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Medical Physics Jul 2022Nuclear medicine probes turned into the key for the identification and precise location of sentinel lymph nodes and other occult lesions (i.e., tumors) by using the... (Review)
Review
Nuclear medicine probes turned into the key for the identification and precise location of sentinel lymph nodes and other occult lesions (i.e., tumors) by using the systemic administration of radiotracers. Intraoperative nuclear probes are key in the surgical management of some malignancies as well as in the determination of positive surgical margins, thus reducing the extent and potential surgery morbidity. Depending on their application, nuclear probes are classified into two main categories, namely, counting and imaging. Although counting probes present a simple design, are handheld (to be moved rapidly), and provide only acoustic signals when detecting radiation, imaging probes, also known as cameras, are more hardware-complex and also able to provide images but at the cost of an increased intervention time as displacing the camera has to be done slowly. This review article begins with an introductory section to highlight the relevance of nuclear-based probes and their components as well as the main differences between ionization- (semiconductor) and scintillation-based probes. Then, the most significant performance parameters of the probe are reviewed (i.e., sensitivity, contrast, count rate capabilities, shielding, energy, and spatial resolution), as well as the different types of probes based on the target radiation nature, namely: gamma (γ), beta (β) (positron and electron), and Cherenkov. Various available intraoperative nuclear probes are finally compared in terms of performance to discuss the state-of-the-art of nuclear medicine probes. The manuscript concludes by discussing the ideal probe design and the aspects to be considered when selecting nuclear-medicine probes.
Topics: Gamma Rays; Humans; Neoplasms; Nuclear Medicine; Radionuclide Imaging; Sentinel Lymph Node
PubMed: 35526220
DOI: 10.1002/mp.15690 -
Saudi Pharmaceutical Journal : SPJ :... Feb 2023The paper begins by identifying the key historical elements in the development of nuclear medicine imaging, focusing on the Anger camera and single photon emission... (Review)
Review
The paper begins by identifying the key historical elements in the development of nuclear medicine imaging, focusing on the Anger camera and single photon emission computed tomography (SPECT) technologies. In this context, key reference is made to the physics of detection in Anger camera systems, especially key components such as the sodium iodide crystal, the function and performance of photomultiplier tubes, and the collimator design. It is discovered that within each component of technology, there are fundamental physical relationships that govern the performance of each component, and that overall image quality is the result of the complex interaction of all such elements. The increasing use of SPECT/CT imaging is described and illustrated with a range of typical clinical applications, which include brain, spinal, cardiac, and cancer studies. The use of CT imaging functionality allows for SPECT image correction based on compensation for absorption within tissue. Reference is also made to the basics of positron emission tomography (PET) imaging and, in particular, to the integration of PET/CT systems where the anatomy profile of the CT image is used to provide correction for photon absorption. A summary is provided of the radionuclides and radiopharmaceuticals commonly used in PET/CT imaging and a range of image studies referenced includes those of nasopharyngeal carcinoma, lung cancer investigation, brain investigation (cancer detection and dementia) and cardiac function. Reference is made to the development of "time of flight" (TOF) technology for improving of image resolution in PET/CT systems. Furthermore, SPECT/CT and PET/CT imaging systems are compared, where a key factor identified is the significantly higher number of photons detected with PET/CT technology and improved image resolution.
PubMed: 36942267
DOI: 10.1016/j.jsps.2022.12.013 -
Nuclear Instruments & Methods in... Oct 2019Wide-field time-correlated single photon counting detection techniques, where the position and the arrival time of the photons are recorded simultaneously using a... (Review)
Review
Wide-field time-correlated single photon counting detection techniques, where the position and the arrival time of the photons are recorded simultaneously using a camera, have made some advances recently. The technology and instrumentation used for this approach is employed in areas such as nuclear science, mass spectroscopy and positron emission tomography, but here, we discuss some of the wide-field TCSPC methods, for applications in fluorescence microscopy. We describe work by us and others as presented in the Ulitima fast imaging and tracking conference at the Argonne National Laboratory in September 2018, from phosphorescence lifetime imaging (PLIM) microscopy on the microsecond time scale to FLIM) on the nanosecond time scale, and highlight some applications of these techniques.
