Quantitative analysis of patient motion in walk-through PET scanner and standard axial field of view pet scanner using infrared-based tracking.

Background: Long-axial field-of-view (LAFOV) Positron Emission Tomography (PET) scanners provide high sensitivity, but throughput is limited because of time-consuming patient positioning. To enhance throughput, a novel Walk-Through PET (WT-PET) scanner has been developed, allowing patients to stand upright, supported by an adjustable headrest and hand supports. This study evaluates the degree of motion in the WT-PET system and compares it with the standard PET-CT.

Influence of X-ray spectrum and bowtie filter characterisation on the accuracy of Monte Carlo simulated organ doses: Validation in a whole-body CT scanning mode.

Purpose: For patient-specific CT dosimetry, Monte Carlo dose simulations require an accurate description of the CT scanner. However, quantitative spectral information and information on the bowtie filter material and shape from the manufacturer is often not available. In this study, the influence of different X-ray spectra and bowtie filter characterisation methods on simulated CT organ doses is studied.

Assessing the deep learning based image quality enhancements for the BGO based GE omni legend PET/CT.

Background: This study investigates the integration of Artificial Intelligence (AI) in compensating the lack of time-of-flight (TOF) of the GE Omni Legend PET/CT, which utilizes BGO scintillation crystals.

Methods: The current study evaluates the image quality of the GE Omni Legend PET/CT using a NEMA IQ phantom. It investigates the impact on imaging performance of various deep learning precision levels (low, medium, high) across different data acquisition durations.

Accuracy of patient-specific CT organ doses from Monte Carlo simulations: influence of CT-based voxel models.

Monte Carlo simulations using patient CT images as input are the gold standard to perform patient-specific dosimetry. However, in standard clinical practice patient's CT images are limited to the reconstructed CT scan range. In this study, organ dose calculations were performed with ImpactMC for chest and cardiac CT using whole-body and anatomy-specific voxel models to estimate the accuracy of CT organ doses based on the latter model.

Comparison of a 3D CZT and conventional SPECT/CT system for quantitative Lu-177 SPECT imaging.

Purpose: Next-generation SPECT/CT systems with CdZnTe (CZT) digital detectors in a ring-like setup are emerging to perform quantitative Lu-177 SPECT imaging in clinical routine. It is essential to assess how the shorter acquisition time might affect the image quality and uncertainty on the mean absorbed dose of the tumors and organs at risk compared to a conventional system.

Methods: A NEMA Image Quality phantom was scanned with a 3D CZT SPECT/CT system (Veriton, by Spectrum Dynamics) using 6 min per bed position and with a conventional SPECT/CT system (Symbia T16, by Siemens) using 16 min per bed position.

A systematic review and meta-analysis on the radiation dose of computed tomography in hybrid nuclear medicine imaging.

Background: While diagnostic reference levels (DRLs) are well-established for the radiopharmaceutical part, published DRLs for the CT component of positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/computed tomography (SPECT/CT) are limited. This systematic review and meta-analysis provides an overview of the different objectives of CT in hybrid imaging and summarizes reported CT dose values for the most common PET/CT and SPECT/CT examinations. Also, an overview of already proposed national DRLs is given.

Direct co-registration of [F]FDG uptake and histopathology in surgically excised malignancies of the head and neck: a feasibility study.

Purpose: Recent technical advancements in PET imaging have improved sensitivity and spatial resolution. Consequently, clinical nuclear medicine will be confronted with PET images on a previously unfamiliar resolution. To better understand [F]FDG distribution at submillimetric scale, a direct correlation of radionuclide-imaging and histopathology is required.

High-Resolution F-FDG PET/CT for Assessing Three-Dimensional Intraoperative Margins Status in Malignancies of the Head and Neck, a Proof-of-Concept.

The surgical treatment of head and neck malignancies relies on the complete removal of tumoral tissue, while inadequate margins necessitate the use of adjuvant therapy. However, most positive margins are identified postoperatively as deep margins, and intraoperative identification of the deep positive margins could help achieve adequate surgical margins and decrease adjuvant therapies. To improve deep-margin identification, we investigated whether the use of high-resolution preclinical PET and CT could increase certainty about the surgical margins in three dimensions.

