Exposure creep in computed radiography: a longitudinal study

Comparing the standard knee X-ray exposure factor, 10 kV rule, and modified 10 kV rule techniques in digital radiography to reduce patient radiation dose without loss of image quality

INTRODUCTION

The 10 Kilovoltage (kV) rule was a historic exposure adaption technique designed for film screen X-ray imaging to reduce ionising radiation dose without loss of image quality. This study evaluates knee X-ray radiation dose and image quality between standard patient exposure factors, the historic 10 kV rule (-50 % Milliampere-second (mAs), and a modified 10 kV rule (-75 % mAs) using a digital radiography (DR) system.

METHOD

Applying the exposure factors of 63 kV and 8 mAs (standard pre-set exposure), 73 kV and 4 mAs (historic 10 kV rule) and 73 kV and 2 mAs (modified 10 kV) to a phantom knee and recording entrance skin dose (ESD) using thermoluminescence dosemeters (TLDs). The ESD was analysed with a t-test. The image quality was assessed using a Likert 5-point Visual Grading Analysis (VGA) by (n = 3) independent observers. The ESD data was analysed with Analysis of Variance (ANOVA) for differences between the techniques.

RESULTS

The ESD reduction for the historic 10 kV rule was 32.1-33.7 % (20.9 μGy; p = 0.00), and the modified 10 kV rule 81.5-81.8 % (42.1-43.7 μGy; p = 0.00) compared to the standard pre-set exposure technique. The historic and modified 10 kV exposure parameters image quality for the AP views knee X-rays scored higher (p = 0.00) than the standard preset exposure images. The VGA for the lateral knee view using the historic (-0.1 VGA; p = 0.02) and the modified 10 kV (-0.3 VGA; p = 0.00) were slightly lower than the standard preset image quality, related to the trabeculae pattern and cortical outlines.

CONCLUSION

The findings suggest dose reductions could be made by modifying the exposure factors without reducing the quality of diagnostic images in the AP Knee position. The findings for the lateral knee X-rays indicate the image quality scored lower but was still within diagnostic range. Further research is required in laboratory conditions of exposure adaptations over a larger sample of anatomy thickness and applying a wider exposure (kV) range.

IMPLICATIONS FOR PRACTICE

One of a radiographer's many roles are to optimise techniques to improve image quality of anatomy and reduce the radiation dose to the patient. The findings have shown there is potential for further research using the modified 10 kV rule.

An Overview of Factors Affecting Exposure Level in Digital Detector Systems and their Relevance in Constructing Exposure Tables in Equine Digital Radiography

The aim of this review is to describe the steps of constructing exposure tables for use of digital detector systems (DRx) in equine practice. Introductory, selected underlying technical aspects of digital radiography are illustrated. Unlike screen-film radiography (SFR), DRx have a uniform signal response of the detector over a large dose range. This enables generation of diagnostic images from exposures that were previously nondiagnostic on SFR, thus reducing retakes. However, with decreasing detector entrance dose, image noise increasingly hampers the image quality. Conversely, unlike the blackening observed on SFR, overexposures can go visibly undetected by the observer. In DRx the numeric exposure indicator value is the only dose-control tool. In digital radiography the challenge is to reduce the dose and reduce the radiation risk to staff whilst maintaining diagnostic image quality. We provide a stepwise method of developing exposure tables as tools for controlling exposure levels. The identified kVp - mAs combinations in the table are derived from the predefined exposure indicator values of the detector system. Further recommendations are given as to how the exposure indicator can be integrated into routine workflow for rechecking the reliability of the formerly identified settings and how these tables might serve a basis for further reduction of the exposure level. Detector quantum efficiency (DQE) is an important parameter of assessing performance of an imaging system. Detectors with higher DQE can generate diagnostic images with a lower dose, thus having a greater potential for dose reduction than detectors with low DQE.

