Nuclear Imaging Research Articles

A review of alternative measurements in strain imaging for ventricular arrhythmia prediction.

Global longitudinal strain has been established as a reliable tool to assess global left ventricular function and a marker of subclinical left ventricular dysfunction unrecognized by the ejection fraction. On the other hand, ventricular arrhythmias are the most common cause of sudden cardiac death. Their early detection is a challenge. Possible prognostic markers for the risk of ventricular arrhythmias are discussed in the literature - electrocardiographic, cardiac magnetic resonance, computed tomography, radionuclide imaging, and markers from new echocardiographic techniques. Of the latter, at this stage of knowledge, several markers have been discussed as informative for predicting ventricular arrhythmias - global longitudinal strain, radial strain and mechanical dispersion, and most recently, myocardial work. As far as we are informed, global longitudinal strain is particularly useful in patients with normal echocardiographic parameters such as left ventricular ejection fraction, left atrial diameter, left ventricular wall thickness, and aortic root. The relationship between mechanical dispersion and ventricular arrhythmias has been widely studied. The relationship has been studied more in some patient populations - heart failure, ischemic heart disease, long QT syndrome and arrhythmogenic cardiomyopathy, congenital heart disease. The role of mechanical dispersion as a predictor of ventricular arrhythmias in metabolic syndrome is scarce.

Quantitative Characterization of Surfactant Displacement Efficiency by NMR—Take the Tight Oil of Chang 8 Member of Yanchang Formation in Fuxian Area, Ordos Basin, as an Example

Surfactant flooding is a pivotal technique for enhancing oil recovery efficiency. The Chang 8 member of the Yanchang Formation in the Ordos Basin exemplifies a quintessential tight oil reservoir. Specifically, 47.9% of wells yield less than 0.1 t/d, 27.0% produce between 0.1 and 0.2 t/d, and 18.8% generate outputs ranging from 0.2 to 0.3 t/d, while only a mere 6.3% exceed production rates of over 0.3 t/d, indicating minimal efficacy of water flooding development in this context. In this study, we conducted an extensive investigation into the geological characteristics of the Yanchang 8 reservoir within the Ordos Basin, leading to the identification and evaluation of three surfactants based on their interfacial tension properties. The optimal injection concentration was determined through on-line displacement nuclear magnetic resonance imaging analysis that refined surface activity conducive to developing the Chang 8 member, ultimately resulting in increased spread volume and enhanced crude oil production from individual wells. The results indicate the following: (1) The interfacial tension of NP-10, FSD-952, and GPHQ-1 at concentrations of 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% exhibited a pattern of initial decrease followed by an increase. The mass concentration corresponding to the minimum interfacial tension for NP-10 is identified as 0.1%, which is also the case for GPHQ-1; however, for FSD-952, this occurs at a concentration of 0.4%. Among the surface-active agents NP-10, GPHQ-1, and FSD-952, GPHQ-1 demonstrated the lowest interfacial tension value at an impressive measurement of 0.0762 mN/m. (2) When the displacement of the 0.1% GPHQ-1 surfactant reaches 10 PV, the displacement efficiency improves from 69.69% to 76.36%, representing an increase of 6.67%. The minimum pore size observed during GPHQ-1 surfactant displacement is 0.01 μm. In contrast, when the displacement of the NP-10 surfactant at a concentration of 0.1% reaches 10 PV, the efficiency rises from 68.32% to 72.02%, indicating an enhancement of 3.7%. The corresponding minimum pore size for NP-10 surfactant displacement is recorded at 0.02 μm. Furthermore, when the displacement of the FSD-952 surfactant at a concentration of 0.4% achieves 10 PV, its efficiency increases from 69.93% to 74.77%, reflecting an improvement of 4.81%. The minimum pore size associated with the activated portion of FSD-952 is noted as being approximately 0.03 μm.

Nuclear imaging of PD-L1 expression promotes the synergistic antitumor efficacy of targeted radionuclide therapy and immune checkpoint blockade.

