Radiation exposure related to cardiovascular CT examination: comparison between conventional 64-MDCT and third-generation dual-source MDCT.

PURPOSE: To compare radiation exposure associated with daily practice cardiovascular (CV) examinations performed on two different multidetector computed tomography (MDCT) scanners, a conventional 64-MDCT and a third-generation dual-source (DS) MDCT. MATERIALS AND METHODS: In this retrospective study, 1458 patients who underwent CV examinations between January 2017 and August 2018 were enrolled. A single-source 64-MDCT (Lightspeed VCT, GE) scan was performed in 705 patients from January to August 2017 (207 coronary examinations and 498 vascular examinations) and 753 patients underwent third-generation 192 × 2-DSCT (Somatom FORCE, Siemens) scan from January to August 2018 (302 coronary examinations and 451 vascular examinations). Volume CT dose index (CTDIvol), dose length product (DLP), effective dose (ED), tube voltage (TV) and exposure time (ET), pitch factor (PF) were registered for each patient. Student's t test was used to compare mean values between each corresponding group of MDCT and DSCT. RESULTS: In coronary examinations with DSCT, CTDIvol was 24.4% lower (23.1 mGy vs 30.6 mGy, p < 0.0001) and DLP and ED reductions were 35.6% than with MDCT (465.0 mGy * cm vs 732.3 mGy * cm and 6.5 mSv and 10.3 mSv; vs p < 0.0001). Concerning scan parameters, kVp and ET reductions were 12.7% and 69.4%, respectively (p < 0.0001); PF increase was 73.8% (p < 0.0001). In all vascular studies, DSCT, compared with MDCT, permitted to reduce CTDIvol from 43.5 to 70.6%; DLP and ED reductions were from 50.3 to 73.1%; kVp and ET decreases were from 10.7 to 32.5% and from 26.3 to 68.7%. PF increase was from 16.7 to 58.1% (all differences with p < 0.0001). CONCLUSIONS: In daily practice, CV examinations CTDI, DLP, ED, ET and TV were lower and PF was higher with 192 × 2-DSCT compared to 64-MDCT.

A questionnaire study of radiography educator opinions about patient lead shielding during digital projection radiography.

BACKGROUND: In projection radiography, lead rubber shielding has long been used to protect the gonads both within and outside the collimated field. However, the relative radio-sensitivity of the gonads is considered lower than previously, and doses from digital projection radiography are reported as being lower than in previous eras. These factors, along with technical difficulties encountered in placing lead shielding effectively, lead to varied opinions on the efficacy of such shielding in peer reviewed literature. This current study has investigated what is currently being taught as good practice concerning the use of lead shielding during projection radiography. METHOD: An online questionnaire was distributed to a purposive sample of 44 radiography educators across 15 countries, with the aim of establishing radiography educators' opinions about patient lead shielding and its teaching. RESULTS: From the 27 responding educators, 57% (n = 15) teach students to apply gonadal shielding across a range of radiographic examinations; only 22% (n = 6) do the same for the breast, despite respondents being aware that the breast has higher relative radio-sensitivity than the gonads. Radiation protection was the primary reason given for using shielding. Students are generally expected to apply patient lead shielding during assessments, although a small number of respondents report that students must justify whether or not to apply lead shielding. Educators generally held the opinion that no matter what they are taught, students are influenced by what they see radiographers do in clinical practice. CONCLUSIONS: The current study has not found consensus in literature or in radiography educators' opinions concerning the use of patient lead shielding. Findings suggest that a large scale empirical study to establish a specific evidence base for the appropriate use of lead shielding across a range of projection radiography examinations would be useful.