ICRP PUBLICATION 153 Approved by the Commission in September 2022

Veterinary use of radiation in the diagnosis, management, and treatment of disease has expanded and diversified, as have the corresponding radiological protection concerns. Radiological exposure of personnel involved in veterinary procedures and, where applicable, members of the public providing assistance (e.g. owners or handlers) has always been included within the system of radiological protection. Veterinary practice is now addressed explicitly as the modern complexities associated with this practice warrant dedicated consideration, and there is a need to clarify and strengthen the application of radiological protection principles in this area. The Commission recommends that the system of radiological protection should be applied in veterinary practice principally for the protection of humans, but with explicit attention to the protection of exposed animals. Additionally, consideration should be given to the risk of potential contamination of the environment associated with applications of nuclear medicine in veterinary practice. This publication focuses primarily on justification and optimisation in veterinary practice, and sets the scene for more detailed guidance to follow in future Recommendations. It is intended for a wide-ranging audience, including radiological protection professionals, veterinary staff, students, education and training providers, and members of the public, as an introduction to radiological protection in veterinary practice.© 2022 ICRP. Published by SAGE.

A Clinically Optimal Protocol for the Imaging of Enteric Tubes: On the Basis of Radiologist Interpreted Diagnostic Utility and Radiation Dose Reduction

RATIONALE AND OBJECTIVES

The purpose of this study was to develop and evaluate a patient thickness-based protocol specifically for the confirmation of enteric tube placements in bedside abdominal radiographs. Protocol techniques were set to maintain image quality while minimizing patient dose.

MATERIALS AND METHODS

A total of 226 pre-intervention radiographs were obtained to serve as a baseline cohort for comparison. After the implementation of a thickness-based protocol, a total of 229 radiographs were obtained as part of an intervention cohort. Radiographs were randomized and graded for diagnostic quality by seven expert radiologists based on a standardized conspicuity scale (grades: 0 non-diagnostic to 3+). Basic patient demographics, body mass index, ventilatory status, and enteric tube type were recorded and subgroup analyses were performed. Effective dose was estimated for both cohorts.

RESULTS

The dedicated thickness-based protocol resulted in a significant reduction in effective dose of 80% (p-value < 0.01). There was no significant difference in diagnostic quality between the two cohorts with 209 (92.5%) diagnostic radiographs in the baseline and 221 (96.5%) diagnostic radiographs in the thickness-based protocol (p-value 0.06).

CONCLUSION

A protocol optimized for the confirmation of enteric tube placements was developed. This protocol results in lower patient effective dose, without sacrificing diagnostic accuracy. The technique chart is provided for reference. The protocol development process outlined in this work could be readily generalized to other imaging clinical tasks.

Exploring the reliability of the exposure index with a range of kV and mAs values: An experimental study

INTRODUCTION

The exposure index (EI) is a numerical post-exposure tool that provides feedback to diagnostic radiographers undertaking digital X-ray examinations. The EI seeks to provide an indicator of the quantity of incident ionising radiation imparted on an image receptor. However, any large increase to X-ray intensity could interfere with the calculation of the EI. The aim of this paper was to evaluate detector overexposure by increasing X-ray beam intensity and quantifying the resultant effect on the EI.

METHODS

A porcine hip was purchased and exposed with varying tube potentials (50 to 110 kVp) and tube current-time products (5 to 100 mAs). Entrance surface dose (ESD) and EI values were determined for each exposure. For each acquisition parameter, two dose readings were collected. Linear regression was utilised to ascertain the relationship between the EI and varying tube exposures.

RESULTS

Tube exposures between 50 and 80 kVp demonstrated strong positive linear correlation coefficients (r = 0.993, p <0.001; r = 0.999, p <0.001; r = 0.983, p <0.001; r = 0.925, p <0.001) between ESD and EI. However, upon increasing tube exposures (90 to 110 kVp), interference with the EI calculation was demonstrated, which impacted both linearity, strength and direction of correlation (90 kVp r = 0.083, p = .248; 100 kVp r = -0.066, p = .479; 110 kVp r = -0.110, p = .601). Consequently, the use of higher tube exposures demonstrated variability with the EI by not demonstrating an expected positive linear relationship, which remained the initial expectation in this study.

