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Free Radical Biology & Medicine May 2022It has been considered difficult to detect the biological effects of low-dose radiation exposure below approximately 100 mSv in humans. Serum proteomic analysis and...
It has been considered difficult to detect the biological effects of low-dose radiation exposure below approximately 100 mSv in humans. Serum proteomic analysis and oxidative modification profiling were conducted with blood samples collected from residents of a newly discovered high-level natural background radiation area (annual effective dose approximately 50 mSv y) and normal-level area (1.22 mSv y) in Mamuju, Indonesia, where many people have been living for generations. Dose-dependent oxidative modifications in amino acid sequences of human serum albumin, especially the 162 and 356 tyrosine residues and 111 and 470 methionine residues, were found. None of these findings have been reported in humans exposed to chronic low-dose radiation. It can be used as a biomarker not only for the assessment of the presence or absence of radiation exposure but also for dose prediction in living organisms for chronic radiation. These results suggest that traces of radiation exposure are recorded in serum albumin and that there is a possibility of a new methodology that can evaluate biological responses below 100 mSv.
Topics: Background Radiation; Humans; Proteomics; Radiation Dosage; Radiation Exposure
PubMed: 35447332
DOI: 10.1016/j.freeradbiomed.2022.04.006 -
Oral Surgery, Oral Medicine, Oral... Nov 2021The objective of this study was to estimate the possible number of cancer cases produced during 2019 in US dental offices from radiography, estimate the possible...
OBJECTIVES
The objective of this study was to estimate the possible number of cancer cases produced during 2019 in US dental offices from radiography, estimate the possible reduction in those rates resulting from use of intraoral rectangular collimation and selection criteria, and determine the frequency and quality of website radiation risk information and informed consent forms.
STUDY DESIGN
An analysis of dental radiation examinations in 2014 to 2015 US national survey data, Nationwide Evaluation of X-ray Trends, and National Council on Radiation Protection and Measurements surveys was performed, in addition to an analysis of 2008 to 2020 Journal of Clinical Orthodontics national orthodontic surveys for radiographic examination frequencies. Lifetime attributable cancer risk estimates from US and European studies were used to generate the total dental and orthodontic office cancer totals. In total, 150 offices were examined online for the quality and frequency of risk information in websites and consent forms.
RESULTS
The 2019 estimate for all office cancers is 967. Collimation and selection criteria could reduce this to 237 cancer cases. Most cancers arise from intraoral and cone beam computed tomography examinations, with 135 orthodontic cancers over 21 months (average treatment time). Collimation and selection criteria could reduce this to 68. Only 1% of offices use collimators or informed consent for radiography. The website and consent information were of poor quality.
CONCLUSIONS
Dentists are not following selection criteria or using collimators according to guidelines. Up to 75% of cancer cases could be avoided.
Topics: Dental Offices; Humans; Neoplasms; Radiation Dosage; Radiation Protection; Radiography; X-Rays
PubMed: 33741287
DOI: 10.1016/j.oooo.2021.01.027 -
PloS One 2020Dosimetry is an important tool for triage and treatment planning following any radiation exposure accident, and biological dosimetry, which estimates exposure dose using...
Dosimetry is an important tool for triage and treatment planning following any radiation exposure accident, and biological dosimetry, which estimates exposure dose using a biological parameter, is a practical means of determining the specific dose an individual receives. The cytokinesis-blocked micronucleus assay (CBMN) is an established biodosimetric tool to measure chromosomal damage in mitogen-stimulated human lymphocytes. The CBMN method is especially valuable for biodosimetry in triage situations thanks to simplicity in scoring and adaptability to high-throughput automated sample processing systems. While this technique produces dose-response data which fit very well to a linear-quadratic model for exposures to low linear energy transfer (LET) radiation and for doses up for 5 Gy, limitations to the accuracy of this method arise at larger doses. Accuracy at higher doses is limited by the number of cells reaching mitosis. Whereas it would be expected that the yield of micronuclei increases with the dose, in many experiments it has been shown to actually decrease when normalized over the total number of cells. This variation from a monotonically increasing dose response poses a limitation for retrospective dose reconstruction. In this study we modified the standard CBMN assay to increase its accuracy following exposures to higher doses of photons or a mixed neutron-photon beam. The assay is modified either through inhibitions of the G2/M and spindle checkpoints with the addition of caffeine and/or ZM447439 (an Aurora kinase inhibitor), respectively to the blood cultures at select times during the assay. Our results showed that caffeine addition improved assay performance for photon up to 10 Gy. This was achieved by extending the assay time from the typical 70 h to just 74 h. Compared to micronuclei yields without inhibitors, addition of caffeine and ZM447439 resulted in improved accuracy in the detection of micronuclei yields up to 10 Gy from photons and 4 Gy of mixed neutrons-photons. When the dose-effect curves were fitted to take into account the turnover phenomenon observed at higher doses, best fitting was achieved when the combination of both inhibitors was used. These techniques permit reliable dose reconstruction after high doses of radiation with a method that can be adapted to high-throughput automated sample processing systems.
