for SUVmax and SUVmean was within the typical range seen for 18F. COV is relatively high for small targets (8 mm) but is dramatically reduced with high radiotracer uptake.
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Affiliation(s)
- Michael S Silosky
- Department of Radiology, University of Colorado Anschutz Medical CampusAurora, CO 80045, USA
| | - Luke W Patten
- Department of Biostatistics and Informatics, University of Colorado Anschutz Medical CampusAurora, CO 80045, USA
| | - Bennett B Chin
- Department of Radiology, University of Colorado Anschutz Medical CampusAurora, CO 80045, USA
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Ichikawa H, Kawakami K, Onoguchi M, Shibutani T, Nagatake K, Hosoya T, Ito T, Kato T, Tsuchikame H, Shimada H. Automatic quantification package (Hone Graph) for phantom-based image quality assessment in bone SPECT: computerized automatic classification of detectability. Ann Nucl Med 2021; 35:937-946. [PMID: 34028702 DOI: 10.1007/s12149-021-01631-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/12/2021] [Indexed: 01/12/2023]
Abstract
OBJECTIVE We previously developed a custom-design thoracic bone scintigraphy-specific phantom ("SIM2 bone phantom") to assess image quality in bone single-photon emission computed tomography (SPECT). We aimed to develop an automatic assessment system for imaging technology in bone SPECT and demonstrate the validity of this system. METHODS Four spherical lesions of 13-, 17-, 22-, and 28-mm diameters in the vertebrae of SIM2 bone phantom simulating the thorax were filled with radioactivity (target-to-background ratio: 4). Dynamic SPECT acquisitions were performed for 15 min; reconstructions were performed using ordered subset expectation maximization at 3-15-min timepoints. Consequently, 216 lesions (54 SPECT images) were obtained: 120 and 96 lesions were used for software development and validation, respectively. The developed software used statistical parametric mapping to rigidly register and automatically calculate quantitative indexes (contrast-to-noise ratio, % coefficient of variance, % detectability equivalence volume, recovery coefficient, target-to-normal bone ratio, and full width at half maximum). A detectability score (DS) was used to define the four observation types (4, excellent; 3, adequate; 2, average; 1, poor) to score hot spherical lesions. The gold standard for DSs was independently classified by three experienced board-certified nuclear medicine technologists using the four observation types; thereafter, a consensus regarding the gold standard for DSs was reached. Using 120 lesions for development, decision tree analysis was performed to determine DS based on the quantitative indexes. We verified the validation of the quantitative indexes and their threshold values for automatic classification using 96 lesions for validation. RESULTS The trends in the automatically calculated quantitative indices were consistent. Decision tree analysis produced four terminal groups; two quantitative indexes (% detectability equivalence volume and contrast-to-noise ratio) were used to classify DS. The automatically classified DSs exhibited an almost perfect agreement with the gold standard. The percentage agreement and kappa coefficient were 91.7% and 0.93, respectively, in 96 lesions for validation. CONCLUSIONS The developed software automatically classified the detectability of hot lesions in the SIM2 bone phantom using the automatically calculated quantitative indexes, suggesting that this software could provide a means to automatically perform detectability analysis after data input that is excellent in reproducibility and accuracy.
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Affiliation(s)
- Hajime Ichikawa
- Department of Radiology, Toyohashi Municipal Hospital, 50 Aza Hachiken Nishi, Aotake-Cho, Toyohashi, Aichi, 4418570, Japan
- Department of Quantum Medical Technology, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 9200942, Japan
| | - Kazunori Kawakami
- Diagnostic Products Marketing Dept, FUJIFILM Toyama Chemical Co, Ltd. 14-1, Kyobashi 2-Chome, Chuo-Ku, Tokyo, 1040031, Japan
| | - Masahisa Onoguchi
- Department of Quantum Medical Technology, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 9200942, Japan.