CONCLUSION

The EI value is generally associated with providing reliable feedback to radiographers, yet this paper identifies some unexpected findings at high tube exposures (90 to 110 kVp). In short, this experiment provides insight that the EI value demonstrates inconsistent values within certain energy ranges.

IMPLICATIONS FOR PRACTICE

The findings have implications because it identifies variability of EI values at higher tube exposures. EI values may, therefore, not be helpful in providing meaningful feedback to radiographers when making changes to exposure factors.

Diagnostic radiography students' experiences of a practical method demonstrating the effect of milliampere-second in digital X-ray imaging systems

BACKGROUND

The effect of exposure technique factors varies between analogue and digital X-ray imaging systems (DR). Understanding these variations is paramount to optimising radiation protection, yet radiographers are unclear about these effects. A practical method to demonstrate milliampere second (mAs) effect in DR was developed to assist diagnostic radiography students in understanding exposure technique factors in DR.

OBJECTIVES

To explore second-year diagnostic radiography students' experiences of a practical method to demonstrate the effect of mAs in DR.

METHODS

A qualitative research approach employing an open-ended questionnaire explored second-year diagnostic radiography students' experiences of the practical method demonstrating the effect of mAs in DR. Twenty students participated in the study, and the data collected underwent thematic analysis.

RESULTS

Students appreciated working in small groups and provided suggestions to improve the practical method's instruction sheet. Most students' predicted outcome differed from the actual outcome of the demonstration. Seeing and documenting the effect of mAs in DR not only enhanced students' understanding of it but showed the implications of increasing mAs on image quality and radiation exposure.

CONCLUSION

Students found that the practical method enhanced their understanding of mAs and exposure technique factors in DR. Additionally, the practical method highlighted exposure creep in DR and radiographers' role in protecting patients from overexposure to ionising radiation in the digital era.

Investigating perceptions of 'dose creep' amongst student radiographers: A grounded theory study

INTRODUCTION

The dose creep phenomenon is now a widely recognized concept in diagnostic radiography in light of recent technological advancements transnationally. However, this still remains underexplored amongst radiography students preparing to enter the radiography profession. In response, this study explores the perceptions of dose creep amongst undergraduate student radiographers.

METHODS

The methodological approach utilized in this research study was grounded theory. The qualitative approach aimed to uncover findings from a higher education institution in Australia. Six students were recruited and took part in semi-structured interviews. This enabled the exploration of previously uncovered data, leading to the construction of original theory within the clinical and academic environment. The data analysis employed was constant comparative analysis (CCA).

RESULTS

A number of insights emerged from the qualitative data set. For instance, the radiography students understanding of the term 'dose creep' and decision making leading to dose creep in the clinical environment is captured. This is further supported with assessment of image evaluation determining appropriate exposure factor selection and future impact upon graduation as diagnostic radiographers. The findings identify some important learning needs and actions for both clinical and academic settings which may help foster good use of X-ray exposures.

CONCLUSION

This paper concludes by affirming some challenges surrounding optimal exposure selection and the known phenomenon, dose creep. Further, this study identifies the importance of learning and teaching in the clinical environment whereby learned behaviour leads to suboptimum practices.

IMPLICATIONS FOR PRACTICE

This study advances the existing evidence base by providing a unique lens into the knowledge and understanding of dose creep amongst radiography students in both academic and clinical contexts. It is anticipated this paper will help practitioners and educators better understand potential instances of dose creep within the clinical environment.

Optimising default radiographic exposure factors using Deviation Index

INTRODUCTION

Radiographers have a duty to ensure that radiation doses to patients are as low as reasonably achievable. With digital technologies, exposure factors which achieve the optimum balance between image noise and patient dose must be sought. In digital radiography, Deviation Index (DI) values provide the radiographer with feedback on the appropriateness of individual exposures but can also be tracked as part of a departmental quality assurance programme.