In order to maximize synergistic effect of targeted radionuclide therapy (TRT) and immune checkpoint blockade (ICB) as well as reduce the toxicity, we pioneered a strategy guided by PD-L1-targeted nuclear medicine imaging for the combination of TRT and ICB towards precision cancer therapy. As a novel targeted radiotherapeutic agent, 177Lu-AB-3PRGD2 targeting integrin αvβ3 was developed to achieve sustained antitumor effect by introducing an albumin binder (AB) into the structure of 3PRGD2. The 177Lu-AB-3PRGD2 TRT as well as different types of combination therapies of 177Lu-AB-3PRGD2 TRT and anti-PD-L1 ICB were performed in animal models. The changes of PD-L1 expression in tumors after TRT were evaluated in vitro and in vivo by PD-L1-specific SPECT/CT imaging of 99mTc-MY1523. 177Lu-AB-3PRGD2 showed improved tumor uptake and prolonged tumor retention, leading to significantly enhanced tumor growth suppression. Moreover, 177Lu-AB-3PRGD2 TRT remodeled the tumor immune microenvironment by upregulating PD-L1 expression and increasing tumor-infiltrating CD8+ T cells, facilitating immunotherapy. We found that the anti-PD-L1 treatment was more effective during the upregulation of tumor PD-L1 expression, and the time window could be determined by 99mTc-MY1523 SPECT/CT. We developed a novel and long-acting radiotherapeutic agent 177Lu-AB-3PRGD2, and pioneered a strategy guided by PD-L1-targeted nuclear medicine imaging for the combination of TRT and ICB towards precision cancer therapy, optimizing the therapeutic efficacy and reducing the cost and potential toxicity risks. This strategy could also be adapted for clinical practice, combining conventional radiotherapy or chemotherapy with ICB to enhance therapeutic efficacy.

Emerging New-Generation Semiconductor Single Crystals of Metal Halide Perovskites for Radiation Detection

Radiation detection uses semiconductor materials to convert high-energy photons into charge (direct detection) or low-energy photons (indirect detection), and it has a wide range of applications in nuclear physics, medical imaging, astronomical detection, homeland security, and other fields. Metal halide perovskites have the advantages of high frequency number, high carrier mobility, high defect tolerance, low defect density, adjustable band gap, and fast light response, and they have wide application prospects in the field of radiation detection. However, the research is still in its infancy stage, and it is far from meeting the requirements of industrial application. This paper focuses on the advantages of metal halide perovskite single-crystal materials in both semiconductors-based direct conversion detection and scintillator-based indirect detection as well as the latest progress in this promising field. This paper not only introduces the latest application of lead halide perovskite monocrystalline materials in high-energy electromagnetic radiation detection (X-ray and γ-rays), but it also introduces the latest development of α-particle/β-particle/neutron detection. Finally, this paper points out the challenges and future prospects of metal halide perovskite single-crystal materials in radiation detection.

Characterization of Crystal Properties and Defects in CdZnTe Radiation Detectors

CdZnTe-based detectors are highly valued because of their high spectral resolution, which is an essential feature for nuclear medical imaging. However, this resolution is compromised when there are substantial defects in the CdZnTe crystals. In this study, we present a learning-based approach to determine the spatially dependent bulk properties and defects in semiconductor detectors. This characterization allows us to mitigate and compensate for the undesired effects caused by crystal impurities. We tested our model with computer-generated noise-free input data, where it showed excellent accuracy, achieving an average RMSE of 0.43% between the predicted and the ground truth crystal properties. In addition, a sensitivity analysis was performed to determine the effect of noisy data on the accuracy of the model.

Lesion Characterization by 99mTc-MIBI Myocardial Perfusion Imaging (MPI) & 18F-FDG Cardiac PET Following Myocardial Infarction Before Revascularization & Outcome Prediction: Initial Experience in Bangladesh

99mTc-MIBI SPECT myocardial perfusion imaging (MPI) and 18F-FDG cardiac positron emission tomography (Cardiac PET) can assess the extent and severity of myocardial perfusion and metabolic defect following myocardial infarction (MI) and also able to predict the outcome before revascularization in known coronary artery disease patients. About 135 cases of known coronary artery disease patients were enrolled here for combined nuclear imaging tests, rest only ECG gated MPI and FDG cardiac PET to assess myocardial perfusion and viability status following MI prior to revascularization. In this study we want to figure out the utility of this combined protocol for myocardial lesion characterization and its role for clinical decision-making in-patient selection prior to revascularization and treatment planning. We are also intended to share the initial outcome in available follow up cases. J Inv Clin Cardiol 2023; 5(2): 45-52

PET imaging of pheochromocytoma and paraganglioma - 18F-FDOPA vs. somatostatin analogues.

