Objective: The purpose of this study was to examine the correlation between quality visually graded patient (clinical) chest images and a quantitative assessment phantom (physical) acquired with computed radiography (CR) imaging system. Methods: results previously published study, in which four experienced image evaluators computer-simulated postero-anterior using visual grading analysis scoring (VGAS) scheme, were used for clinical measurement. Contrast-to-noise ratio (CNR) effective dose...

The purpose of this study was to develop and validate a computer model produce realistic simulated computed radiography (CR) chest images using CT data sets real patients.Anatomical noise, which is the limiting factor in determining pathology radiography, realistically by data, frequency-dependent noise has been added post-digitally reconstructed radiograph (DRR) generation simulate exposure reduction. Realistic scatter fractions were measured phantom acquired on CR system post-DRR...

We are implementing the use of magnetic resonance (MR) images for head and neck radiotherapy planning, which involves their registration with computed tomography (CT). The quality assurance (QA) process was an initial step this program. A phantom built, appropriate materials were identified to produce clinically relevant MR contrast its constituent “anatomy.” performed a characterization distortion detectable within our phantom. Finally, we assessed accuracy image by contouring structures in...

The purpose of this study was to derive an optimum radiographic technique for computed radiography (CR) chest imaging using a digitally reconstructed radiograph computer simulator. simulator is capable producing CR radiographs adults with various tube potentials, receptor doses and scatter rejection.Four experienced image evaluators graded images average obese adult patients at different potentials (average-sized, n=50; obese, n=20), (n=10) rejection techniques n=20; n=20). quality the...

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

The purpose of this study was to determine the optimum tube voltage and amount added copper (Cu) filtration for processed chest radiographs obtained with an Agfa 75.0 Computed Radiography (CR) system. contrast-to-noise ratio (CNR) measured in lung, heart/spine diaphragm compartments a validated phantom using various voltages amounts Cu filtration. CNR derived as function air kerma at CR plate effective dose. As rib contrast can interfere detection nodules radiography, tissue-to-rib (TRR)...

The aim of this study was to investigate via simulation a proposed change clinical practice for chest radiography. validity using scatter rejection grid across the diagnostic energy range (60-125 kVp), in conjunction with appropriate tube current-time product (mAs) imaging computed radiography (CR) system investigated.A digitally reconstructed radiograph algorithm used, which capable simulating CR radiographs various voltages, receptor doses and methods. Four experienced image evaluators...

We are implementing the use of magnetic resonance (MR) images for head and neck radiotherapy planning, which involves their registration with computed tomography (CT).The quality assurance (QA) process was an initial step this program.A phantom built, appropriate materials were identified to produce clinically relevant MR T 1 2 contrast its constituent "anatomy."We performed a characterization distortion detectable within our phantom.Finally, we assessed accuracy image by contouring...

The use of cone beam CT in common radiotherapy treatments is increasing with the growth image guided radiotherapy. Whilst benefits that this technology offers are clear, such as improved patient positioning prior to treatment, it always important consider implications intensive imaging regimes on patient, especially when considering fundamental radiation protection requirements for justification and optimisation.

Higher doses are delivered over a short duration for stereotactic ablative radiotherapy (SABR) and as result individual fraction times significantly higher compared with conventional radiotherapy. Furthermore, many lung SABR patients elderly associated co-morbidities may not be able to retain their treatment position adequately. These benefit from faster deliveries which can achieved by using flattening filter free (FFF) beams. To determine clinically appropriate FFF energy accurate...

The purpose of this study was to investigate whether the exposure (speed) class (EC) an Agfa computed radiography (CR) system could be used optimise chest radiography. frequency-dependent normalised noise-power spectra (NNPS(f)) were determined for a range EC settings (25-1200) receptor dose 4 microGy. Signal-to-noise ratios (SNRs) measured in lung, heart and diaphragm areas phantom with ECs 400 600 at four tube voltages (60, 75, 90 125 kVp). As anatomical background can factor detection...

The use of computer simulated digital x-radiographs for optimisation purposes has become widespread in recent years. To make these investigations effective, it is vital radiographs contain accurate anatomical and system noise. Computer algorithms that simulate based solely on the incident detector x-ray intensity ('dose') have been reported extensively literature. However, while established mammography beam quality an important factor when modelling noise images there are no such studies...

