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background CT perfusion (CTP) infarct and penumbra estimations determine the eligibility of patients with acute ischemic stroke (AIS) for endovascular intervention. This study aimed to determine volumetric and spatial agreement of predicted RAPID, Vitrea, and Sphere CTP infarct with follow- up fluid attenuation inversion recovery (FLAIR) MRI infarct. Methods 108 consecutive patients with AIS and large vessel occlusion were included in the study between April 2019 and January 2020 . Patients were divided into two groups: endovascular intervention (n=58) and conservative treatment (n=50). Intervention patients were treated with mechanical thrombectomy and achieved successful reperfusion (Thrombolysis in Cerebral Infarction 2b/2 c/3) while patients in the conservative treatment group did not receive mechanical thrombectomy or intravenous thrombolysis. Intervention and conservative treatment patients were included to assess infarct and penumbra estimations, respectively. It was assumed that in all patients treated conservatively, penumbra converted to infarct. CTP infarct and penumbra volumes were segmented from RAPID, Vitrea, and Sphere to assess volumetric and spatial agreement with follow- up FLAIR MRI. results Mean infarct differences (95% CIs) between each CTP software and FLAIR MRI for each cohort were: intervention cohort: RAPID=9.0±7.7 mL, Sphere=0.2±8.7 mL, Vitrea=-7.9±8.9 mL; conservative treatment cohort: RAPID=-31.9±21.6 mL, Sphere=-26.8±17.4 mL, Vitrea=-15.3±13.7 mL. Overlap and Dice coefficients for predicted infarct were (overlap, Dice): intervention cohort: RAPID=(0.57, 0.44), Sphere=(0.68, 0.60), Vitrea=(0.70, 0.60); conservative treatment cohort: RAPID=(0.71, 0.56), Sphere=(0.73, 0.60), Vitrea=(0.72, 0.64). Conclusions Sphere proved the most accurate in patients who had intervention infarct assessment as Vitrea and RAPID overestimated and underestimated infarct, respectively. Vitrea proved the most accurate in penumbra assessment for patients treated conservatively although all software overestimated penumbra. [ABSTRACT FROM AUTHOR]

The objective of the study was to calculate neck uptake by γ-camera-based and uptake-probe-based methods and compare it with uptake by diagnostic whole-body and neck radioiodine scanning in thyroid carcinoma patients. Methods: Of the 46 patients, 14 were male (average age, 47.5 y) and 32 female (average age, 38 y). All had already undergone thyroidectomy followed by 131I treatment at least once and came to the institute after 6 mo for follow-up. As per the institutional protocol, they underwent scanning 72 h after administration of a low-dose capsule (111-148 MBq) of 131I, and the uptake was calculated by both probe- and camera-based methods using medium-energy parallel-hole collimators. Results: The neck was negative for uptake in 24 patients by both the probe-based method (with 0.1% as the cutoff) and the camera-based method, as well as by the scan. The neck was positive for uptake in 10 patients by both methods and by the scan. In 10 patients, the neck was positive for uptake by the probe-based method but negative by the camera-based method and the scan; in most of these cases, nontarget counts contributed to high scatter radiation. In 2 patients, the neck was negative for uptake by the probe-based method but positive by the camera-based method and the scan. Thus, the two methods were concordant in 34 of the 46 patients (74%) but discordant in 12 (26%). On the basis of these results, we propose that 0.03% be the cutoff for positivity for the camera-based method. In 85.7% of patients with negative scan results and systemic metastases near the neck (n = 7), an uptake cutoff of 0.1% resulted in positive results. All patients had true-negative results with a camera-based cutoff of 0.03%. In view of this discordance between the probe-based method and the scan, we further propose that 0.2%, rather than 0.1%, be the cutoff for positivity for the probe-based method in order to reduce false positivity. Conclusion: In thyroid carcinoma patients undergoing 131I low-dose scans, camera-based uptake is as reliable as, and can substitute for, probe-based uptake in evaluating functioning metastases near the neck or nonspecific high physiologic accumulation. [ABSTRACT FROM AUTHOR]

Objectives: Laser speckle flowgraphy is a new method that enables the rapid evaluation of foot blood flow without contact with the skin. We used laser speckle flowgraphy to evaluate foot blood flow in peripheral arterial disease patients before and after surgical revascularization.Materials and Methods: A prospective single-center study. Thirty-one patients with 33 limbs that underwent surgical revascularization for peripheral arterial disease were included. Pre- and postoperative foot blood flows were measured on the plantar surface via laser speckle flowgraphy and skin perfusion pressure. The laser speckle flowgraphy device was used to visualize the blood flow distribution of the target skin and processed the pulse wave velocity of synchronized heart beats. The mean blood flow, which was expressed as the area of the pulse wave as the beat strength of skin perfusion on laser speckle flowgraphy converted into a numerical value, was assessed as dynamic changes following surgery. Beat strength of skin perfusion was also investigated in non-peripheral arterial disease controls (23 patients/46 limbs).Results: The suitability of beat strength of skin perfusion in non-peripheral arterial disease controls was achieved; the beat strength of skin perfusion value was significantly higher in every area of interest in non-peripheral arterial disease controls compared to that in peripheral arterial disease limbs at the preoperative stage (105.8 ± 8.2 vs. 26.3 ± 8.2; P < 0.01). Although the pulse wave before surgery was visually flat in peripheral arterial disease patients, the pulse wave was remarkably and immediately improved through surgical revascularization. Beat strength of skin perfusion showed a dynamic change in foot blood flow (26.3 ± 8.2 at preoperation, 98.5 ± 6.7 immediately after surgery, 107.6 ± 5.7 at seven days after surgery, P < 0.01 for each compared to preoperation) that correlated with an improvement in skin perfusion pressure.Conclusions: Laser speckle flowgraphy is a noninvasive, contact-free modality that is easy to implement, and beat strength of skin perfusion is a useful indicator of foot circulation during the perioperative period. Further analysis with a larger number of cases is necessary to establish appropriate clinical use. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Medical Imaging & Radiation Sciences is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aims We validated a 1-day myocardial perfusion imaging (MPI) protocol using an ultra low-dose(ULD) equal for stress and rest on a cadmium zinc telluride (CZT). Methods and results Fifty-six patients underwent a 1-day MPI protocol using a standard (SD) 99mTc-tetrofosmin dose at stress (320 MBq) and rest (960 MBq) with 5 min acquisition time each (SD). Within 2 weeks MPI was repeated using ULD 99mTc-tetrofosmin equal for stress and rest (160 MBq) with 15 min acquisition time each (ULD). All scans were performed on a CZT camera (DNM 570c, GE Healthcare). Background subtraction was applied on the rest MPI of the ULD using P-mod software. Presence and extent of perfusion defect were analysed. Pearson's correlation was used to compare ejection fraction (EF), end diastolic volume (EDV), and end systolic volume (ESV) between both protocols. SD revealed ischaemia in 23, scar in 3, and an equivocal finding in 1 patient, while normal findings were documented in 29 patients. ULD resulted in the following findings: ischaemia 23, scar 3, and 30 normal scans. Congruence of SD and ULD was 22/23 for ischaemia, 3/3 for scar, and 29/29 in normal patients; one patient with ischaemia in SD was classified as scar in ULD. Overall agreement of ULD with SD was 98%. The mean extent of defect was comparable between SD and ULD for the stress (10% vs. 11%, respectively, P  = NS) and rest studies (5% vs. 7%, respectively, P  = NS). An excellent correlation between SD and ULD was found for EF (r  = 0.93), EDV (r  = 0.95), and ESV (r  = 0.97). Conclusion CZT cameras may enable reliable MPI scanning in patients with known or suspected coronary artery disease using protocols with about a factor 4-decrease in radiation dose exposure compared with traditional protocols. [ABSTRACT FROM AUTHOR]

