scholarly journals 2516 Ultra-low Na18F tracer dosing for preclinical skeletal imaging enables new concepts in digital PET/CT

2018 ◽  
Vol 2 (S1) ◽  
pp. 34-35
Author(s):  
Maria I. Menendez ◽  
Richard Moore ◽  
Katherine Binzel ◽  
Michael Friel ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Animal Model ◽  
Nuclear Medicine ◽  
Image Quality ◽  
Low Dose ◽  
Distal Femur ◽  
Standard Dose ◽  
Lumbar Vertebra ◽  
Whole Body ◽  
Nuclear Medicine Imaging ◽  
Acceptable Image Quality

OBJECTIVES/SPECIFIC AIMS: The aim of this study was to assess the ultra-dose Na18F dPET protocol feasibility for skeleton imaging in a canine model with reduced radiation dose and preserved quantitative characteristics. We hypothesized that administering an ultra-low Na18F dose would provide suitable image quality while reducing subject’s exposure to radiation. METHODS/STUDY POPULATION: In total, 13 adult male beagles [weight (kg) mean±SD; 14.3±2.2] were scanned. The dogs were administered 3 different Na18F doses: 3 (standard dose/SD), 1 (low dose/LD), and 0.05 (ultra-low dose/ULD) mCi. Imaging started ≃45 minutes post injection for ≃ 33 minute total acquisition time. Covering the whole body, 11 bed positions, acquiring 120 (3 mCi) and 180 (1, 0.05 mCi) seconds per bed position. All imaging was performed on a digital photon counting system (Philips Vereos, pre-commercial release). PET list mode data were reconstructed using Time-of-flight with 4, 2, and 1 mm3 voxel volumes. Point spread function, and Gaussian filtering were applied. Two experienced blinded readers evaluated image sets overall quality, tissue characterization, and quality of background in the whole body skeleton. Three-dimensional (3D) regions of interest (ROI) were traced over the distal femur, first lumbar vertebra, and a portion of the liver, recording standard uptake values (SUVmax and SUVmean). RESULTS/ANTICIPATED RESULTS: All the scans and reconstructions were successfully completed in all subjects. Decreasing Na18F dose from the standard dose (3 mCi) to the ultra-low dose/ULDO (0.05 mCi), demonstrated acceptable image quality and quantification. Ultra-low dose Na18F SUVmean values for the 3D ROIs reported (mean±SD) 2.6±0.7, 2.5±1.1, 9±1.6, and 0.6±0.3 from the right and left distal femur, first lumbar vertebra, and a portion of the liver, respectively. When compared the SD with the LD and ULD, dPET demonstrated acceptable image quality and definition for qualitative overall assessment. This was also found for the overall quantitative ROI assessment of the healthy canine skeletons. DISCUSSION/SIGNIFICANCE OF IMPACT: Ultra-low dose Na18F at a level of 50 μCi for a 14 kg canine appears to be diagnostically feasible and a robust option to reduce (60-fold) radiotracer doses in a translational animal model using a dPET system. Furthermore, it allows us to move preclinical nuclear medicine imaging forward with substantial reduced exposure levels while preserving image quality. Both visual and quantitative results indicate that the standard-dose bone Na18F dPET can be decreased with a satisfactory diagnostic image quality. Ultra-low Na18F dose is indeed important for younger populations, control patients, and nononcological diseases/conditions. Favorable pharmacokinetics of Na18F (such as high bone uptake, minimal binding to serum proteins, rapid single-pass extraction, and fast clearance from the soft tissues) in addition to the technological capabilities of dPET/CT demonstrated feasibility enabling dose reduction strategies. Ultra-low dose has diagnostic reproducibility and lower radiation burden compared with higher fixed dose techniques in current available guidelines [Society of Nuclear Medicine and Molecular Imaging; SNMMI (5–10 mCi)]. Na18F dPET/CT provides higher sensitivity and diagnostic accuracy, which enables high-quality images with lower tracer activity in this translational animal model. Future research will apply the same methodology to other anatomical targets as well as to the use of different tracers. Preclinical nuclear medicine imaging using ultra-low tracer doses, demonstrated the potential to obtain reasonable quality images and diminishing radiation surveillance in accordance with as low as reasonably achievable tracer levels.