| | - Takayuki Shibutani
- Department of Quantum Medical Technology, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 9200942, Japan
| | - Kazuki Nagatake
- Quality Assurance Department, FUJIFILM Toyama Chemical Co., Ltd, 14-1, Kyobashi 2-Chome, Chuo-Ku, Tokyo, 1040031, Japan
| | - Tetsuo Hosoya
- Quality Assurance Department, FUJIFILM Toyama Chemical Co., Ltd, 14-1, Kyobashi 2-Chome, Chuo-Ku, Tokyo, 1040031, Japan
| | - Toshimune Ito
- Department of Radiological Technology, Faculty of Medical Technology, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8605, Japan
| | - Toyohiro Kato
- Department of Radiology, Toyohashi Municipal Hospital, 50 Aza Hachiken Nishi, Aotake-Cho, Toyohashi, Aichi, 4418570, Japan
| | - Hirotatsu Tsuchikame
- Department of Radiology, Saiseikai Yokohamashi Tobu Hospital, Tsurumi Ward, 3-6-1 Shimosueyoshi, Yokohama, Kanagawa, 2300012, Japan
| | - Hideki Shimada
- Department of Radiology, Toyohashi Municipal Hospital, 50 Aza Hachiken Nishi, Aotake-Cho, Toyohashi, Aichi, 4418570, Japan
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Abstract
AIM To assess if digital PET/CT improves liver lesion detectability compared to analog PET/CT in patients with known or suspected liver metastases. MATERIALS AND METHODS We prospectively included 83 cancer patients, with one or more of these conditions: history of liver metastases, clinical risk of having liver metastases or presence of suspected liver metastases on the first of the two PET/CTs. All patients were consecutively scanned on each PET/CT on the same day after a single [18F]fluorodeoxyglucose dose injection. The order of acquisition was randomly assigned. Three nuclear medicine physicians assessed both PET/CTs by counting the foci of high uptake suspicious of liver metastases. Findings were correlated with appropriate reference standards; 19 patients were excluded from the analysis due to insufficient lesion nature confirmation. The final sample consisted of 64 patients (34 women, mean age 68 ± 12 years). RESULTS As per-patient analysis, the mean number of liver lesions detected by the digital PET/CT (3.84 ± 4.25) was significantly higher than that detected by the analog PET/CT (2.91 ± 3.31); P < 0.001. Fifty-five patients had a positive PET/CT study for liver lesions. In 26/55 patients (47%), the digital PET/CT detected more lesions; 7/26 patients (27%) had detectable lesions only by the digital system and had <10 mm of diameter. Twenty-nine patients had the same number of liver lesions detected by both systems. In nine patients both PET/CT systems were negative for liver lesions. CONCLUSION Digital PET/CT offers improved detectability of liver lesions over the analog PET/CT in patients with known or suspected liver metastases.
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Radiologic Assessment of Osteosarcoma Lung Metastases: State of the Art and Recent Advances. Cells 2021; 10:cells10030553. [PMID: 33806513 PMCID: PMC7999261 DOI: 10.3390/cells10030553] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/28/2021] [Accepted: 03/02/2021] [Indexed: 12/14/2022] Open
Abstract
The lung is the most frequent site of osteosarcoma (OS) metastases, which are a critical point in defining a patient’s prognosis. Chest computed tomography (CT) represents the gold standard for the detection of lung metastases even if its sensitivity widely ranges in the literature since lung localizations are often atypical. ESMO guidelines represent one of the major references for the follow-up program of OS patients. The development of new reconstruction techniques, such as the iterative method and the deep learning-based image reconstruction (DLIR), has led to a significant reduction of the radiation dose with the low-dose CT. The improvement of these techniques has great importance considering the young-onset of the disease and the strict chest surveillance during follow-up programs. The use of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT is still controversial, while volume doubling time (VDT) and computer-aided diagnosis (CAD) systems are recent diagnostic tools that could support radiologists for lung nodules evaluation. Their use, well-established for other malignancies, needs to be further evaluated, focusing on OS patients.
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20
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Kersting D, Jentzen W, Sraieb M, Costa PF, Conti M, Umutlu L, Antoch G, Nader M, Herrmann K, Fendler WP, Rischpler C, Weber M. Comparing lesion detection efficacy and image quality across different PET system generations to optimize the iodine-124 PET protocol for recurrent thyroid cancer. EJNMMI Phys 2021; 8:14. [PMID: 33587222 PMCID: PMC7884562 DOI: 10.1186/s40658-021-00361-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/28/2021] [Indexed: 12/13/2022] Open
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. Supplementary Information The online version contains supplementary material available at 10.1186/s40658-021-00361-y.
