Quantitative imaging of iodine-124 with PET (original) (raw)
Related papers
PET quantitation and imaging of the non-pure positron-emitting iodine isotope 124I
Applied Radiation and Isotopes, 2002
A series of PET studies using phantoms is presented to characterize the imaging and quantitative performance of the positron-emitting iodine isotope 124 I. Measurements were performed on the 2D-PET scanner GE 4096+ as well as on the Siemens PET scanner HR+ operated in both 2D and 3D modes. No specific correction was applied for the grays emitted together with the positrons. As compared to 18 F, in studies with 124 I there is a small loss of image resolution and contrast, and an increase in background. The quantitative results varied between different scanners and various acquisition as well as reconstruction modes, with an average relative difference of À6713% (mean7SD) in respect of the phantom radioactivity as measured with gray spectroscopy. We conclude that quantitation of a radiopharmaceutical labelled with 124 I is feasible and may be improved by the development of specific corrections.
2019
Univerzita Karlova, Farmaceutická fakulta v Hradci Králové Katedra Katedra farmakiologie a toxikologie Kandidát Mgr. Adam Čepa Školitel Prof. PharmDr. Ing. Milan Lázníček, CSc. Název disertační práce Modifikace fragmentů protilátek, jejich značení nekonvenčními pozitronovými zářiči a biologické testování pro diagnostiku PET Zvláštní onkologická diagnostika vyžaduje nové typy selektivních radiofarmak, zejména těch, které jsou vhodné pro molekulární PET zobrazování a terapii potažmo teranostiku. Cílem této práce je představit nová radiofarmaka s cílenou distribucí pro diagnostiku immunoPET a terapii založenou na monoklonální protilátce IgG M75 zaměřené na humánní karboanhydrázu IX, nimotuzumab (hR-3) cílící receptor pro epidermální růstový faktor (EGFR) a jeden z derivátů bombesinu (BBN) cílící GRP receptory. Tyto molekuly byly značeny radionuklidy 64Cu (t1/2 12,70 hod.), 61Cu (t1/2 3,33 hod), 68Ga (t1/2 68 min) a 177Lu (t1/2 6,71 dne). Tato potenciální radiofarmaka byla hodnocena in ...
Recent developments in positron emission tomography (PET) instrumentation
NDT & E International, 1994
This paper presents recent detector developments and perspectives for positron emission tomography (PET) instrumentation used for medical research, as well as the physical processes in positron annihilation, photon scattering and detection, tomograph design considerations, and the potentials for new advances in detectors.
Assessment of a fully 3D Monte Carlo reconstruction method for preclinical PET with iodine-124
Physics in Medicine and Biology, 2015
Iodine-124 is a radionuclide well suited to the labeling of intact monoclonal antibodies. Yet, accurate quantification in preclinical imaging with I-124 is challenging due to the large positron range and a complex decay scheme including high-energy gammas. The aim of this work was to assess the quantitative performance of a fully 3D Monte Carlo (MC) reconstruction for preclinical I-124 PET. The high-resolution small animal PET Inveon (Siemens) was simulated using GATE 6.1. Three system matrices (SM) of different complexity were calculated in addition to a Siddon-based ray tracing approach for comparison purpose. Each system matrix accounted for a more or less complete description of the physics processes both in the scanned object and in the PET scanner. One homogeneous water phantom and three heterogeneous phantoms including water, lungs and bones were simulated, where hot and cold regions were used to assess activity recovery as well as the trade-off between contrast recovery and noise in different regions. The benefit of accounting for scatter, attenuation, positron range and spurious coincidences occurring in the object when calculating the system matrix used to reconstruct I-124 PET images was highlighted. We found that the use of an MC SM including a thorough modelling of the detector response and physical effects in a uniform water-equivalent phantom was efficient to get reasonable quantitative accuracy in homogeneous and heterogeneous phantoms. Modelling the phantom heterogeneities in the SM did not necessarily yield the most accurate estimate of the activity distribution, due to the high variance affecting many SM elements in the most sophisticated SM.