Low-dose whole-body CT using deep learning image reconstruction: image quality and lesion detection

2021 ◽  
Vol 94 (1121) ◽  
pp. 20201329
Author(s):  
Yoshifumi Noda ◽  
Tetsuro Kaga ◽  
Nobuyuki Kawai ◽  
Toshiharu Miyoshi ◽  
Hiroshi Kawada ◽  
...  
Keyword(s):  
Deep Learning ◽  
Image Reconstruction ◽  
Image Quality ◽  
Low Dose ◽  
Standard Dose ◽  
Lesion Detection ◽  
Whole Body ◽  
Hybrid Iterative Reconstruction ◽  
Whole Body Ct ◽  
Attenuation Values

Objectives: To evaluate image quality and lesion detection capabilities of low-dose (LD) portal venous phase whole-body computed tomography (CT) using deep learning image reconstruction (DLIR). Methods: The study cohort of 59 consecutive patients (mean age, 67.2 years) who underwent whole-body LD CT and a prior standard-dose (SD) CT reconstructed with hybrid iterative reconstruction (SD-IR) within one year for surveillance of malignancy were assessed. The LD CT images were reconstructed with hybrid iterative reconstruction of 40% (LD-IR) and DLIR (LD-DLIR). The radiologists independently evaluated image quality (5-point scale) and lesion detection. Attenuation values in Hounsfield units (HU) of the liver, pancreas, spleen, abdominal aorta, and portal vein; the background noise and signal-to-noise ratio (SNR) of the liver, pancreas, and spleen were calculated. Qualitative and quantitative parameters were compared between the SD-IR, LD-IR, and LD-DLIR images. The CT dose-index volumes (CTDIvol) and dose-length product (DLP) were compared between SD and LD scans. Results: The image quality and lesion detection rate of the LD-DLIR was comparable to the SD-IR. The image quality was significantly better in SD-IR than in LD-IR (p < 0.017). The attenuation values of all anatomical structures were comparable between the SD-IR and LD-DLIR (p = 0.28–0.96). However, background noise was significantly lower in the LD-DLIR (p < 0.001) and resulted in improved SNRs (p < 0.001) compared to the SD-IR and LD-IR images. The mean CTDIvol and DLP were significantly lower in the LD (2.9 mGy and 216.2 mGy•cm) than in the SD (13.5 mGy and 1011.6 mGy•cm) (p < 0.0001). Conclusion: LD CT images reconstructed with DLIR enable radiation dose reduction of >75% while maintaining image quality and lesion detection rate and superior SNR in comparison to SD-IR. Advances in knowledge: Deep learning image reconstruction algorithm enables around 80% reduction in radiation dose while maintaining the image quality and lesion detection compared to standard-dose whole-body CT.

scholarly journals Implementation of ultra-low-dose lung protocols in CT-guided lung biopsies: feasibility and safety in the clinical setting

2017 ◽  
Vol 45 (6) ◽  
pp. 2101-2109 ◽  
Author(s):  
Barbara K Frisch ◽  
Karin Slebocki ◽  
Kamal Mammadov ◽  
Michael Puesken ◽  
Ingrid Becker ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Low Dose ◽  
Standard Dose ◽  
Complication Rates ◽  
Dose Length Product ◽  
Ct Guided ◽  
Total Radiation Dose ◽  
Lung Biopsies ◽  
Histological Results

