Effects of Breast Shielding during Heart Imaging on DNA Double-Strand-Break Levels: A Prospective Randomized Controlled Trial

Reporting of Participant Demographics in Clinical Trials Published in General Radiology Journals

OBJECTIVES

The reporting of research participant demographics provides insights into study generalizability. Our study aimed to determine the frequency at which participant age, sex/gender, race/ethnicity, and socioeconomic status (SES) are reported and used for subgroup analyses in radiology randomized controlled trials (RCTs) and their secondary analyses; as well as the study characteristics associated with, and the classification systems used for demographics reporting.

METHODS

RCTs and their secondary analyses published in 8 leading radiology journals between 2013 and 2021 were included. Associations between study characteristics and demographic reporting were tested with the chi-square goodness of fit test for categorical variables, Wilcoxon-Mann-Whitney test for impact factor, and logistic regression for publication year.

RESULTS

Among 432 included articles, 89.4% (386) reported age, 90.3% (390) sex/gender, 5.6% (24) race/ethnicity, and 3.0% (13) SES. Among articles that reported these demographics and were not specific to a subgroup, results were analyzed by age in 14.2% (55/386), sex/gender in 19.4% (66/340), race/ethnicity in 13.6% (3/22), and SES in 46.2% (6/13). Journal, impact factor, and last author continent were predictors of race/ethnicity and SES reporting. Funding was associated with race/ethnicity reporting. No study reported sex and gender separately, or documented transgender, nonbinary gender spectrum or intersex participants. A single category for race/ethnicity was used in 37.5% (9/24) of studies, consisting of either "White" or "Caucasian."

CONCLUSION

The reporting of participant demographics in radiology trials is variable and not always representative of the population diversity. Editorial guidelines on the reporting and analysis of participant demographics could help standardize practices.

Is It Appropriate to Completely Eliminate Contact Shielding during CT Examination? A Discourse Based on Experimental Findings

OBJECTIVE

Through the integration of experimental data and literature, this study examines whether complete elimination of contact shielding during CT examination is warranted, with a particular focus on potential impacts to children's thyroid and pregnant women, as well as limitations associated with contact shielding. Methods: The thermoluminescent dosimeter (TLD) tablets were inserted into the phantom's five organs and tissues. Select fixed exposure, automatic exposure control (AEC), and use contact shielding combined into four experimental modes, with scanning of the phantom's four parts. Obtain the absorbed dose measurements within or outside the FOV. Statistical analysis was conducted using SPSS software. Results: (1) The AEC significantly reduces dose within and outside the FOV, with a dose reduction of 40%-60%. (2) The application of contact shielding outside the FOV significantly reduced the dose adjoin the FOV. (3) Both the use of AEC mode and contact shielding can effectively minimize the dose, with a reduction of 50-80%. (4) The shielding within the FOV may introduce image artifacts or interfere with AEC, the implementation of contact shielding outside FOV provides little reduction in radiation exposure risk through previous literature. (5) Contact shielding exhibits certain drawbacks in all aspects. Conclusion: The utilization of AEC mode in clinical CT should be widely adopted to minimize patient radiation exposure. In general, contact shielding both inside and outside the FOV should be avoided during exposure. However for children under 12 years old with thyroid gland examination, contact shielding could maximally reduce external radiation and may be appropriate. Pregnant women require careful evaluation when considering the use of contact shielding. Contact shielding should not be entirely abandoned.

An evaluation of DNA double strand break formation and excreted guanine species post whole body PET/CT procedure

Ionizing radiation-induced oxidation and formation of deoxyribonucleic acid (DNA) double strand breaks (DSBs) are considered the exemplar of genetic lesions. Guanine bases are most prone to be oxidized when DNA and Ribonucleic acid (RNA) are damaged. The repair processes that are initiated to correct this damage release multiple oxidized guanine species into the urine. Hence, the excretion of guanine species can be related with the total repair process. Our study quantified the total DSBs formation and the amount of guanine species in urine to understand the DNA break and repair process after whole body (WB) exposure to 18F-FDG positron emission tomography/computed tomography (PET/CT). A total of 37 human participants were included with control and test groups and the average radiation dose was 27.50 ± 2.91 mSv. γ-H2AX foci assay in the collected blood samples was performed to assess the DSBs, and excreted guanine species in urine were analyzed by a competitive ELISA method. We observed a significant increase of DNA damage that correlated well with the increasing dose (p-value 0.009) and body weight (p-value 0.05). In the test group, excreted guanine species in urine sample significantly increased (from 24.29 ± 5.82 to 33.66 ± 7.20 mg/mmol creatinine). A minimum (r2 = 0.0488) correlation was observed between DSBs formation and excreted guanine species. A significant difference of DNA damage and 8-OHdG formation was seen in the test group compared to controls. Larger population studies are needed to confirm these observations, describe the fine-scale timing of changes in the biomarker levels after exposure, and further clarify any potential risks to patients from PET/CT procedures.