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Affiliation(s)
- David Kersting
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany. .,West German Cancer Center (WTZ), Essen, Germany. .,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany.
| | - Walter Jentzen
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Pedro Fragoso Costa
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | | | - Lale Umutlu
- West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany.,Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, 45147, Essen, Germany
| | - Gerald Antoch
- German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany.,Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, 40225, Dusseldorf, Germany
| | - Michael Nader
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Wolfgang Peter Fendler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
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21
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Silosky MS, Karki R, Morgan R, Anderson J, Chin BB. Physical characteristics of 68Ga DOTATATE PET/CT affecting small lesion detectability. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2021; 11:27-39. [PMID: 33688453 PMCID: PMC7936248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND PURPOSE 68Ga DOTATATE PET/CT protocols are similar to 18F FDG protocols despite differences in physical properties, biodistribution, and tumor uptake. The purpose of this study is to evaluate the impact of scan time (counts), and target activity on signal-to-noise ratio (SNR) in various sized targets, or lesions. To evaluate this, phantom experiments and analysis of clinical 68Ga DOTATATE PET/CT studies were performed. MATERIALS AND METHODS 68Ga was first compared to 18F in phantom studies to evaluate recovery coefficients and SNR. 68Ga phantom studies were also acquired in list mode, and at varying target activities to evaluate the effects of acquisition time and high target concentrations on SNR in clinically relevant small (8 mm) and larger targets (≥ 12 mm). Clinical studies (n = 50) were analyzed to determine if phantom target concentrations and SNR are present in clinical 68Ga DOTATATE studies at similarly very high tumor activity concentrations (n = 159). RESULTS In phantoms, recovery coefficient and SUVmax for 68Ga were ~87% of 18F. SNR for 68Ga was ~65% of 18F. For the 68Ga small target (8 mm) at standard T/B = 2.4, increasing scan time from 5 to 15 minutes increased SNR from < 1 to 1.6, and did not result in target identification. Increasing T/B from 2.4 to 10.9, however, dramatically increased SNR from < 1 to 22.3. Increased T/B resulted in clear visibility of the 8 mm target, even for 1-minute scans. In patients, high hepatic tumor SUVmax (27.3±29.6), resulted in high SNR (12.5±9.8). For extrahepatic tumors, high SUVmax (41.6±42.8), resulted in high SNR (43.8±49.9). CONCLUSION Very high target or T/B, even in small targets, can offset the physical limitations of 68Ga. High target uptake and high T/B are primary factors influencing small lesion detectability.
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Affiliation(s)
- Michael S Silosky
- Department of Radiology, Division of Nuclear Medicine, University of Colorado School of Medicine Anschutz Medical CampusAurora, CO, USA
| | - Ramesh Karki
- Department of Radiology, Division of Nuclear Medicine, University of Colorado School of Medicine Anschutz Medical CampusAurora, CO, USA
| | - Rustain Morgan
- Department of Radiology, Division of Nuclear Medicine, University of Colorado School of Medicine Anschutz Medical CampusAurora, CO, USA
| | - Janet Anderson
- Department of Radiology, Division of Nuclear Medicine, University of Colorado Hospital, University of Colorado Health SystemAurora, CO, USA
| | - Bennett B Chin
- Department of Radiology, Division of Nuclear Medicine, University of Colorado School of Medicine Anschutz Medical CampusAurora, CO, USA
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22
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Park SY, Na SJ, Kumar M, Mosci C, Wardak M, Koglin N, Bullich S, Mueller A, Berndt M, Stephens AW, Cho YM, Ahn H, Chae SY, Kim HO, Moon DH, Gambhir SS, Mittra ES. Clinical Evaluation of (4S)-4-(3-[ 18F]Fluoropropyl)-L-glutamate ( 18F-FSPG) for PET/CT Imaging in Patients with Newly Diagnosed and Recurrent Prostate Cancer. Clin Cancer Res 2020; 26:5380-5387. [PMID: 32694158 DOI: 10.1158/1078-0432.ccr-20-0644] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/25/2020] [Accepted: 07/14/2020] [Indexed: 12/24/2022]
Abstract
PURPOSE (4S)-4-(3-[18F]Fluoropropyl)-L-glutamic acid (18F-FSPG) is a radiopharmaceutical for PET imaging of system xC - activity, which can be upregulated in prostate cancer. We present data on the first evaluation of patients with newly diagnosed or recurrent prostate cancer with this radiopharmaceutical. EXPERIMENTAL DESIGN Ten patients with primary and 10 patients with recurrent prostate cancer were enrolled in this prospective multicenter study. After injection of 300 MBq of 18F-FSPG, three whole-body PET/CT scans were obtained. Visual analysis was compared with step-section histopathology when available as well as other imaging studies and clinical outcomes. Metabolic parameters were measured semiquantitatively. Expression levels of xCT and CD44 were evaluated by IHC for patients with available tissue samples. RESULTS 18F-FSPG PET showed high tumor-to-background ratios with a relatively high tumor detection rate on a per-patient (89%) and per-lobe (87%) basis. The sensitivity was slightly higher with imaging at 105 minutes in comparison with 60 minutes. The maximum standardized uptake values (SUVmax) for cancer was significantly higher than both normal (P < 0.005) and benign pathology (P = 0.011), while there was no significant difference between normal and benign pathology (P = 0.120). In the setting of recurrence, agreement with standard imaging was demonstrated in 7 of 9 patients (78%) and 13 of 18 lesions (72%), and revealed true local recurrence in a discordant case. 18F-FSPG accumulation showed moderate correlation with CD44 expression. CONCLUSIONS 18F-FSPG is a promising tumor imaging agent for PET that seems to have favorable biodistribution and high cancer detection rate in patients with prostate cancer. Further studies are warranted to determine the diagnostic value for both initial staging and recurrence, and how it compares with other investigational radiotracers and conventional imaging modalities.