METHODS

In November 2017, exposure logs were extracted from six digital radiography (DR) x-ray systems, collated and analysed. Five examinations were identified which frequently produced DI values outside the manufacturer's recommended Optimal Range (-3 to +2). Incremental improvements were made to the default exposure settings for these examinations via a cyclical process of modification and re-evaluation. A full data collection exercise was then repeated in April 2019.

RESULTS

At baseline, 10,658 out of 29,637 (36.0%) exposures had DI values outside the manufacturer's recommended Optimal Range, but for some individual examinations the proportion was as high as 547 out of 725 (74.5%). Following multiple optimisation cycles, the overall proportion of examinations outside the Optimal Range had fallen to 7611 out of 26,759 (28.4%). Default milliampere-seconds (mAs) values for these examinations were reduced by between 22% and 50%.

CONCLUSION

A marked reduction in patient doses can be achieved through a departmental programme of DI value monitoring and targeted optimisation of default exposure settings.

IMPLICATIONS FOR PRACTICE

DI values should be routinely monitored as part of routine quality assurance programmes. Radiographers have a responsibility to ensure that they possess a clear understanding of DI values and that appropriate exposure settings are selected for each individual patient.

Can the anode heel effect be used to optimise radiation dose and image quality for AP pelvis radiography?

INTRODUCTION

A study was conducted to determine whether the anode heel effect can be used to influence optimisation of radiation dose and image quality (IQ) for AP pelvis radiography.

METHODS

ATOM dosimetry phantom and an anthropomorphic phantom were positioned for AP pelvis. Using a CR system, images were acquired and doses were measured with phantom feet toward anode and then feet toward cathode. Exposure factors (kVp, mAs and SID) were systematically generated using a factorial design. Images were scored visually for quality using relative visual grading together with a 3 point Likert scale. Signal to noise ratio was also calculated as a physical measure of image quality. Dosimetry data were collected for the ovaries and testes.

RESULTS

The optimum technique for male, which resulted in lower dose and suitable image quality, was with feet positioned toward the anode (0.80 ± 0.03 mGy; SNR of 38 ± 2.9; visual IQ score 3.13 ± 0.35). The optimum technique for female was with feet toward anode (0.23 ± 0.02 mGy; SNR of 34.7 ± 2.6; visual IQ score 3.15 ± 0.26). kVp had the biggest effect on both visual and physical image quality metrics (p < 0.001) for both tube orientations, whereas SID had the lowest effect on both visual and physical image quality metrics compared with mAs and kVp (p < 0.001). The effect of SID on the SNR was not significant (p > 0.05) with feet toward anode.

CONCLUSION

Positioning the patient with feet toward the anode, as opposed to the cathode, has no adverse effect on visual image quality assessment but it does have an effect on physical image quality.

IMPLICATIONS FOR PRACTICE

This study would add a new clinical concept in positioning of AP pelvis radiography especially for male positioning.

Evaluation of radiographers' knowledge and attitudes of image quality optimisation in paediatric digital radiography in Saudi Arabia and Australia: a survey-based study

INTRODUCTION

Digital radiography (DR) systems enable radiographers to reduce the radiation dose to patients while maintaining optimised image quality. However, concerns still exist about paediatric patients who may be exposed to an increased level of radiation dose which is not needed for clinical practice. The purpose of this study was to evaluate the knowledge, awareness and attitudes, in terms of image quality optimisation of radiographers undertaking paediatric DR in Australia and Saudi Arabia.

METHODS

A survey-based study was devised and distributed to radiographers from Australia and Saudi Arabia. Questions focused on Australian and Saudi Arabian radiographers' knowledge and attitude of paediatric DR examinations.

RESULTS

There were 376 participants who responded to the survey from both countries. A major finding showed that most participants lack knowledge in the area of paediatric DR examinations. Most participants from Australia had received no formal training in paediatric digital radiography (79%), whereas nearly half of the participants from Saudi Arabia received no training (45%). Approximately three out of four radiographers from both countries believed that when using DR they did not need to change the way they collimate the beam as DR images can be cropped using post-processing methods.