Topics: Adult; Benzamides; Caffeine; Cells, Cultured; Cytogenetics; Dose-Response Relationship, Radiation; Female; Humans; Lymphocytes; Male; Micronucleus Tests; Middle Aged; Neutrons; Protons; Quinazolines; Radiation Dosage; Radiometry
PubMed: 32320391
DOI: 10.1371/journal.pone.0228350 -
European Radiology Jun 2021The study aimed to investigate the diagnostic performance of simulated ultra-low-dose CT (ULD-CT) for torsion measurement of the lower limb.
OBJECTIVES
The study aimed to investigate the diagnostic performance of simulated ultra-low-dose CT (ULD-CT) for torsion measurement of the lower limb.
METHODS
Thirty retrospectively identified patients were included (32.3 ± 14.2 years; 14 women, 16 men). ULD-CT simulations were generated at dose levels of 100%, 10%, 5%, and 1% using two reconstruction methods: standard filtered back projection (FBP) and iterative reconstruction (ADMIRE). Two readers measured the lower limb torsion in all data sets. The readers also captured image noise in standardized anatomical landmarks. All data sets were evaluated regarding subjective diagnostic confidence (DC; 5-point Likert scale). Effective radiation dose of the original data sets and the simulated ULD-CT was compared.
RESULTS
There was no significant difference of measured lower limb torsion in any simulated dose level compared to the original data sets in both readers. Dose length product (DLP) of the original examinations was 402.1 ± 4.3 mGy cm, which resulted in an effective radiation dose of 4.00 ± 2.12 mSv. Calculated effective radiation dose in ULD-CT at 1% of the original dose was 0.04 mSv. Image noise increased significantly with dose reduction (p < 0.0001) and was dependent on the reconstructional method (p < 0.0001) with less noise using ADMIRE compared to FBP. Both readers rated DC at doses 100%, 10%, and 5% with 5.0/5: there were no ratings worse than 3/5 at 1% dose level.
CONCLUSIONS
The results suggest that radiation dose reduction down to 1% of original CT dose levels may be achieved in CT torsion measurements of the lower limb without compromising diagnostic accuracy.
KEY POINTS
• Modern CT delivers exceptional high image quality in musculoskeletal imaging, especially for evaluation of osseous structures. • Usually, this high image quality is accompanied by significant radiation exposure to the patient and may not always be required for the intended purpose, e.g., pure delineation of cortical bone of the lower limb. • This study shows the tremendous prospects of radiation dose reduction without compromising diagnostic confidence in CT torsion measurement of the lower limb.
Topics: Algorithms; Female; Humans; Lower Extremity; Male; Radiation Dosage; Radiographic Image Interpretation, Computer-Assisted; Retrospective Studies; Tomography, X-Ray Computed
PubMed: 33241518
DOI: 10.1007/s00330-020-07528-8 -
Tomography (Ann Arbor, Mich.) Apr 2023Due to the concerns about radiation dose associated with medical imaging, radiation dose monitoring systems (RDMSs) are now utilized by many radiology providers to...
Due to the concerns about radiation dose associated with medical imaging, radiation dose monitoring systems (RDMSs) are now utilized by many radiology providers to collect, process, analyze, and manage radiation dose-related information. Currently, most commercially available RDMSs focus only on radiation dose information and do not track any metrics related to image quality. However, to enable comprehensive patient-based imaging optimization, it is equally important to monitor image quality as well. This article describes how RDMS design can be extended beyond radiation dose to simultaneously monitor image quality. A newly designed interface was evaluated by different groups of radiology professionals (radiologists, technologists, and physicists) on a Likert scale. The results show that the new design is effective in assessing both image quality and safety in clinical practices, with an overall average score of 7.8 out of 10.0 and scores ranging from 5.5 to 10.0. Radiologists rated the interface highest at 8.4 out of 10.0, followed by technologists at 7.6 out of 10.0, and medical physicists at 7.5 out of 10.0. This work demonstrates how the assessment of the radiation dose can be performed in conjunction with the image quality using customizable user interfaces based on the clinical needs associated with different radiology professions.
