1
|
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.
Collapse
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
| |
Collapse
|
2
|
Sipilä O, Liukkonen J, Halme HL, Tolvanen T, Sohlberg A, Hakulinen M, Manninen AL, Tahvanainen K, Tunninen V, Ollikainen T, Kangasmaa T, Kangasmäki A, Vuorela J. Variability in PET image quality and quantification measured with a permanently filled 68Ge-phantom: a multi-center study. EJNMMI Phys 2023; 10:38. [PMID: 37322376 DOI: 10.1186/s40658-023-00551-w] [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: 12/29/2022] [Accepted: 05/15/2023] [Indexed: 06/17/2023] Open
Abstract
BACKGROUND This study evaluated, as a snapshot, the variability in quantification and image quality (IQ) of the clinically utilized PET [18F]FDG whole-body protocols in Finland using a NEMA/IEC IQ phantom permanently filled with 68Ge. METHODS The phantom was imaged on 14 PET-CT scanners, including a variety of models from two major vendors. The variability of the recovery coefficients (RCmax, RCmean and RCpeak) of the hot spheres as well as percent background variability (PBV), coefficient of variation of the background (COVBG) and accuracy of corrections (AOC) were studied using images from clinical and standardized protocols with 20 repeated measurements. The ranges of the RCs were also compared to the limits of the EARL 18F standards 2 accreditation (EARL2). The impact of image noise on these parameters was studied using averaged images (AVIs). RESULTS The largest variability in RC values of the routine protocols was found for the RCmax with a range of 68% and with 10% intra-scanner variability, decreasing to 36% when excluding protocols with suspected cross-calibration failure or without point-spread-function (PSF) correction. The RC ranges of individual hot spheres in routine or standardized protocols or AVIs fulfilled the EARL2 ranges with two minor exceptions, but fulfilling the exact EARL2 limits for all hot spheres was variable. RCpeak was less dependent on averaging and reconstruction parameters than RCmax and RCmean. The PBV, COVBG and AOC varied between 2.3-11.8%, 9.6-17.8% and 4.8-32.0%, respectively, for the routine protocols. The RC ranges, PBV and COVBG were decreased when using AVIs. With AOC, when excluding routine protocols without PSF correction, the maximum value dropped to 15.5%. CONCLUSION The maximum variability of the RC values for the [18F]FDG whole-body protocols was about 60%. The RC ranges of properly cross-calibrated scanners with PSF correction fitted to the EARL2 RC ranges for individual sphere sizes, but fulfilling the exact RC limits would have needed further optimization. RCpeak was the most robust RC measure. Besides COVBG, also RCs and PVB were sensitive to image noise.
Collapse
Affiliation(s)
- O Sipilä
- HUS Diagnostic Center, Clinical Physiology and Nuclear Medicine, Helsinki University Hospital and University of Helsinki, P. O. Box 442, 00029, Helsinki, Finland.
| | - J Liukkonen
- Radiation and Nuclear Safety Authority, Vantaa, Finland
| | - H-L Halme
- HUS Diagnostic Center, Clinical Physiology and Nuclear Medicine, Helsinki University Hospital and University of Helsinki, P. O. Box 442, 00029, Helsinki, Finland
| | - T Tolvanen
- Turku PET Centre, Turku University Hospital, Turku, Finland
| | - A Sohlberg
- Department of Nuclear Medicine, Päijät-Häme Central Hospital, Lahti, Finland
| | - M Hakulinen
- Department of Clinical Physiology and Nuclear Medicine, Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - A-L Manninen
- OYS Department of Nuclear Medicine and Radiology, Oulu University Hospital, Oulu, Finland
- Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - K Tahvanainen
- HUS Diagnostic Center, Clinical Physiology and Nuclear Medicine, Helsinki University Hospital and University of Helsinki, P. O. Box 442, 00029, Helsinki, Finland
| | - V Tunninen
- Department of Clinical Physiology and Nuclear Medicine, Satakunta Central Hospital, Pori, Finland