Comparison of an in-house acquired brain F-18 FDG PET normal database with commercially available normal data.

Introduction: Current guidelines recommend the use of semiautomated assessment of F-18 FDG PET brain studies. Accuracy is influenced by the normal data, which requires knowledge of the included subjects and how they were acquired. Due to confidentiality, such information is often not completely disclosed.

Monte Carlo Simulations of the GE Signa PET/MR for Different Radioisotopes.

Unlabelled: NEMA characterization of PET systems is generally based on F because it is the most relevant radioisotope for the clinical use of PET. F has a half-life of 109.7 min and decays into stable O via β+ emission with a probability of over 96% and a maximum positron energy of 0.

Hepatobiliary scintigraphy and kinetic growth rate predict liver failure after ALPPS: a multi-institutional study.

Background: Post hepatectomy liver failure (PHLF) after ALPPS has been related to the discrepancy between liver volume and function. Pre-operative hepatobiliary scintigraphy (HBS) can predict post-operative liver function and guide when it is safe to proceed with major hepatectomy. Aim of this study was to evaluate the role of HBS in predicting PHLF after ALPPS, defining a safe cut-off.

Noise reduction using a Bayesian penalized-likelihood reconstruction algorithm on a time-of-flight PET-CT scanner.

Purpose: Q.Clear is a block sequential regularized expectation maximization (BSREM) penalized-likelihood reconstruction algorithm for PET. It tries to improve image quality by controlling noise amplification during image reconstruction.

NEMA NU 2-2007 performance characteristics of GE Signa integrated PET/MR for different PET isotopes.

Background: Fully integrated PET/MR systems are being used frequently in clinical research and routine. National Electrical Manufacturers Association (NEMA) characterization of these systems is generally done with F which is clinically the most relevant PET isotope. However, other PET isotopes, such as Ga and Y, are gaining clinical importance as they are of specific interest for oncological applications and for follow-up of Y-based radionuclide therapy.

Radiation Dosimetry and Biodistribution of F-PSMA-11 for PET Imaging of Prostate Cancer.

Prostate-specific membrane antigen (PSMA) is highly overexpressed in prostate cancer. Many PSMA analog radiotracers for PET/CT prostate cancer staging have been developed, such as Ga-PSMA-11. This radiotracer has achieved good results in multiple clinical trials, but because of the superior imaging characteristics of F-fluoride, F-PSMA-11 was developed.

Hemodynamic changes in ALPPS influence liver regeneration and function: results from a prospective study.

Background: Excessive increase of portal flow and pressure following extended hepatectomy have been associated to insufficient growth or function of the future liver remnant (FLR), with the risk of post-hepatectomy liver failure (PHLF). We prospectively assess the influence of liver hemodynamics on FLR regeneration and function in Associating Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS).

Methods: Twenty-three patients underwent ALPPS; liver hemodynamics were assessed throughout the procedures.

Tc-labelled S-HYNIC certolizumab pegol in rheumatoid arthritis and spondyloarthritis patients: a biodistribution and dosimetry study.

Background: Biologicals directed against tumour necrosis factor (TNF) have proven their efficacy in the treatment of spondyloarthritis and rheumatoid arthritis. We present a radiolabelling method for certolizumab pegol (CZP), a commercially available humanized Fab'-fragment directed against TNF. A biodistribution and dosimetry study was conducted.

Validation of 18F-FDG PET at conventional and delayed intervals for the discrimination of high-grade from low-grade gliomas: a stereotactic PET and MRI study.

Aim: The aim of this study was to validate 18F-FDG PET imaging for differentiating high-grade gliomas (HGGs) from low-grade gliomas (LGGs).

Methods: Twenty-one patients with gliomas undergoing a stereotactic biopsy underwent PET scanning at conventional and delayed intervals, diagnostic and stereotactic MR examinations. To calculate the uptake at the biopsy site, a 2-mm voxel was selected.

