SPECT Modalities Research Articles

Evaluation of functional significance of intermediate coronary artery lesions noninvasively by tissue doppler echocardiography and single photon emission computed tomography versus invasively by IFR

Background: Myocardial perfusion imaging by single photon emission computed tomography (MPI–SPECT) is noninvasive test that can give an important information for the diagnosis of coronary artery disease (CAD), detect reversible ischemia, quantify defect sizes and help in clinical decisions of interventions as well as assessment of disease prognosis. Tissue Doppler imaging (TDI) emerged as a potential modality for assessing systolic and diastolic LV performance. Strain doppler echocardiography (SDE) is a new tool for measuring regional myocardial deformation excluding the effect of adjacent myocardial tissue. The development of Instantaneous wave-free Ratio (IFR) as a relatively new invasive method for physiological assessment of coronary lesions without the use of pharmacologic hyperemic agents is the golden standard test for assessment of intermediate coronary lesions and guiding the revascularization decision. Methods: This Cross-sectional study was done was conducted on 50 cases with intermediate coronary artery lesions admitted at the Cardiology departments in Benha University, Kobry Elkobba Military Hospital and Air Force Specialized Hospital. All groups were subjected to history and clinical examination, cardiac examination, 12 lead ECG, 2D echocardiography, routine laboratory investigations, coronary angiography with evaluation of intermediate lesion by IFR then TDI and SDE for evaluation the regional myocardial deformation of the segments supplied by the same coronary artery, after that 99mTc-sestamibi (MIBI) SPECT imaging was done to quantify defect size and finally correlation was done between results of IFR, TDI and SPECT to guide the revascularization decision. Results: Pearson’s correlation analysis showed that; Gated single-photon emission computed moderate and severe Ischemia, Sm-velocity, WMSI, DT, had a highly significant positive correlation with IFR value (p < 0.001). E/A ratio, Mean E/e’ velocity ratio, FS, LVEF and LV GLS had a highly significant negative correlation with IFR value (p < 0.001). Conclusions: Instantaneous wave-free Ratio (IFR) modality is a reliable measure to guide functional significance of the intermediate coronary artery lesions for decision making and guiding plan of management. But it is an expensive and invasive modality. On the other hand, SPECT and tissue doppler modalities showed high sensitivity and specificity in the same group of patients with less expensive, non-invasive and no contrast use advantages.

A Neck-Thyroid Phantom with Small Sizes of Thyroid Remnants for Postsurgical I-123 and I-131 SPECT/CT Imaging.

Post-surgical I-123 and I-131 SPECT/CT imaging can provide information on the presence and sizes of thyroid remnants and/or metastasis for an accurate re-staging of disease to apply an individualized radioiodine therapy. The purpose of this study was to develop and validate a neck-thyroid phantom with small sizes of thyroid remnants to be utilized for the optimization of post-surgical SPECT/CT imaging. 3D printing and molding techniques were used to develop the hollow human-shaped and -sized phantom which enclosed the trachea, esophagus, cervical spine, clavicle, and multiple detachable sections with different sizes of thyroid remnant in clinically relevant positions. CT images were acquired to evaluate the morphology of the phantom and the sizes of remnants. Triple-energy window scattered and attenuation corrected SPECT images were acquired for this phantom and for a modified RS-542 commercial solid neck-thyroid phantom. The response and sensitivity of the SPECT modality for different administered I-123 and I-131 activities within the equal-size remnants of both phantoms were calculated. When we compared the phantoms, using the same radiopharmaceutical and similar activities, we found that the measured sensitivities were comparable. In all cases, the I-123 counting rate was higher than the I-131 one. This phantom with capabilities to insert different small sizes of remnants and simulate different background-to-remnants activity ratios can be utilized to evaluate postsurgical thyroid SPECT/CT imaging procedures.