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Affiliation(s)
- Sonya Youngju Park
- Department of Radiology, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul, Republic of Korea (South).,Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, Stanford, California
| | - Sae Jung Na
- Department of Radiology, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul, Republic of Korea (South).,Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Republic of Korea (South)
| | - Meena Kumar
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, Stanford, California
| | - Camila Mosci
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, Stanford, California
| | - Mirwais Wardak
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, Stanford, California
| | | | | | | | | | | | - Yong Mee Cho
- Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Republic of Korea (South)
| | - Hanjong Ahn
- Department of Urology, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Republic of Korea (South)
| | - Sun Young Chae
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Republic of Korea (South)
| | - Hye Ok Kim
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Republic of Korea (South).,Department of Nuclear Medicine, Ewha Woman's University College of Medicine, Seodaemun-gu, Seoul, Republic of Korea (South)
| | - Dae Hyuk Moon
- Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Republic of Korea (South)
| | - Sanjiv S Gambhir
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, Stanford, California.,Department of Bioengineering, Department of Materials Science & Engineering, Stanford Bio-X Program, Stanford University, Stanford, California
| | - Erik S Mittra
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, Stanford, California. .,Department of Diagnostic Radiology, Oregon Health & Science University, Portland, Oregon
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23
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Detection of sub-centimeter lesions using digital TOF-PET/CT system combined with Bayesian penalized likelihood reconstruction algorithm. Ann Nucl Med 2020; 34:762-771. [DOI: 10.1007/s12149-020-01500-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/01/2020] [Indexed: 12/19/2022]
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Abstract
PURPOSE To retrospectively investigate the uptake of F-fluciclovine on PET/CT in patients with suspected recurrent high-grade glioma (HGG). METHODS Twenty-one patients were included. The standard of truth was histopathologic interpretation if available. When histopathology was not available or rebiopsy did not show signs of malignancy, clinical follow-up including MRI and clinical outcome was considered the standard of truth. RESULTS All 21 patients met the reference standard of either histopathologic proof of HGG recurrence (n = 10) or disease progression clinically and with tumor growth corresponding to the primary tumor sites on follow-up MRI (n = 11). Median time from PET/CT to death was 5 months (range, 1-20 months). Median time from primary diagnosis to death was 14.5 months (range, 6 to >400). Average SUVmax of the lesions was 8.3 ± 5.3 (SD) and 0.34 ± 0.13 for normal brain tissue. Median lesion-to-background ratio was 21.6 (range, 3.1-84.4). In 4 patients, F-fluciclovine PET/CT detected small satellite tumors that had not been reported on MR. CONCLUSIONS The uptake of F-fluciclovine in clinically and/or histopathologically confirmed recurrent HGG is high compared with the uptake reported for other amino acid PET tracers. Because of the high tumor uptake and thus high tracer contrast, small satellite tumors with a diameter below usual reported PET spatial resolution and not reported on MRI were detected in 4 patients. As no patients with confirmed treatment-related changes were included, we cannot as of yet ascertain the ability of F-fluciclovine PET to discriminate between recurrent HGG and treatment-related changes, for example, pseudoprogression and radionecrosis.