BACKGROUND: A novel cardiac SPECT camera with cadmium-zinc-telluride (CZT) based technology has a fixed array of semiconductor detectors paired with pinhole collimators focused on the heart. Image acquisition in obese patients can be challenging because of much smaller detector field of view compared to conventional gamma cameras. The aim of this study was to evaluate the impact on high body mass on the feasibility of CZT myocardial perfusion imaging (MPI). The additional aim was to investigate the mechanism of the banana-shaped/obesity artifact, as referred to in literature, and to attempt at simulating it on a phantom study. MATERIAL AND METHODS: Study group consisted of 43 patients with morbid obesity (BMI ≥ 40 kg/m²). All these patients underwent myocardial perfusion imaging on both CZT cardiac camera and general purpose SPECT/CT gamma camera. Control group consisted of all patients who underwent myocardial perfusion imaging on CZT camera throughout one calendar year and whose BMI was lower than 40 kg/m2. In this group, all repeated studies were re-analyzed for estimating the frequency of heart mispositioning in the camera field of view. The number of studies performed was 1180. A static cardiac phantom was used to simulate a banana-shaped artifact. A series of phantom acquisitions during which the phantom position was altered in the camera field of view was performed. RESULTS: In control group, 3.7% of all cardiac scintigrams required repetition, 18.9% of which were repeated due to wrong heart positioning; median BMI in this group of patients was 36.0. A banana-shaped artifact was observed in one female patient with BMI 36.0. In morbid obesity group, 32.6% of the studies were non-diagnostic with "truncation effect" on Scan Quality Control (QC). Median BMI in patients with diagnostic scans was 42.0, while in patients with not acceptable quality control test it was 45.0 (p < 0.05). Banana-shaped artifacts were observed in 5 non-diagnostic studies. In a phantom study an artifact of banana shape was obtained when gantry was distant from the phantom and target was on the edge of the camera field of view and was slightly truncated. CONCLUSIONS: Problem with heart mispositioning during imaging on the CZT camera affects less than 1% of all performed studies. Morbid obesity is not a contraindication to perform myocardial perfusion scintigraphy with the use of a CZT camera because over 2/3 of the studies of very obese patients is diagnostic. [ABSTRACT FROM AUTHOR]

Molecular breast imaging (MBI) is a nuclear medicine test that uses dedicated γ-cameras designed for imaging of the breast. Despite growing adoption of MBI, there is currently a lack of guidance on appropriate quality control procedures for MBI systems. Tests designed for conventional γ-cameras either do not apply or must be modified for dedicated detectors. Our objective was to provide practical guidance for physics testing of MBI systems by adapting existing quality control procedures for conventional systems. Methods: Quality control tests designed for conventional γ-cameras were attempted on a dedicated MBI system and then modified as necessary to accommodate the pixelated detector, limited space between dual-detector heads, and inability to fully rotate the detector gantry. Results: MBI systems were found to warrant quality control testing of uniformity, spatial resolution, count sensitivity, energy resolution, and lesion contrast. The modified procedures and special considerations needed for these tests were investigated and described. Physics tests of intrinsic uniformity, count rate parameters, and overall system performance for SPECT did not apply to dedicated MBI systems. Conclusion: Routine physics testing of dedicated MBI equipment is important for verifying system specifications and monitoring changes in performance. As adoption of MBI grows, routine testing may be required for obtaining and maintaining accreditation from regulatory bodies. [ABSTRACT FROM AUTHOR]

Volleyball is played by means of fundamentals serve, serve reception, set, attack, block and defense using a set of techniques that can interfere in the quality of actions. The aim of this research was to analyze the association of the technique used in the actions of the serve, serve reception, set and attack with the quality of actions. Eleven schools / teams competed during the “Paraíba School Games”, 12 to 14 years old, female. The games were filmed using a camera for further analysis. In the total 27 games were analyzed, resulting in 47 sets, in the actions of serve (2.380), serve reception (2,157), set (1,358) and attack (1,299). To classify the quality of actions, two scales were used according to the purpose of the action. The Chi-square test was used to verify the association of applied techniques in each foundation with the quality of actions. The standing type was the predominant used in the serve (81.2%), forearm pass for serve reception and set (85% and 65,8%, respectively) and spike with and without jump for attack (Σ = 53.6 %). There was association between the techniques and the quality of the serve action (ꭕ²= 114,612; p< 0,001), serve reception (ꭕ²= 70,693; p< 0,001), set (ꭕ²= 205,864; p< 0,001) and attack (ꭕ²= 241,678; p<0,001). The results of this study demonstrate that the technique interferes in the quality of actions. Thus, the main techniques were standing type (serve), overhand (serve reception and set) and spike with jump (attack). [ABSTRACT FROM AUTHOR]

Background: Technetium-99m diethylene triaminepentaacetic acid (Tc-99m DTPA) renal scintigraphy using modified Gate's method is commonly adopted to calculate glomerular filtration rate (GFR). Objectives: The purpose of this study was to find the correlations between GFRs, which are calculated by the in-house and non-inhouse workstations from gamma cameras (GC) manufactured by different firms. Patients and Methods: Medical records of patients receiving Tc-99m DTPA renal scan between January and December 2016 were analyzed. Patients were allocated randomly to a GC (1 or 2). The calculated GFRs were conducted by the in-house workstation (group A: workstation 1/ GC 1; group B: workstation2/ GC 2) and the non-in-house workstation from the GC (group C: workstation 2/ GC 1; group D: workstation 1/ GC 2). All patients had their creatinine levels checked to calculate the estimated GRF (eGFR) as the reference data. Comparison of correlation and difference between GFR calculations (group A, B, C and D), eGFRs and clinical parameters was analyzed. Results: Forty patients (24 men, 16 women) were enrolled in this study. The average of eGFRs was 63.0 ± 38.5 mL/min/1.73m². The GFRs (group A to D) calculated were all significantly correlated with the eGFR. However, there was a significant difference between group C and eGFR (P = 0.0021), and group D and eGFR (P = 0.0262). Eight patients (20%) had changed stage of chronic kidney disease when using non-in-house workstations, compared to in-house workstations from GC. Conclusion: GFRs calculated by the non-in-house workstation were significantly different from eGFR. Use of workstation and GC from the same manufacturer would provide more accurate data in the clinical setting. [ABSTRACT FROM AUTHOR]

The main objective of this study was to check the validity of using gamma camera as an alternate method to thyroid uptake probe, for counting 25uCi (0.925 MBq) and 50uCi (1.85 MBq) 131I capsules before administration to thyroid patients. Methods: - 10 sets each of 25uCi (0.925 MBq) and 50uCi (1.85 MBq) 131I capsules received from Board Of Radiation and Isotope Technology, Department Of Atomic Energy, India (BRIT, DAE) have been counted individually using thyroid uptake probe for 10 seconds following institutional protocol and also by keeping individual capsule of a set with 8cm gap between each of them .These capsules were also scanned by Scintillation gamma camera for 100 seconds. Capsules having counts within the range of mean ±2 Standard Deviation (SD) were accepted for patient administration. After analysing both the data, correlation coefficient between these two methods has been evaluated. Results: Scanned images were analysed by drawing Identical ROI around each set of 25uCi (0.925 MBq) and 50uCi (1.85 MBq) 131I capsules. Capsules with counts within 2 Standard Deviation from mean were accepted for patient administration. Good correlation coefficient (r >0.95) was observed between these two counts set. Conclusion: Gamma camera based 131I -capsule counting method is an easy and time saving method compared to probe based capsule counting method as we can scan a set of capsules in a single acquisition. It can provide uniformity information for a batch of 131I -capsules and avoid the time consuming method of individual capsule counting with the thyroid uptake probe. [ABSTRACT FROM AUTHOR]