Effects of movement artifacts in nuclear hybrid modalities for image diagnostic

In the obtention of medical images, the patients’ movement can modify the identification of the body components in an image. The combination of imaging techniques may not always be a solution to improve the imaging quality; therefore, an artifact analysis is commonly required prior to applying an imaging procedure in patients. In this work, we systematically evaluated the movements’ artifacts caused by the patients’ breathing during the images acquisition and their impact on the fusion of SPECT and CT modalities. We used a specific phantom placed on a platform to emulate the respiratory movement, finding artifacts not appreciable under the standard condition used to obtain the SPECT images due to its low spatial resolution. The artifacts produced a deformation of elements on the images. Therefore, image processing was necessary to identify the registration accuracy with SPECT and CT modalities in two states (phantom at rest and for a phantom with simulated respiratory movements). A systematic difference was obtained for the first case (11.7 mm), and a range of (7.4 mm to 16.1 mm) for the second one. For the volumes’ evaluation, the optimal threshold value for CT was 0.40 and for SPECT was 0.25, giving a rapid solution to reduce the artifacts’ impact on medical images.

99mTc-BBPA]: A possible SPECT agent to understand the role of 18-kDa translocator protein (PBR/TSPO) during neuro-glial interaction

The translocator protein (TSPO, 18 kDa) is one of the most promising biomarker to understand the role of neuroinflammation in human as well as in different animal species. Here we report a new TSPO-selective ligand 2-(5-(2-(bis(pyridin-2-yl methyl)amino)acetamido)-2-oxobenzo[d] oxazol-3(2H)-yl)-N-methyl-N-phenylacetamide, BBPA, which is supposed to be a potential probe to understand the role of TSPO in neuro-glial interaction through SPECT modality.

Performance assessment of the ALBIRA II pre-clinical SPECT S102 system for 99mTc imaging.

The performance characteristics of the SPECT sub-system S102 of the ALBIRA II PET/SPECT/CT are analyzed for the 80mm field of view (FOV) to evaluate the potential in-vivo imaging in rats, based on measurements of the system response for the commonly used Technetium-99m (99mTc) in small animal imaging. The ALBIRA II tri-modal µPET/SPECT/CT pre-clinical system (Bruker BioSpin, Ettlingen, Germany) was used. The SPECT modality is made up of two opposite gamma cameras (Version S102) with Sodium doped Cesium Iodide (CsI(Na)) single continuous crystal detectors coupled to position-sensitive photomultipliers (PSPMTs). Imaging was performed with the NEMA NU-4 image quality phantom (Data Spectrum Corporation, Durham, USA). Measurements were performed with a starting activity concentration of 4.76MBq/mL 99mTc. An energy window of 20% at 140keV was selected in this study. The system offers a 20mm, 40mm, 60mm and an 80mm field of view (FOV) and in this study the 80mm FOV was used for all the acquisitions. The data were reconstructed with an ordered subset expectation maximization (OSEM) algorithm. Sensitivity, spatial resolution, count rate linearity, convergence of the algorithm and the recovery coefficients (RC) were analyzed. All analyses were performed with PMOD and MATLAB software. The sensitivities measured at the center of the 80mm FOV with the point source were 23.1 ± 0.3 cps/MBq (single pinhole SPH) and 105.6 ± 5.5 cps/MBq (multi pinhole MPH). The values for the axial, tangential and radial full width at half maximum (FWHM) were 2.51, 2.54, and 2.55mm with SPH and 2.35, 2.44 and 2.32mm with MPH, respectively. The corresponding RC values for the 5mm, 4mm, 3mm and 2mm rods were 0.60 ± 0.28, 0.61 ± 0.24, 0.29 ± 0.11 and 0.20 ± 0.06 with SPH and 0.56 ± 0.20, 0.50 ± 0.18, 0.38 ± 0.09 and 0.23 ± 0.06 with MPH. To obtain quantitative imaging data, the image reconstructions should be performed with 12 iterations. The ALBIRA II preclinical SPECT sub-system S102 has a favorable sensitivity and spatial resolution for the 80mm FOV setting for both the SPH and MPH configurations and is a valuable tool for small animal imaging.

Climbing the steps of the evidence-based medicine pyramid: highlights from Annals of Nuclear Medicine 2019.

We aimed to provide an overview on research path in nuclear medicine climbing the steps of the Evidence-Based Medicine (EBM) pyramid using review of 14 subjectively selected papers out of 111 published in the Annals of Nuclear Medicine during January-December 2019. Following the structure of the EBM hierarchy, we chose at least one study for each step of the pyramid from the basis (pre-clinical research, expert opinion, case report and case series), to the middle (case-control and cohort studies, randomised controlled trials), towards the top (meta-analyses and systematic reviews). Additionally, we collected information on the promoter of each included study: investigator-initiated trials (IITs) vs industry-sponsored trials (ISTs). We found that pre-clinical studies are primarily focused on the development of novel molecular targets in cancer, with promising results. At the same time, clinical investigations deal with cardiological, neurological, infectious and oncological applications using both SPECT and PET modalities. Additionally, radionuclide therapy gained interest and is experiencing comprehensive clinical implementation. Our overview confirms the current central role of IITs as compared with ISTs. Challenges and future directions in Nuclear Medicine research are discussed.

