1
|
Hinsen M, Nagel AM, May MS, Wiesmueller M, Uder M, Heiss R. Lung Nodule Detection With Modern Low-Field MRI (0.55 T) in Comparison to CT. Invest Radiol 2024; 59:215-222. [PMID: 37490031 DOI: 10.1097/rli.0000000000001006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
OBJECTIVES The aim of this study was to evaluate the accuracy of modern low-field magnetic resonance imaging (MRI) for lung nodule detection and to correlate nodule size measurement with computed tomography (CT) as reference. MATERIALS AND METHODS Between November 2020 and July 2021, a prospective clinical trial using low-field MRI at 0.55 T was performed in patients with known pulmonary nodules from a single academic medical center. Every patient underwent MRI and CT imaging on the same day. The primary aim was to evaluate the detection accuracy of pulmonary nodules using MRI with transversal periodically rotated overlapping parallel lines with enhanced reconstruction in combination with coronal half-Fourier acquired single-shot turbo spin-echo MRI sequences. The secondary outcome was the correlation of the mean lung nodule diameter with CT as reference according to the Lung Imaging Reporting and Data System. Nonparametric Mann-Whitney U test, Spearman rank correlation coefficient, and Bland-Altman analysis were applied to analyze the results. RESULTS A total of 46 participants (mean age ± SD, 66 ± 11 years; 26 women) were included. In a blinded analysis of 964 lung nodules, the detection accuracy was 100% for those ≥6 mm (126/126), 80% (159/200) for those ≥4-<6 mm, and 23% (147/638) for those <4 mm in MRI compared with reference CT. Spearman correlation coefficient of MRI and CT size measurement was r = 0.87 ( P < 0.001), and the mean difference was 0.16 ± 0.9 mm. CONCLUSIONS Modern low-field MRI shows excellent accuracy in lesion detection for lung nodules ≥6 mm and a very strong correlation with CT imaging for size measurement, but could not compete with CT in the detection of small nodules.
Collapse
Affiliation(s)
- Maximilian Hinsen
- From the Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany (M.H., A.M.N., M.S.M., M.W., M.U., R.H.); and Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany (A.M.N.)
| | | | | | | | | | | |
Collapse
|
2
|
Jamshidi MH, Karami A, Salimi Y, Keshavarz A. Patient effective dose and radiation biological risk in the chest and abdominopelvic computed tomography. Appl Radiat Isot 2023; 193:110628. [PMID: 36577360 DOI: 10.1016/j.apradiso.2022.110628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 11/03/2022] [Accepted: 12/21/2022] [Indexed: 12/25/2022]
Abstract
The incidence and mortality (per 100,000) rates in chest CT are highest for the lungs and breasts (incidence: lung = 116, breast = 98.64; mortality: lung = 113.43, breast = 49.72). Abdominopelvic CT scans showed the highest incidence for stomach (79.57), colon (62.86), bladder (48.69), and liver (28.63), respectively. Mortality is highest for the bladder (80.44), stomach (72.43), colon (69.02), and liver (63.78), respectively. This study helps to better understand the concept of radiation dose and the numbers reported as organ dose and effective dose and identify the probability of the stochastic effect.