Purpose: Cadmium zinc telluride (CZT) detectors have recently been introduced to the field of clinical nuclear cardiology. However, the feasibility of using them for organs other than the heart remains unclear. The aim of this study was to evaluate the potential of a cardiac CZT camera to acquire thyroid and parathyroid images. We used custom-made phantoms and the currently available standard protocols for CZT, instead of a sodium-iodine scintillation (NaI) camera. Materials and Methods: Thyroid phantoms with or without parathyroid adenomas were made from agar using radiopharmaceuticals (99mTc or 123I) and imaged using CZT and NaI cameras. Using the CZT camera data, we prepared maximum intensity projection (MIP) images and planar equivalent (PE) images. Image counts were compared to those from the NaI camera, and the radioactivity of the phantoms was measured. For parathyroid imaging, three different protocols with the NaI camera were tested using MIP images. Results: For thyroid imaging, MIP could provide images as clear as those obtained from the NaI camera. The radioactivity and image counts correlated better for the PE images than the MIP images, especially for 123I images. We succeeded in obtaining clear parathyroid adenoma images from MIP images using all three protocols. Conclusion: A cardiac CZT camera can effectively perform qualitative and quantitative assessments of the thyroid and parathyroid organs. [ABSTRACT FROM AUTHOR]

A heart-to-mediastinum (H/M) ratio of 1.6 or greater on planar 123I-iobenguane (123I-MIBG) images identifies heart failure patients at low risk of experiencing an adverse cardiac event. This phase-4 study used standardized phantoms to assess the intercamera, intracamera, and interhead variability in H/M ratio determinations from planar cardiac 123I-MIBG imaging using commercially available, dual-head γ-cameras. Methods: A fillable thorax phantom was developed to simulate the typical uptake of 123I-MIBG. The phantom had a nominal H/M ratio of 1.6 on the reference camera. Commercial cameras used in the study were dual-head and capable of 90° configuration for cardiac imaging. The target sample size was 8 units (examples) per camera model. Two imaging technologists independently analyzed planar images of simulated 123I-MIBG uptake from the thorax phantom. H/M was the ratio of the average counts per pixel of the heart and mediastinum regions of interest. The primary endpoint, intercamera variability in H/M ratio from head 1, was determined for each camera model via comparison with the H/M ratio on the reference camera. Only cameras with at least 8 units tested (n ≥ 8) were included in the primary analysis. Intracamera and interhead variability in the H/M ratio were also evaluated. Results: Nine camera models were studied. The mean H/M ratio ranged from 1.342 to 1.677. The primary analysis (6 camera models) using a mixed-model, repeated-measures analysis showed no significant difference in H/M ratio between any camera model and the reference camera. Intracamera variability (head 1) in the H/M ratio among camera models with 8 units or more was high, with SDs ranging from 0.0455 to 0.1193. Interhead variability was low (SDs of the interhead difference, 0.017-0.074). Conclusion: Commonly used γ-cameras produced H/M ratios from simulated 123I-MIBG phantom images that were not significantly different from those on the reference camera. This finding indicates that the results of previous clinical trials of 123I-MIBG, involving many different clinical sites and camera models, are valid. The assessment of the performance of a given camera unit using an 123I planar phantom before H/M results from 123I-MIBG imaging are used for classifying risk in heart failure patients is encouraged. [ABSTRACT FROM AUTHOR]

Background: In 177Lu-DOTATATE treatments, bone marrow (BM) is one of the most important organs at risk. The authors previously developed an image-based two-compartment method for BM dosimetry, showing a significant correlation between absorbed dose to BM and hematological toxicity in 177Lu-DOTATATE treatments. In the present study, they aimed to further evaluate this BM dosimetry method by finding optimal settings for dividing the whole body into two compartments; in terms of minimizing the coefficient of variation (CV) for the individual absorbed doses and studying its correlation to the BM response. The authors have also added specific absorbed fractions for male and female. Finally, they compare this two-compartment method with whole-body dosimetry.Methods: This study included 46 patients with advanced neuroendocrine tumors treated with 177Lu-DOTATATE on two to five occasions at Sahlgrenska University Hospital. Planar gamma camera images were collected at four time points postinjection, and a segmentation tool using a normalized number of uptake foci (nNUF) to divide the whole body into high- and low-uptake compartments was used. The authors characterized the two-compartment model and compared it with whole-body dosimetry.Results and Conclusion: The dosimetry method was robust, with an optimal nNUF value of 0.1-0.2. Using an nNUF value of 0.15, the absorbed BM dose was estimated as 0.20 Gy/7.4 GBq, and the CV as 8.4%. Compared to whole-body dosimetry, stronger correlation was found between absorbed dose to BM and hematological response using the two-compartment method. The two-compartment method has potential as a valuable image-based alternative to blood-based BM dosimetry. [ABSTRACT FROM AUTHOR]

Background: Cardiac 123I-meta-iodobenzylguanidine (MIBG) uptake is quantified using the heart-to-mediastinum ratio (HMR) with an Anger camera. The relationship between HMR determined using D-SPECT with a cadmium-zinc-telluride detector and an Anger camera is not fully understood. Therefore, the present study aimed to define this relationship using images derived from a phantom and from patients.Methods: Cross-calibration phantom studies using an Anger camera with a low-energy high-resolution (LEHR) collimator and D-SPECT, and clinical 123I-MIBG studies proceeded in 40 consecutive patients (80 studies). In the phantom study, a conversion coefficient (CC) was defined based on phantom experiments and applied to the Anger camera and the D-SPECT detector. The HMR was calculated using anterior images with the Anger camera and anterior planograms with D-SPECT. First, the HMR from D-SPECT was cross-calibrated to the Anger camera, and then, the HMR from both cameras were converted to the medium-energy general-purpose collimator condition (CC 0.88; ME88 condition). The relationship between HMR and corrected and uncorrected methods was examined. A 123I-MIBG washout rate was calculated using both methods with and without background subtraction.Results: Based on the phantom experiments, the CC of the Anger camera with an LEHR collimator and of D-SPECT using an anterior planogram was 0.55 and 0.63, respectively. The original HMR from the Anger camera and D-SPECT was 1.76 ± 0.42 and 1.86 ± 0.55, respectively (p < 0.0001). After D-SPECT HMR was converted to the Anger camera condition, the corrected D-SPECT HMR became comparable to the values under the Anger camera condition (1.75 ± 0.48, p = n. s.). When the HMR measured using the two cameras were converted under the ME88 condition, the average standardized HMR from the Anger camera and D-SPECT became comparable (2.21 ± 0.65 vs. 2.20 ± 0.75, p = n. s.). After standardization to the ME88 condition, a systematic difference in the linear regression lines disappeared, and the HMR from both the Anger (StdHMRAnger) and D-SPECT (StdHMRDSPECT) became comparable. Additional correction using a regression line further improved the relationship between both HMR [StdHMRDSPECT = 0.09 + 0.98 × StdHMRAnger (R 2 = 0.91)]. The washout rate closely correlated with and without background correction between both methods (R 2 = 0.83 and 0.65, respectively).Conclusion: The phantom-based conversion method is applicable to D-SPECT and enables the common application of HMR irrespective of D-SPECT and the Anger camera. [ABSTRACT FROM AUTHOR]