Topics: Humans; Radiation Dosage; Radiology; Tomography, X-Ray Computed
PubMed: 37104136
DOI: 10.3390/tomography9020065 -
European Radiology Feb 2021To investigate the impact of the interventionalist's experience and gender on radiation dose and procedural time in CT-guided interventions.
OBJECTIVES
To investigate the impact of the interventionalist's experience and gender on radiation dose and procedural time in CT-guided interventions.
METHODS
We retrospectively analyzed 4380 CT-guided interventions performed at our institution with the same CT scanner from 2009 until 2018, 1287 (29%) by female and 3093 (71%) by male interventionalists. Radiation dose, number of CT fluoroscopy images taken per intervention, total procedural time, type of intervention, and degree of difficulty were derived from the saved dose reports and images. All 16 interventionalists included in this analysis performed their first CT-guided interventions during the study period, and interventions performed by each interventionalist were counted to assess the level of experience for each intervention in terms of the number of prior interventions performed by her or him. The Mann-Whitney U test (MWU test), multivariate regression, and linear mixed model analysis were performed.
RESULTS
Assessment of the impact of gender with the MWU test revealed that female interventionalists took a significantly smaller number of images (p < 0.0001) and achieved a lower dose-length product per intervention (p < 0.0001) while taking more time per intervention (p = 0.0001). This finding was confirmed for most types of interventions when additionally accounting for other possible impact factors in multivariate regression analysis. In linear mixed model analysis, we found that radiation dose, number of images taken per intervention, and procedural time decreased statistically significantly with interventionalist's experience.
CONCLUSIONS
Radiation doses of CT-guided interventions are reduced by interventionalist's experience and, for most types of interventions, when performed by female interventionalists.
KEY POINTS
• Radiation doses in CT-guided interventions are lower when performed by female interventionalists. • Procedural times of CT-guided interventions are longer when performed by female interventionalists. • Radiation doses of CT-guided interventions decrease with the interventionalist's experience.
Topics: Female; Fluoroscopy; Humans; Male; Radiation Dosage; Radiography, Interventional; Retrospective Studies; Tomography, X-Ray Computed
PubMed: 32851446
DOI: 10.1007/s00330-020-07185-x -
In Vivo (Athens, Greece) 2022The effective atomic number (Z) and electron density relative to water (ρ or Rho) of elements can be derived in dual-energy computed tomography (DECT). The aim of this...
BACKGROUND/AIM
The effective atomic number (Z) and electron density relative to water (ρ or Rho) of elements can be derived in dual-energy computed tomography (DECT). The aim of this phantom study was to investigate the effect of different photon energies, radiation doses, and reconstruction kernels on Z and Rho measured in DECT.
MATERIALS AND METHODS
An anthropomorphic head phantom including five probes of known composition was scanned under three tube-voltage combinations in DECT: Sn140/100 kV, 140/80 kV and Sn140/80 kV with incremented radiation doses. Raw data were reconstructed with four reconstruction kernels (I30, I40, I50, and I70). Rho and Z were measured for each probe for all possible combinations of scan and reconstruction parameters.
RESULTS
DECT-based Rho and Z closely approached the reference values with a mean and maximum error of 1.7% and 6.8%, respectively. Rho was lower for 140/80 kV compared with Sn140/100 kV and Sn140/80 kV with differences being 0.009. Z differed among all tube voltages with the most prominent difference being 0.28 between 140/80 kV and Sn140/100 kV. Z was lower in I70 compared with those of I30 and I40 with a difference of 0.07. Varying radiation dose yielded a variation of 0.0002 in Rho and 0.03 in Z, both considered negligible in practice.
CONCLUSION
DECT comprises a feasible method for the extraction of material-specific information. Slight variations should be taken into account when different radiation doses, photon energies, and kernels are applied; however, they are considered small and in practice not crucial for an effective tissue differentiation.
Topics: Computers; Phantoms, Imaging; Photons; Radiation Dosage; Tomography, X-Ray Computed
PubMed: 35241522
DOI: 10.21873/invivo.12753 -
Scientific Reports Apr 2022To compare the patient radiation doses during angiographic selective adrenal vein sampling (AVS) before and after an imaging technology upgrade. In this retrospective...