Objective To evaluate the use of ultra-low-dose computed tomography (ULDCT) for CT-guided lung biopsy versus standard-dose CT (SDCT). Methods CT-guided lung biopsies from 115 patients (50 ULDCT, 65 SDCT) were analyzed retrospectively. SDCT settings were 120 kVp with automatic mAs modulation. ULDCT settings were 80 kVp with fixed exposure (20 mAs). Two radiologists evaluated image quality (i.e., needle artifacts, lesion contouring, vessel recognition, visibility of interlobar fissures). Complications and histological results were also evaluated. Results ULDCT was considered feasible for all lung interventions, showing the same diagnostic accuracy as SDCT. Its mean total radiation dose (dose–length product) was significantly reduced to 34 mGy-cm (SDCT 426 mGy-cm). Image quality and complication rates ( P = 0.469) were consistent. Conclusions ULDCT for CT-guided lung biopsies appears safe and accurate, with a significantly reduced radiation dose. We therefore recommend routine clinical use of ULDCT for the benefit of patients and interventionalists.

scholarly journals Low Dose Computed Tomography in Diagnosis of Ureteric Calculus in Obese Patients

2020 ◽  
Vol 9 (1) ◽  
pp. 27-31
Author(s):  
Mahesh Gautam ◽  
Aziz Ullah ◽  
Manish Raj Pathak
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Standard Dose ◽  
Reconstruction Technique ◽  
Obese Patients ◽  
Low Dose Computed Tomography ◽  
Effective Radiation

Background: Standard dose computed tomography is standard imaging modality in diagnosis of urolithiasis. The introduction of low dose techniques results in decrease radiation dose without significant change in image quality. However, the image quality of low dose computed tomography is affected by skin fold thickness and subcutaneous abdominal adipose tissue. The aim of this study to evaluate stone location, size, and density using low dose computed tomography compared with standard dose computed tomography in obese population. Material and Methods: This non-randomized non-inferiority trial includes 120 patient having BMI≥25kg/m2 with acute ureteric colic. The low dose and standard dose computed tomography were performed accordingly. Effective radiation doses were calculated from dose-length product obtained from scan report using conversion factor of 0.015. The images were reconstructed using iterative reconstruction algorithm. Effective dose, number and size of stone, Hounsfield Unit value of stone and image quality was assessed. Results: Stones were located in 69 (57.5%) in right and 51 (42.5%) in left ureter. There was no statistical difference in mean diameter, number and density of stones in low dose as compared with standard dose. The radiation dose was significantly lower with low dose. (3.68 mSv) The delineation of the ureter, outline of the stones and image quality in low dose was overall sufficient for diagnosis. No images of low dose scan were subjectively rated as non-diagnostics. Conclusion: Low dose computed tomography with iterative reconstruction technique is as effective as standard dose in diagnosis of ureteric stones in obese patients with lower effective radiation dose.

scholarly journals Value of whole-body low-dose computed tomography in patients with ventriculoperitoneal shunts: a retrospective study

2018 ◽  
Vol 129 (6) ◽  
pp. 1598-1603 ◽  
Author(s):  
Andrej Pala ◽  
Fadi Awad ◽  
Michael Braun ◽  
Michal Hlavac ◽  
Arthur Wunderlich ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Radiation Exposure ◽  
Low Dose ◽  
Whole Body ◽  
Consecutive Series ◽  
Dose Length Product ◽  
Shunt System ◽  
Distal Catheter ◽  
Vp Shunt