Background: Cadmium-zinc-telluride (CZT) cameras have improved the evaluation of patients with chest pain. However, inferior/inferolateral attenuation artifacts similar to those seen with conventional Anger cameras persist. We added prone acquisitions and CT attenuation correction (CTAC) to the standard supine image acquisition and analyzed the resulting examinations.Methods and Results: Seventy-two patients referred for invasive coronary angiography (CAG), and who also underwent rest/stress myocardial perfusion imaging (MPI) on a CZT camera in the supine and prone positions plus CTAC imaging, to examine known or suspected CAD between April 2013 and March 2014 were included. A sixteen-slice CT scan acquired on a SPECT/CT scanner between rest and stress imaging provided data for iterative reconstruction. Sensitivity, specificity, accuracy, and positive and negative likelihood ratios (LRs) were calculated to compare MPI with CAG on a per-patient basis. Per-patient sensitivity, specificity, and accuracy of supine images to predict coronary abnormalities on CAG were 35% [95% confidence interval (CI) 19-52], 86% (95% CI 80-92), and 74% (95% CI 66-82); those of prone imaging were 65% (95% CI 45-81), 82% (95% CI 76-87), and 78% (95% CI 68-85); and those of CTAC were 59% (95% CI 41-71), 93% (95% CI 87-97), and 85% (95% CI 76-91), respectively.Conclusions: Prone acquisition and CTAC images improve the ability to assess the inferior/inferolateral area. [ABSTRACT FROM AUTHOR]

Purpose: To report the first clinical results and value assessment of prompt gamma imaging for in vivo proton range verification in pencil beam scanning mode.Methods and Materials: A stand-alone, trolley-mounted, prototype prompt gamma camera utilizing a knife-edge slit collimator design was used to record the prompt gamma signal emitted along the proton tracks during delivery of proton therapy for a brain cancer patient. The recorded prompt gamma depth detection profiles of individual pencil beam spots were compared with the expected profiles simulated from the treatment plan.Results: In 6 treatment fractions recorded over 3 weeks, the mean (± standard deviation) range shifts aggregated over all spots in 9 energy layers were -0.8 ± 1.3 mm for the lateral field, 1.7 ± 0.7 mm for the right-superior-oblique field, and -0.4 ± 0.9 mm for the vertex field.Conclusions: This study demonstrates the feasibility and illustrates the distinctive benefits of prompt gamma imaging in pencil beam scanning treatment mode. Accuracy in range verification was found in this first clinical case to be better than the range uncertainty margin applied in the treatment plan. These first results lay the foundation for additional work toward tighter integration of the system for in vivo proton range verification and quantification of range uncertainties. [ABSTRACT FROM AUTHOR]

Purpose: Several preclinical imaging systems are commercially available, but their purchase and maintenance costs make them unaffordable for the majority of small- and medium-sized groups. Taking into account the needs of average users, we developed "γ-eye", a mouse-sized, benchtop γ-camera suitable for in vivo scintigraphic imaging.Procedures: The γ-eye is based on two position-sensitive photomultiplier tubes, coupled to a CsI(Na) pixelated scintillator and a low-energy lead collimator with parallel hexagonal holes.Results: The spatial resolution of the system is 2 mm at 0 mm. The energy resolution is 26 % at 140 keV and the maximum recorded sensitivity 210 cps/MBq. The system was evaluated in a proof-of-concept animal study, using three different clinical Tc-99m-labeled radiopharmaceuticals. Phantom and animal studies demonstrate its ability to provide semiquantitative results even for short scans.Conclusions: Systems' performance, dimensions, and cost make γ-eye a unique solution for efficient whole-body mouse nuclear imaging. [ABSTRACT FROM AUTHOR]

Objective: In addition to the trade-off between resolution and sensitivity which is a common problem among all types of parallel hole collimators (PCs), obtained images by high energy PCs (HEPCs) suffer from hole-pattern artifact (HPA) due to further septa thickness. In this study, a new design on the collimator has been proposed to improve the trade-off between resolution and sensitivity and to eliminate the HPA.Methods: A novel PC, namely high energy extended PC (HEEPC), is proposed and is compared to HEPCs. In the new PC, trapezoidal denticles were added upon the septa in the detector side. The performance of the HEEPCs were evaluated and compared to that of HEPCs using a Monte Carlo-N-particle version5 (MCNP5) simulation. The point spread functions (PSF) of HEPCs and HEEPCs were obtained as well as the various parameters such as resolution, sensitivity, scattering, and penetration ratios, and the HPA of the collimators was assessed. Furthermore, a Picker phantom study was performed to examine the effects of the collimators on the quality of planar images.Results: It was found that the HEEPCD with an identical resolution to that of HEPCC increased sensitivity by 34.7%, and it improved the trade-off between resolution and sensitivity as well as to eliminate the HPA. In the picker phantom study, the HEEPCD indicated the hot and cold lesions with the higher contrast, lower noise, and higher contrast to noise ratio (CNR).Conclusion: Since the HEEPCs modify the shaping of PSFs, they are able to improve the trade-off between the resolution and sensitivity; consequently, planar images can be achieved with higher contrast resolutions. Furthermore, because the HEEPCS reduce the HPA and produce images with a higher CNR, compared to HEPCs, the obtained images by HEEPCs have a higher quality, which can help physicians to provide better diagnosis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Medical Imaging & Radiation Sciences is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Surgical resection of the abnormal parathyroid glands is the only curative treatment for primary hyperparathyroidism (PHPT). Radioguided parathyroidectomy with technetium-99m (TC-99m) sestamibi has been successfully used in patients with PHPT. This study was designed to evaluate the results of a series of patients with PHPT who underwent minimally invasive radioguided parathyroidectomy (MIRP) using very low dose (1 mCi) of TC-99m sestamibi (MIBI) without application of intraoperative parathyroid hormone (PTH) assay or frozen section analysis.Methods: Eighty-seven patients with PHPT were prospectively studied from November 2012 to January 2015. Following neck ultrasound (US) and MIBI scan concordant for single gland disease, patients underwent MIRP using a handheld gamma probe. The technique involved injecting of 1 mCi MIBI in the operative room before the beginning of the intervention. All patients were followed up for a minimum of 6 months postoperatively.Results: MIRP was successfully performed in 86 out of 87 patients (98.85%). The Gamma probe was particularly useful in detection of ectopic parathyroid adenomas in upper mediastinum. Mean operative time was 23.95 ± 7.982 min and mean hospital stay was 1.44 ± 0.604 days. No major surgical complications were recorded.Conclusions: The MIRP technique using very low dose (1 mCi) of Tc-99m MIBI without intraoperative PTH assay and frozen section analysis resulted in excellent cure rate for PHPT. This technique involves a radiation exposure to patients and surgical staffs 20 times lower than conventional MIRP using 20 mCi Tc-99m MIBI. Besides, patients with PHPT due to ectopic parathyroid adenoma may especially benefit from MIRP. [ABSTRACT FROM AUTHOR]