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25
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Øen SK, Aasheim LB, Eikenes L, Karlberg AM. Image quality and detectability in Siemens Biograph PET/MRI and PET/CT systems-a phantom study. EJNMMI Phys 2019; 6:16. [PMID: 31385052 PMCID: PMC6682841 DOI: 10.1186/s40658-019-0251-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 07/23/2019] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The technology of modern positron emission tomography (PET) systems continuously improving, and with it the possibility to detect smaller lesions. Since first introduced in 2010, the number of hybrid PET/magnetic resonance imaging (MRI) systems worldwide is constantly increasing. It is therefore important to assess and compare the image quality, in terms of detectability, between the PET/MRI and the well-established PET/computed tomography (CT) systems. For this purpose, a PET image quality phantom (Esser) with hot spheres, ranging from 4 to 20 mm in diameter, was prepared with fluorodeoxyglucose and sphere-to-background activity concentrations of 8:1 and 4:1, to mimic clinical conditions. The phantom was scanned on a PET/MRI and a PET/CT system for both concentrations to obtain contrast recovery coefficients (CRCs) and contrast-to-noise ratios (CNRs), for a range of reconstruction settings. The detectability of the spheres was scored by three human observers for both systems and concentrations and all reconstructions. Furthermore, the impact of acquisition time on CNR and observer detectability was investigated. RESULTS Reconstructions applying point-spread-function modeling (and time-of-flight for the PET/CT) yielded the highest CRC and CNR in general, and PET/CT demonstrated slightly higher values than PET/MRI for most sphere sizes. CNR was dependent on reconstruction settings and was maximized for 2 iterations, a pixel size of less than 2 mm and a 4 mm Gaussian filter. Acquisition times of 97 s (PET/MRI) and 150 s (PET/CT) resulted in similar total net true counts. For these acquisition times, the smallest detected spheres by the human observers in the 8:1 activity concentration was the 6-mm sphere with PET/MRI (CNR = 5.6) and the 5-mm sphere with PET/CT (CNR = 5.5). With an acquisition time of 180 s, the 5-mm sphere was also detected with PET/MRI (CNR = 5.8). The 8-mm sphere was the smallest detected sphere in the 4:1 activity concentration for both systems. CONCLUSION In this experimental study, similar detectability was found for the PET/MRI and the PET/CT, although for an increased acquisition time for the PET/MRI.
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Affiliation(s)
- Silje Kjærnes Øen
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Postbox 8905, N-7491, Trondheim, Norway.
| | - Lars Birger Aasheim
- Department of Radiology and Nuclear Medicine, St. Olavs University Hospital, Olav Kyrres gt 17, N-7006, Trondheim, Norway
| | - Live Eikenes
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Postbox 8905, N-7491, Trondheim, Norway
| | - Anna Maria Karlberg
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Postbox 8905, N-7491, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St. Olavs University Hospital, Olav Kyrres gt 17, N-7006, Trondheim, Norway
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26
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Kwee SA, Tiirikainen M, Sato MM, Acoba JD, Wei R, Jia W, Le Marchand L, Wong LL. Transcriptomics Associates Molecular Features with 18F-Fluorocholine PET/CT Imaging Phenotype and Its Potential Relationship to Survival in Hepatocellular Carcinoma. Cancer Res 2019; 79:1696-1704. [PMID: 30760520 DOI: 10.1158/0008-5472.can-18-3837] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/22/2019] [Accepted: 02/05/2019] [Indexed: 12/15/2022]
Abstract
Studies involving transcriptomics have revealed multiple molecular subtypes of hepatocellular carcinoma (HCC). Positron emission tomography/computed tomography (PET/CT) has also identified distinct molecular imaging subtypes, including those with increased and decreased choline metabolism as measured by the tissue uptake of the radiopharmaceutical 18F-fluorocholine. Gene signatures reflecting the molecular heterogeneity of HCC may identify the biological and clinical significance of these imaging subtypes. In this study, 41 patients underwent 18F-fluorocholine PET/CT, followed by tumor resection and gene expression profiling. Over- and underexpressed components of previously published gene signatures were evaluated for enrichment between tumors with high and low 18F-fluorocholine uptake using gene set analysis. Significant gene sets were enumerated by FDR based on phenotype permutation. Associations with overall survival were analyzed by univariate and multivariate proportional hazards regression. Ten gene sets related to HCC were significantly associated with high tumor 18F-fluorocholine uptake at FDR q < 0.05, including those from three different clinical molecular classification systems and two prognostic signatures for HCC that showed predictive value in the study cohort. Tumor avidity for 18F-fluorocholine was associated with favorable characteristics based on these signatures with lower mortality based on survival analysis (HR 0.36; 95% confidence interval, 0.14-0.95). Tumors demonstrating high 18F-fluorocholine uptake were also enriched for genes involved in oxidative phosphorylation, fatty acid metabolism, peroxisome, bile acid metabolism, xenobiotic metabolism, and adipogenesis. These results provide a pathobiological framework to further evaluate 18F-fluorocholine PET/CT as a molecular and prognostic classifier in HCC. SIGNIFICANCE: A pathobiological framework for HCC brings together multiple prognostically relevant gene signatures via convergence with 18F-fluorocholine PET/CT imaging phenotype.