| | - T Ollikainen
- Clinical Physiology and Neurophysiology, North Karelia Central Hospital, Joensuu, Finland
| | - T Kangasmaa
- Department of Clinical Physiology and Nuclear Medicine, Vaasa Central Hospital, Wellbeing Services County of Ostrobothnia, Vaasa, Finland
| | - A Kangasmäki
- Department of Imaging and Radiotherapy, Docrates Cancer Center, Helsinki, Finland
| | - J Vuorela
- Clinical Physiology and Nuclear Medicine, Central Finland Health Care District, Jyväskylä, Finland
| |
Collapse
|
3
|
Ruan W, Qin C, Liu F, Pi R, Gai Y, Liu Q, Lan X. Q.Clear reconstruction for reducing the scanning time for 68 Ga-DOTA-FAPI-04 PET/MR imaging. Eur J Nucl Med Mol Imaging 2023; 50:1851-1860. [PMID: 36847826 DOI: 10.1007/s00259-023-06134-2] [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: 10/28/2022] [Accepted: 02/04/2023] [Indexed: 03/01/2023]
Abstract
PURPOSE This study aims to determine whether Q.Clear positron emission tomography (PET) reconstruction may reduce tracer injection dose or shorten scanning time in 68Gallium-labelled fibroblast activation protein inhibitor (68 Ga-FAPI) PET/magnetic resonance (MR) imaging. METHODS We retrospectively collected cases of 68 Ga-FAPI whole-body imaging performed on integrated PET/MR. PET images were reconstructed using three different methods: ordered subset expectation maximization (OSEM) reconstruction with full scanning time, OSEM reconstruction with half scanning time, and Q.Clear reconstruction with half scanning time. We then measured standardized uptake values (SUVs) within and around lesions, alongside their volumes. We also evaluated image quality using lesion-to-background (L/B) ratio and signal-to-noise ratio (SNR). We then compared these metrics across the three reconstruction techniques using statistical methods. RESULTS Q.Clear reconstruction significantly increased SUVmax and SUVmean within lesions (more than 30%) and reduced their volumes in comparison with OSEM reconstruction. Background SUVmax also increased significantly, while background SUVmean showed no difference. Average L/B values for Q.Clear reconstruction were only marginally higher than those from OSME reconstruction with half-time. SNR decreased significantly in Q.Clear reconstruction compared with OSEM reconstruction with full time (but not half time). Differences between Q.Clear and OSEM reconstructions in SUVmax and SUVmean values within lesions were significantly correlated with SUVs within lesions. CONCLUSIONS Q.Clear reconstruction was useful for reducing PET injection dose or scanning time while maintaining the image quality. Q.Clear may affect PET quantification, and it is necessary to establish diagnostic recommendations based on Q.Clear results for Q.Clear application.
Collapse
Affiliation(s)
- Weiwei Ruan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Key Laboratory of Biological Targeted Therapy, the Ministry of Education, Wuhan, 430022, China
| | - Chunxia Qin
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Key Laboratory of Biological Targeted Therapy, the Ministry of Education, Wuhan, 430022, China
| | - Fang Liu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Key Laboratory of Biological Targeted Therapy, the Ministry of Education, Wuhan, 430022, China
| | - Rundong Pi
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Key Laboratory of Biological Targeted Therapy, the Ministry of Education, Wuhan, 430022, China
| | - Yongkang Gai
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Key Laboratory of Biological Targeted Therapy, the Ministry of Education, Wuhan, 430022, China
| | - Qingyao Liu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Key Laboratory of Biological Targeted Therapy, the Ministry of Education, Wuhan, 430022, China
| | - Xiaoli Lan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China.
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China.
- Key Laboratory of Biological Targeted Therapy, the Ministry of Education, Wuhan, 430022, China.