PubMed: 31645797
DOI: 10.1016/j.nima.2019.162365 -
Seminars in Nuclear Medicine Sep 2022Breast cancer survival is significantly improved over the past decades due to major improvements in anti-tumor therapies and the implementation of regular screening,... (Review)
Review
Breast cancer survival is significantly improved over the past decades due to major improvements in anti-tumor therapies and the implementation of regular screening, which leads to early detection of breast cancer. Therefore, it is of utmost importance to prevent patients from long-term side effects, including radiotherapy-induced cardiotoxicity. Radiotherapy may contribute to damage of myocardial structures on the cellular level, which eventually could result in various types of cardiovascular problems, including coronary artery disease and (non-)ischemic cardiomyopathy, leading to heart failure. These cardiac complications of radiotherapy are preceded by alterations in myocardial perfusion and blood flow. Therefore, early detection of these alterations is important to prevent the progression of these pathophysiological processes. Several radionuclide imaging techniques may contribute to the early detection of these changes. Single-Photon Emission Computed Tomography (SPECT) cameras can be used to create Multigated Acquisition scans in order to assess the left ventricular systolic and diastolic function. Furthermore, SPECT cameras are used for myocardial perfusion imaging with radiopharmaceuticals such as Tc-sestamibi and Tc-tetrofosmin. Accurate quantitative measurement of myocardial blood flow (MBF), can be performed by Positron Emission Tomography (PET), as the uptake of some of the tracers used for PET-based MBF measurement almost creates a linear relationship with MBF, resulting in very accurate blood flow quantification. Furthermore, there are PET and SPECT tracers that can assess inflammation and denervation of the cardiac sympathetic nervous system. Research over the past decades has mainly focused on the long-term development of left ventricular impairment and perfusion defects. Considering laterality of the breast cancer, some early studies have shown that women irradiated for left-sided breast cancer are more prone to cardiotoxic side effects than women irradiated for right-sided breast cancer. The left-sided radiation field in these trials, which predominantly used older radiotherapy techniques without heart-sparing techniques, included a larger volume of the heart and left ventricle, leading to increased unavoidable radiation exposure to the heart due to the close proximity of the radiation treatment volume. Although radiotherapy for breast cancer exposes the heart to incidental radiation, several improvements and technical developments over the last decades resulted in continuous reduction of radiation dose and volume exposure to the heart. In addition, radiotherapy reduces loco-regional tumor recurrences and death from breast cancer and improves survival. Therefore, in the majority of patients, the benefits of radiotherapy outweigh the potential very low risk of cardiovascular adverse events after radiotherapy. This review addresses existing nuclear imaging techniques, which can be used to evaluate (long-term) effects of radiotherapy-induced mechanical cardiac dysfunction and discusses the potential use of more novel nuclear imaging techniques, which are promising in the assessment of early signs of cardiac dysfunction in selected irradiated breast cancer patients.
Topics: Breast Neoplasms; Cardiotoxicity; Female; Heart Diseases; Humans; Neoplasm Recurrence, Local; Nuclear Medicine; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon
PubMed: 35246310
DOI: 10.1053/j.semnuclmed.2022.02.001 -
Cancers Dec 2021Developments throughout the history of nuclear medicine have involved improvements in both instrumentation and radionuclides, which have been intertwined.... (Review)
Review
Developments throughout the history of nuclear medicine have involved improvements in both instrumentation and radionuclides, which have been intertwined. Instrumentation developments always occurred during the search to improving devices' sensitivity and included advances in detector technology (with the introduction of cadmium zinc telluride and digital Positron Emission Tomography-PET-devices with silicon photomultipliers), design (total body PET) and configuration (ring-shaped, Single-Photon Emission Computed Tomography (SPECT), Compton camera). In the field of radionuclide development, we observed the continual changing of clinically used radionuclides, which is sometimes influenced by instrumentation technology but also driven by availability, patient safety and clinical questions. Some areas, such as tumour imaging, have faced challenges when changing radionuclides based on availability, when this produced undesirable clinical findings with the introduction of unclear focal uptakes and unspecific uptakes. On the other end of spectrum, further developments of PET technology have seen a resurgence in its use in nuclear cardiology, with rubidium-82 from strontium-82/rubidium-82 generators being the radionuclide of choice, moving away from SPECT nuclides thallium-201 and technetium-99m. These continuing improvements in both instrumentation and radionuclide development have helped the growth of nuclear medicine and its importance in the ever-evolving range of patient care options.