Functional imaging with positron emission tomography (PET) scans is an essential part of the diagnostic workup for pheochromocytoma and paraganglioma (PPGL). The purpose of this review is a) to provide a brief overview of functional imaging for PPGL, b) summarize selected present and older guideline and review recommendations, and c) conduct a literature review on the diagnostic performance of the most used PET tracers for PPGL. We conducted a systematic literature search in PubMed from January 2004 to August 2024 with the search string: ("Pheochromocytoma" OR "Paraganglioma") AND ("Positron-Emission Tomography" OR "Radionuclide Imaging" OR ("PET" AND ("FDG" OR "DOTATOC" OR "DOTANOC" OR "DOTATATE" OR "DOPA" OR "FDOPA"))). Studies involving PET scans of at least 20 individuals with PPGL, or at least five individuals in a rare, well-defined subgroup of PPGL (e.g. sympathetic or head-neck paragangliomas, and specific pathogenic variants) were included. Seventy studies were identified of which 21 were head-to-head comparisons of at least two different PET tracers (18F-fluorodihydroxyphenylalanine, 18F-FDOPA; 68Ga-DOTA-conjugated somatostatin analogues, 68Ga-SSA; and 18F-fluorodeoxyglucose, 18F-FDG). 18F-FDOPA had higher sensitivity for pheochromocytoma compared to 68Ga-SSA and equal sensitivity for metastatic pheochromocytoma. 18F-FDOPA and 68Ga-SSA had similar sensitivity for primary non-SDHx sympathetic and head-neck paraganglioma. However, 68Ga-SSA had higher sensitivity for metastatic sympathetic and head-neck paraganglioma and for SDHx-related paraganglioma. 18F-FDOPA and 68Ga-SSA PET are both sensitive for localizing PPGL. However, 18F-FDOPA is the most sensitive for detecting pheochromocytoma, while 68Ga-SSA is superior to 18F-FDOPA for metastatic sympathetic and head-neck paraganglioma and SDHx-related paraganglioma.

Feasibility of quantitative evaluation of hemodynamics using SPECT/CT in patients with chronic thromboembolic pulmonary hypertension

Abstract Background A ventilation/perfusion (V/Q) lung scan is recommended in the diagnostic work-up of patients with newly diagnosed pulmonary hypertension to rule out chronic thromboembolic pulmonary hypertension (CTEPH). V/Q single-photon emission computed tomography (SPECT) is considered the method of choice for diagnosis in CTEPH because it allows more precise evaluation than planar imaging. However, the evaluation of lung perfusion using V/Q SPECT imaging remains mainly a qualitative evaluation, and no quantitative method has been established. We hypothesized that the standardized uptake value (SUV) technique in Positron Emission Tomography (PET)-CT, a nuclear imaging technique well suited for quantitative of tumor biology, could be applied to quantitative assessment of lung perfusion. Purpose The purpose of this study was to evaluate the correlation between pulmonary perfusion distribution and hemodynamic data in Tc-labeled large-assembly albumin (99mTc-MAA) SPECT images in order to determine the feasibility of SPECT/CT for quantitative assessment of lung perfusion. Methods Twenty-five patients with CTEPH who underwent BPA and received SPECT-CT were included. Since the injected 99mTc-MAA selectively accumulates only in the lungs, SUV normalization was conducted using each patient’s lung volume, calculated by SPECT/CT and defined as SUV lung volume (LV) . The percentage of lung volume below each SUVLV value in total lung volume on SPECT/CT was examined before BPA, after two procedures of BPA, and six months after a series of BPA, and the correlations with hemodynamic parameters on right heart catheterization at each time point were evaluated. Results The Percent lung volume below SUVLV of 0.7 in total lung volume before BPA, after two procedures of BPA, and six months after a series of BPA had the strongest correlation with mean pulmonary artery pressure (mPAP) (rs; 0.727, p<0.001, Figure 1). The percent lung volume below SUVLV of 0.7 decreased with the BPA procedure in each patient with CTEPH (Figure 2). Furthermore, receiver operating characteristic analysis revealed that a threshold for the percent lung volume below SUVLV of 0.7 of 50.3% or greater could identify mPAP greater than 21 mmHg for right heart catheterization (area under the curve = 0.86, 95% CI 0.78-0.94, p<0.001). Conclusion Percent lung volume below SUVLV of 0.7 in total lung volume using SPECT/CT might reflect the severity of hemodynamics in patients with CTEPH. This method would be feasible for quantitative assessment of lung perfusion, even inter-patient and intra-patient.Figure 1Figure 2