Multimodal Tracking of Controlled Staphylococcus aureus Infections in Mice.

There is a need to develop diagnostic and analytical tools that allow noninvasive monitoring of bacterial growth and dissemination in vivo. For such cell-tracking studies to hold translational value to controlled human infections, in which volunteers are experimentally colonized, they should not require genetic modification, and they should allow tracking over a number of replication cycles. To gauge if an antimicrobial peptide tracer, 99mTc-UBI29–41-Cy5, which contains both a fluorescent and a radioactive moiety, could be used for such in vivo bacterial tracking, we performed longitudinal imaging of a thigh-muscle infection with 99mTc-UBI29–41-Cy5-labeled Staphylococcus aureus. Mice were imaged using SPECT and fluorescence-imaging modalities at various intervals during a 28 h period. Biodistribution analyses were performed to quantitate radioactivity in the abscess and other tissues. SPECT and fluorescence imaging in mice showed clear retention of the 99mTc-UBI29–41-Cy5-labeled bacteria following inoculation in the thigh muscle. Despite bacterial replication, the signal intensity in the abscess only modestly decreased within a 28 h period: 52% of the total injected radioactivity per gram of tissue (%ID/g) at 4 h postinfection (pi) versus 44%ID/g at 28 h pi (15% decrease). After inoculation, a portion of the bacteria disseminated from the abscess, and S. aureus cultures were obtained from radioactive urine samples. Bacterial staining with 99mTc-UBI29–41-Cy5 allowed noninvasive bacterial-cell tracking during a 28 h period. Given the versatility of the presented bacterial-tracking method, we believe that this concept could pave the way for precise imaging capabilities during controlled-human-infection studies.

Neuroimaging methods in Epilepsy of Temporal Origin.

Temporal Lobe Epilepsy (TLE) comprises the most common form of symptomatic refractory focal epilepsy in adults. Accurate lateralization and localization of the epileptogenic focus are a significant prerequisite for determining surgical candidacy once the patient has been deemed medically intractable. Structural MR imaging, clinical, electrophysiological, and neurophysiological data have an established role in the localization of the epileptogenic foci. Nevertheless, hippocampal sclerosis cannot be detected on MR images in more than 30% of patients with TLE, and the presurgical assessment remains controversial. In the last years, advanced MR imaging techniques, such as 1H-MRS, DWI, DTI, DSCI, and fMRI, may provide valuable additional information regarding the physiological and metabolic characterization of brain tissue. MR imaging has shifted towards functional and molecular imaging, thus, promising to improve the accuracy regarding the lateralization and the localization of the epileptogenic focus. Additionally, nuclear medicine studies, such as SPECT and PET imaging modalities, have become an asset for the decoding of brain function and activity, and can be diagnostically helpful as well, since they provide valuable data regarding the altered metabolic activity of the seizure foci. Overall, advanced MRI, SPECT, and PET imaging techniques are increasingly becoming an essential part of TLE diagnostics, when the epileptogenic area is not identified on structural MRI or when structural MRI, clinical, and electrophysiological findings are not in concordance.

Hybrid Pixel-Waveform (HPWF) Enabled CdTe Detectors for Small Animal Gamma-Ray Imaging Applications.

This paper presents the design and preliminary evaluation of small-pixel CdTe gamma ray detectors equipped with a hybrid pixel-waveform (HPWF) readout system for gamma ray imaging applications with additional discussion on CZT due to its similarity. The HPWF readout system utilizes a pixelated anode readout circuitry which is designed to only provide the pixel address. This readout circuitry works in coincidence with a high-speed digitizer to sample the cathode waveform which provides the energy, timing, and depth-of-interaction (DOI) information. This work focuses on the developed and experimentally evaluated prototype HPWF-CdTe detectors with a custom CMOS pixel-ASIC to readout small anode pixels of 350 μm in size, and a discrete waveform sampling circuitry to digitize the signal waveform induced on the large cathode. The intrinsic timing, energy, and spatial resolution were experimentally evaluated in this paper in conjunction with methods for depth of interaction (DOI) partitioning of the CdTe crystal. While the experimental studies discussed in this paper are primarily for evaluating HPWF detectors for small animal PET imaging, these detectors could find their applications for ultrahigh-resolution SPECT and other imaging modalities.