Introduction: Approximately one-third of breast cancers are impalpable and require pre-operative image-guided localisation. Hook-wire localisation (HWL) is commonly used but has several disadvantages. Use of a low-activity radioactive iodine-125 seed is a promising alternative technique used in the USA and the Netherlands. This pilot study describes the first use of this in Australia.Methods: In this prospective pilot study, 21 participants with biopsy-proven breast cancer underwent radioguided occult lesion localisation using iodine-125 seed(s) (ROLLIS) with insertion of a hook-wire for back up. Sentinel node biopsy was performed where indicated. Ease of hook-wire and seed insertion, duration of the procedure, dependence on the seed versus hook-wire during surgery, lesion location within the specimen, histopathology including size of radial margins, the ease of seed retrieval in pathology, and safe return of seeds for disposal were documented. Radiation dosimetry of staff was performed.Results: All seeds were placed within 3.5 mm of the lesion. All lesions and seeds were removed. One participant needed re-excision for involved margins. Radiologists and surgeons both preferred ROLLIS. Surgeons were able to depend on the seed for localisation in all but one case. Sentinel node biopsy was successfully performed when required. Pathologists found seed retrieval quick and easy, with no detrimental effect on tissue processing. No radiation doses measurably above background were received by staff.Conclusion: ROLLIS is an easily learnt, safe and effective alternative technique to standard HWL. [ABSTRACT FROM AUTHOR]

Gamma camera is an important apparatus in nuclear medicine imaging. Its detection part is consists of a scintillation detector with a heavy collimator. Substitution of semiconductor detectors instead of scintillator in these cameras has been effectively studied. In this study, it is aimed to introduce a new design of P-N semiconductor detector array for nuclear medicine imaging. A P-N semiconductor detector composed of N-SnO2:F, and P-NiO:Li, has been introduced through simulating with MCNPX monte carlo codes. Its sensitivity with different factors such as thickness, dimension, and direction of emission photons were investigated. It is then used to configure a new design of an array in one-dimension and study its spatial resolution for nuclear medicine imaging. One-dimension array with 39 detectors was simulated to measure a predefined linear distribution of Tc99_m activity and its spatial resolution. The activity distribution was calculated from detector responses through mathematical linear optimization using LINPROG code on MATLAB software. Three different configurations of one-dimension detector array, horizontal, vertical one sided, and vertical double-sided were simulated. In all of these configurations, the energy windows of the photopeak were ± 1%. The results show that the detector response increases with an increase of dimension and thickness of the detector with the highest sensitivity for emission photons 15-30° above the surface. Horizontal configuration array of detectors is not suitable for imaging of line activity sources. The measured activity distribution with vertical configuration array, double-side detectors, has no similarity with emission sources and hence is not suitable for imaging purposes. Measured activity distribution using vertical configuration array, single side detectors has a good similarity with sources. Therefore, it could be introduced as a suitable configuration for nuclear medicine imaging. It has been shown that using semiconductor P-N detectors such as P-NiO:Li, N-SnO2:F for gamma detection could be possibly applicable for design of a one dimension array configuration with suitable spatial resolution of 2.7 mm for nuclear medicine imaging. [ABSTRACT FROM AUTHOR]

Objective To assess the regional cerebral perfusion changes in patients with major depressive illness, with or without suicidal behavior by 99mTc-HMPAO brain perfusion SPECT. Methods 99mTc-HMPAO brain SPECT was performed in 40 subjects including 10 controls in Group A. There were 30 patients with major depression meeting the DSM-IV criteria scoring >17 on the Hamilton Rating Scale. The patients were subclassified into groups B and C. Group B included 16 patients suffering from major depression. Group C included 14 patients with major depression and attempted suicide or who had moderate to severe suicidal risk as assessed by Intent Score Scale. Semiquantitative assessment of cerebral perfusion was perfromed through a brain quantification software program. The cortextocerebellum ratios were calculated in 16 ROIs drawn on coronal section in all the patients. Results The scintigraphic evaluation of the cerebral perfusion in the Group B (nonsuicidal) showed significant hypoperfusion in the prefrontal (p<0.001), orbitofrontal (p<0.01), frontal motor (p<0.01) and the temporal lobes (p<0.01). In the Group C (suicidal), significant hypoperfusion was noticed in the prefrontal (p<0.001), orbitofrontal (p<0.01) and frontal motor areas (p<0.001). The temporal lobe showed hyperperfusion (p< 0.001). Conclusion In major depressive illness, the prefrontal, the orbitofrontal and the frontal motor areas, are markedly hypoperfused. In severe depression not associated with any suicidal behavior, there is hypoperfusion in the temporal lobes, whereas the temporal lobes are hyperperfused in suicidal behavior, with the degree of hyperperfusion related to the severity of the suicidal behaviour. [ABSTRACT FROM AUTHOR]

18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans in the first 49 patients referred with either possible brain tumour or brain tumour recurrence were reviewed. FDG-PET imaging was reported with reference to anatomical imaging. Based on the report the FDG study was classified as either positive or negative for the presence of tumour. Thirty-eight cases were included in the analysis, 21 having pathological data and 17 with diagnostic clinical follow up. Eleven were excluded, as they had inadequate follow-up data. Of the 21 cases with pathology, 18 were shown to have tumour. In this group there were five false-negative scans and two false-positive PET scans. Seventeen cases were assessed by clinical follow up, nine were considered to have been tumour. There were two false negatives with one false positive. The overall sensitivity, specificity and positive and negative predictive values were 74, 73, 87 and 53% respectively. This is similar to figures previously quoted in published work. Despite relatively limited numbers, the utility of FDG PET imaging in our hands is similar to published reports. With a positive predictive value of 87%, a positive FDG study indicates a high likelihood that there is brain tumour present. A negative study does not exclude the presence of tumour. [ABSTRACT FROM AUTHOR]

Positron emission tomography (PET) requires accurate timing of scintillation events to properly discriminate between coincident and noncoincident pairs. The traditional solution to timing is based on custom application specific integrated circuits (ASIC) designs, whose cost may not be justified in the design of experimental small animal PET scanners. The new generation of PET scanners introduces the idea of continuous sampling of the detected scintillation pulse, replacing event-triggered acquisition front-ends. This approach enables new options to the timing procedure based on digital processing of the sampled pulse signal. This work proposes a time stamping algorithm based on the optically matched filter and compares the potential performance benefits of this approach versus other FIR-based timing algorithms, some of which have been already implemented by different authors. Results show that the coincidence timing resolution may be as low as 1.5 ns without the need of expensive high-speed converters when the proper signal processing is applied. [ABSTRACT FROM AUTHOR]

In this paper, we present an experimental and Monte Carlo investigation of the intrinsic spatial resolution that can be achieved with the intensified electron-multiplying charge-coupled device (I-EMCCD) gamma camera [1]-[4]. This detector has a very low readout noise, an ultra-high spatial resolution and a large active area of ∼80 mm diameter, which is well-suited for small animal imaging applications. The intrinsic detector resolutions achieved with different scintillators and under different experimental conditions were compared. In this study, the simple centroiding method was compared with two model-fitting approaches for finding the locations of gamma ray interactions. The results from Monte Carlo simulation have demonstrated that with an appropriate detector configuration, it is possible to achieve an intrinsic resolution of ∼30 μm FWHM for detecting 27-35 keV gamma rays. The I-EMCCD scintillation camera offers a promising candidate for future ultra-high resolution SPECT imaging applications. [ABSTRACT FROM AUTHOR]

We have developed a cross-platform software application that implements all of the basic standardized nuclear medicine scintillation camera quality control analyses, thus serving as an independent complement to camera manufacturers’ software. Our application allows direct comparison of data and statistics from different cameras through its ability to uniformly analyze a range of file types. The program has been tested using multiple gamma cameras, and its results agree with comparable analysis by the manufacturers’ software. [ABSTRACT FROM AUTHOR]