| |
Collapse
|
4
|
Huang Y, Wang M, Jiang L, Wang L, Chen L, Wang Q, Feng J, Wang J, Xu W, Wu H, Han Y. Optimal clinical protocols for total-body 18F-FDG PET/CT examination under different activity administration plans. EJNMMI Phys 2023; 10:14. [PMID: 36808378 PMCID: PMC9938848 DOI: 10.1186/s40658-023-00533-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 02/10/2023] [Indexed: 02/20/2023] Open
Abstract
BACKGROUND Highly sensitive digital total-body PET/CT scanners (uEXPLORER) have great potential for clinical applications and fundamental research. Given their increasing sensitivity, low-dose scanning or snapshot imaging is now possible in clinics. However, a standardized total-body 18F-FDG PET/CT protocol is still lacking. Establishing a standard clinical protocol for total-body 18F-FDG PET/CT examination under different activity administration plans can help provide a theoretical reference for nuclear radiologists. METHODS The NEMA image quality (IQ) phantom was used to evaluate the biases of various total-body 18F-FDG PET/CT protocols related to the administered activity, scan duration, and iterations. Several objective metrics, including contrast recovery (CR), background variability (BV), and contrast-to-noise ratio (CNR), were measured from different protocols. In line with the European Association of Nuclear Medicine Research Ltd. (EARL) guidelines, optimized protocols were suggested and evaluated for total-body 18F-FDG PET/CT imaging for three different injected activities. RESULTS Our NEMA IQ phantom evaluation resulted in total-body PET/CT images with excellent contrast and low noise, suggesting great potential for reducing administered activity or shortening the scan duration. Different to the iteration number, prolonging the scan duration was the first choice for achieving higher image quality regardless of the activity administered. In light of image quality, tolerance of oncological patients, and the risk of ionizing radiation damage, the 3-min acquisition and 2-iteration (CNR = 7.54), 10-min acquisition and 3-iteration (CNR = 7.01), and 10-min acquisition and 2-iteration (CNR = 5.49) protocols were recommended for full-dose (3.70 MBq/kg), half-dose (1.95 MBq/kg), and quarter-dose (0.98 MBq/kg) activity injection schemes, respectively. Those protocols were applied in clinical practices, and no significant differences were observed for the SUVmax of large/small lesions or the SUVmean of different healthy organs/tissues. CONCLUSION These findings support that digital total-body PET/CT scanners can generate PET images with a high CNR and low-noise background, even with a short acquisition time and low administered activity. The proposed protocols for different administered activities were determined to be valid for clinical examination and can maximize the value of this imaging type.
Collapse
Affiliation(s)
- Yanchao Huang
- grid.284723.80000 0000 8877 7471Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Meng Wang
- grid.284723.80000 0000 8877 7471Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Li Jiang
- grid.284723.80000 0000 8877 7471Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Lijuan Wang
- grid.284723.80000 0000 8877 7471Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Li Chen
- grid.284723.80000 0000 8877 7471Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qiaoyu Wang
- grid.284723.80000 0000 8877 7471Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jiatai Feng
- grid.497849.fCentral Research Institute, United Imaging Healthcare, Shanghai, China
| | - Jingyi Wang
- grid.497849.fCentral Research Institute, United Imaging Healthcare, Shanghai, China
| | - Wanbang Xu
- grid.506955.aDepartment of Traditional Chinese Medicine, Guangdong Institute for Drug Control, Guangzhou, China
| | - Hubing Wu
- grid.284723.80000 0000 8877 7471Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yanjiang Han
- Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China.