A radio-theranostic nanoparticle with high specific drug loading for cancer therapy and imaging

We have developed a theranostic nanoparticle delivering the model radionuclide 177Lu based on the versatile lipid-calcium-phosphate (LCP) nanoparticle delivery platform. Characterization of 177Lu-LCP has shown that radionuclide loading can be increased by several orders of magnitude without affecting the encapsulation efficiency or the morphology of 177Lu-LCP, allowing consistency during fabrication and overcoming scale-up barriers typical of nanotherapeutics. The choice of 177Lu as a model radionuclide has allowed in vivo anticancer therapy in addition to radiographic imaging via the dual decay modes of 177Lu. Tumor accumulation of 177Lu-LCP was measured using both SPECT and Cerenkov imaging modalities in live mice, and treatment with just one dose of 177Lu-LCP showed significant in vivo tumor inhibition in two subcutaneous xenograft tumor models. Microenvironment and cytotoxicity studies suggest that 177Lu-LCP inhibits tumor growth by causing apoptotic cell death via double-stranded DNA breaks while causing a remodeling of the tumor microenvironment to a more disordered and less malignant phenotype.

Évaluation des reproductibilités inter- et intra-observateurs de la mesure du futur foie restant par tomoscintigraphie hépato-biliaire à la 99mTc-mébrofénine avant hépatectomie majeure

PurposePerformances of 99mTc-mebrofenin hepatobiliary scintigraphy (HBS) are currently evaluated before major hepatic resection for early detection of liver failure in high risk patients. Published studies included small numbers of patients with planar scintigraphy, and more recently SPECT data. Our aim was to evaluate intra- and interobserver reproducibility of HBS in planar and SPECT modalities for functional assessment of the future remnant liver (FRL) before major hepatic resection. We also evaluated the impact of potential variability factors such as biliary excretion and isocontour threshold choice. MethodsAll the scans were processed twice by three observers. Two regions of interest were drawn around total liver (TL) and FRL, on the planar dataset and with a threshold based algorithm on SPECT after registration with contrast-enhanced CT. Intra- and interobserver reproducibility of the FRL/TL ratio were calculated. When biliary excretion was already visible on SPECT acquisition, it was corrected and the ratio compared before and after correction. The results were also compared between different thresholds of the maximum liver value (−4%, −2%, +2%, +4% of the optimal threshold chosen by the observer). ResultsThirty patients were included. The intraobserver reproducibility was good (R2=0.847, 0.830 and 0.966) when calculated on planar modality and better with SPECT (R2=0.957, 0.962 and 0.984). There was no significant difference after biliary excretion correction (P=0.29, P=0.99 and P=0.61 for the three observers). The threshold modification caused significant but minor differences (1% on average) for the evaluated thresholds. ConclusionsThe FRL functional evaluation with HBS including a SPECT acquisition provides a reproducible assessment, hardly affected by potential variability factors, allowing its use in multicentric studies.

Synthesis and stability test of radiogadolinium(III)-DOTA-PAMAM G3.0-trastuzumab as SPECT-MRI molecular imaging agent for diagnosis of HER-2 positive breast cancer