To compare the patient radiation doses during angiographic selective adrenal vein sampling (AVS) before and after an imaging technology upgrade. In this retrospective single-center-study, cumulative air kerma (AK), cumulative dose area product (DAP), fluoroscopy time and contrast agent dosage were recorded from 70 patients during AVS. 35 procedures were performed before and 35 after an imaging processing technology upgrade. Mean values were calculated and compared using an unpaired student's t-test. DSA image quality was assessed independently by two blinded readers using a four-point Likert scale (1 = poor; 4 = excellent) and compared using Wilcoxon signed-rank test. After the technology upgrade we observed a significant reduction of 35% in AK (1.7 ± 0.7 vs. 1.1 ± 0.7 Gy, p = 0.01) and a significant reduction of 28% in DAP (235.1 ± 113 vs. 170.1 ± 94 Gy*cm, p = 0.01) in comparison to procedures before the upgrade. There were no significant differences between the number of exposure frames (143 ± 86 vs. 132 ± 61 frames, p = 0.53), fluoroscopy time (42 ± 23 vs. 36 ± 18 min, p = 0.22), or the amount of contrast medium used (179.5 ± 84 vs. 198.1 ± 109 ml, p = 0.41). There was also no significant difference regarding image quality (3 (2-4) vs. 3 (2-4), p = 0.67). The angiographic imaging technology upgrade significantly decreases the radiation dose during adrenal vein sampling without increasing time of fluoroscopy or contrast volume and without compromising image quality.
Topics: Drug Tapering; Fluoroscopy; Humans; Radiation Dosage; Radiation Exposure; Retrospective Studies; Technology
PubMed: 35414704
DOI: 10.1038/s41598-022-09984-2 -
Journal of Radiation Research Jan 2023Neuroblastoma (NB) is a common type of cancer found mostly in infants and arising from the immature neural crest cells of the sympathetic nervous system. Using laser...
Neuroblastoma (NB) is a common type of cancer found mostly in infants and arising from the immature neural crest cells of the sympathetic nervous system. Using laser trapping (LT) technique, the present work contributes to advancing radiotherapy (RT), a leading treatment method for cancer. A single, 2-cells, 3-cells, 4-cells, and 5-cells were trapped using the high-intensity gradient infrared laser at 1064 nm and allowed to become ionized. In this work, a systematic study of Threshold Ionization Energy (TIE) and Threshold Radiation Dose (TRD) versus mass for both single and multi-cell ionization using laser trapping (LT) techniques on NB is presented. The results show that TIE increased as the mass of cells increased, meanwhile TRD decreased with the increase of cell mass. We observed an inverse correlation between TRD and cell mass. We demonstrate how to compute the maximum radiation dosage for cell death using the LT technique. Results show a possible blueprint for computing the TRD in vivo. The use of multiple cell ionization to determine radiation dosage along with better data accuracy concerning the tumor size and density will have profound implications for radiation dosimetry. The diminution in TRD becomes more significant in multiple cell ionization as we see in TRD vs the number of cells entering the trap. This is due to the chain effect generated by radiation and the absorption by water molecules at 1064 nm. This result provides us with better insight into the optimization of the therapeutic ratio.
Topics: Infant; Humans; Light; Radiation Dosage; Radiometry; Lasers; Neuroblastoma
PubMed: 36527720
DOI: 10.1093/jrr/rrac082 -
The British Journal of Radiology Oct 2021The practice of placing radiation protective shielding on patients ('in contact') in order to reduce the dose to certain radiosensitive organs for diagnostic X-ray...
The practice of placing radiation protective shielding on patients ('in contact') in order to reduce the dose to certain radiosensitive organs for diagnostic X-ray examination, has been employed for decades. However, there has been a growing body of evidence that this practice is often ineffective or even counterproductive and the use of such shielding can also overemphasise the hazards of ionising radiation in the public mind. This has led to a growing disparity in the application of patient contact shielding and culminated in several professional bodies issuing guidance and statements to provide a consistent approach to patient contact shielding. This, in turn, has led to a healthy discussion and re-evaluation of when and why patient contact shielding should be used, where the main issue centres around the criteria used to arrive at the recommendations. The decision process involves considering, among others, the reported effectiveness of the shielding and a subjective assessment of the subsequent risks from their use. In order to improve the transparency of these recommendations, it is therefore suggested that a threshold for dose and/or risk should be clearly stated, below which no protection is required. A suggested starting point for defining this threshold is discussed. This would enhance uniformity of application and provide clarity for staff, patients and the public. It would also ensure that any future research in this area could be easily incorporated into the general guidance.
Topics: Decision Making; Humans; Radiation Dosage; Radiation Protection; Radiation, Ionizing; Radiography; Risk Factors
PubMed: 34347543
DOI: 10.1259/bjr.20210701