| |
Collapse
|
5
|
Fedrigo R, Segars WP, Martineau P, Gowdy C, Bloise I, Uribe CF, Rahmim A. Development of scalable lymphatic system in the 4D XCAT phantom: Application to quantitative evaluation of lymphoma PET segmentations. Med Phys 2022; 49:6871-6884. [PMID: 36053829 PMCID: PMC9742182 DOI: 10.1002/mp.15963] [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: 06/27/2022] [Revised: 08/01/2022] [Accepted: 08/16/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Digital anthropomorphic phantoms, such as the 4D extended cardiac-torso (XCAT) phantom, are actively used to develop, optimize, and evaluate a variety of imaging applications, allowing for realistic patient modeling and knowledge of ground truth. The XCAT phantom defines the activity and attenuation for a simulated patient, which includes a complete set of organs, muscle, bone, and soft tissue, while also accounting for cardiac and respiratory motion. However, the XCAT phantom does not currently include the lymphatic system, critical for evaluating medical imaging tasks such as sentinel node detection, node density measurement, and radiation dosimetry. PURPOSE In this study, we aimed to develop a scalable lymphatic system in the XCAT phantom, to facilitate improved research of the lymphatic system in medical imaging. Using this scalable lymphatic system, we modeled the lymph node conglomerate pathology that is characteristically observed in primary mediastinal B-cell lymphoma (PMBCL). As an extended application, we evaluated positron emission tomography (PET) image quantification of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of these simulated lymphomas, though the phantoms may be applied to other imaging modalities and study design paradigms (e.g., image quality, detection). METHODS A template model for the lymphatic system was developed based on anatomical data from the Visible Human Project of the National Library of Medicine. The segmented nodes and vessels were fit with non-uniform rational basis spline surfaces, and multichannel large deformation diffeomorphic metric mapping was used to propagate the template to different XCAT anatomies. To model conglomerates observed in PMBCL, lymph nodes were enlarged, converged within the mediastinum, and tracer concentration was increased. We used the phantoms as inputs to a PET simulation tool, which generated images using ordered subsets expectation maximization reconstruction with 2-8 mm Gaussian filters. Fixed thresholding (FT) and gradient segmentation were used to determine MTV and TLG. Percent bias (%Bias) and coefficient of variation (COV) were computed as measures of accuracy and precision, respectively, for each MTV and TLG measurement. RESULTS Using the methodology described above, we introduced a scalable lymphatic system in the XCAT phantom, which allows for the radioactivity and attenuation ground truth to be generated in 116 ± 2.5 s using a 2.3 GHz processor. Within the Rhinoceros interface, lymph node anatomy and function were modified to create a cohort of 10 phantoms with lymph node conglomerates. Using the lymphoma phantoms to evaluate PET quantification of MTV, mean %Bias values were -9.3%, -41.3%, and 20.9%, while COV values were 4.08%, 7.6%, and 3.4% using 25% FT, 40% FT, and gradient segmentations, respectively. Comparatively for TLG, mean %Bias values were -27.4%, -45.8%, and -16.0%, while COV values were 1.9%, 5.7%, and 1.4%, for the 25% FT, 40% FT, and gradient segmentations, respectively. CONCLUSIONS In this work, we upgraded the XCAT phantom to include a lymphatic system, comprised of a network of 276 scalable lymph nodes and corresponding vessels. As an application, we created a cohort of phantoms with lymph node conglomerates to evaluate lymphoma quantification in PET imaging, which highlights an important application of this work.
Collapse
Affiliation(s)
- Roberto Fedrigo
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | | | | | - Claire Gowdy
- Department of Radiology, BC Children’s Hospital, Vancouver, BC V6H 0B3, Canada
| | - Ingrid Bloise
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Carlos F. Uribe
- Functional Imaging, BC Cancer, Vancouver, BC V5Z 4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Arman Rahmim
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| |
Collapse
|
6
|
Maronnier Q, Courbon F, Caselles O. Evaluation of a method based on synthetic data inserted into raw data prior to reconstruction for the assessment of PET scanners. EJNMMI Phys 2022; 9:68. [PMID: 36182994 PMCID: PMC9526779 DOI: 10.1186/s40658-022-00496-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 09/21/2022] [Indexed: 11/21/2022] Open
Abstract
Background Performance assessment of positron emission tomography (PET) scanners is crucial to guide clinical practice with efficiency. Even though clinical data are the final target, their use to characterize systems response is constrained by the lack of ground truth. Phantom tests overcome this limitation by controlling the object of study, but remain simple and are not representative of patient complexity. The objective of this study is to evaluate the accuracy of a simulation method using synthetic spheres inserted into acquired raw data prior to reconstruction, simulating multiple scenarios in comparison with equivalent physical experiments. Methods We defined our experimental framework using the National Electrical Manufacturers Association NU-2 2018 Image Quality standard, but replaced the standard sphere set with more appropriate sizes (4, 5, 6, 8, 10 and 13 mm) better suited to current PET scanner performance. Four experiments, with different spheres-to-background ratios (2:1, 4:1, 6:1 and 8:1), were performed. An additional dataset was acquired with a radioactive background but no activity within the spheres (water only) to establish a baseline. Then, we artificially simulated radioactive spheres to reproduce other experiments using synthetic data inserted into the original sinogram. Images were reconstructed following standard guidelines using ordered subset expectation maximization algorithm along with a Bayesian penalized likelihood algorithm. We first visually compared experimental and simulated images. Afterward, we measured the activity concentration values into the spheres to calculate the mean and maximum recovery coefficients (RCmean and RCmax) which we used in a quantitative analysis. Results No significant visual differences were identified between experimental and simulated series. Mann–Whitney U tests comparing simulated and experimental distributions showed no statistical differences for both RCmean (P value = 0.611) and RCmax (P value = 0.720). Spearman tests revealed high correlation for RCmean (ρ = 0.974, P value < 0.001) and RCmax (ρ = 0.974, P value < 0.001) between both datasets. From Bland–Altman plots, we highlighted slight shifts in RCmean and RCmax of, respectively, 2.1 ± 16.9% and 3.3 ± 22.3%. Conclusions We evaluated the efficiency of our hybrid method in faithfully mimicking practical situations producing satisfactory results compared to equivalent experimental data. Supplementary Information The online version contains supplementary material available at 10.1186/s40658-022-00496-6.