Nonivasive diagnosis of cancer can be provided by molecular imaging using hybrid modality to obtain better sensitivity, specificity and depiction localization of the disease. In this study, we developed a new molecular imaging agent, radiogadolinium(III)-DOTA-PAMAM G3.0-trastuzumab in the form of 147Gd-DOTA-PAMAM G3.0-trastuzumab, that can be both target-specific radiopharmaceutical in SPECT as well as targeted contrast agent in MRI for the purpose of diagnosis of HER-2 positive breast cancer. 147Gd radionuclide emits γ-rays that can be used in SPECT modality, but because of technical constraint, 147Gd radionuclide was simulated by its radioisotope, 153Gd. Gd-DOTA complex has also been known as good MRI contrast agent. PAMAM G3.0 is useful to concentrate Gd-DOTA compelexes in large quantities, thus minimizing the number of trastuzumab molecules used. Trastuzumab is human monoclonal antibody that can spesifically interact with HER-2. Synthesis of radiogadolinium(III)-DOTA-PAMAM G3.0-trastuzumab was initiated by conjugating DOTA NHS ester ligand with PAMAM G3.0 dendrimer. The DOTA-PAMAM G3.0 produced was conjugated to trastuzumab molecule and labeled with 153Gd. Characterization DOTA-PAMAM G3.0-trastuzumab immunoconjugate was performed using HPLC system equipped with SEC. The formation of immunoconjugate was indicated by the shorter retention time (6.82 min) compared to that of trastuzumab (7.06 min). Radiochemical purity of radiogadolinium(III)-DOTA-PAMAM G3.0-trastuzumab was >99% after purification process by PD-10 desalting column. Radiogadolinium(III)-DOTA-PAMAM G3.0-trastuzumab compound was stable at room temperature and at 2–8 0C as indicated by its radiochemical purity 97.6 ± 0.5%–99.1 ± 0.5% after 144 h storage.

Performance of Myocardial Perfusion Imaging Using Multi-focus Fan Beam Collimator with Resolution Recovery Reconstruction in a Comparison with Conventional SPECT.

IQ-SPECT is an advanced high-speed SPECT modality for myocardial perfusion imaging (MPI), which uses a multi-focus fan beam collimator with resolution recovery reconstruction. The aim of this study was to compare IQ-SPECT with conventional SPECT in terms of performance, based on standard clinical protocols. In addition, we examined the concordance between conventional and IQ_SPECT in patients with coronary artery disease (CAD). Fifty-three patients, undergoing rest-gated MPI for the evaluation of known or suspected CAD, were enrolled in this study. In each patient, conventional SPECT ((99m)Tc-tetrofosmin, 9.6 min and (201)Tl, 12.9 min) was performed, immediately followed by IQ-SPECT, using a short acquisition time (4.3 min for (99m)Tc-tetrofosmin and 6.2 min for (201)Tl). A quantitative analysis was performed on an MPI polar map, using a 20-segment model of the left ventricle. An automated analysis by gated SPECT was carried out to determine the left ventricular volume and function including end-diastolic volume (EDV), end-systolic volume (ESV), and left ventricular ejection fraction (LVEF). The degree of concordance between conventional SPECT and IQ-SPECT images was evaluated according to linear regression and Bland-Altman analyses. The segmental percent uptake exhibited a significant correlation between IQ-SPECT and conventional SPECT (P<0.05). The mean differences in (99m)Tc-tetrofosmin studies were 1.1±6.6% (apex), 2.8±5.7% (anterior wall), 2.9±6.2% (septal wall), 4.9±6.7% (lateral wall), and 1.8±5.6% (inferior wall). Meanwhile, regarding the (201)Tl-SPECT studies, these values were 1.6±6.9%, 2.0±6.6%, 2.1±5.9%, 3.3±7.2%, and 2.4±5.8%, respectively. Although the mean LVEF in IQ-SPECT tended to be higher than that observed in conventional SPECT (conventional SPECT=64.8±11.8% and IQ-SPECT=68.3±12.1% for (99m)Tc-tetrofosmin; conventional SPECT= 56.0±11.7% and IQ-SPECT=61.5±12.2% for (201)Tl), quantitative parameters were not significantly different between IQ-SPECT and conventional SPECT. According to the (99m)Tc-tetrofosmin and (201)Tl protocols, IQ-SPECT images were comparable to and in agreement with conventional SPECT images. Our results suggest that IQ-SPECT is a useful technology for MPI SPECT, and can lead to an increase in scan efficiency and patient comfort.

Cardiac Imaging Modalities in the Diagnosis of Coronary Artery Disease

Coronary artery disease is the leading cause of death in advanced countries. Early detection and diagnosis of coronary artery disease plays an important role in the identification of disease severity and prediction of disease outcome, consequently improving patient management. Diagnosis and management of coronary artery disease is increasingly dependent on less-invasive imaging modalities, including coronary CT angiography, cardiac magnetic resonance imaging, cardiac radionuclide imaging such as SPECT and PET modalities. Rapid developments of these imaging modalities have significantly improved the diagnostic performance of each imaging technique with high diagnostic accuracy achieved in both diagnostic and prognostic value in coronary artery disease. This editorial provides an overview of the diagnostic applications of a variety of less-invasive imaging modalities in the diagnosis of coronary artery disease. This special issue of “Arteriosclerotic Vascular Disease: Part II” in the journal of Clinical and Experimental Cardiology will give particular attention to contributions focusing on the clinical applications of these imaging modalities in the arteriosclerotic vascular disease, in particular, coronary artery disease.

