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Journal of Nuclear Medicine : Official... Jul 2017PET was developed in the 1970s as an in vivo method to measure regional pathophysiologic processes. In the 1990s the focus moved to the detection of local increases in... (Review)
Review
PET was developed in the 1970s as an in vivo method to measure regional pathophysiologic processes. In the 1990s the focus moved to the detection of local increases in uptake, first in the brain (activation studies) and later in oncology (finding metastases), with F-FDG emerging as a highly sensitive staging technique. This focus on sensitivity has overshadowed the other main characteristic of PET, its quantitative nature. In recent years there has been a shift. PET is now seen as a promising tool for drug development and precision medicine-that is, a method to monitor or even predict response to therapy. Quantification is essential for precision medicine, but many studies today use simplified semiquantitative methods without properly validating them. This review provides several examples illustrating that simplified methods may lead to less accurate or even misleading results. Simplification is important for routine clinical practice, but finding the optimal balance between accuracy and simplicity requires careful studies. It is argued that the use of simplified approaches without proper validation not only may waste time and resources but also may raise ethical questions, especially in drug development studies.
Topics: Biomarkers; Brain Diseases; Humans; Image Interpretation, Computer-Assisted; Molecular Imaging; Positron-Emission Tomography
PubMed: 28522743
DOI: 10.2967/jnumed.116.188029 -
Zeitschrift Fur Medizinische Physik Feb 2023PET/CT imaging plays an increasing role in radiotherapy treatment planning. The aim of this article was to identify the major use cases and technical as well as medical... (Review)
Review
PET/CT imaging plays an increasing role in radiotherapy treatment planning. The aim of this article was to identify the major use cases and technical as well as medical physics challenges during integration of these data into treatment planning. Dedicated aspects, such as (i) PET/CT-based radiotherapy simulation, (ii) PET-based target volume delineation, (iii) functional avoidance to optimized organ-at-risk sparing and (iv) functionally adapted individualized radiotherapy are discussed in this article. Furthermore, medical physics aspects to be taken into account are summarized and presented in form of check-lists.
Topics: Positron Emission Tomography Computed Tomography; Radiotherapy Planning, Computer-Assisted; Tomography, X-Ray Computed; Positron-Emission Tomography; Physics
PubMed: 36272949
DOI: 10.1016/j.zemedi.2022.09.001 -
Nanotheranostics 2021With the rapid development of anti-cancer cell-based therapies, such as adoptive T cell therapies using tumor-infiltrating T cells, T cell receptor transduced T cells,... (Review)
Review
With the rapid development of anti-cancer cell-based therapies, such as adoptive T cell therapies using tumor-infiltrating T cells, T cell receptor transduced T cells, and chimeric antigen receptor T cells, there has been a growing interest in imaging technologies to non-invasively track transferred cells . Cell tracking using cell labeling with positron emitting radioisotopes for positron emission tomography (PET) imaging has potential advantages over single-photon emitting radioisotopes. These advantages include intrinsically higher resolution, higher sensitivity, and higher signal-to-background ratios. Here, we review the current status of recently developed Zirconium-89 (Zr)-oxine cell labeling with PET imaging focusing on its applications and future perspectives. Labeling of cells with Zr-oxine is completed in a series of relatively simple steps, and its low radioactivity doses required for imaging does not interfere with the proliferation or function of the labeled immune cells. Preclinical studies have revealed that Zr-oxine PET allows high-resolution tracking of labeled cells for 1-2 weeks after cell transfer both in mice and non-human primates. These results provide a strong rationale for the clinical translation of Zr-oxine PET-based imaging of cell-based therapy.
Topics: Animals; Humans; Mice; Oxyquinoline; Positron-Emission Tomography; Radioisotopes; Zirconium
PubMed: 33391973
DOI: 10.7150/ntno.51391 -
Nature Nanotechnology May 2024Positron emission particle tracking (PEPT) enables 3D localization and tracking of single positron-emitting radiolabelled particles with high spatiotemporal resolution....