Gender and Ethnicity Bias of Text-to-Image Generative Artificial Intelligence in Medical Imaging, Part 2: Analysis of DALL-E 3.

Disparity among gender and ethnicity remains an issue across medicine and health science. Only 26%-35% of trainee radiologists are female, despite more than 50% of medical students' being female. Similar gender disparities are evident across the medical imaging professions. Generative artificial intelligence text-to-image production could reinforce or amplify gender biases. Methods: In March 2024, DALL-E 3 was utilized via GPT-4 to generate a series of individual and group images of medical imaging professionals: radiologist, nuclear medicine physician, radiographer, nuclear medicine technologist, medical physicist, radiopharmacist, and medical imaging nurse. Multiple iterations of images were generated using a variety of prompts. Collectively, 120 images were produced for evaluation of 524 characters. All images were independently analyzed by 3 expert reviewers from medical imaging professions for apparent gender and skin tone. Results: Collectively (individual and group images), 57.4% (n = 301) of medical imaging professionals were depicted as male, 42.4% (n = 222) as female, and 91.2% (n = 478) as having a light skin tone. The male gender representation was 65% for radiologists, 62% for nuclear medicine physicians, 52% for radiographers, 56% for nuclear medicine technologists, 62% for medical physicists, 53% for radiopharmacists, and 26% for medical imaging nurses. For all professions, this overrepresents men compared with women. There was no representation of persons with a disability. Conclusion: This evaluation reveals a significant overrepresentation of the male gender associated with generative artificial intelligence text-to-image production using DALL-E 3 across the medical imaging professions. Generated images have a disproportionately high representation of white men, which is not representative of the diversity of the medical imaging professions.

Analysis of Water Adsorption Capacity, Thermal Behavior, Antioxidant Activity, and Smoke Volume by Polyol Ester in Reconstituted Tobacco.

A series of ester derivatives with hydroxyl groups were created by esterification of 1,2-propanediol and glycerol with o-toluoyl chloride via the catalyst 4-dimethylaminopyridine (DMAP). All the compounds were verified using nuclear magnetic resonance (1H NMR, 13C NMR), infrared spectroscopy, and high resolution mass spectrometry. Moisture absorption and desorption experiments were carried out on the compounds' pure systems and their systems in reconstituted tobacco, while their hygroscopicity and moisturizing properties were evaluated using low-field nuclear magnetic resonance imaging. Two compounds with better absorption and moisture retention were selected: 4 (1-hydroxypropan-2-yl 2-methylbenzoate) and 6 (2,3-dihydroxypropyl 2-methylbenzoate), respectively. Moreover, the thermal stability of compounds 4 and 6 were investigated using thermogravimetric (TG) analysis. The results of TG-DTG showed that the maximum mass loss rate of compound 4 appeared at 251.67 °C, with a mass loss rate of 87.61%. At the peak temperature of 291.83 °C, 6 showed the highest decomposition rate with 49.23% mass loss rate. To explore the antioxidant properties, we constructed three different antioxidant systems. Furthermore, compound 6 showed excellent effects, with scavenging rates reaching 69.28%, 71.92%, and 75.93%, respectively. Smoke volume results indicated that the compounds optimally replaced propanediol and glycerol at a rate of 40%. The results provide a theoretical reference for the development of new moisturizing agents based on polyol esters in the tobacco industry.

TRU-IMP: techniques for reliable use of images in medical physics; a graphical user interface to analyze and compare segmentations in nuclear medicine.