CONCLUSION

The finding of this study demonstrates that radiographers from both countries should improve their understanding and clinical use of DR in paediatric imaging. More education and training for both students and clinicians is needed to enhance radiographer performance in digital radiography and improve their clinical practices.

Impact of acquisition parameters on dose and image quality optimisation in paediatric pelvis radiography-A phantom study

PURPOSE

Within paediatric pelvis imaging there is a lack of systematic dose optimisation studies which consider age and size variations. This paper presents data from dose optimisation studies using digital radiography and pelvis phantoms representing 1 and 5-year-old children.

MATERIAL AND METHOD

Dose optimisation included assessments of image quality and radiation dose. Systematic variations using a factorial design for acquisition factors (kVp, mAs, source-detector distance [SDD] and filtration) were undertaken to acquire AP pelvis X-ray images. Perceptual image quality was assessed using a relative and absolute visual grading assessment (VGA) method. Radiation doses were measured by placing a dosimeter at the radiographic centring point on the surface of each phantom. Statistical analyses for determining the optimised parameters included main effects analysis.

RESULTS

Optimised techniques, with diagnostically acceptable image quality, for each paediatric age were: 1-year-old; 65 kVp, 2 mAs and 115 cm SDD, while, 5-year-old; 62 kVp, 8 mAs and 130 cm SDD both included 1 mm Al +0.1 mm Cu additional filtration. The main effect analysis identified situations in which image quality and radiation dose increased or decreased, except for kVp which showed peak image quality when exposure factors were increased. A set of minimum mAs values for producing diagnostic image quality were identified. Increasing SDD, unlike the other exposure factors, showed no trends for producing non-diagnostic images.

CONCLUSION

The factorial design provided an opportunity to identify suitable acquisition factors. This study provided a method for investigating the combined effect of multiple acquisition parameters on image quality and radiation dose for children.

Development of a zoomorphic test specimen for constancy testing on digital X-ray systems in veterinary radiology

Background

Technical failures and incorrect usage of digital X-ray systems may lead to a decreasing image quality, artefacts and a higher dose exposure of staff and patients. Although there are no regulations regarding constancy testing in veterinary radiology all operators are required to avoid unnecessary exposure. The aim of this study was to develop a reasonably inexpensive zoomorphic 3D-printed test specimen for constancy testing that allows the detection of changing image quality by visual analysis.

Primarily, a calibration curve of the attenuation factor of the 3D-printing material (ZP150) was determined. MATLAB converted every pixel value of a thorax X-ray image of a Beagle dog into an equivalent thickness of printing material. The thickness distribution was printed using a 3D-printer. This printed test specimen was additionally provided with five thin aluminium discs to simulate lung nodules.

To evaluate the usability for constancy testing 12 X-ray images of the test specimen were made. Two images (reference and control) were taken with the minimum dose in order to obtain images suitable for diagnosis purposes. Eight images were taken with a dose differing 30–140% from the reference dose by varying current–time product (mAs) or tube voltage (kVp). Two images were taken with the same parameters as the reference image but edited with different image processing. Six veterinarians (general practitioners) evaluated ten chosen structures in the X-ray images in a Visual Grading Analysis and scored the image quality of these structures for every image in comparison to the reference image. A Visual Grading Analysis Score was calculated and statistically analysed.

Results

A higher current–time product led to a negligibly better evaluation of the X-ray image. The lower the current–time product the worse the X-ray images were scored. Likewise, both increasing and decreasing of the tube voltage led to lower scores.

Conclusions

A zoomorphic test specimen can be used for constancy testing of digital X-ray systems in veterinary medicine. Especially a lower dose can be recognised due to deviation in the image quality when compared to the reference image. The 3D-printed test specimen is less expensive than test equipment used in human medicine.

Evaluating the use of exposure indicators in digital x-ray imaging system: Gauteng South Africa

INTRODUCTION

Exposure indicators (EIs) are the only indicator of correct exposure technique in digital x-ray imaging systems but the use of such indicators remains largely unexplored in a South African setting. With exposure creep in the digital radiography age being a worldwide phenomenon, the study investigated radiographers' familiarity and use of EIs, providing insight into current exposure technique practices in this setting.