Positron emission particle tracking (PEPT) enables 3D localization and tracking of single positron-emitting radiolabelled particles with high spatiotemporal resolution. The translation of PEPT to the biomedical imaging field has been limited due to the lack of methods to radiolabel biocompatible particles with sufficient specific activity and protocols to isolate a single particle in the sub-micrometre size range, below the threshold for capillary embolization. Here we report two key developments: the synthesis and Ga-radiolabelling of homogeneous silica particles of 950 nm diameter with unprecedented specific activities (2.1 ± 1.4 kBq per particle), and the isolation and manipulation of a single particle. We have combined these developments to perform in vivo PEPT and dynamic positron emission tomography (PET) imaging of a single radiolabelled sub-micrometre size particle using a pre-clinical positron emission tomography/computed tomography scanner. This work opens possibilities for quantitative assessment of haemodynamics in vivo in real time, at the whole-body level using minimal amounts of injected radioactive dose and material.
Topics: Animals; Positron-Emission Tomography; Gallium Radioisotopes; Mice; Silicon Dioxide; Particle Size; Nanoparticles; Positron Emission Tomography Computed Tomography
PubMed: 38242986
DOI: 10.1038/s41565-023-01589-8 -
European Journal of Nuclear Medicine... Jan 2023[C]Metomidate positron emission tomography (PET) is currently used for staging of adrenocortical carcinoma and for lateralization in primary aldosteronism (PA). Due to...
PURPOSE
[C]Metomidate positron emission tomography (PET) is currently used for staging of adrenocortical carcinoma and for lateralization in primary aldosteronism (PA). Due to the short half-life of carbon-11 and a high non-specific liver uptake of [C]metomidate there is a need for improved adrenal imaging methods. In a previous pre-clinical study para-chloro-2-[F]fluoroethyletomidate has been proven to be a specific adrenal tracer. The objective is to perform a first evaluation of para-chloro-2-[F]fluoroethyletomidate positron emission computed tomography ([F]CETO-PET/CT) in patients with adrenal tumours and healthy volunteers.
METHODS
Fifteen patients underwent [F]CETO-PET/CT. Five healthy volunteers were recruited for test-retest analysis and three out of the five underwent additional [O]water PET/CT to measure adrenal blood flow. Arterial blood sampling and tracer metabolite analysis was performed. The kinetics of [F]CETO were assessed and simplified quantitative methods were validated by comparison to outcome measures of tracer kinetic analysis.
RESULTS
Uptake of [F]CETO was low in the liver and high in adrenals. Initial metabolization was rapid, followed by a plateau. The kinetics of [F]CETO in healthy adrenals and all adrenal pathologies, except for adrenocortical carcinoma, were best described by an irreversible single-tissue compartment model. Standardized uptake values (SUV) correlated well with the uptake rate constant K. Both K and SUV were highly correlated to adrenal blood flow in healthy controls. Repeatability coefficients of K, SUV, and SUV were 25, 22, and 17%.
CONCLUSIONS
High adrenal uptake combined with a low unspecific liver uptake suggests that F]CETO is a suitable tracer for adrenal imaging. Adrenal SUV, based on a whole-body scan at 1 h p.i., correlated well with the net uptake rate K.
TRIAL REGISTRATION
ClinicalTrials.gov , NCT05361083 Retrospectively registered 29 April 2022. at, https://clinicaltrials.gov/ct2/show/NCT05361083.
Topics: Humans; Positron Emission Tomography Computed Tomography; Adrenocortical Carcinoma; Kinetics; Positron-Emission Tomography; Adrenal Cortex Neoplasms
PubMed: 36074157
DOI: 10.1007/s00259-022-05957-9 -
American Journal of Veterinary Research Feb 2022To perform qualitative and quantitative analysis of positron emission tomography (PET)/CT images using spontaneous ventilation (SV) and positive-pressure breath-hold...
