Tube voltage in chest and abdomen DR imaging: Which settings return maximal non-prewhitening model observer with eye filter (NPWE) detectability?

Background: The non-prewhitening computational model observer with eye filter (NPWE) has been shown to reasonably predict human observer performance in general radiography and is an appropriate substitute when real clinical trials are not feasible. In this study, the NPWE model observer is used to detect specific tasks (circular designer nodules) ranging between 1 and 30 mm in diameter using chest and abdomen phantom images acquired across the diagnostic energy range (60-125 kVp) with and without an anti-scatter grid.

Purpose: The aim of this study was to derive tube voltage (kVp) settings that return maximal NPWE detectability (d') of designer nodules, for digital radiography (DR) chest and abdomen imaging.

A comparison of physical image quality of two hologic digital mammography systems that utilise linear and 2D anti-scatter grids.

. Full-field digital mammography (FFDM) systems manufactured by Hologic that utilise either a 2D or linear anti-scatter grid have recently been installed in our clinic. The manufacturer advise that for matched dose, both grids deliver comparable image quality.

Optimisation of tube voltage range (kVp) for AP abdomen, pelvis and spine imaging of average patients with a digital radiography (DR) imaging system using a computer simulator.

Objectives: To investigate via computer simulation, an optimised tube voltage (kVp) range for caesium iodide (CsI)-based digital radiography (DR) of the abdomen, pelvis and lumbar spine.

Methods: Software capable of simulating abdomen, pelvis and spine radiographs was used. Five evaluators graded clinical image criteria in images of 20 patients at tube voltages ranging from 60 to 120 kVp in 10 kVp increments.

Use of a computer simulator to investigate optimized tube voltage for chest imaging of average patients with a digital radiography (DR) imaging system.

Objective: The aim of this study was to investigate via computer simulation a proposed improvement to clinical practice by deriving an optimized tube voltage (kVp) range for digital radiography (DR) chest imaging.

Methods: A digitally reconstructed radiograph algorithm was used which was capable of simulating DR chest radiographs containing clinically relevant anatomy. Five experienced image evaluators graded clinical image criteria, overall quality, rib, lung, hilar, spine, diaphragm and lung nodule in images of 20 patients at tube voltages across the diagnostic energy range.

The usefulness of large sample size patient dose audits for optimisation of CT automatic exposure control (AEC) settings.

The aim of this study was to demonstrate the usefulness of large sample size patient dose audits for optimisation of CT automatic exposure control (AEC) settings, even when the investigation is limited to only three scanners at a single institution. Pre-optimisation patient dose audits of common CT examinations (n > 200 for each protocol) on three CT scanners (two Philips Brilliance and one Toshiba Aquilion) using radiology information system (RIS) data were conducted showing sub-optimal CT AEC performance on the Toshiba scanner. Based on these results, an optimisation exercise was carried out on the non-optimally performing scanner by phantom measurement and investigation of system configuration.

Measurement of effective detective quantum efficiency for a photon counting scanning mammography system and comparison with two flat panel full-field digital mammography systems.

Effective detective quantum efficiency (eDQE) describes the resolution and noise properties of an imaging system along with scatter and primary transmission, all measured under clinically appropriate conditions. Effective dose efficiency (eDE) is the eDQE normalised to mean glandular dose and has been proposed as a useful metric for the optimisation of clinical imaging systems. The aim of this study was to develop a methodology for measuring eDQE and eDE on a Philips microdose mammography (MDM) L30 photon counting scanning system, and to compare performance with two conventional flat panel systems.

UK guidance on the management of personal dosimetry systems for healthcare staff working at multiple organizations.

There has been concern expressed by the UK regulator, the Health & Safety Executive, regarding the management of occupation dose for healthcare radiation workers who work across multiple organizations. In response to this concern, the British Institute of Radiology led a working group of relevant professional bodies to develop guidance in this area. The guidance addresses issues of general system management that would apply to all personal dosimetry systems, regardless of whether or not the workers within that system work across organizational boundaries, along with exploring efficient strategies to comply with legislation where those workers do indeed work across organizational boundaries.

A method to incorporate the effect of beam quality on image noise in a digitally reconstructed radiograph (DRR) based computer simulation for optimisation of digital radiography.

The use of computer simulated digital x-radiographs for optimisation purposes has become widespread in recent years. To make these optimisation investigations effective, it is vital simulated radiographs contain accurate anatomical and system noise. Computer algorithms that simulate radiographs based solely on the incident detector x-ray intensity ('dose') have been reported extensively in the literature.

Accounting for patient size in the optimization of dose and image quality of pelvis cone beam CT protocols on the Varian OBI system.

Objective: The purpose of this study was to develop size-based radiotherapy kilovoltage cone beam CT (CBCT) protocols for the pelvis.

Methods: Image noise was measured in an elliptical phantom of varying size for a range of exposure factors. Based on a previously defined "small pelvis" reference patient and CBCT protocol, appropriate exposure factors for small, medium, large and extra-large patients were derived which approximate the image noise behaviour observed on a Philips CT scanner (Philips Medical Systems, Best, Netherlands) with automatic exposure control (AEC).