OBJECTIVEThe gold standard for evaluation of ventriculoperitoneal (VP) shunt position, dislocation, or disconnection is conventional radiography. Yet, assessment with this modality can be challenging because of low image quality and can result in repetitive radiation exposure with high fluctuation in the radiation dose. Recently, CT-based radiation doses have been significantly reduced by using low-dose protocols. Thus, whole-body low-dose CT (LDCT) has become applicable for routine use in VP shunt evaluation. The authors here compared image quality and approximate radiation dose between radiography and LDCT in patients with implanted VP shunt systems.METHODSVentriculoperitoneal shunt systems have been investigated with LDCT scanning at the authors’ department since 2015. A consecutive series of 57 patients (70 investigations) treated between 2015 and 2016 was retrospectively assessed. A historical patient cohort that had been evaluated with radiography was compared with the LDCT patients in terms of radiation dose and image quality. Three independent observers evaluated projection of the valve pressure level and correct intraperitoneal position, as well as complete shunt projection, using a Likert-type scale of 1–5, where 1 indicated “not assessable” and 5 meant “assessable with high accuracy.” Descriptive statistics and the Mann-Whitney U-test were used for analysis.RESULTSTwenty-seven radiographs (38.6%) and 43 LDCT scans (61.4%) were analyzed. The median dose-length product (DLP) of the LDCT scans was 100 mGy·cm (range 59.9–183 mGy·cm). The median total dose-area product (DAP) of the radiographic images was 3177 mGy·cm2 (range 641–13,833 mGy·cm2). The estimated effective dose (EED) was significantly lower with the LDCT scan (p < 0.001). The median EED was 4.93 and 1.90 mSv for radiographs and LDCT, respectively. Significantly better identification of the abdominal position of the distal shunt catheter was achieved with LDCT (p < 0.001). Simultaneously, significantly improved visualization of the entire shunt system was realized with this technique (p < 0.001). On the contrary, identification of the valve settings was significantly worse with LDCT (p < 0.001).CONCLUSIONSWhole-body LDCT scanning allows good visualization of the distal catheter after VP shunt placement. Despite the fact that only a rough estimation of effective doses is possible in a direct comparison of LDCT and radiography, the data showed that shunt assessment via LDCT does not lead to greater radiation exposure. Thus, especially in difficult anatomical conditions, as in patients who have undergone multiple intraabdominal surgeries, have a high BMI, or are immobile, the use of LDCT shunt evaluation has high clinical value. Further data are needed to determine the value of LDCT for the evaluation of complications or radiation dose in pediatric patients.

scholarly journals Antimicrobial Peptides as Infection Imaging Agents: Better Than Radiolabeled Antibiotics

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Muammad Saeed Akhtar ◽  
Muhammad Babar Imran ◽  
Muhammad Afzal Nadeem ◽  
Abubaker Shahid
Keyword(s):  
Nuclear Medicine ◽  
Antimicrobial Peptides ◽  
Imaging Techniques ◽  
Whole Body ◽  
Whole Body Imaging ◽  
Nuclear Medicine Imaging ◽  
Human Immune System ◽  
Large Member ◽  
Infection And Inflammation ◽  
Radiolabeled Compounds

Nuclear medicine imaging techniques offer whole body imaging for localization of number and site of infective foci inspite of limitation of spatial resolution. The innate human immune system contains a large member of important elements including antimicrobial peptides to combat any form of infection. However, development of antibiotics against bacteria progressed rapidly and gained popularity over antimicrobial peptides but even powerful antimicrobials failed to reduce morbidity and mortality due to emergence of mutant strains of bacteria resulting in antimicrobial resistance. Differentiation between infection and inflammation using radiolabeled compounds with nuclear medicine techniques has always been a dilemma which is still to be resolved. Starting from nonspecific tracers to specific radiolabeled tracers, the question is still unanswered. Specific radiolabeled tracers included antibiotics and antimicrobial peptides which bind directly to the bacteria for efficient localization with advanced nuclear medicine equipments. However, there are merits and demerits attributed to each. In the current paper, radiolabeled antibiotics and radiolabeled peptides for infection localization have been discussed starting with the background of primitive nonspecific tracers. Radiolabeled antimicrobial peptides have certain merits compared with labeled antibiotics which make them superior agents for localization of infective focus.

scholarly journals Usefulness of a No-Reference Metric for Evaluation of Images in Nuclear Medicine -A Comparative Study with Visual Assessment

2021 ◽  
Author(s):  
Shigeaki Higashiyama ◽  
Yutaka Katayama ◽  
Atsushi Yoshida ◽  
Nahoko Inoue ◽  
Takashi Yamanaga ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
Image Quality ◽  
Paired Comparison ◽  
Evaluation Criteria ◽  
Visual Assessment ◽  
Comparison Method ◽  
Natural Image ◽  
Nuclear Medicine Imaging ◽  
Visual Evaluation ◽  
Long Time

