Radiation dose tracking in computed tomography: Red alerts and feedback. Implementing a radiation dose alert system in CT

INTRODUCTION

This study investigates instances of elevated radiation dose on a radiation tracking system to determine their aetiologies. It aimed to investigate the impact of radiographer feedback on these alerts.

METHODS

Over two six-month periods 11,298 CT examinations were assessed using DoseWatch. Red alerts (dose length products twice the median) were identified and two independent reviewers established whether alerts were true (unjustifiable) or false (justifiable). During the second time period radiographers used a feedback tool to state the cause of the alert. A Chi-Square test was used to assess whether red alert incidence decreased following the implementation of radiographer feedback.

RESULTS

There were 206 and 357 alerts during the first and second time periods, respectively. These occurred commonly with CT pulmonary angiography, brain, and body examinations. Procedural documentation errors and patient size accounted for 57% and 43% of false alerts, respectively. Radiographer feedback was provided for 17% of studies; this was not associated with a significant change in the number of alerts, but the number of true alerts declined (from 7 to 3) (χ2 = 4.14; p = 0.04).

CONCLUSION

Procedural documentation errors as well as patient-related factors are associated with false alerts in DoseWatch. Implementation of a radiographer feedback tool reduced true alerts.

IMPLICATIONS FOR PRACTICE

The implementation of a radiographer feedback tool reduced the rate of true dose alerts. Low uptake with dose alert systems is an issue; the workflow needs to be considered to address this.

A self-directed learning intervention for radiographers rating mammographic breast density

PURPOSE

Subjective methods of mammographic breast density (MBD) assessment are prone to inter-reader variability. This work aims to assess the impact of a short self-directed, experiential learning intervention on radiographers' reproducibility of MBD assessment.

METHOD

The study used two sets of images (test and learning intervention) containing left craniocaudal and left mediolateral oblique views. The test set had MBD ratings from Volpara™ and radiologists using the fourth edition Breast Imaging and Data Systems (BI-RADS^®). Seven radiographers rated the MBD of the test set before and after a self-directed learning intervention using the percentage descriptors in the fourth edition BI-RADS^® Atlas. The inter-reader agreement, the agreement between radiographers and Volpara™ as well as radiologists, was assessed using a Weighted Kappa (к_w).

RESULTS

Overall, radiographers' inter-reader agreement (к_w) was substantial (0.79; 95% CI: 0.70-0.87) before the intervention and almost perfect (0.84; 95% CI: 0.77-0.90) after the intervention. Before the intervention, radiographers demonstrated fair agreement with radiologists (0.24; 95% CI: -0.46-0.61) and Volpara™ (0.24; 95% CI: -0.41-0.59). A fair but slightly improved agreement was also observed between radiographers and radiologists (0.31; 95% CI: -0.33-0.64) as well as Volpara™ (0.28; 95% CI: -0.34-0.61) after the intervention.

CONCLUSION

Findings demonstrate that a short duration self-directed, experiential learning intervention reduces inter-reader differences in MBD classification, but has a negligible impact on improving the agreement between inexperienced and expert readers.

Radiographers' performance in chest X-ray interpretation: the Nigerian experience

OBJECTIVE

To assess the performance of Nigerian radiographers in interpretation of plain chest radiographs and to assess whether age, years since qualification and sector of practice are associated with performance.

METHODS

A test set of 50 radiographs containing 23 cases with no pathology (normal) and 27 abnormal cases (cardiopulmonary conditions) independently confirmed by 3 radiologists were presented to 51 radiographers in a random order. Readers independently evaluated radiographs for absence or presence of disease and stated the location, radiographic features and diagnosis. Readers self-reported their age, years since qualification and sector of practice. Receiver operating characteristic was used to assess the performance. Mann-Whitney U test was used to assess whether age, years since qualification and sector of practice were associated with performance.

RESULTS

Mean location sensitivity was 88.9 [95% confidence interval (CI), 0.787-0.980]. Mean sensitivity and specificity were 76.9 (95% CI, 0.658-0.864) and 79.8 (95% CI, 0.658-0.864), respectively. Age was not associated with performance (p = 0.07). Number of years qualified as radiographer (p = 0.005) and private practice (p = 0.004) were positively associated with performance.

CONCLUSION

Nigerian radiographers can correctly report chest radiographs to a reasonable standard, and performance is associated with number of years since qualification and the sector of practice.

ADVANCES IN KNOWLEDGE

There are less than 300 radiologists serving a Nigerian population of about 170 million; therefore, X-ray interpretation by radiographers deserves consideration. Nigerian radiographers have potential to interpret chest X-ray in the clinical setting, and this may significantly improve radiology service delivery in this region.

Measurement of breast density with digital breast tomosynthesis--a systematic review

Digital breast tomosynthesis (DBT) has gained acceptance as an adjunct to digital mammography in screening. Now that breast density reporting is mandated in several states in the USA, it is increasingly important that the methods of breast density measurement be robust, reliable and consistent. Breast density assessment with DBT needs some consideration since quantitative methods are modelled for two-dimensional (2D) mammography. A review of methods used for breast density assessment with DBT was performed. Existing evidence shows Cumulus has better reproducibility than that of the breast imaging reporting and data system (BI-RADS®) but still suffers from subjective variability; MedDensity is limited by image noise, whilst Volpara and Quantra are robust and consistent. The reported BI-RADs inter-reader breast density agreement (k) ranged from 0.65 to 0.91, with inter-reader correlation (r) ranging from 0.70 to 0.93. The correlation (r) between BI-RADS and Cumulus ranged from 0.54-0.94, whilst that of BI-RADs and MedDensity ranged from 0.48-0.78. The reported agreement (k) between BI-RADs and Volpara is 0.953. Breast density correlation between DBT and 2D mammography ranged from 0.73 to 0.97, with agreement (k) ranging from 0.56 to 0.96. To avoid variability and provide more reliable breast density information for clinicians, automated volumetric methods are preferred.

A reduction in radiographic exposure and image quality in film screen postero-anterior chest radiography

PURPOSE

To develop a protocol for the optimization of diagnostic chest radiography examination, the effect of radiographic exposure reduction on image quality is investigated.

PROCEDURE

Fourty-eight adult patients presenting for posterior-anterior (PA) chest radiography in a tertiary health care centre were categorized into 3 groups to assess the effects of exposure (tube current/time mAs) reduction on clinical image quality using in film screen (FS) chest radiography. Images were obtained at existing departmental exposure protocol (T1) while a record of the exposure factors was made. Test exposures obtained by reducing average mAs values by 20% (T2) and 50% (T3) were used to obtain radiographic images of patients following normal ethically based clinical practice. To make up for the reduction in mAs, a 4% increase in the T1 kVp was used. The quality of images obtained with each exposure protocol was studied by two consultant radiologists, using the image quality criteria of the Commission of European Communities (CEC). Assessors used the method of ranked scoring and worked independently.

RESULTS

Results showed no change in image quality following the 20% exposure (mAs) reduction. However, there was a significant change in image quality at 50% reduction of mAs values (P < 0.05) with higher image quality scores suggesting improved perceptibility of all assessed criteria among the observers.

CONCLUSION

Improving radiation protection of the patient while maintaining diagnostic quality of the radiographic image at reduced exposures is a clinically desirable development. This study will find application in current efforts at optimization of radiography procedures in the area of study.