Molecular imaging probes for diagnosis and therapy evaluation of breast cancer.

Breast cancer is a major cause of cancer death in women where early detection and accurate assessment of therapy response can improve clinical outcomes. Molecular imaging, which includes PET, SPECT, MRI, and optical modalities, provides noninvasive means of detecting biological processes and molecular events in vivo. Molecular imaging has the potential to enhance our understanding of breast cancer biology and effects of drug action during both preclinical and clinical phases of drug development. This has led to the identification of many molecular imaging probes for key processes in breast cancer. Hormone receptors, growth factor receptor, and angiogenic factors, such as ER, PR, HER2, and VEGFR, have been adopted as imaging targets to detect and stage the breast cancer and to monitor the treatment efficacy. Receptor imaging probes are usually composed of targeting moiety attached to a signaling component such as a radionuclide that can be detected using dedicated instruments. Current molecular imaging probes involved in breast cancer diagnosis and therapy evaluation are reviewed, and future of molecular imaging for the preclinical and clinical is explained.

Diagnostic value of SPECT, PET and PET/CT in the diagnosis of coronary artery disease: A systematic review.

Purpose:The purpose of the study was to investigate the diagnostic value of SPECT, PET and PET/CT in the diagnosis of coronary artery disease, based on a systematic review.Material and Methods:A search of PubMed/Medline and Sciencedirect databases in the English-language literature published over the last 24 years was performed. Only studies with at least 10 patients comparing SPECT, PET or combined PET/CT with invasive coronary angiography in the diagnosis of coronary artery disease (50% stenosis) were included for analysis. Sensitivities and specificities estimates pooled across studies were analysed using a Chi-square test.Results:Twenty-five studies met the selection criteria and were included for the analysis. Ten studies were performed with SPECT alone; while another six studies were performed with PET alone. Five studies were carried out with both PET and SPECT modalities, and the remaining four studies were investigated with integrated PET-CT. The mean value of sensitivity, specificity and accuracy of these imaging modalities for the diagnosis of coronary artery disease was 82% (95%CI: 76 to 88), 76% (95%CI: 70 to 82) and 83% (95%CI: 77 to 89) for SPECT; 91% (95%CI: 85 to 97), 89% (95%CI: 83 to 95) and 89% (95%CI: 83 to 95) for PET; and 85% (95%CI: 79 to 90), 83% (95%CI: 77 to 89) and 88% (95%CI: 82 to 94) for PET/CT, respectively. The diagnostic accuracy of these imaging modalities was dependent on the radiotracers used in these studies, with ammonia resulting in the highest diagnostic value.Conclusion:Our review shows that PET has high diagnostic value for diagnosing coronary artery disease, and this indicates that it is a valuable technique for both detection and prediction of coronary artery disease.

Design, synthesis and biological evaluation of choline based SPECT imaging agent: Ga(iii)-DO3A-EA-Choline

The enhanced choline uptake and phosphorylation in tumor cells has motivated the development of radiolabeled choline derivatives as diagnostic markers for imaging cell membrane proliferation and noninvasive detection of prostate, brain and breast tumors. In the present work, we report a facile strategy for the synthesis of choline functionalized macrocyclic chelating agent (DO3A-EA-choline) and its radiocomplexation with (67)Ga for potential tumor imaging applications. The synthesis of the desired compound featured quaternization of N,N-dimethylaminoethanol with 1,2-dibromoethane followed by subsequent alkylation with trisubstituted cyclen (DO3A). All intermediates and final compounds have been fully characterized by spectroscopic techniques, namely, (1)H, (13)C NMR and mass spectroscopy. The compound has been successively labeled with (67)Ga-citrate in ammonium acetate buffer (pH 6.5) at 80 °C. MTT assays have been performed on the HEK cell line to determine the cytotoxicity of the compound. Cell uptake studies carried out on the U-87 MG cell line exhibited saturable binding of the radioconjugate in picomolar range with a K(d) value of 0.528 pM. The in vivo biodistribution and blood kinetics studies exhibited rapid clearance of the radiolabeled complex and excretion through the renal and hepatobiliary route. The present studies demonstrate the potential applications of (67)Ga-DO3A-EA-choline as a radiopharmaceutical for molecular imaging using ((67/68)Ga) SPECT and PET modalities.