METHODS

An explorative and descriptive quantitative study was conducted at 10 randomly selected radiography clinical training facilities in Gauteng, South Africa. The study used a questionnaire consisting of 26 questions based on familiarity with and use of EIs and radiographers' attitude to ionising radiation.

RESULTS

A response of rate of 49.3% was achieved. Results show a low number of respondents (54.3%) had a perfectly correct understanding of the exposure indicator (EI) and only 55.7% of respondents made correct use of the EI.

CONCLUSION

Observable lack of familiarity and use of the EI suggests that improvements could be made to the training radiographers receive on digital imaging systems. Moreover radiographers need to be vigilant against making decisions in digital radiography using knowledge that may relate exclusively to analogue radiography.

Retrospective evaluation of exposure indicators: a pilot study of exposure technique in digital radiography

INTRODUCTION

Digital radiography lacks visual clues of exposure techniques used to obtain radiographs, therefore manufacturers have included exposure indicators (EIs). EIs provides feedback about exposure techniques used and evaluating EIs will yield much needed information about exposure trends used in digital radiography.

METHODS

A retrospective explorative quantitative study was conducted at nine randomly selected imaging departments in Gauteng, South Africa. Data pertaining to EI was retrospectively collected using quota sampling and compared to manufacturer recommended (MR) standards.

RESULTS

A total of 1422 EIs were collected. 50% of these were within the MR standard. 27% of EI indicated overexposure and 23% indicated underexposure.

CONCLUSIONS

Greater evidence of overexposure was noted in the retrospective analysis of the EI. This pilot study shows the need for further investigation into exposure technique practices in digital radiography and the need for measures to halt the evidenced overexposure.

Digital imaging and radiographic practise in diagnostic radiography: An overview of current knowledge and practice in Europe

INTRODUCTION

Recent research has identified the issue of 'dose creep' in diagnostic radiography and claims it is due to the introduction of CR and DR technology. More recently radiographers have reported that they do not regularly manipulate exposure factors for different sized patients and rely on pre-set exposures. The aim of the study was to identify any variation in knowledge and radiographic practice across Europe when imaging the chest, abdomen and pelvis using digital imaging.

METHODS

A random selection of 50% of educational institutes (n = 17) which were affiliated members of the European Federation of Radiographer Societies (EFRS) were contacted via their contact details supplied on the EFRS website. Each of these institutes identified appropriate radiographic staff in their clinical network to complete an online survey via SurveyMonkey. Data was collected on exposures used for 3 common x-ray examinations using CR/DR, range of equipment in use, staff educational training and awareness of DRL. Descriptive statistics were performed with the aid of Excel and SPSS version 21.

RESULTS

A response rate of 70% was achieved from the affiliated educational members of EFRS and a rate of 55% from the individual hospitals in 12 countries across Europe. Variation was identified in practice when imaging the chest, abdomen and pelvis using both CR and DR digital systems. There is wide variation in radiographer training/education across countries.

CONCLUSION

There is a need for standardisation of education and training including protocols and exposure parameters to ensure that there is continued adherence to the ALARA principle.

Side marker creep: have radiographers changed their side marker habits?

Has side marker use changed with the introduction of digital radiography? This editorial explores this question.

Technical innovation changes standard radiographic protocols in veterinary medicine: is it necessary to obtain two dorsoproximal-palmarodistal oblique views of the equine foot when using computerised radiography systems?