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Affiliation(s)
- Sandi A Kwee
- Hamamatsu/Queen's PET Imaging Center, The Queen's Medical Center, Honolulu, Hawaii. .,Cancer Biology Program, Clinical Sciences Program, and Epidemiology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Maarit Tiirikainen
- Cancer Biology Program, Clinical Sciences Program, and Epidemiology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Miles M Sato
- The Queen's Medical Center, Queen's Cancer Center, Honolulu, Hawaii
| | - Jared D Acoba
- Cancer Biology Program, Clinical Sciences Program, and Epidemiology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii.,The Queen's Medical Center, Queen's Cancer Center, Honolulu, Hawaii
| | - Runmin Wei
- Cancer Biology Program, Clinical Sciences Program, and Epidemiology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Wei Jia
- Cancer Biology Program, Clinical Sciences Program, and Epidemiology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Loic Le Marchand
- Cancer Biology Program, Clinical Sciences Program, and Epidemiology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Linda L Wong
- Cancer Biology Program, Clinical Sciences Program, and Epidemiology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii.,Department of Surgery, University of Hawaii John A. Burns School of Medicine, Honolulu, Hawaii
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27
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Nguyen NC, Vercher-Conejero J, Faulhaber P. Tumor volume delineation: A pilot study comparing a digital positron-emission tomography prototype with an analog positron-emission tomography system. World J Nucl Med 2019; 18:45-51. [PMID: 30774546 PMCID: PMC6357708 DOI: 10.4103/wjnm.wjnm_22_18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We evaluated the potential differences of a digital positron-emission tomography (PET) prototype equipped with photon-counting detectors (D-PET, Philips Healthcare, Cleveland, Ohio, USA) in tumor volume delineation compared with the analog Gemini TF PET system (A-PET, Philips). Eleven oncologic patients first underwent clinical fluorodeoxyglucose (FDG) PET/computed tomography (CT) on A-PET. The D-PET ring was then inserted between the PET and CT scanner of A-PET and the patient was scanned for the second time. Two interpreters reviewed the two sets of PET/CT images for image quality and diagnostic confidence. FDG avid lesions were evaluated for volume measured at 35% and 50% of maximum standard uptake value (SUV) thresholds (35% SUV, 50% SUV), and for SUV gradient as a measure of lesion sharpness. Bland–Altman plots were used to assess the agreement between the two PET scans. Qualitative lesion conspicuity, sharpness, and diagnostic confidence were greater at D-PET than that of A-PET with favorable inter-rater agreements. Median lesion size of the 24 measured lesions was 1.6 cm. The lesion volume at D-PET was smaller at both 35% SUV and 50% SUV thresholds compared with that of A-PET, with a mean difference of − 3680.0 mm3 at 35% SUV and − 835.3 mm3 at 50% SUV. SUV gradient was greater at D-PET than at A-PET by 49.2% (95% confidence interval: 34.1%–60.8%). Given the smaller volume definition, coupled with improved conspicuity and sharpness, digital PET may be more robust and accurate in tumor rendering compared with analog PET not only for radiotherapy planning but also in prognostication and systemic treatment monitoring.
