Preclinical PET Imaging and Toxicity Study of a Ga-Functionalized Polymeric Cardiac Blood Pool Agent.

Cardiac blood pool imaging is currently performed almost exclusively with Tc-based compounds and SPECT/CT imaging. Using a generator-based PET radioisotope has a few advantages, including not needing nuclear reactors to produce it, obtaining better resolution in humans, and potentially reducing the radiation dose to the patient. When the shortlived radioisotope Ga is used, it can be applied repeatedly on the same day-for example, for the detection of bleeding.

Selection of optimal tube potential settings for dual-energy CT virtual mono-energetic imaging of iodine in the abdomen.

Purpose: To determine the appropriate tube potential settings for dual-source, dual-energy data acquisition across a range of phantom sizes, and to determine the optimal photon energies for virtual mono-energetic imaging.

Methods: Water phantoms (15-50-cm wide) containing an iodine test object were scanned on a third-generation dual-source CT scanner using all available tube potential pairs. Virtual mono-energetic images at 40, 50, 60, and 70 keV were produced using Mono-energetic Plus.

Implementation and evaluation of a protocol management system for automated review of CT protocols.

Protocol review is important to decrease the risk of patient injury and increase the consistency of CT image quality. A large volume of CT protocols makes manual review labor-intensive, error-prone, and costly. To address these challenges, we have developed a software system for automatically managing and monitoring CT proto-cols on a frequent basis.

Technical Note: Improved CT number stability across patient size using dual-energy CT virtual monoenergetic imaging.

Purpose: The purpose of this study was to evaluate, over a wide range of phantom sizes, CT number stability achieved using two techniques for generating dual-energy computed tomography (DECT) virtual monoenergetic images.

Methods: Water phantoms ranging in lateral diameter from 15 to 50 cm and containing a CT number test object were scanned on a DSCT scanner using both single-energy (SE) and dual-energy (DE) techniques. The SE tube potentials were 70, 80, 90, 100, 110, 120, 130, 140, and 150 kV; the DE tube potential pairs were 80/140, 70/150Sn, 80/150Sn, 90/150Sn, and 100/150Sn kV (Sn denotes that the 150 kV beam was filtered with a 0.

The influence of focal spot blooming on high-contrast spatial resolution in CT imaging.

Purpose: The objective of this work was to investigate focal spot blooming effects on the spatial resolution of CT images and to evaluate an x-ray tube that uses dynamic focal spot control for minimizing focal spot blooming.

Methods: The influence of increasing tube current at a fixed tube potential of 80 kV on high-contrast spatial resolution of seven different CT scanner models (scanners A-G), including one scanner that uses dynamic focal spot control to reduce focal spot blooming (scanner A), was evaluated. Spatial resolution was assessed using a wire phantom for the modulation transfer function (MTF) calculation and a copper disc phantom for measuring the slice sensitivity profile (SSP).

Comparison of internal dose estimates obtained using organ-level, voxel S value, and Monte Carlo techniques.

Purpose: The authors' objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient-specific anatomy on the final dose estimate.

Methods: Six patients injected with 99mTc-hydrazinonicotinamide-Tyr3-octreotide were included in this study.

JADA: a graphical user interface for comprehensive internal dose assessment in nuclear medicine.

Purpose: The main objective of this work was to design a comprehensive dosimetry package that would keep all aspects of internal dose calculation within the framework of a single software environment and that would be applicable for a variety of dose calculation approaches.

Methods: Our MATLAB-based graphical user interface (GUI) can be used for processing data obtained using pure planar, pure SPECT, or hybrid planar/SPECT imaging. Time-activity data for source regions are obtained using a set of tools that allow the user to reconstruct SPECT images, load images, coregister a series of planar images, and to perform two-dimensional and three-dimensional image segmentation.

The accuracy and reproducibility of SPECT target volumes and activities estimated using an iterative adaptive thresholding technique.

Objective: Our aim was to design a practical and reproducible image segmentation method for calculations of total absorbed doses in organs and tumours for internally delivered radioisotopes. We have built upon our previously proposed use of two separate thresholds and employed an iterative technique for semiautomatic selection of background regions for segmenting an object of interest using thresholds that depend on the source-to-background ratio of activity concentrations.

Methods: The parameters of curves relating volume and activity thresholds to source-to-background ratio were established using phantoms with 20 different inserts.

Personalized image-based radiation dosimetry for routine clinical use in peptide receptor radionuclide therapy: pretherapy experience.

Patient-specific dose calculations are not routinely performed for targeted radionuclide therapy procedures, partly because they are time consuming and challenging to perform. However, it is becoming widely recognized that a personalized dosimetry approach can help plan treatment and improve understanding of the dose-response relationship. In this chapter, we review the procedures and essential elements of an accurate internal dose calculation and propose a simplified approach that is aimed to be practical for use in a busy nuclear medicine department.

Patient-specific radiation dosimetry of 99mTc-HYNIC-Tyr3-octreotide in neuroendocrine tumors.

Unlabelled: (99m)Tc-hydrazinonicotinamide-Tyr(3)-octreotide ((99m)Tc-HYNIC-TOC) is increasingly gaining acceptance as a new radiopharmaceutical for the diagnosis of pathologic lesions overexpressing somatostatin receptors. However, little information has been published about the radiation dosimetry of this agent. The aim of this study was to assess the biodistribution and radiation dosimetry of commercially available (99m)Tc-HYNIC-TOC.