Since the 1950s, veterinary practitioners have included two separate dorsoproximal-palmarodistal oblique (DPr-PaDiO) radiographs as part of a standard series of the equine foot. One image is obtained to visualise the distal phalanx and the other to visualise the navicular bone. However, rapid development of computed radiography and digital radiography and their post-processing capabilities could mean that this practice is no longer required. The aim of this study was to determine differences in perceived image quality between DPr-PaDiO radiographs that were acquired with a computerised radiography system with exposures, centring and collimation recommended for the navicular bone versus images acquired for the distal phalanx but were subsequently manipulated post-acquisition to highlight the navicular bone. Thirty images were presented to four clinicians for quality assessment and graded using a 1-3 scale (1=textbook quality, 2=diagnostic quality, 3=non-diagnostic image). No significant difference in diagnostic quality was found between the original navicular bone images and the manipulated distal phalanx images. This finding suggests that a single DPr-PaDiO image of the distal phalanx is sufficient for an equine foot radiographic series, with appropriate post-processing and manipulation. This change in protocol will result in reduced radiographic study time and decreased patient/personnel radiation exposure.

Homogeneous Canine Chest Phantom Construction: A Tool for Image Quality Optimization

Digital radiographic imaging is increasing in veterinary practice. The use of radiation demands responsibility to maintain high image quality. Low doses are necessary because workers are requested to restrain the animal. Optimizing digital systems is necessary to avoid unnecessary exposure, causing the phenomenon known as dose creep. Homogeneous phantoms are widely used to optimize image quality and dose. We developed an automatic computational methodology to classify and quantify tissues (i.e., lung tissue, adipose tissue, muscle tissue, and bone) in canine chest computed tomography exams. The thickness of each tissue was converted to simulator materials (i.e., Lucite, aluminum, and air). Dogs were separated into groups of 20 animals each according to weight. Mean weights were 6.5 ± 2.0 kg, 15.0 ± 5.0 kg, 32.0 ± 5.5 kg, and 50.0 ± 12.0 kg, for the small, medium, large, and giant groups, respectively. The one-way analysis of variance revealed significant differences in all simulator material thicknesses (p < 0.05) quantified between groups. As a result, four phantoms were constructed for dorsoventral and lateral views. In conclusion, the present methodology allows the development of phantoms of the canine chest and possibly other body regions and/or animals. The proposed phantom is a practical tool that may be employed in future work to optimize veterinary X-ray procedures.

Decision Making and Variation in Radiation Exposure Factor Selection by Radiologic Technologists

The goal of radiographic imaging is to produce a diagnostically useful image while minimizing patient radiation dose. This study aimed to review variations in exposure factor selection by radiologic technologists for virtual patients with varying body mass index characteristics. Eleven technologists were asked to assign exposure parameters (kVp, mAs, source-to-image receptor distance, and grid use) to 10 computer-generated patient images for each of four radiographic examinations (anteroposterior [AP] shoulder; AP lumbar spine; lateral lumbar spine; AP portable chest). The virtual patients represented five body mass index categories-underweight, healthy weight, overweight, obese, and superobese. As participants assigned exposures, their visual patterns were recorded by a Tobii TX300 eye-tracker. Significant (P < .05) correlation was found between radiographer age/experience and assignment of mAs for AP shoulder and lumbar examinations. Greater age/experience correlated with higher mAs for the AP shoulder examination, but with lower values for lumbar examinations. Strong correlations also existed between times to first fixations on relevant anatomic areas, and kVp/mAs values existed for the AP portable chest examination. Exposure selection differences related to age/experience highlight inconsistencies in the practice of exposure parameter setting. The reason for these inconsistencies requires further investigation, and how to address deficiencies in practice requires consideration to optimize safe patient care. Because of the small sample size used, further research into the relationship between visual factors and individual examinations is suggested, after the findings regarding the AP portable chest examination.

Advanced imaging use in intensive care units has decreased, resulting in lower charges without negative effects on patient outcomes

PURPOSE

There has been both greater recognition and scrutiny of the increased use of advanced imaging. Our aim was to determine whether there has been a change over time in the use of computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US) modalities in the intensive care units (ICUs).

MATERIALS AND METHODS

A retrospective review of 75657 admissions to 20 ICUs was conducted. Results were analyzed with multivariate linear, negative binomial, and Poisson regressions. Primary outcomes were rates of use of CT, MRI, and US per 1000 ICU admissions every 6 months. Secondary outcomes were changes in radiology use associated with impacts on mortality, hospital length of stay (LOS), ICU LOS, and hospital charges.