We evaluated the usefulness of (99m)Tc-tetrofosmin planar scintigraphy acquired with a high-resolution (HR) dedicated breast camera in comparison with conventional single-photon emission computed tomography (SPECT) and pinhole-SPECT (P-SPECT) in breast cancer (BC) axillary lymph node metastasis detection in a consecutive series of 76 BC patients, 28 of whom had axillary lymph node metastases, including 9 positive at clinical examination. HR planar scintigraphy was true positive in only 7 patients with >3 palpable metastases (sensitivity: 25%), while SPECT was true positive in 23 of 28 cases (sensitivity: 82.1%) and P-SPECT in 25 of 28 (sensitivity: 89.3%). SPECT was false negative in 5 patients with nonpalpable 3 metastatic nodes. SPECT should be preferred, significantly improving the sensitivity of planar scintigraphy, especially when using a pinhole collimator. [ABSTRACT FROM AUTHOR]

Abstract: One contribution to the time resolution of a scintillation detector is the signal time spread due to path length variations of the detected photons from a point source. In an experimental study, a rectangular scintillator was excited by means of a fast pulsed ultraviolet laser at different positions along its longitudinal axis. Timing measurements with a photomultiplier tube in a detection plane displaced from the scintillator end face showed a correlation between signal time and tube position indicating only a small distortion of photon angles during transmission. The data is in good agreement with a Monte Carlo simulation used to compute the average photon angle with respect to the detection plane and the average propagation time. Limitations on timing performance that arise from propagation time dispersion are expected for long and thin scintillators used in future particle identification systems. [Copyright &y& Elsevier]

The use of coded-aperture masks with dimensions of 31 × 33 and 63 × 65 in scintillation cameras has been investigated in experiments with point γ-ray sources. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the present study was to evaluate the imaging performance of YAP:Ce powder scintillating screens under exposure conditions employed in diagnostic radiology (50–140kV). Various screens were prepared in our laboratory from YAP: Ce powder (Phosphor Technology, Ltd.), with coating thickness ranging from 53 to 110mg/cm2. The imaging performance of the screens was assessed by experimental determination of the modulation transfer function (MTF) and the noise transfer function (NTF). MTF was determined by the edge spread function (ESF) method while NTF was estimated by noise power spectrum (NPS) measurements after uniform screen irradiation. In addition, parameters related to overall image quality, such as the signal-to-noise ratio transfer (MTF/NTF), were estimated. MTF curves were affected by the beam hardening effects caused by the patient simulating 20mm thick aluminum phantom. Under these conditions MTF values were found to increase with the mean X-ray photon energy. A similar effect was observed for NTF curves. Results were compared with data obtained on CsI:Tl scintillator. Taking into consideration the very fast response of YAP:Ce, these data may be of interest in designing X-ray imaging detectors. [Copyright &y& Elsevier]

Purpose: To evaluate two potential approaches to predicting site-specific patterns of recurrence after yttrium-90 ibritumomab tiuxetan radioimmunotherapy (RIT) for CD20+ B-cell Non-Hodgkin's lymphoma. These predictive methods may be useful in evaluating the utility of local intensification of individual nodal or extranodal sites using external beam radiotherapy. Methods and Materials: Records and images were evaluated for 20 patients previously treated with yttrium-90 ibritumomab RIT. Intensity of isotope uptake on the pretreatment two-dimensional antibody scans and maximal extent of tumor deposits found on computed tomography images of each anatomic site were correlated with response and subsequent patterns of recurrence or progression. Results: Our data failed to suggest a significant correlation between the site-by-site two-dimensional image intensity on the pre-RIT scan and the likelihood of response at those sites. In contrast, an analysis of pretreatment target volumes did correlate significantly with progression. A collective analysis of disease sites from all 20 patients found that 83% (10/12) sites of "bulky" (maximal diameter > or = 5 cm) disease displayed evidence of progression vs. 28% (26/93) of "nonbulky" disease sites containing gross disease but no area measuring >5 cm (p < 0.001). All patients with at least one site of bulky disease had initial disease progression occur at a bulky site, with a bulky site being the sole first site of progression in approximately 50%. In patients with only nonbulky disease sites, approximately one third progressed initially at an entirely new site of disease. Conclusion: We conclude that we can use tumor bulk to establish a statistical hierarchy of likely tumor progression sites and use this pattern to direct the use of additional external beam radiotherapy to augment treatment. [ABSTRACT FROM AUTHOR]

Background: Prior studies with first-pass radionuclide angiography (RNA) during treadmill exercise used a single-crystal (Anger) or multicrystal gamma camera and technetium 99m tracers. Motion correction, when done, used point sources, which limited correction to only plane movement.Methods and Results: We examined the performance of a multiwire gamma camera (MWGC), generator-produced tantalum 178, and a novel method of motion correction during treadmill exercise testing. We studied 100 patients in whom rest and stress gated tomographic myocardial perfusion images were obtained. Eight patients were excluded because of incomplete data. There were 53 men and 39 women aged 52 +/- 12 years. The resting left ventricular (LV) ejection fraction (EF) was 61% +/- 12% by gated single photon emission computed tomography. Stress myocardial perfusion was normal in 83 patients and abnormal in 9 patients. The resting RNA EF in the upright position was 57% +/- 12% (r = 0.52, P = .0001 vs gated EF). At peak exercise, the EF by MWGC was 60% +/- 26% if uncorrected and 69% +/- 13% after motion correction. Among the 80 patients with normal perfusion and normal resting EF by gated single photon emission computed tomography, a normal response to exercise was seen in 52 (63%) without motion correction and 74 (89%) with motion correction (P < .05).Conclusion: Assessment of LV function is feasible with MWGC. The motion-corrected images significantly improved the results. [ABSTRACT FROM AUTHOR]

Aim: Wire-guided localization (WGL) of clinically occult breast lesions is a well established technique. The aim of this study was to evaluate radio-guided localization (ROLL) within the breast screening service of a district general hospital. Method: The study group comprised 70 women who underwent ROLL under US and stereotaxis. This required an injection of Technetium-labelled colloidal albumen into the impalpable breast lesion. The women then proceeded to theatre, where localization was achieved with the use of a gamma probe. The lesion was identified by the presence of a high signal, caused by the injected isotope. The results of 70 consecutive cases in which a breast lesion was localized using ROLL were compared with the results of the latest 70 WGLs. Results: All 140 lesions were successfully localized. However, the change in technique from WGL to ROLL offered significant benefits to patients. Conclusion: Our study demonstrated that ROLL is a practical and reliable localization technique. It can be implemented in hospital units without using valuable gamma camera time. The cost compares well with WGL. There is an improved cosmetic outcome for patients, and the very small quantity of radioactivity used is safe for both patients and staff. [ABSTRACT FROM AUTHOR]

Dual–modality imaging is a technique in which computed tomography (CT) or magnetic resonance imaging is combined with positron emission tomography or single–photon emission CT to acquire structural and functional images with an integrated system. The data are acquired in a single procedure; the patient remains on the scanner table while undergoing both x-ray and radionuclide studies to facilitate correlation between the structural and functional images. The resulting data can aid in localization, enabling more specific diagnosis than can be obtained with a conventional imaging study. In addition, the anatomic information can be used to compensate the correlated radionuclide data for physical perturbations such as photon attenuation, scatter radiation, and partial volume errors. Thus, dual–modality imaging provides a priori information that can improve both the visual quality and the quantitative accuracy of the radionuclide images. Dual–modality imaging systems are also being developed for biologic research involving small animals. Small–animal dual–modality systems offer advantages for measurements that currently are performed invasively with autoradiography and tissue sampling. By acquiring data noninvasively, dual–modality imaging permits serial studies in a single animal, enables measurements to be performed with fewer animals, and improves the statistical quality of the data. [Copyright &y& Elsevier]