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Affiliation(s)
- Nghi C Nguyen
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jose Vercher-Conejero
- Department of Radiology, Case Western Reserve University, University Hospitals Case Medical Center, Cleveland, OH, USA
| | - Peter Faulhaber
- Department of Radiology, Case Western Reserve University, University Hospitals Case Medical Center, Cleveland, OH, USA
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Young CR, Adler S, Eary JF, Lindenberg ML, Jacobs PM, Collins J, Kummar S, Kurdziel KA, Choyke PL, Mena E. Biodistribution, Tumor Detection, and Radiation Dosimetry of 18F-5-Fluoro-2'-Deoxycytidine with Tetrahydrouridine in Solid Tumors. J Nucl Med 2018; 60:492-496. [PMID: 30389817 DOI: 10.2967/jnumed.118.216994] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/12/2018] [Indexed: 01/27/2023] Open
Abstract
In preclinical studies, 5-fluoro-2'-deoxycytidine (FdCyd), an inhibitor of DNA methyltransferase and DNA hypermethylation, has shown treatment efficacy against multiple malignancies by suppressing epigenetic hypermethylation in tumor cells. Several ongoing clinical trials are using FdCyd, and although some patients may respond to this drug, in most patients it is ineffective. Thus, establishing a noninvasive imaging modality to evaluate the distribution of the drug may provide insight into the variable responses. A novel experimental radiopharmaceutical, 18F-labeled FdCyd, was developed as a companion imaging agent to the nonradioactive form of the drug, FdCyd. We present the first-in-humans radiation dosimetry results and biodistribution of 18F-FdCyd, administered along with tetrahydrouridine, an inhibitor of cytidine/deoxycytidine deaminase, in patients with a variety of solid tumors undergoing FdCyd therapy. Methods: This phase 0 imaging trial examined the 18F-FdCyd biodistribution and radiation dosimetry in 5 human subjects enrolled in companion therapy trials. In each subject, 4 sequential PET scans were acquired to estimate whole-body and individual organ effective dose, using OLINDA/EXM, version 1.0. Tumor-to-background ratios were also calculated for the tumor sites visualized on PET/CT imaging. Results: The average whole-body effective dose for the experimental radiopharmaceutical 18F-FdCyd administered in conjunction with tetrahydrouridine was 2.12E-02 ± 4.15E-03 mSv/MBq. This is similar to the radiation dose estimates for 18F-FDG PET. The critical organ, with the highest absorbed radiation dose, was the urinary bladder wall at 7.96E-02 mSv/MBq. Other organ doses of note were the liver (6.02E-02mSv/MBq), kidneys (5.26E-02 mSv/MBq), and gallbladder (4.05E-02 mSv/MBq). Tumor target-to-background ratios ranged from 2.4 to 1.4, which potentially enable tumor visualization in static PET images. Conclusion: This phase 0 imaging clinical trial provides evidence that 18F-FdCyd administered in conjunction with tetrahydrouridine yields acceptable individual organ and whole-body effective doses, as well as modest tumor-to-background ratios that potentially enable tumor visualization. Dose estimates for 18F-FdCyd are comparable to those for other PET radiopharmaceuticals, such as 18F-FDG. Further studies with larger study populations are warranted to assess 18F-FdCyd imaging as a predictor of FdCyd treatment effectiveness.
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Affiliation(s)
- Colin R Young
- Department of Radiology, Walter Reed National Military Medical Center, Bethesda, Maryland
| | - Stephen Adler
- Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research, Inc., National Cancer Institute, Frederick, Maryland
| | - Janet F Eary
- Cancer Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - M Liza Lindenberg
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Paula M Jacobs
- Cancer Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Jerry Collins
- Developmental Therapeutics Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Shivaani Kummar
- Stanford University School of Medicine, Palo Alto, California
| | - Karen A Kurdziel
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Peter L Choyke
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Esther Mena
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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29
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Central Nervous System Myelomatosis Delineated by High-Resolution Brain Images From Fully Digital 18F-FDG PET. Clin Nucl Med 2018; 43:e372-e373. [PMID: 30153147 DOI: 10.1097/rlu.0000000000002243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Central nervous system myelomatosis is uncommon and is associated with a particularly poor prognosis. PET images, from a 53-year-old man referred to a fully digital F-FDG PET for relapsed multiple myeloma, revealed high F-FDG uptakes located in the cortex and sulci of the right central area and within the meningeal envelopes of the cerebellum, the trigeminal nerves, and on the spinal canal. These particular uptakes gave evidence of a central nervous system myelomatosis subsequently confirmed by plasma cells documented in cerebrospinal fluid. Such interesting images could be obtained owing to the potential of high-resolution images provided by fully digital F-FDG PET.