Collapse
Affiliation(s)
- Quentin Maronnier
- Medical Physics Department, Institut Claudius Regaud, Toulouse, France.
| | - Frédéric Courbon
- Medical Physics Department, Institut Claudius Regaud, Toulouse, France
| | - Olivier Caselles
- Medical Physics Department, Institut Claudius Regaud, Toulouse, France
| |
Collapse
|
7
|
Wyrzykowski M, Siminiak N, Kaźmierczak M, Ruchała M, Czepczyński R. Impact of the Q.Clear reconstruction algorithm on the interpretation of PET/CT images in patients with lymphoma. EJNMMI Res 2020; 10:99. [PMID: 32845406 PMCID: PMC7450027 DOI: 10.1186/s13550-020-00690-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 08/19/2020] [Indexed: 12/24/2022] Open
Abstract
Background Q.Clear is a new Bayesian penalized-likelihood PET reconstruction algorithm. It has been documented that Q.Clear increases the SUVmax values of different malignant lesions. Purpose SUVmax values are crucial for the interpretation of PET/CT images in patients with lymphoma, particularly when the early and final responses to treatment are evaluated. The aim of the study was to systematically analyse the impact of the use of Q.Clear on the interpretation of PET/CT in patients with lymphoma. Methods A total of 280 18F-FDG PET/CT scans in patients with lymphoma were performed for staging (sPET), for early treatment response (iPET), after the end of treatment (ePET) and when a relapse of lymphoma was suspected (rPET). Scans were separately reconstructed with two algorithms, Q.Clear and OSEM, and further compared. Results The stage of lymphoma was concordantly diagnosed in 69/70 patients with both algorithms on sPET. Discordant assessment of the Deauville score (p < 0.001) was found in 11 cases (15.7%) of 70 iPET scans and in 11 cases of 70 ePET scans. An upgrade from a negative to a positive scan by Q.Clear occurred in 3 cases (4.3%) of iPET scans and 7 cases (10.0%) of ePET scans. The results of all 70 rPET scans were concordant. The SUVmax values of the target lymphoma lesions measured with Q.Clear were higher than those measured with OSEM in 88.8% of scans. Conclusion Although the Q.Clear algorithm may alter the interpretations of PET/CT in only a small proportion of patients, we recommend using standard OSEM reconstruction for the assessment of treatment response.
Collapse
Affiliation(s)
| | - Natalia Siminiak
- Department of Endocrinology and Metabolism, Poznan University of Medical Sciences, Poznań, Poland
| | - Maciej Kaźmierczak
- Department of Hematology and Bone Marrow Transplantation, Poznan University of Medical Sciences, Poznań, Poland
| | - Marek Ruchała
- Department of Endocrinology and Metabolism, Poznan University of Medical Sciences, Poznań, Poland
| | - Rafał Czepczyński
- Department of Nuclear Medicine, Affidea Poznań, Poznań, Poland.,Department of Endocrinology and Metabolism, Poznan University of Medical Sciences, Poznań, Poland
| |
Collapse
|