Background: In cardiac imaging systems, an elliptic acquisition orbit about the patient can be used to enhance resolution of single photon emission computed tomography (SPECT) images by minimizing the distance between the object imaged and the rotating detector system. In this study artifacts from images acquired with the standard circular acquisition are compared with those acquired with various elliptic acquisitions.Methods and Results: With the use of elliptic camera orbits of different eccentricities, simulated projection data were generated from a slice through the left ventricle (LV). The projection data included a simulation of the degradation due to the depth-dependent response of the collimator. As is common in many clinical systems, SPECT images were reconstructed with the standard filtered backprojection algorithm without correction for the collimator response. When the ratio of the major-to-minor axis of the acquisition arc is changed from 1 (circular) to 1.5 (elliptic), reconstructed SPECT images show an additional loss of counts (about 10%) in the apical region of the LV. The severity of the apical defect is also dependent on the starting angle of the acquisition arc. When the starting angle is changed from 0 degrees (detector parallel to the major axis of the LV) to 60 degrees, the ratio between the minimum count in the apical region and the maximum count in the left ventricular myocardial wall decreases by as much as 20%.Conclusions: SPECT image artifacts from elliptic acquisitions are significantly more severe than those from circular acquisitions. Because of the significant difference in images reconstructed from circular and elliptic acquisitions, standardized normal files acquired from circular acquisitions should not be used for comparisons with patient data acquired from elliptic acquisitions. [ABSTRACT FROM AUTHOR]

Background: The use of genetically altered mice as a model system to study cardiovascular disease has created a need for accurate and quantitative assessment of murine ventricular function. To address this very challenging problem, we have developed a technique of murine first-pass radionuclide angiography using pinhole imaging and the short-lived isotope tantalum 178 (Ta-178) with a high-speed multiwire proportional camera (MPC). METHODS AND RESULTS. An MPC was fitted with a pinhole lens of 2-mm-diameter aperture positioned 15 cm from the camera face. The short-lived isotope Ta-178 (half-life 9.3 minutes) was generated from the tungsten 178 (W-178) (half-life 21.7 days)/Ta-178 generator and concentrated on site to an injection volume of 15 to 20 microL. Mice were imaged in the supine position with the chest wall 3 mm from the camera pinhole aperture, and images were acquired at 160 frames per second after a rapid bolus injection of Ta-178. In the absence of a true gold standard, the technology was validated with measurements in control mice and mice with surgically ligated left anterior descending arteries (LADs). In addition, the effects of pharmacologic intervention with verapamil and with dobutamine were observed. Finally, peak aortic velocity measurements obtained with this technology were compared with those obtained with echocardiographic Doppler ultrasonography, the only available quantitative comparator. There was a significant decrease in the mean left ventricular ejection fraction (LVEF) between normal mice (62% +/- 4.6% [mean +/- SEM], n = 12) and mice with experimentally induced myocardial infarction produced by surgical LAD ligation (22% +/- 2.0%, n = 41; P <.01). The LVEF decreased from 51% +/- 5.8% to 37% +/- 3.5% in a group of normal mice receiving verapamil (P <.05, n = 8) and increased from 34% +/- 2.2% to 43% +/- 2.3% in a group of LAD-ligated mice receiving dobutamine (P <.01, n = 48). Peak camera sensitivity during first pass was 25,000 cps/mCi injected. Intraobserver and interobserver variability of LVEF was studied, yielding r = 0.9639 and 0.9529 and SE of the estimate 2.6% and 3.1%, respectively. Reproducibility in serial studies was excellent (r = 0.92, SE of the estimate 5.18).Conclusions: This study demonstrates the development and use of a promising new method that uses the short-lived radioisotope Ta-178 and MPC for noninvasive quantification of murine ventricular function, that produces accurate and highly reproducible results, and that can be applied in multiple serial studies. [ABSTRACT FROM AUTHOR]

Presents a study which investigated the positioning algorithms for scintillation cameras and evaluated the maximum likelihood estimation techniques and centroid-based methods. Methodology; Results and discussion; Conclusions.

Purpose: To evaluate a simple method for quantification of focal activity in bone scintigraphy (BS).Material and Methods: The gamma camera was calibrated using a phantom. Quantitative bone scintigraphy (QBS) was performed on 11 men recently diagnosed with prostate cancer (PCa), for whom routine BS showed involvement of the skeleton. Following endocrine therapy for 4 to 8 months, a second QBS was performed. Changes in QBS values were then compared to changes in serum levels of prostate-specific antigen (PSA).Results: PSA response indicating regression of PCa was accompanied by a decrease in the QBS value in 8 of the 11 patients. The overall mean error of the QBS values was 15%.Conclusion: QBS according to this method is a relatively simple procedure that might contribute to objective evaluation of therapeutic effects in skeletal metastases, although its validity must be tested in a larger clinical material. [ABSTRACT FROM AUTHOR]

Deals with a study that developed a small gamma camera based on coupling wavelength-shifting fibres (WSF) to the surface of inorganic scintillation crystal for scintimammography. Camera design; Light output of WSF; Simulation of the pulse height distribution of the centroids; Energy resolution.

Recent developments in the use of pinhole SPECT and dedicated PET for UHR small animal imaging have identified the technology that can be used to provide images with spatial resolution of the order of 1 to 3 mm. In SPECT imaging, rotating camera pinhole SPECT has provided the means to use existing equipment to achieve UHR images. It has the disadvantages of low sensitivity and requires special image software to reconstruct tomographic slices. However, with minimal additional cost to an imaging laboratory, pinhole SPECT can provide a quantitatively accurate imaging technique for small-animal studies. New detector technology offers considerable promise; however, more studies are required before any one system can be singled out as offering major advantages over the pinhole SPECT method for general purpose small-animal SPECT imaging. The search for the means to achieve better sensitivity with UHR continues. In PET imaging, with few exceptions, the general trend has been to design systems dedicated to small-animal imaging to achieve UHR images with satisfactory sensitivity for quantitative UHR imaging. Several of the ring configuration, small-animal PET imaging systems provide good sensitivity and high spatial resolution. The cost of many of these systems, however, is relatively high, and investigators continue to explore different detector materials and imaging geometries to develop an instrument with acceptable levels of sensitivity with UHR imaging capability. We believe that both small-animal SPECT and PET imaging techniques now offer practical UHR imaging methods for quantitative small-animal imaging. As these tools are implemented in the investigation of new radiopharmaceuticals, we expect the utility of in vivo small animal assays will support further research in optimizing this technology. [ABSTRACT FROM AUTHOR]

The transport function of the uterus and oviducts and its modulation by oxytocin has been examined using hysterosalpingoscintigraphy, recording of intrauterine pressure, electrohysterography and Doppler sonography of the Fallopian tubes. After application to the posterior vaginal fornix, a rapid (within minutes) uptake of the labelled particles into the uterus was observed during the follicular and during the luteal phase of the cycle in all patients. Transport into the oviducts, however, could only be demonstrated during the follicular phase. Transport was directed predominantly into the tube ipsilateral to the ovary bearing the dominant follicle; the contralateral oviduct appeared to be functionally closed. The proportion of patients exhibiting ipsilateral transport did increase concomitant with the increase of the diameter of the dominant follicle. That ipsilateral transport has biological significance is suggested by the observation that the pregnancy rate following spontaneous intercourse or insemination was significantly higher in those women in whom ipsilateral transport could be demonstrated than in those who failed to exhibit lateralization. Oxytocin administration was followed by a dramatic increase in the amount of material transported to the ipsilateral tube, as demonstrated by radionuclide imaging and by Doppler sonography following instillation of ultrasound contrast medium. Continuous recording of intrauterine pressure before and after oxytocin administration did show an increase in basal tonus and amplitude of contractions and a reversal of the pressure gradient from a fundo-cervical to a cervico-fundal direction. These actions of oxytocin were accompanied by an increase in amplitude of potentials recorded by electrohysterography. These data support the view that uterus and Fallopian tubes represent a functional unit that is acting as a peristaltic pump and that the increasing activity of this pump during the follicular phase of the menstrual cycle is reflected by an increased transport into the oviduct ipsilateral to the ovary bearing the dominant follicle. In addition, they strongly suggest a critical role of oxytocin in this process. Failure of this mechanism appears to be a cause of subfertility or infertility, as indicated by the low pregnancy rate following intrauterine insemination or normal intercourse in the presence of patent Fallopian tubes. It may be regarded as a new nosological entity for which we propose the term tubal transport disorder (TTD). Since pregnancy rate of such patients is normal when treated with in-vitro fertilization (IVF), hysterosalpingoscintigraphy seems to be useful for the choice of treatment modalities in patients with patent Fallopian tubes suffering from infertility. [ABSTRACT FROM AUTHOR]