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30
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Machado MAD, Menezes VO, Namías M, Vieira NS, Queiroz CC, Matheoud R, Alessio AM, Oliveira ML. Protocols for Harmonized Quantification and Noise Reduction in Low-Dose Oncologic 18F-FDG PET/CT Imaging. J Nucl Med Technol 2018; 47:47-54. [PMID: 30076252 DOI: 10.2967/jnmt.118.213405] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/26/2018] [Indexed: 11/16/2022] Open
Affiliation(s)
- Marcos A D Machado
- Nuclear Medicine Department, São Rafael Hospital, Salvador, Brazil
- Hospital das Clínicas da Universidade Federal de Bahia/Ebserh, Salvador, Brazil
| | - Vinícius O Menezes
- Nuclear Medicine Department, São Rafael Hospital, Salvador, Brazil
- Hospital das Clínicas da Universidade Federal de Pernambuco/Ebserh, Recife, Brazil
| | - Mauro Namías
- Fundación Centro Diagnóstico Nuclear, Buenos Aires, Argentina
| | - Naiara S Vieira
- Nuclear Medicine Department, São Rafael Hospital, Salvador, Brazil
| | - Cleiton C Queiroz
- Nuclear Medicine Department, São Rafael Hospital, Salvador, Brazil
- Hospital Universitario Professor Alberto Antunes/Ebserh, Maceió, Brazil
| | - Roberta Matheoud
- Department of Medical Physics, Azienda Ospedaliera Maggiore della Carità, Novara, Italy
| | - Adam M Alessio
- Department of Radiology, University of Washington, Seattle, Washington; and
| | - Mércia L Oliveira
- Centro Regional de Ciências Nucleares (CRCN-NE)/CNEN, Recife, Brazil
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31
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Abstract
Therapeutics that block kinases, transcriptional modifiers, immune checkpoints and other biological vulnerabilities are transforming cancer treatment. As a result, many patients achieve dramatic responses, including complete radiographical or pathological remission, yet retain minimal residual disease (MRD), which results in relapse. New functional approaches can characterize clonal heterogeneity and predict therapeutic sensitivity of MRD at a single-cell level. Preliminary evidence suggests that iterative detection, profiling and targeting of MRD would meaningfully improve outcomes and may even lead to cure.
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Affiliation(s)
- Marlise R. Luskin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA,
| | - Mark A. Murakami
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA,
| | - Scott R. Manalis
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA
- Corresponding authors: (S. R. M.) and (D. M. W.)
| | - David M. Weinstock
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA,
- Broad Institute of MIT and Harvard University, Cambridge, Massachusetts, 02142, USA
- Corresponding authors: (S. R. M.) and (D. M. W.)
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32
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Hashimoto N, Morita K, Tsutsui Y, Himuro K, Baba S, Sasaki M. Time-of-Flight Information Improved the Detectability of Subcentimeter Spheres Using a Clinical PET/CT Scanner. J Nucl Med Technol 2018; 46:268-273. [PMID: 29599404 DOI: 10.2967/jnmt.117.204735] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 01/06/2018] [Indexed: 11/16/2022] Open
Abstract
Recent advancements in clinical PET/CT scanners have improved the detectability of small lesions. However, the ideal reconstruction parameters for detecting small lesions have not yet been sufficiently clarified. The purpose of this study was to investigate the detectability of subcentimeter spheres using a clinical PET/CT scanner. Methods: We used a clinical PET/CT scanner to obtain the data of a National Electrical Manufacturers Association body phantom consisting of 6 small spheres (inner diameters, 4.0, 5.0, 6.2, 7.9, 10, and 37 mm) containing 18F solution. The background activity was 2.65 kBq/mL, and the sphere-to-background ratio was 8. The PET data obtained for 2 and 120 min were reconstructed using ordered-subsets expectation maximization (OSEM), OSEM + point-spread function (PSF), and OSEM + time-of-flight (TOF) with voxel sizes of 2.04 × 2.04 × 2.00 mm (2-mm voxels) and 4.07 × 4.07 × 3.99 mm (4-mm voxels). A gaussian filter was not used. The image quality was evaluated by visual assessment, as well as by physical assessment of the detectability index and recovery coefficients. Results: According to the visual assessment, the detectability of the spheres improved using TOF and a longer acquisition. Using the OSEM+TOF model, the smallest visually detected spheres were 5 mm in diameter with a 120-min acquisition and 6 mm in diameter with a 2-min acquisition. According to physical assessment, the detectability of spheres 10 mm or smaller using the OSEM+TOF image was superior to that using the OSEM image. In addition, the detectability of each hot sphere and recovery coefficient with 2-mm voxels was superior to that with 4-mm voxels. Although OSEM+PSF images showed less background noise, detectability and the recovery coefficient were not improved for spheres 8 mm or smaller. Conclusion: The TOF model with 2-mm voxels improved the detectability of subcentimeter hot spheres on a clinical PET/CT scanner.
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Affiliation(s)
- Naoki Hashimoto
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; and
| | - Keishin Morita
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; and
| | - Yuji Tsutsui
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; and.,Division of Radiology, Department of Medical Technology, Kyushu University, Fukuoka, Japan
| | - Kazuhiko Himuro
- Division of Radiology, Department of Medical Technology, Kyushu University, Fukuoka, Japan
| | - Shingo Baba
- Division of Radiology, Department of Medical Technology, Kyushu University, Fukuoka, Japan
| | - Masayuki Sasaki
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; and
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