OBJECTIVE
To perform qualitative and quantitative analysis of positron emission tomography (PET)/CT images using spontaneous ventilation (SV) and positive-pressure breath-hold (PPBH) techniques in order to demonstrate the feasibility of PPBH PET/CT to decrease respiration-induced artifacts.
ANIMALS
5 healthy female mixed-breed dogs.
PROCEDURES
2-([18F]fluoro)-2-deoxy-D-glucose (was administered to each anesthetized dog. An SV PET/CT scan was performed from the head to the femur using 8 bed positions (3 min/bed) followed by a PPBH scan centered over the diaphragm with a single bed position (1.5 min/bed). PET image quality, the misalignment of organs between PET and CT images, and standardized uptake values (SUVs) of liver adjacent to diaphragm were compared between SV and PPBH.
RESULTS
Overall image quality and conspicuity of anatomic structures were superior in PPBH than in SV PET images. PPBH induced significantly less misalignment of the liver and diaphragm in all planes compared to SV. For the gall bladder, PPBH showed significantly less misalignment than SV only in the transverse plane. The maximum SUV in all of the liver areas was significantly higher with PPBH compared to SV. PPBH exhibited significantly higher mean SUV in the liver adjacent to the left diaphragmatic dome and left lateral border and higher minimum SUV only in the liver adjacent to the left diaphragmatic dome.
CLINICAL RELEVANCE
PPBH was demonstrated to be a feasible PET/CT protocol with higher PET image quality, less organ misalignment on fused PET/CT, and more accurate SUVs of the liver compared to SV PET/CT in healthy dogs.
Topics: Animals; Artifacts; Dogs; Female; Fluorodeoxyglucose F18; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Respiration; Thorax
PubMed: 35175931
DOI: 10.2460/ajvr.21.08.0102 -
Japanese Journal of Radiology Jul 2022To develop an anomaly detection system in PET/CT with the tracer F-fluorodeoxyglucose (FDG) that requires only normal PET/CT images for training and can detect abnormal...
PURPOSE
To develop an anomaly detection system in PET/CT with the tracer F-fluorodeoxyglucose (FDG) that requires only normal PET/CT images for training and can detect abnormal FDG uptake at any location in the chest region.
MATERIALS AND METHODS
We trained our model based on a Bayesian deep learning framework using 1878 PET/CT scans with no abnormal findings. Our model learns the distribution of standard uptake values in these normal training images and detects out-of-normal uptake regions. We evaluated this model using 34 scans showing focal abnormal FDG uptake in the chest region. This evaluation dataset includes 28 pulmonary and 17 extrapulmonary abnormal FDG uptake foci. We performed per-voxel and per-slice receiver operating characteristic (ROC) analyses and per-lesion free-response receiver operating characteristic analysis.
RESULTS
Our model showed an area under the ROC curve of 0.992 on discriminating abnormal voxels and 0.852 on abnormal slices. Our model detected 41 of 45 (91.1%) of the abnormal FDG uptake foci with 12.8 false positives per scan (FPs/scan), which include 26 of 28 pulmonary and 15 of 17 extrapulmonary abnormalities. The sensitivity at 3.0 FPs/scan was 82.2% (37/45).
CONCLUSION
Our model trained only with normal PET/CT images successfully detected both pulmonary and extrapulmonary abnormal FDG uptake in the chest region.
Topics: Bayes Theorem; Deep Learning; Fluorodeoxyglucose F18; Humans; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Radiopharmaceuticals
PubMed: 35094221
DOI: 10.1007/s11604-022-01249-2 -
The Quarterly Journal of Nuclear... Sep 2022[F]fluorodeoxyglucose (FDG) PET/CT can be used to image the inflammation in rheumatoid arthritis. Specifically, the synovial metabolic activity can be evaluated visually...