Collapse
Affiliation(s)
- Mohammad Hossein Jamshidi
- Department of Medical Imaging and Radiation Sciences, School of Allied Medical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
| | - Aida Karami
- Department of Medical Imaging and Radiation Sciences, School of Allied Medical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Yazdan Salimi
- Department of Biomedical Engineering and Medical Physics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amirhesam Keshavarz
- Department of Anatomical Science, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| |
Collapse
|
3
|
Martin CJ, Barnard M. Potential risks of cardiovascular and cerebrovascular disease and cancer due to cumulative doses received from diagnostic CT scans? JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:1243-1257. [PMID: 34525460 DOI: 10.1088/1361-6498/ac270f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
Potential risks from radiation exposure on the development of cardiovascular and cerebrovascular disease are indicated by epidemiological studies. Medical exposures give the largest dose to the population from artificial sources, with cumulative doses from multiple CT scans being significant. Data on doses from scans performed on 12 CT scanners in three hospitals over a period of 5½ years, derived using RadimetricsTMsoftware, have been reviewed for 105 757 patients. Data have been downloaded for heart, brain, thyroid, and effective doses, and cumulative doses analysed using ExcelTMspreadsheets. 2.4% of patients having body CT scans received cumulative doses to the heart over 100 mSv, 9% of whom were under 50 years. 9.6% of patients having head CT scans received cumulative doses to the brain over 100 mSv with 0.08% over 500 mSv from whom 41% were under 50 years, but only 1.3% of patients scanned had thyroid/carotid artery doses over 100 mSv. An approximate evaluation of potential risks from exposures of the heart above 100 mSv and brain over 500 mSv for patients under 60 years would suggest that at most only one patient would demonstrate any excess risk from vascular disease resulting from the exposures. 0.67% of patients scanned received effective doses over 100 mSv, in line with results from European studies, with 8.4% being under 50 years. The application of age and sex specific risk coefficients relating to excess cancer incidence suggests that two or three patients with effective doses over 100 mSv and five patients with effective doses between 50 and 100 mSv, from those examined, might develop cancer as a result of exposure. However, this will be an overestimate, since it does not take patients' health into account. Exposure management software can aid in evaluating cumulative doses and identifying individual patients receiving substantial doses from repetitive imaging.
Collapse
Affiliation(s)
- Colin J Martin
- Department of Clinical Physics and Bioengineering, University of Glasgow, Glasgow, United Kingdom
| | - Michael Barnard
- Department of Radiation Physics and Protection, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| |
Collapse
|
4
|
Harrison JD, Balonov M, Bochud F, Martin C, Menzel HG, Ortiz-Lopez P, Smith-Bindman R, Simmonds JR, Wakeford R. ICRP Publication 147: Use of Dose Quantities in Radiological Protection. Ann ICRP 2021; 50:9-82. [PMID: 33653178 DOI: 10.1177/0146645320911864] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
5
|
Individual Calculation of Effective Dose and Risk of Malignancy Based on Monte Carlo Simulations after Whole Body Computed Tomography. Sci Rep 2020; 10:9475. [PMID: 32528028 PMCID: PMC7289876 DOI: 10.1038/s41598-020-66366-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/14/2020] [Indexed: 01/30/2023] Open
Abstract
Detailed knowledge about radiation exposure is crucial for radiology professionals. The conventional calculation of effective dose (ED) for computed tomography (CT) is based on dose length product (DLP) and population-based conversion factors (k). This is often imprecise and unable to consider individual patient characteristics. We sought to provide more precise and individual radiation exposure calculation using image based Monte Carlo simulations (MC) in a heterogeneous patient collective and to compare it to phantom based MC provided from the National Cancer Institute (NCI) as academic reference. Dose distributions were simulated for 22 patients after whole-body CT during Positron Emission Tomography-CT. Based on MC we calculated individual Lifetime Attributable Risk (LAR) and Excess Relative Risk (ERR) of cancer mortality. EDMC was compared to EDDLP and EDNCI. EDDLP (13.2 ± 4.5 mSv) was higher compared to EDNCI (9.8 ± 2.1 mSv) and EDMC (11.6 ± 1.5 mSv). Relative individual differences were up to -48% for EDMC and -44% for EDNCI compared to EDDLP. Matching pair analysis illustrates that young age and gender are affecting LAR and ERR significantly. Because of these uncertainties in radiation dose assessment automated individual dose and risk estimation would be desirable for dose monitoring in the future.