Given the increasing use of computed tomography (CT) in UK over last 30 years, it is essential to ensure that all imaging protocols are optimised keep radiation doses as low reasonably practicable, consistent with intended clinical task. However, complexity modern CT equipment can make this task difficult achieve practice. Recent results local patient dose audits have shown discrepancies between two Philips scanners DoseRight 2.0 automatic exposure control (AEC) system 'automatic' mode...

A test methodology using an anthropomorphic-equivalent chest phantom is described for the optimization of Agfa computed radiography "MUSICA" processing algorithm radiography. The contrast-to-noise ratio (CNR) in lung, heart and diaphragm regions phantom, "system modulation transfer function" (sMTF) lung region, were measured tools embedded phantom. Using these parameters MUSICA was optimized with respect to low-contrast detectability spatial resolution. Two optimum "MUSICA parameter sets"...

Objectives: Radiotherapy plan quality may vary considerably depending on planner’s experience and time constraints. The variability in treatment plans can be assessed by calculating the difference between achieved optimal dose distribution. still suboptimal if there is further scope to reduce organs-at-risk doses without compromising target coverage deliverability. This study aims develop a knowledge-based planning (KBP) model of volumetric modulated arc therapy (VMAT) lung predicting...

This work assessed the appropriateness of signal-to-noise ratio improvement factor (KSNR) as a metric for optimisation computed radiography (CR) chest. The results previous study in which four experienced image evaluators graded computer simulated chest images using visual grading analysis scoring (VGAS) scheme to quantify benefit an anti-scatter grid were used clinical quality measurement (number patients = 80). KSNR was calculate physical measured phantom. correlation with VGAS function...

High levels of beam modulation complexity (MC) and monitor units (MU) can compromise the plan deliverability intensity-modulated radiotherapy treatments. Our study evaluates effect three treatment planning system (TPS) parameters on MC MU using different multi-leaf collimator (MLC) architectures.192 volumetric modulated arc therapy plans were calculated one virtual prostate phantom considering main settings: (1) TPS-parameters (Convergence; Aperture Shape Controller, ASC; Dose Calculation...

Machine learning (ML) methods have been implemented in radiotherapy to aid virtual specific-plan verification protocols, predicting gamma passing rates (GPR) based on calculated modulation complexity metrics because of their direct relation dose deliverability. Nevertheless, these might not comprehensively represent the complexity, and automatically extracted features from alternative predictors associated with are needed. For this reason, three convolutional neural networks (CNN) models...

The purpose of this study was to examine the use three physical image quality metrics in calibration an automatic exposure control (AEC) device for chest radiography with a computed (CR) imaging system. assessed were signal-to-noise ratio (SNR), contrast-to-noise (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using uniform phantom. Subsequent curves derived ensure each metric held constant across tube voltage range. Each curve its clinical appropriateness by...

The expansion and increasing availability of computed tomography (CT) imaging means that there is a greater need for the development efficient optimisation strategies are able to inform clinical practice, without placing significant burden on limited departmental resources. One most fundamental aspects any programme collection patient dose information, which can be compared with appropriate diagnostic reference levels. This study has investigated implementation large-scale audit technique,...

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

The use of three physical image quality metrics, signal-to-noise ratio (SNR), contrast-to-noise (CNR) and mean effective noise equivalent quanta (eNEQm) have recently been examined by our group for their appropriateness in the calibration an automatic exposure control (AEC) device chest radiography with Agfa computed (CR) imaging system. This study uses same methodology but investigates AEC abdomen, pelvis spine CR imaging. curves were derived using a simple uniform phantom (equivalent to 20...

This work investigated a method to calibrate the irradiation by an x-ray cabinet of tumours inserted on flanks mice. For energies used such devices, radiotherapy treatment metric absorbed dose water (D W) requires knowledge half value layer (HVL) beam spectrum. is usually measured in scatter free environment, but measurement inside with our specific exposure geometry impractical. Therefore, novel way evaluating HVL was devised and RS 2000 terms D W. calibration relevant IPEMB code practice...

In this paper, an investigation of the ablation polymer CR-39 (allyl diglycol carbonate) surface using 157 nm F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser radiation was described, motivated by interest in producing optical microstructures and possibility revealing damage tracks photoablation. The effective absorption coefficient etch depth-fluence were plotted. Canonical structure developed compared to that other UV...