Molecular Imaging and Biology, 2019
Purpose: The increasing interest and availability of non-standard positron-emitting radionuclides has heightened the relevance of radionuclide choice in the development and optimization of new positron emission tomography (PET) imaging procedures, both in preclinical research and clinical practice. Differences in achievable resolution arising from positron range can largely influence application suitability of each radionuclide, especially in small-ring preclinical PET where system blurring factors due to annihilation photon acollinearity and detector geometry are less significant. Some resolution degradation can be mitigated with appropriate range corrections implemented during image reconstruction, the quality of which is contingent on an accurate characterization of positron range. Procedures: To address this need, we have characterized the positron range of several standard and non-standard PET radionuclides (As-72, F-18, Ga-68, Mn-52, Y-86, and Zr-89) through imaging of small-animal quality control phantoms on a benchmark preclinical PET scanner. Further, the Particle and Heavy Ion Transport code System (PHITS v3.02) code was utilized for Monte Carlo modeling of positron range-dependent blurring effects.
Trends in PET quantification: opportunities and challenges
Clinical and Translational Imaging, 2014
Since its inception, positron emission tomography (PET) has emerged as a non-invasive imaging modality that allows, in different fields (neurology, cardiology and oncology), in vivo quantitative assessment of molecular and physiological biomarkers in healthy and disease states . Quantitative analysis makes it possible to establish a direct relationship between the time-varying activity concentration in organs/tissues of interest and the functional parameters representing the underlying biological processes at the cellular level . It should, however, be emphasized that the term quantification has often been used inappropriately in the medical imaging literature to indicate different measurement approaches such as [5]: (1) semi-quantification (a contradiction in terms) or relative quantification (e.g., measurement of SUV), (2) absolute quantification of activity concentration, usually incorporating careful corrections for physical degrading factors (e.g., measurement of tracer uptake in MBq), and proper physiological quantification, where the absolute activity concentration [obtained in ] is converted into molecular parameters of interest [e.g., glucose metabolic rate (rGMCglc) expressed as mol/100 g/min].
Development of an instrument for time–activity curve measurements during PET imaging of rodents
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007
Molecular imaging using PET in small rodents requires commonly the knowledge of the input function of the tracer (quantitative and kinetic studies of the metabolism, development of new drugs or new tracers, etc.). In this paper, we report the status and the performances of the prototype of a counting system that is under development at DAPNIA a in collaboration with SHFJ b . The detection device is made of silicon diodes of 0.3 mm thickness proper to measure the positrons emitted by the radiotracer contained in arterial blood flowing in a thin-wall microtube. Such diodes are poorly efficient for the 511 keV gammas from the rodent and thus require a rather light lead shielding and allow operating very close by to the animal. The detectors, the front-end electronics (for signal preamplification, shaping, and discrimination) and the acquisition circuits are mounted on a single card. The device is connected directly to a portable computer via an USB port.
Cancer Imaging
This review describes the main benefits of using long axial field of view (LAFOV) PET in clinical applications. As LAFOV PET is the latest development in PET instrumentation, many studies are ongoing that explore the potentials of these systems, which are characterized by ultra-high sensitivity. This review not only provides an overview of the published clinical applications using LAFOV PET so far, but also provides insight in clinical applications that are currently under investigation. Apart from the straightforward reduction in acquisition times or administered amount of radiotracer, LAFOV PET also allows for other clinical applications that to date were mostly limited to research, e.g., dual tracer imaging, whole body dynamic PET imaging, omission of CT in serial PET acquisition for repeat imaging, and studying molecular interactions between organ systems. It is expected that this generation of PET systems will significantly advance the field of nuclear medicine and molecular im...
124Iodine: A Longer-Life Positron Emitter Isotope—New Opportunities in Molecular Imaging
BioMed Research International, 2014
Iodine (124 I) with its 4.2 d half-life is particularly attractive for in vivo detection and quantification of longer-term biological and physiological processes; the long half-life of 124 I is especially suited for prolonged time in vivo studies of high molecular weight compounds uptake. Numerous small molecules and larger compounds like proteins and antibodies have been successfully labeled with 124 I. Advances in radionuclide production allow the effective availability of sufficient quantities of 124 I on small biomedical cyclotrons for molecular imaging purposes. Radioiodination chemistry with 124 I relies on well-established radioiodine labeling methods, which consists mainly in nucleophilic and electrophilic substitution reactions. The physical characteristics of 124 I permit taking advantages of the higher PET image quality. The availability of new molecules that may be targeted with 124 I represents one of the more interesting reasons for the attention in nuclear medicine. We aim to discuss all iodine radioisotopes application focusing on 124 I, which seems to be the most promising for its half-life, radiation emissions, and stability, allowing several applications in oncological and nononcological fields.