Preliminary quantitative evaluation of radiation-induced DNA damage in peripheral blood lymphocytes after cardiac dual-isotope imaging

DNA double-strand breaks (DSBs) of peripheral blood lymphocyte were prospectively assessed in 9 patients who were injected with ²⁰¹Tl-chloride and ¹²³I-beta-methyl-p-iodophenyl-pentadecanoic acid in dual-isotope imaging. Phosphorylated H2AX (γH2AX) was used as a biomarker for detecting DSBs, and the mean number of γH2AX foci per cell was measured microscopically. Mean γH2AX foci before administration of radiopharmaceuticals and at 3, 6, and 24 h following administration were 0.22 ± 0.34, 0.10 ± 0.14, 0.59 ± 0.46, and 0.52 ± 0.40, respectively (p = n.s. for all combinations).

Abdominopelvic 1.5-T and 3.0-T MR Imaging in Healthy Volunteers: Relationship to Formation of DNA Double-Strand Breaks

Purpose To investigate the relationship between abdominopelvic magnetic resonance (MR) imaging and formation of DNA double-strand breaks (DSBs) in peripheral blood lymphocytes among a cohort of healthy volunteers. Materials and Methods Blood samples were obtained from 40 healthy volunteers (23 women and 17 men; mean age, 27.2 years [range, 21-37 years]) directly before and 5 and 30 minutes after abdominopelvic MR imaging performed at 1.5 T (n = 20) or 3.0 T (n = 20). The number of DNA DSBs in isolated blood lymphocytes was quantified after indirect immunofluorescent staining of a generally accepted DSB marker, γ-H2AX, by means of high-throughput automated microscopy. As a positive control of DSB induction, blood lymphocytes from six volunteers were irradiated in vitro with x-rays at a dose of 1 Gy (70-90 keV). Statistical analysis was performed by using a Friedman test. Results No significant alteration in the frequency of DNA DSB induction was observed after MR imaging (before imaging: 0.22 foci per cell, interquartile range [IQR] = 0.54 foci per cell; 5 minutes after MR imaging: 0.08 foci per cell, IQR = 0.39 foci per cell; 30 minutes after MR imaging: 0.09 foci per cell, IQR = 0.63 foci per cell; P = .057). In vitro radiation of lymphocytes with 1 Gy led to a significant increase in DSBs (0.22 vs 3.43 foci per cell; P = .0312). The frequency of DSBs did not differ between imaging at 1.5 T and at 3.0 T (5 minutes after MR imaging: 0.23 vs 0.06 foci per cell, respectively [P = .57]; 30 minutes after MR imaging: 0.12 vs 0.08 foci per cell [P = .76]). Conclusion Abdominopelvic MR imaging performed at 1.5 T or 3.0 T does not affect the formation of DNA DSBs in peripheral blood lymphocytes.

Comparison of the effect of radiation exposure from dual-energy CT versus single-energy CT on double-strand breaks at CT pulmonary angiography

PURPOSE

To compare the effect of dual-source dual-energy CT versus single-energy CT on DNA double-strand breaks (DSBs) in blood lymphocytes at CT pulmonary angiography (CTPA).

METHODS AND MATERIALS

Sixty-two patients underwent either dual-energy CTPA (Group 1: n = 21, 80/Sn140 kVp, 89/38 mAs; Group 2: n = 20, 100/Sn140 kVp, 89/76 mAs) or single-energy CTPA (Group 3: n = 21, 120 kVp, 110 mAs). Blood samples were obtained before and 5 min after CTPA. DSBs were assessed with fluorescence microscopy and Kruskal-Walls tests were used to compare DSBs levels among groups. Volume CT dose index (CTDIvol), dose length product (DLP) and organ radiation dose were compared using ANOVA.

RESULTS

There were increased excess DSB foci per lymphocyte 5 min after CTPA examinations in three groups (Group 1: P = .001; Group 2: P = .001; Group 3: P = .006). There were no differences among groups regarding excess DSB foci/cell and percentage of excess DSBs (Group 1, 23%; Group 2, 24%; Group 3, 20%; P = .932). CTDIvol, DLP and organ radiation dose in Group 1 were the lowest among the groups (all P < .001).

CONCLUSION

DSB is increased following dual-source and single-source CTPA, while dual-source dual-energy CT protocols do not increase the estimated radiation dose and also do not result in a higher incidence of DNA DSBs in patients undergoing CTPA.

Image quality in coronary CT angiography: challenges and technical solutions

Multidetector CT angiography (CTA) has become a widely accepted examination for non-invasive evaluation of the heart and coronary arteries. Despite its ongoing success and worldwide clinical implementation, it remains an often-challenging procedure in which image quality, and hence diagnostic value, is determined by both technical and patient-related factors. Thorough knowledge of these factors is important to obtain high-quality examinations. In this review, we discuss several key elements that may adversely affect coronary CTA image quality as well as potential measures that can be taken to mitigate their impact. In addition, several recent vendor-specific advances and future directions to improve image quality are discussed.