RESULTS

The rate of imaging use decreased by 13.5% between 2007 and 2011 (incidence rate ratio [IRR], 0.982; P < .001). Most of this decrease was by CTs (21.0%; IRR, 0.973; P < .001). Use of MRI decreased by 6.0% (IRR, 0.991; P = .04), whereas US increased by 18.9% (IRR, 1.012; P < .001). The charges associated with imaging decreased by $74 per ICU admission, which would save an estimated $1.2 million in charges during 2011. Decreased imaging was not associated with changes in mortality, hospital, and ICU LOS.

CONCLUSION

Advanced imaging use decreased for 5 years in the ICUs, resulting in decreased charges without negative effects on patient outcomes.

Patient-based radiographic exposure factor selection: a systematic review

Introduction

Digital technology has wider exposure latitude and post-processing algorithms which can mask the evidence of underexposure and overexposure. Underexposure produces noisy, grainy images which can impede diagnosis and overexposure results in a greater radiation dose to the patient. These exposure errors can result from inaccurate adjustment of exposure factors in response to changes in patient thickness. This study aims to identify all published radiographic exposure adaptation systems which have been, or are being, used in general radiography and discuss their applicability to digital systems.

Methods

Studies in EMBASE, MEDLINE, CINAHL and SCOPUS were systematically reviewed. Some of the search terms used were exposure adaptation, exposure selection, exposure technique, 25% rule, 15% rule, DuPont™ Bit System and radiography. A manual journal-specific search was also conducted in The Radiographer and Radiologic Technology. Studies were included if they demonstrated a system of altering exposure factors to compensate for variations in patients for general radiography. Studies were excluded if they focused on finding optimal exposures for an ‘average’ patient or focused on the relationship between exposure factors and dose.

Results

The database search uncovered 11 articles and the journal-specific search uncovered 13 articles discussing systems of exposure adaptation. They can be categorised as simple one-step guidelines, comprehensive charts and computer programs.

Conclusion

Only two papers assessed the efficacy of exposure adjustment systems. No literature compares the efficacy of exposure adaptations system for film/screen radiography with digital radiography technology nor is there literature on a digital specific exposure adaptation system.

Digital radiography exposure indices: A review

Digital radiography (DR) technologies have the advantage of a wide dynamic range compared to their film-screen predecessors, however, this poses a potential for increased patient exposure if left unchecked. Manufacturers have developed the exposure index (EI) to counter this, which provides radiographers with feedback on the exposure reaching the detector. As these EIs were manufacturer-specific, a wide variety of EIs existed. To offset this, the international standardised EI has been developed by the International Electrotechnical Commission (IEC) and the American Association of Physicists in Medicine (AAPM). The purpose of this article is to explore the current literature relating to EIs, beginning with the historical development of the EI, the development of the standardised EI and an exploration of common themes and studies as evidenced in the research literature. It is anticipated that this review will provide radiographers with a useful guide to understanding EIs, their application in clinical practice, limitations and suggestions for further research.

The Image Gently pediatric digital radiography safety checklist: tools for improving pediatric radiography

Transition from film-screen to digital radiography requires changes in radiographic technique and workflow processes to ensure that the minimum radiation exposure is used while maintaining diagnostic image quality. Checklists have been demonstrated to be useful tools for decreasing errors and improving safety in several areas, including commercial aviation and surgical procedures. The Image Gently campaign, through a competitive grant from the FDA, developed a checklist for technologists to use during the performance of digital radiography in pediatric patients. The checklist outlines the critical steps in digital radiography workflow, with an emphasis on steps that affect radiation exposure and image quality. The checklist and its accompanying implementation manual and practice quality improvement project are open source and downloadable at www.imagegently.org. The authors describe the process of developing and testing the checklist and offer suggestions for using the checklist to minimize radiation exposure to children during radiography.