Background. In the context of pharmacokinetic analyses, the segmentation method one uses has a large impact on the results obtained, thus the importance of transparency.Innovation. This paper introduces a graphical user interface (GUI), TRU-IMP, that analyzes time-activity curves and segmentations in dynamic nuclear medicine. This GUI fills a gap in the current technological tools available for the analysis of quantitative dynamic nuclear medicine image acquisitions. The GUI includes various techniques of segmentations, with possibilities to compute related uncertainties.Results. The GUI was tested on image acquisitions made on a dynamic nuclear medicine phantom. This allows the comparison of segmentations via their time-activity curves and the extracted pharmacokinetic parameters.Implications. The flexibility and user-friendliness allowed by the proposed interface make the analyses both easy to perform and adjustable to any specific case. This GUI permits researchers to better show and understand the reproducibility, precision, and accuracy of their work in quantitative dynamic nuclear medicine.Availability and Implementation. Source code freely available on GitHub:https://github.com/ArGilfea/TRU-IMPand location of the interface available from there. The GUI is fully compatible with iOS and Windows operating systems (not tested on Linux). A phantom acquisition is also available to test the GUI easily.

SNMMI Procedure Standard/EANM Practice Guideline for Brain [18F]FDG PET Imaging, Version 2.0.

PREAMBLEThe Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and professional organization founded in 1954 to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM) is a professional nonprofit medical association that facilitates communication worldwide between individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. The EANM was founded in 1985. SNMMI and EANM members are physicians, technologists, and scientists specializing in the research and practice of nuclear medicine.The SNMMI and EANM will periodically define new guidelines for nuclear medicine practice to help advance the science of nuclear medicine and to improve the quality of service to patients throughout the world. Existing practice guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated.Each practice guideline, representing a policy statement by the SNMMI/EANM, has undergone a thorough consensus process in which it has been subjected to extensive review. The SNMMI and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guideline by those entities not providing these services is not authorized.These guidelines are an educational tool designed to assist practitioners in providing appropriate care for patients. They are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, both the SNMMI and the EANM caution against the use of these guidelines in litigation in which the clinical decisions of a practitioner are called into question.The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by the physician or medical physicist in light of all the circumstances presented. Thus, there is no implication that an approach differing from the guidelines, standing alone, is below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the guidelines.The practice of medicine includes both the art and the science of the prevention, diagnosis, alleviation, and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment.Therefore, it should be recognized that adherence to these guidelines will not ensure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources, and the needs of the patient to deliver effective and safe medical care. The sole purpose of these guidelines is to assist practitioners in achieving this objective.

Innovations in Nuclear Medicine Imaging for Reactive Oxygen Species: Applications and Radiopharmaceuticals.

Reactive oxygen species (ROS) are generated during normal cellular energy production and play a critical role in maintaining cellular function. However, excessive ROS can damage cells and tissues, contributing to the development of diseases such as cardiovascular, inflammatory, and neurodegenerative disorders. This review explores the potential of nuclear medicine imaging techniques for detecting ROS and evaluates various radiopharmaceuticals used in these applications. Radiopharmaceuticals, which are drugs labeled with radionuclides, can bind to specific biomarkers, facilitating their identification in vivo using nuclear medicine equipment, i.e., positron emission tomography and single photon emission computed tomography, for diagnostic purposes. This review includes a comprehensive search of PubMed, covering radiopharmaceuticals such as analogs of fluorescent probes and antioxidant vitamin C, and biomarkers targeting mitochondrial complex I or cystine/glutamate transporter.

TRAITER: transformer-guided diagnosis and prognosis of heart failure using cell nuclear morphology and DNA damage marker.

Heart failure (HF), a major cause of morbidity and mortality, necessitates precise diagnostic and prognostic methods. This study presents a novel deep learning approach, Transformer-based Analysis of Images of Tissue for Effective Remedy (TRAITER), for HF diagnosis and prognosis. Using image segmentation techniques and a Vision Transformer, TRAITER predicts HF likelihood from cardiac tissue cell nuclear morphology images and the potential for left ventricular reverse remodeling (LVRR) from dual-stained images with cell nuclei and DNA damage markers. In HF prediction using 31158 images from 9 patients, TRAITER achieved 83.1% accuracy. For LVRR prediction with 231840 images from 46 patients, TRAITER attained 84.2% accuracy for individual images and 92.9% for individual patients. TRAITER outperformed other neural network models in terms of receiver operating characteristics, and precision-recall curves. Our method promises to advance personalized HF medicine decision-making. The source code and data are available at the following link: https://github.com/HamanoLaboratory/predict-of-HF-and-LVRR.