[F]fluorodeoxyglucose (FDG) PET/CT can be used to image the inflammation in rheumatoid arthritis. Specifically, the synovial metabolic activity can be evaluated visually and measured using standard uptake values. Fluorine-18-labeled Sodium fluoride (NaF) PET/CT can be used to determine synovial osteoblastic activity. Response assessment using FDG PET/CT is routine in many cancers and this is now an emerging technique for rheumatoid arthritis. Vasculitis in rheumatoid arthritis (RA) can be also studied with FDG PET/CT and aortic calcification with NaF PET/CT. These techniques could be useful in determining RA disease severity. FDG PET/CT is a useful technique to exclude underlying malignancy when RA does not follow the expected course. A number of novel tracers are being studied with regard to their applicability in rheumatoid arthritis and some of these could even be used in a theranostic manner in the future.
Topics: Arthritis, Rheumatoid; Fluorodeoxyglucose F18; Humans; Neoplasms; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Sodium Fluoride
PubMed: 36066112
DOI: 10.23736/S1824-4785.22.03461-6 -
Annual Review of Biomedical Engineering 2015Positron emission tomography (PET) imaging is based on detecting two time-coincident high-energy photons from the emission of a positron-emitting radioisotope. The... (Review)
Review
Positron emission tomography (PET) imaging is based on detecting two time-coincident high-energy photons from the emission of a positron-emitting radioisotope. The physics of the emission, and the detection of the coincident photons, give PET imaging unique capabilities for both very high sensitivity and accurate estimation of the in vivo concentration of the radiotracer. PET imaging has been widely adopted as an important clinical modality for oncological, cardiovascular, and neurological applications. PET imaging has also become an important tool in preclinical studies, particularly for investigating murine models of disease and other small-animal models. However, there are several challenges to using PET imaging systems. These include the fundamental trade-offs between resolution and noise, the quantitative accuracy of the measurements, and integration with X-ray computed tomography and magnetic resonance imaging. In this article, we review how researchers and industry are addressing these challenges.
Topics: Algorithms; Animals; Biomedical Engineering; Biophysical Phenomena; Humans; Image Interpretation, Computer-Assisted; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Multimodal Imaging; Positron-Emission Tomography; Scattering, Radiation; Tomography, X-Ray Computed
PubMed: 26643024
DOI: 10.1146/annurev-bioeng-071114-040723 -
NeuroImage May 2023Super-resolution (SR) is a methodology that seeks to improve image resolution by exploiting the increased spatial sampling information obtained from multiple...
Super-resolution (SR) is a methodology that seeks to improve image resolution by exploiting the increased spatial sampling information obtained from multiple acquisitions of the same target with accurately known sub-resolution shifts. This work aims to develop and evaluate an SR estimation framework for brain positron emission tomography (PET), taking advantage of a high-resolution infra-red tracking camera to measure shifts precisely and continuously. Moving phantoms and non-human primate (NHP) experiments were performed on a GE Discovery MI PET/CT scanner (GE Healthcare) using an NDI Polaris Vega (Northern Digital Inc), an external optical motion tracking device. To enable SR, a robust temporal and spatial calibration of the two devices was developed as well as a list-mode Ordered Subset Expectation Maximization PET reconstruction algorithm, incorporating the high-resolution tracking data from the Polaris Vega to correct motion for measured line of responses on an event-by-event basis. For both phantoms and NHP studies, the SR reconstruction method yielded PET images with visibly increased spatial resolution compared to standard static acquisitions, allowing improved visualization of small structures. Quantitative analysis in terms of SSIM, CNR and line profiles were conducted and validated our observations. The results demonstrate that SR can be achieved in brain PET by measuring target motion in real-time using a high-resolution infrared tracking camera.
Topics: Animals; Positron Emission Tomography Computed Tomography; Motion Capture; Positron-Emission Tomography; Motion; Brain; Phantoms, Imaging; Algorithms; Image Processing, Computer-Assisted
PubMed: 36977452
DOI: 10.1016/j.neuroimage.2023.120056