Dual photon absorptiometry measurements of the spine are subject to drift associated with source, source strength, and truncal thickness. This study was conducted to determine the extent to which this drift in bone mineral density (BMD) measurements can be improved by analysis of scans with a new software version, 08C, and by applying external standard or phantom corrections to scans analyzed with the older version, 08B. A phantom, consisting of human lumbar vertebrae embedded in acrylic, and five clear acrylic plates to simulate a soft-tissue thickness range of 15.2-27.9 cm, was measured on a Lunar Radiation Corp DP3 scanner over the life of a 153-gadolinium (Gd) source and scans analyzed with software versions 08B and 08C. Phantom BMD was lower with 08C at both high [0.012 +/- 0.002 (SEM) g/cm2, P less than 0.001] and low (0.027 +/- 0.003 g/cm2, P less than 0.001) count rates than with 08B. Phantom BMD of scans analyzed with 08B increased with increasing source age and the source strength-related increment increased significantly as acrylic thickness increased (P = 0.014). When the same scans were analyzed with 08C, the thickness-related effect was corrected whereas a small (0.011 g/cm2/year) source-strength effect persisted. The effects of source strength and truncal thickness on BMD were also evaluated in 40 humans scanned at two detector collimations to vary count rate. With 08B, mean BMD was 1% greater when measured with 8 than with 13 mm collimation (mean difference 0.011 +/- 0.003 g/cm2, P = 0.001), whereas the version 08C, mean BMD was the same at the two collimations.(ABSTRACT TRUNCATED AT 250 WORDS) [ABSTRACT FROM AUTHOR]

Objective: Performance of pulmonary scintigraphy (PS) for suspected pulmonary embolism (PE) in ICU patients normally involves the added risk of transporting unstable patients to the nuclear medicine unit (NMU) and poses technical difficulties in ventilating intubated patients. This retrospective study addresses the feasibility of performing PS as the bedside.Material and Methods: During a 2-year period, all ICU patients with suspected PE underwent PS at the bedside, performed with a mobile gamma-camera. 99mTc-labelled albumin macroaggregates were used for the perfusion studies. Gasified 99mTc or 81mKr gas was administered by an adapting technique in intubated patients.Results: 45 patients were studied, 29 (64%) of whom were intubated and 21 (47%) of whom were in shock. PE was confirmed or excluded by PS in 49% of patients. Angiography was performed in 4 patients (8%). In the rest, a combination of low clinical and low or very low PS probabilities rendered PE highly unlikely. There was no evidence of PE in the subsequent follow-up.Conclusions: In ICU patients with suspected PE, PS can be performed at the bedside with a mobile gamma-camera. The risk of transporting unstable patients can thus be avoided. [ABSTRACT FROM AUTHOR]

Background: This study evaluates the feasibility of performing tomographic studies with a multicrystal gamma camera combined with a rotating chair.Methods and Results: Tomographic acquisitions were performed with a cardiac phantom containing eight defects of different sizes. Defect size was determined from the fraction of counts in the short-axis slices that fell below a fixed threshold value. Image contrast was determined from the ratio of minimum/maximum counts. Images of an American College of Nuclear Physicians cardiac single-photon emission computed tomographic phantom were acquired and the results were compared with those obtained from 194 centers in the United States. For cardiac studies with 201Tl and 99mTc, threshold values of 65% to 70% gave the best correlation (R2 > 0.94) between true and measured defect sizes, although the slope of the regression line was less than 0.95 for both isotopes. Small inferior defects demonstrated poor image contrast, particularly for 99mTc. Of the three defects in the American College of Nuclear Physicians phantom, the two largest were identified in the tomographic images.Conclusions: A multicrystal gamma camera system coupled with a rotating chair can be used for tomographic studies of the heart. Image quality is poorer than that seen on conventional single-photon emission computed tomographic systems, particularly for 99mTc. [ABSTRACT FROM AUTHOR]

A significant body of evidence now suggests that clinically adequate planar and SPECT myocardial perfusion/FDG metabolism studies can be performed for assessment of myocardial viability with conventional gamma cameras. This might reduce the need for more sophisticated PET scanners in this patient subgroup and also increase the general applicability of metabolic assessment of myocardial viability with FDG. The procedure is technically demanding in terms of both equipment and interpretation, and requires further careful evaluation before it can be recommended for widespread use. Nevertheless, it appears to have enough potential to warrant evaluation along with improving techniques of using myocardial perfusion tracers, PET imaging, and stress echocardiography to identify the most cost-effective options for assessing viability of myocardium in clinical situations in which this becomes important. [ABSTRACT FROM AUTHOR]

Multiheaded rotating gamma cameras can do more than simply decrease the time required for cardiac single-photon emission computed tomographic (SPECT) acquisitions. They give their users a flexibility to improve image quality that cannot be achieved so easily with single-headed systems. Multiheaded cameras can be used to acquire quickly those radiopharmaceuticals whose distributions washout very rapidly, increase count levels in noisy images without lengthening imaging time, permit high-resolution collimation or electrocardiographic gating with little or no decrease in counts, or acquire transmission images for attenuation correction concurrently with an emission study. This new generation of SPECT scanners gives the nuclear cardiology community a unique opportunity to create a new generation of cardiac SPECT images. [ABSTRACT FROM AUTHOR]

The use of radioactive labels for tracers is an important part of the investigation of renal disease. These techniques seldom replace, but often complement radiographic techniques. Generally, the radionuclide methods provide functional and dynamic information in a non-invasive, non-traumatic type of examination. The examinations usually are relatively simple to perform and carry a very low risk of untoward reaction. The past decade has seen significant advances in radiopharmaceutical design and instrumentation. It is expected that the next decade will produce an even greater advance in this field. [ABSTRACT FROM PUBLISHER]

The advantages of lung scanning in suspected pulmonary embolism are its diagnostic sensitivity, simplicity and safety. The ability to delineate regional pulmonary ischaemia, to quantitate its extent and to follow its response to therapy provides valuable clinical data available by no other simple means. The negative scan effectively excludes pulmonary embolism but, although certain of its features favour the diagnosis of embolism, the positive scan inherently lacks specificity and requires angiographic confirmation when embolectomy, caval plication or infusion of a thrombolytic agent are contemplated. The addition of simple ventilation imaging techniques with radioxenon overcomes this limitation by providing accurate analog estimation or digital quantitation of regional ventilation: perfusion (V/Q) ratios fundamental to understanding the pathophysiologic consequences of embolism and other diseases of the lung. [ABSTRACT FROM PUBLISHER]