Abstract Purpose The normalized mean square error (NMSE) method is widely used to evaluate images in nuclear medicine. However, its use in clinical practice requires creating target images over a long time, which is difficult. It also requires standard images and reference teacher data that can be used at facilities worldwide because methods and doses in nuclear medicine imaging are yet to be standardized. This study examined the validity of perception-based image quality evaluator (PIQE), a no-reference metric that does not require a target image for image evaluation in nuclear medicine.Methods The Hoffman brain phantom with 18F-fluoro-2-deoxy-D-glucose (FDG) was imaged and evaluated on slices in which the frontal and temporal lobes, bilateral lateral ventricles, and basal ganglia were drawn. Sixteen images with different pixel numbers and acquisition times were created and evaluated from the same slice. For the images obtained, visual evaluation criteria were developed for two endpoints: separation of white and gray matter boundaries, and uniformity of accumulation. Five evaluators assessed all the images using a paired comparison method, and then scored and ranked them. The images were also physically evaluated by the PIQE and a natural image quality evaluator (NIQE). The rankings obtained from the visual and physical evaluations were statistically compared.Results Based on Spearman's test of significance, visual evaluation rankings showed a strong correlation with those obtained with PIQE (rs = 0.9559, p < 0.0001) and no correlation with those obtained with NIQE (rs = 0.2324 and p = 0.3865).Conclusions Evaluation of images by PIQE is as effective as visual evaluation.

Image Quality in Low-dose Multidetector Computed Tomography: A Pilot Study to Assess Feasibility and Dose Optimization in Whole-body Bone Imaging

2010 ◽  
Vol 61 (5) ◽  
pp. 258-264 ◽  
Author(s):  
Tadhg G. Gleeson ◽  
Brenda Byrne ◽  
Pat Kenny ◽  
Jason Last ◽  
Patricia Fitzpatrick ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Multidetector Computed Tomography ◽  
Low Dose ◽  
Interobserver Agreement ◽  
Skeletal Survey ◽  
Whole Body ◽  
Altman Plot ◽  
Low Dose Ct ◽  
Effective Doses

Objective To study the impact of dose parameters on image quality at whole-body low-dose multidetector computed tomography (CT) in an attempt to derive parameters that allow diagnostic quality images of the skeletal system without incurring significant radiation dose in patients referred for investigation of plasma cell dyscrasias. Methods By using a single cadaver, 14 different whole-body low-dose CT protocols were individually assessed by 2 radiologists, blinded to acquisition parameters (kVp and mAs, reconstruction algorithm, dose reduction software). Combinations of kVps that range from 80-140 kVp, and tube current time product from 14–125 mAs were individually scored by using a Likert scale from 1–5 in 4 separate anatomical areas (skull base, thoracic spine, pelvis, and distal femora). Correlation between readers scores and effective doses were obtained by using correlation coefficient statistical analysis, statistical significance was considered P < .01. Interobserver agreement was assessed by using a Bland and Altman plot. Interobserver agreement in each of the 4 anatomical areas was assessed by using kappa statistics. A single set of parameters was then selected for use in future clinical trials in a cohort of patients referred for investigation of monoclonal gammopathy, including multiple myeloma. Results Several sets of exposure parameters allowed low-dose whole-body CT to be performed with effective doses similar to skeletal survey while preserving diagnostic image quality. Individual reader's and average combined scores showed a strong inverse correlation with effective dose (reader 1, r = −0.78, P = .0001; reader 2, r = −0.75, P = .0003); average combined scores r = −0.81, P < .0001). Bland and Altman plot of overall scores shows reasonable interobserver agreement, with a mean difference of 1.055. Conclusion Whole-body low-dose CT can be used to obtain adequate CT image quality to assess normal osseous detail while delivering effective doses similar to those associated with conventional radiographic skeletal survey.