Retraction Note: Nanoparticle analysis based on optical ion beam in nuclear imaging by deep learning architectures

Retraction Note: Nanoparticle analysis based on optical ion beam in nuclear imaging by deep learning architectures

PET Imaging of Breast Cancer: Current Applications and Future Directions.

As molecular imaging use expands for patients with breast cancer, it is important for breast radiologists to have a basic understanding of molecular imaging, including PET. Although breast radiologists may not directly interpret such studies, basic knowledge of molecular imaging will enable the radiologist to better direct diagnostic workup of patients as well as discuss diagnostic imaging with the patient and other treating physicians. Several new tracers are now available to complement imaging glucose metabolism with FDG. Because it provides a noninvasive assessment of disease status across the whole body, PET offers specific advantages over tissue-based assays. Paired with targeted therapy, molecular imaging has the potential to guide personalized treatment of breast cancer, including guiding dosing during drug trials as well as predicting and assessing clinical response. This review discusses the current established applications of FDG, which remains the most widely used PET radiotracer for malignancy, including breast cancer, and highlights potential areas for expanded use based on recent research. It also summarizes research to date on the U.S. Food and Drug Administration (FDA)-approved PET tracer 16α-18F-fluoro-17β-estradiol (FES), which targets ER, including the current guidelines from the Society of Nuclear Medicine and Molecular Imaging on the appropriate use of FES-PET/CT for breast cancer as well as areas of active investigation for other potential applications. Finally, the review highlights several of the most promising novel PET tracers that are poised for clinical translation in the near future.

Quantitative spatial visualization of X-ray irradiation via redox reaction by dynamic nuclear polarization magnetic resonance imaging

The dose of X-ray irradiation is commonly measured by point assessment with an ionization chamber dosimeter. However, to achieve spatially accurate delivery of X-ray to avoid the exposure to normal tissues, an accurate imaging method for spatially and quantitatively detecting exposure is required. Herein, we present a novel method to visualize X-ray exposure using low-field dynamic nuclear polarization magnetic resonance imaging (DNP-MRI) with nitroxyl radical tempol as the chemical dosimeter. In this system, gel phantoms containing glutathione (GSH) and the paramagnetic tempol radical were used to monitor the deposited X-ray-irradiation via the redox reaction. The tempol radical level was evaluated by DNP-MRI whose signal intensity was linearly correlated with the radical concentration. The radical level in the presence of GSH decreased in proportion to the dose of X-irradiation deposited. In an imaging experiment simulating clinical radiotherapy, we used a clinical linear accelerator with a radiotherapy planning software to confirm the utility of the exposure imaging. The X-ray exposure and its distribution were clearly visualized on the gel phantom image acquired by DNP-MRI. The results were consistent with those specified in the radiotherapy plan where the intensity of the radiation beam was modulated. This exposure estimation will be useful for determining an accurate irradiation field and reducing off-target exposure in clinical settings.

Concurrent photothermal therapy and nuclear magnetic resonance imaging with plasmonic–magnetic nanoparticles: A numerical study

Background and Objective: Theranostics is the combination of the diagnostic and therapeutic phases. Here we focus on simultaneous use of photothermal therapy and magnetic resonance imaging, employing a contrast-photothermal agent that converts incident light into heat and affects the transverse relaxation time, a key magnetic resonance imaging parameter. Our work considers a gold–magnetite nanoshell platform to gauge the feasibility of magnetic resonance imaging monitoring of the heating associated with phototherapy, by studying the modification of the transverse relaxation rate induced by laser illumination of a solution containing these hybrid nanoparticles. Methods:We simulate a system composed of an aqueous solution with hybrid nanoshells under continuous laser irradiation, enabling the evaluation of spatial variations of the transverse relaxation rate within the sample. We work with the hybrid nanoshell platform comprising a metal/gold shell for thermoplasmonic effects and a magnetite core for magnetic resonance imaging contrast enhancement. The optical properties of the nanoshells are first obtained through simulations using the finite element method. Next, the heating generated by the laser illumination is calculated by numerical integration. Finally, the transverse relaxation rate is obtained through the application of an analytical model. Additionally, we conduct an optimization of the nanoshell geometry to fulfill requirements of both magnetic resonance imaging and phototherapy techniques. Results:Our findings demonstrate a narrow range of nanoshell sizes exhibiting both a plasmonic absorption peak in the human biological window and a high response to laser illumination of the transverse relaxation rate. Furthermore, the illumination can induce up to a 30% modification in transverse relaxation rate compared to the non-illuminated scenario in this range of nanoshell sizes. Conclusions:In this work we establish the numerical understanding of the interplay between phototherapy and nuclear magnetic resonance imaging when employed concurrently. This allows magnetic resonance imaging monitoring of the heating associated with phototherapy.