In vivo SPECT/CT imaging of human orthotopic ovarian carcinoma xenografts with 111In-labeled monoclonal antibodies

Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor 3 (VEGFR-3) are expressed in the tumor area during the progression of ovarian carcinoma. Monoclonal antibodies developed against these receptors are potential diagnostic molecules for in vivo imaging of ovarian carcinoma. Biodistribution of the monoclonal antibodies cetuximab against EGFR and mF4-31C1 against VEGFR-3 was studied in nude mice with orthotopic SKOV-3m human ovarian carcinoma xenografts. The biodistribution of (111)Indium-labeled antibodies was followed up to 48 h postinjection using combined SPECT and CT imaging modality. Organ samples were collected postmortem and specific organ activity was measured. Accumulation of the intravenously injected antibodies in the tumor tissue and lymph nodes was verified using immunohistology. Imaging studies with SPECT/CT showed clear accumulation of both antibodies into tumor area. The tumor uptake was 8.78 ± 0.74 %ID/g for cetuximab and 5.77 ± 0.62 %ID/g for mF4-31C1 after 48 h postinjection. Cetuximab had lower liver tropism and faster tumor homing rate. In addition, after 48 h two of five tumor-bearing mice showed a clear accumulation of the In-labeled mF4-31C1 at the left axillary area. Both intravenously administered antibodies could also be detected from the tumor sections by immunohistological staining but only mF4-31C1 forms in the lymph nodes. These results demonstrate the accumulation of EGFR- and VEGFR-3-specific antibodies in orthotopic ovarian carcinoma tumors. Systemically administered they had slow pharmacokinetics which is typical for antibodies. Accumulation of mF4-31C1 antibody in the lymph nodes suggests the remote activation of VEGFR-3 by the primary tumor.

Differential Diagnosis of Dementia with Lewy Bodies and Alzheimer Disease Using Combined MR Imaging and Brain Perfusion Single-Photon Emission Tomography

Diagnostic performance by MR imaging or by SPECT alone in discriminating DLB patients from AD patients has been estimated previously. However, the performance of a combination of MR imaging and SPECT has not yet been evaluated. Our aim was to evaluate the usefulness of combining MR imaging and SPECT to discriminate mild DLB from AD. Nineteen patients with mild DLB and 19 age- and cognitive decline-matched patients with mild AD underwent both SPECT and MR imaging. Hippocampal, occipital, and striatal volume and SPECT count ratios were compared. Linear discriminant and ROC analyses were performed by using the parameters of striatal volume and the occipital SPECT ratio. The striatal volume ratio in the DLB group was significantly lower than that in the AD group. The occipital SPECT ratio in the DLB group was lower than that in the AD group. The mean area under the ROC curve from combined MR imaging and SPECT (AUC = 0.898) was higher than that from MR imaging (AUC = 0.679) or SPECT (AUC = 0.798) alone. By combining MR imaging and SPECT, we were able to distinguish patients with mild DLB from those with AD with a high level of accuracy. Our findings suggest that combining MR imaging and SPECT modalities is a useful and practical approach for diagnostically differentiating DLB from AD.

Chilaiditi's syndrome demonstrated by SPECT/CT

Purpose: Chilaiditi’s syndrome is a rare condition commonly diagnosed as an incidental radiological finding. The aim of this report is to show the role of SPECT-CT in this syndrome and state the functional and anatomical role of this hybrid imaging modality. &#x0D; Materials and Methods: A case report.&#x0D; Results: A 49-year-old female patient was referred for gallium-67 citrate for a possible&#x0D; granulomatous myositis and underwent SPECT-CT of the abdomen to assess the area of decreased gallium uptake on planar images of the liver. The combined SPECT and CT modality demonstrated findings consistent with the clinical evidence of Chilaiditi’s syndrome. The anatomical part of this hybrid modality made it easier to evaluate the area of gallium lack of uptake which was due to air in the colon.&#x0D; Conclusion: This case does not only show the role of SPECT-CT in this syndrome but also suggest that the use of such modality should be considered whenever available in the evaluation of patients in whom the localization of active disease becomes imperative.