The impact of subjective image quality evaluation in mammography.

INTRODUCTION: According to the guidelines, the mammograms obtained in a screening program must be evaluated to ensure that the quality of the images obtained is above 75% of score 1 (perfect and good) and less than 3% of score 3 (inadequate). This is performed by a person (usually a radiographer), so subjectivity may influence the final evaluation of the images. The aim of this study was to evaluate the impact of subjectivity on breast positioning assessments on resultant screening mammograms. MATERIALS AND METHODS: Five radiographers evaluated a total of 1000 mammograms. One radiographer was an expert in assessing mammography images, while the other four evaluators had varying levels of experience. All images were anonymized, and the ViewDEX software was used for visual grading analysis. The evaluators were divided into two groups, each with two evaluators. Each group evaluated 600 images, with 200 images identical between the two groups. All images had already been evaluated by the expert radiographer. All scores were compared using the Fleiss' and Cohen's kappa coefficient and accuracy score. RESULTS: The results from Fleiss' kappa showed fair agreement in the mediolateral oblique (MLO) projection in the first group of evaluators whereas the other results showed poor agreement. When comparing the results from Cohen's kappa a maximum value of agreement between the evaluators was moderate 0.433 [95% CI 0.264-0.587] for the craniocaudal (CC) projection and 0.374 [95% CI 0.212-0.538] for the MLO projection. CONCLUSIONS: Based on our results, we can conclude that the agreement between all five raters was poor for both CC (κ = 0.165) and MLO (κ = 0.135) projections, based on the results of Fleiss' kappa statistic. The results show that the influence of subjectivity has a great impact on the evaluation of the quality of mammography images. IMPLICATIONS FOR PRACTICE: Thus, the images are evaluated by a person, which has a high impact on subjectivity in the assessment of positioning in mammography. To achieve a more objective assessment of the images and the resulting agreement between the evaluators, we would propose to change the method of assessment. The images could be evaluated by two persons, and in the event of a discrepancy, the images would be evaluated by a third person. A computer programme could also be developed that would allow a more objective evaluation based on the geometric characteristics of the image (angle and length of the pectoral muscle, symmetry, etc.).

How does a non-optimal tube potential influence radiation dose to the patient in lumbar spine radiography?

INTRODUCTION: When comparing the radiation dose to the patient, the lumbar spine has one of the highest dose values in general radiography, therefore the procedure needs to be optimised. The aim of this study was to investigate the effect of a non-optimal tube potential (66 kV) during anteroposterior (AP) lumbar spine radiography on the radiation dose received by the patient compared with the radiation dose when an optimal tube potential (79 kV) is used, in accordance with European guidelines. METHODS: This retrospective study involved 100 patients referred for lumbar radiography in two different diagnostic departments. Half of the patients were admitted to a department which used optimal tube potential and the other half to the department which used non-optimal tube potential for AP lumbar spine radiography protocols. The height and weight of the patients were collected to calculate the body mass index (BMI) of the patients. The image field size and dose area product (DAP) values were collected after each imaging session. The effective dose and selected organ dose were calculated using the PCXMC 2.0 program. RESULTS: The results showed that a non-optimal tube potential resulted in a significant increase in the DAP value by 360% (p < 0.001) and a significant increase in the effective dose by 160% (p < 0.001). Dose to selected organs due to non-optimal tube potential increased from 107% (breasts) up to 631% (prostate) (p < 0.001). The images were not assessed using visual grading characteristics (VGC) analysis, but the radiologists evaluated all the images appropriate for diagnostic reading. CONCLUSION: Based on our study's stated results, we can conclude that optimal tube potential use is essential to achieve the ALARA principle. IMPLICATIONS FOR PRACTICE: The study shows the effect of a non-optimal tube potential on the radiation dose received by the patient during radiography of the lumbar spine. This could influence possible diagnostic departments to consider protocol optimisation due to the high radiation dose received by the patient.