Evaluation of an iterative model-based reconstruction of pediatric abdominal CT with regard to image quality and radiation dose

2017 ◽  
Vol 59 (6) ◽  
pp. 740-747
Author(s):  
Marie-Louise Aurumskjöld ◽  
Marcus Söderberg ◽  
Fredrik Stålhammar ◽  
Kristina Vult von Steyern ◽  
Anders Tingberg ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Pediatric Patients ◽  
Standard Dose ◽  
Reconstruction Method ◽  
Abdominal Ct ◽  
Model Based ◽  
Iterative Model

Background In pediatric patients, computed tomography (CT) is important in the medical chain of diagnosing and monitoring various diseases. Because children are more radiosensitive than adults, they require minimal radiation exposure. One way to achieve this goal is to implement new technical solutions, like iterative reconstruction. Purpose To evaluate the potential of a new, iterative, model-based method for reconstructing (IMR) pediatric abdominal CT at a low radiation dose and determine whether it maintains or improves image quality, compared to the current reconstruction method. Material and Methods Forty pediatric patients underwent abdominal CT. Twenty patients were examined with the standard dose settings and 20 patients were examined with a 32% lower radiation dose. Images from the standard examination were reconstructed with a hybrid iterative reconstruction method (iDose4), and images from the low-dose examinations were reconstructed with both iDose4 and IMR. Image quality was evaluated subjectively by three observers, according to modified EU image quality criteria, and evaluated objectively based on the noise observed in liver images. Results Visual grading characteristics analyses showed no difference in image quality between the standard dose examination reconstructed with iDose4 and the low dose examination reconstructed with IMR. IMR showed lower image noise in the liver compared to iDose4 images. Inter- and intra-observer variance was low: the intraclass coefficient was 0.66 (95% confidence interval = 0.60–0.71) for the three observers. Conclusion IMR provided image quality equivalent or superior to the standard iDose4 method for evaluating pediatric abdominal CT, even with a 32% dose reduction.

Ultra-low-dose computed tomography and its utility in wrist trauma in the emergency department

2021 ◽  
pp. 028418512198995
Author(s):  
Erdal Tekin ◽  
Kutsi Tuncer ◽  
Ibrahim Ozlu ◽  
Recep Sade ◽  
Rustem Berhan Pirimoglu ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Low Dose ◽  
Standard Dose ◽  
Control Group ◽  
Study Group ◽  
Effective Radiation Dose ◽  
Wrist Trauma ◽  
Effective Radiation

Background The use and frequency of computed tomography (CT) are increasing day by day in emergency departments (ED). This increases the amount of radiation exposed. Purpose To evaluate the image quality obtained by ultra-low-dose CT (ULDCT) in patients with suspected wrist fractures in the ED and to investigate whether it is an alternative to standard-dose CT (SDCT). Material and Methods This is a study prospectively examining 336 patients who consulted the ED for wrist trauma. After exclusion criteria were applied, the patients were divided into the study and control groups. Then, SDCT (120 kVp and 100 mAs) and ULDCT (80 kVp and 5 mAs) wrist protocols were applied simultaneously. The images obtained were evaluated for image quality and fracture independently by a radiologist and an emergency medical specialist using a 5-point scale. Results The effective radiation dose calculated for the control group scans was 41.1 ± 2.1 µSv, whereas the effective radiation dose calculated for the study group scans was 0.5 ± 0.0 µSv. The effective radiation dose of the study group was significantly lower than that of the control group ( P < 0.01). The CT images in the study group showed no significant differences in the mean image quality score between observer 1 and observer 2 (3.4 and 4.3, respectively; P = 0.58). Both observers could detect all fractures using the ULDCT images. Conclusion ULDCT provides high-quality images in wrist traumas while reducing the radiation dose by approximately 98% compared to SDCT without any changes in diagnostic accuracy.

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