Preoperative visualization of parathyroid pathology in patients with primary hyperparathyroidism using PAT/KT: a retrospective study

INTRODUCTION: Topical diagnosis of pathologically altered parathyroid glands in patients with primary hyperparathyroidism is a challenge both for specialists of radial diagnostics and for planning the scope of surgical intervention. The choice of diagnostic modality for localization of parathyroid glands depends on the availability of the method for a particular medical center. PET/CT is a promising method to determine the localization of parathyroid adenomaOBJECTIVE: To analyze the experience of using PET/CT with 11C-methionine and PET/CT with 11C-choline for preoperative diagnosis of parathyroid pathology in patients with primary hyperparathyroidism.MATERIALS AND METHODS: 72 patients diagnosed with PHPT and underwent surgical treatment were included in the study. Before surgical intervention all patients underwent laboratory and instrumental investigations in the scope of: blood tests for PTH, TTH, ionized calcium, calcitonin, 25(OH)D, creatinine, phosphorus, ultrasound of the neck, computer tomography of the neck with intravenous bolus contrasting.RESULTS: PET/CT showed the highest rates of DA in the patient group before primary surgery — 90.9%, compared with ultrasound (89.6%) and CT with IV contrast (84.9%). In the group of solitary adenomas of ectopic MTCS, PET/CT also had a higher DA — 92.8% than the other modalities. In patients with relapsed or persistent disease, the informativity rates of CT with intravenous contrast and PET/CT were similar (Se — 100%, Sp — 94.1%, DT — 96.2%).DISCUSSION: The algorithm for preoperative evaluation of patients to identify the location of pathologic parathyroid glands now includes imaging with two modalities: Neck ultrasound and radionuclide imaging: planar scintigraphy (washout/subtraction), SPECT, SPECT-CT. If the results are questionable, a CT scan of the neck with contrast or PET/CT is performed as a second step. None of the modalities has 100% diagnostic accuracy. Our study demonstrated the superiority of PET/CT over ultrasound and CT w/in contrast in a group of patients scheduled for primary surgical treatment. In a small group of patients, high informative rates of PET/CT and CT with contrast were demonstrated before reoperation, confirming the great potential of these techniques in these patients.CONCLUSION: PET/CT with 11C-methionine and PET/CT with 11C-choline have high diagnostic accuracy in patients with primary hyperparathyroidism before reoperation. PET/CT and CT with contrast showed similarly high diagnostic accuracy for the diagnosis of parathyroid adenoma with persistence or recurrence of the disease in patients with primary hyperparathyroidism.

Upstaging of Invasive Lobular Cancer With FES PET/CT.

A 78-year-old woman diagnosed with left breast invasive lobular carcinoma with left axillary nodal metastasis underwent 18 F-fluoroestradiol (FES) PET/CT imaging for further evaluation of indeterminate right axillary lymph nodes seen on staging 18 F-FDG PET/CT. 18 F-FES PET/CT revealed abnormal 18 F-FES-avid right axillary and bilateral cervical nodes, subsequently biopsy-proven metastases, upstaging the patient from stage II to IV and greatly changing patient management. This case demonstrates the value of 18 F-FES PET/CT in accurately staging metastatic invasive lobular carcinoma at diagnosis, an indication for which 18 F-FES PET/CT "may be appropriate" per current Society of Nuclear Medicine and Molecular Imaging guidelines.