PubMed: 34944803
DOI: 10.3390/cancers13246183 -
Journal of Personalized Medicine Oct 2020Molecular radiotherapy, or targeted radionuclide therapy, uses systemically administered drugs bearing a suitable radioactive isotope, typically a beta emitter. These... (Review)
Review
Molecular radiotherapy, or targeted radionuclide therapy, uses systemically administered drugs bearing a suitable radioactive isotope, typically a beta emitter. These are delivered via metabolic or other physiological pathways to cancer cells in greater concentrations than to normal tissues. The absorbed radiation dose in tumour deposits causes chromosomal damage and cell death. A partner radiopharmaceutical, most commonly the same vector labelled with a different radioactive atom, with emissions suitable for gamma camera or positron emission tomography imaging, is used to select patients for treatment and to assess response. The use of these pairs of radio-labelled drugs, one optimised for therapy, the other for diagnostic purposes, is referred to as . Theragnostics is increasingly moving away from a fixed number of defined activity administrations, to a much more individualised or personalised approach, with the aim of improving treatment outcomes, and minimising toxicity. There is, however, still significant scope for further progress in that direction. The main tools for personalisation are the following: imaging biomarkers for better patient selection; predictive and post-therapy dosimetry to maximise the radiation dose to the tumour while keeping organs at risk within tolerance limits; imaging for assessment of treatment response; individualised decision making and communication about radiation protection, adjustments for toxicity, inpatient and outpatient care.
PubMed: 33081161
DOI: 10.3390/jpm10040174 -
Physics in Medicine and Biology May 2021Built on top of the Geant4 toolkit, GATE is collaboratively developed for more than 15 years to design Monte Carlo simulations of nuclear-based imaging systems. It is,... (Review)
Review
Built on top of the Geant4 toolkit, GATE is collaboratively developed for more than 15 years to design Monte Carlo simulations of nuclear-based imaging systems. It is, in particular, used by researchers and industrials to design, optimize, understand and create innovative emission tomography systems. In this paper, we reviewed the recent developments that have been proposed to simulate modern detectors and provide a comprehensive report on imaging systems that have been simulated and evaluated in GATE. Additionally, some methodological developments that are not specific for imaging but that can improve detector modeling and provide computation time gains, such as Variance Reduction Techniques and Artificial Intelligence integration, are described and discussed.
Topics: Artificial Intelligence; Computer Simulation; Monte Carlo Method; Software; Tomography, X-Ray Computed
PubMed: 33770774
DOI: 10.1088/1361-6560/abf276 -
Scientific Reports Feb 2022For radiological diagnosis and radionuclide therapy, X-ray and gamma-ray imaging technologies are essential. Single-photon emission tomography (SPECT) and positron...
For radiological diagnosis and radionuclide therapy, X-ray and gamma-ray imaging technologies are essential. Single-photon emission tomography (SPECT) and positron emission tomography (PET) play essential roles in radiological diagnosis, such as the early detection of tumors. Radionuclide therapy is also rapidly developing with the use of these modalities. Nevertheless, a limited number of radioactive tracers are imaged owing to the limitations of the imaging devices. In a previous study, we developed a hybrid Compton camera that conducts simultaneous Compton and pinhole imaging within a single system. In this study, we developed a system that simultaneously realizes three modalities: Compton, pinhole, and PET imaging in 3D space using multiple hybrid Compton cameras. We achieved the simultaneous imaging of Cs-137 (Compton mode targeting 662 keV), Na-22 (PET mode targeting 511 keV), and Am-241 (pinhole mode targeting 60 keV) within the same field of view. In addition, the imaging of Ga-67 and In-111, which are used in various diagnostic scenarios, was conducted. We also verified that the 3D distribution of the At-211 tracer inside a mouse could be imaged using the pinhole mode.
PubMed: 35169183
DOI: 10.1038/s41598-022-06401-6