SIRT of liver metastases: physiological and pathophysiological considerations.

Available literature on the differences in circulation and microcirculation of normal liver and liver metastases as well as in rheology of the different radiolabelled microspheres [(99m)Tc-labelled macroaggregates of albumin (MAA), (90)Y-TheraSpheres and (90)Y-SIR-spheres] used in selective internal radiation therapy (SIRT) are reviewed and implications thereof on the practice of SIRT discussed. As a result of axial accumulation and skimming, large microspheres are preferentially deposited in regions of high flow, whereas smaller microspheres are preferentially diverted to regions of low flow. As flow to normal liver tissue is considerably variable between segments and also within one segment, microspheres will be delivered heterogeneously within the microvasculature of normal liver tissue.

Standardized added metabolic activity (SAM): a partial volume independent marker of total lesion glycolysis in liver metastases.

Purpose: The standardized added metabolic activity (SAM) is a new marker of total lesion glycolysis that avoids partial volume effect (PVE) and thresholding. SAM is calculated by drawing a volume of interest (VOI(1)) around the tumour and a larger VOI (VOI(2)) around VOI(1). Subtracting the background activity in VOI(2)-VOI(1) from VOI(1) yields SAM.

Tuberculous lymphadenitis: FDG PET and CT findings in responsive and nonresponsive disease.

Purpose: No data is available on the different FDG PET and CT findings in the lymph nodes (LN) of patients with HIV and tuberculosis (TB) who respond compared with those who do not respond to anti-TB treatment by 4 months after initiation of TB treatment. These findings were the focus of our study.

Methods: PET/CT scans performed at 4 months after initiation of TB treatment in 20 consecutive HIV patients were analysed.

Nuclear medicine imaging in tuberculosis using commercially available radiopharmaceuticals.

In this paper, data available on nuclear medicine imaging using commercially available radiopharmaceuticals for the differentiation, staging, and prediction or assessment of the response to treatment in tuberculosis (TB) are reviewed. Limited available studies suggest that single photon emission computed tomography (SPECT) using either 201Tl, 99mTc-sestamibi, or 99mTc-tetrofosmin is accurate (≥85%) and has a high negative predictive value (≥90%) for the differentiation of TB from carcinoma in patients presenting with a solitary pulmonary nodule (SPN). The criteria for detection of TB on 201Tl SPECT are nondepiction of the suspicious lesion in the delayed image or a negative retention index [washout on the delayed images (3–4 h postinjection) vs.

99mTc-labeled tricarbonyl his-CNA35 as an imaging agent for the detection of tumor vasculature.

Unlabelled: Given the importance of angiogenesis for a tumor's survival and growth, several therapeutic strategies rely on the selective inhibition of angiogenesis and the destruction of existing tumor vasculature. These strategies raise the need for a noninvasive tool to evaluate tumor vasculature. We describe the radiosynthesis and evaluation of an imaging tracer that specifically binds tumor subendothelial collagen and thereby images tumor vasculature.

In vitro and in vivo evaluation of [99mTc]-labeled tricarbonyl His-annexin A5 as an imaging agent for the detection of phosphatidylserine-expressing cells.

Introduction: Apoptosis is one of the mechanisms behind successful chemotherapy and radiation treatment. Radiolabeled annexin A5 has been demonstrated to be a successful tool in the detection of apoptosis following chemotherapy in vivo.

Methods: His-tagged annexin A5 was labeled with [(99m)Tc]-tricarbonyl and evaluated as apoptosis imaging radiotracer in vitro and in vivo.

A simple test to determine the quality of your clinical PET images.

Objective: The objective of the study was to present a simple method for comparing clinical PET images to a set of increasing quality images. Those different quality images were obtained by varying the activity concentration and the acquisition time.

Methods: Images of a Jaszczak phantom were acquired with scan times that were calculated with a spreadsheet application for a personal computer to obtain 500, 1000, 2000, 5000, 7000 and 9000 counts/4 mm(3) voxel.