Collapse
|
6
|
Radiation dose and risk of exposure-induced death associated with common computed tomography procedures in Yazd Province. Eur J Radiol 2020; 126:108932. [DOI: 10.1016/j.ejrad.2020.108932] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 02/07/2020] [Accepted: 03/02/2020] [Indexed: 01/12/2023]
|
7
|
Zgheib H, Wakil C, Shayya S, Kanso M, Bou Chebl R, Bachir R, El Sayed M. Retrospective cohort study on clinical predictors for acute abnormalities on CT scan in adult patients with abdominal pain. Eur J Radiol Open 2020; 7:100218. [PMID: 33102637 PMCID: PMC7569409 DOI: 10.1016/j.ejro.2020.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/09/2020] [Accepted: 01/17/2020] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Identification of clinical predictors of acute and surgical pathologies on abdominal CT in patients with non-traumatic abdominal pain (NTAP). METHODS Retrospective chart review cohort study of adults who had abdominal CT scans for investigation of NTAP in the Emergency Department in a tertiary care center in Lebanon. Multivariate analyses were performed to identify predictors of pathologies on CT scan. RESULTS This study included 147 patients who had abdominal CT scans for NTAP. Mean age was 39.8 ± 15.1 years and 58.5 % of patients were females. Less than half (44.9 %) had normal scans. Women had significantly higher rates of normal scans compared to males. Right lower quadrant (RLQ) tenderness was associated with significantly higher odds of having acute abnormalities on CT and of having surgical diagnoses, while epigastric tenderness was negatively associated with these two outcomes. Right and left upper quadrants and diffuse abdominal tenderness, and an abnormal neutrophil count were found to be associated with surgical diagnoses on CT. CONCLUSIONS Women are less likely to have acute and surgical pathologies on CT ordered for non traumatic abdominal pain. Epigastric tenderness is negatively associated with abnormal and surgical CT results while RLQ tenderness is associated with an abnormal CT that is likely surgical in nature. These findings should help improve diagnostic accuracy of ordering providers and improve resource utilization.
Collapse
Affiliation(s)
- Hady Zgheib
- Department of Emergency Medicine, American University of Beirut Medical Center, PO Box: 11-0236 Riad El Solh, 1107 2020, Beirut, Lebanon
| | - Cynthia Wakil
- Department of Emergency Medicine, American University of Beirut Medical Center, PO Box: 11-0236 Riad El Solh, 1107 2020, Beirut, Lebanon
| | - Sami Shayya
- Department of Emergency Medicine, American University of Beirut Medical Center, PO Box: 11-0236 Riad El Solh, 1107 2020, Beirut, Lebanon
| | - Mohamad Kanso
- Department of Emergency Medicine, American University of Beirut Medical Center, PO Box: 11-0236 Riad El Solh, 1107 2020, Beirut, Lebanon
| | - Ralph Bou Chebl
- Department of Emergency Medicine, American University of Beirut Medical Center, PO Box: 11-0236 Riad El Solh, 1107 2020, Beirut, Lebanon
| | - Rana Bachir
- Department of Emergency Medicine, American University of Beirut Medical Center, PO Box: 11-0236 Riad El Solh, 1107 2020, Beirut, Lebanon
| | - Mazen El Sayed
- Department of Emergency Medicine, American University of Beirut Medical Center, PO Box: 11-0236 Riad El Solh, 1107 2020, Beirut, Lebanon
- Emergency Medical Services and Prehospital Care Program, American University of Beirut Medical Center, PO Box: 11-0236 Riad El Solh, 1107 2020, Beirut, Lebanon
| |
Collapse
|
8
|
Kotiaho A, Manninen AL, Nikkinen J, Nieminen MT. COMPARISON OF ORGAN-BASED TUBE CURRENT MODULATION AND BISMUTH SHIELDING IN CHEST CT: EFFECT ON THE IMAGE QUALITY AND THE PATIENT DOSE. RADIATION PROTECTION DOSIMETRY 2019; 185:42-48. [PMID: 30544171 DOI: 10.1093/rpd/ncy242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/10/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
The aim of the study was to compare the absorbed doses and image quality of organ-based tube current modulation (OBTCM) and bismuth shielding of breasts and thyroid against regular tube current modulation in chest CT scan. An anthropomorphic phantom and MOSFET dosemeters were used to evaluate absorbed doses. Image quality was assessed from HU and noise. Relative to the reference scan, the average absorbed dose reduction with OBTCM was 5.2% and with bismuth shields 24.2%. Difference in HU values compared to the reference varied between -4.1 and 4.2 HU in OBTCM scan and between -22.2 and 118.6 HU with bismuth shields. Image noise levels varied between 10.0 to 26.3 HU in the reference scan, from 9.6 to 27.7 HU for the OBTCM scan and from 11.9 to 43.9 HU in the bismuth scan. The use of bismuth shields provided greatest dose reduction compared to the investigated OBTCM.
Collapse
Affiliation(s)
- Antti Kotiaho
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Department of Radiology, Oulu University Hospital, Oulu, Finland
- Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
| | | | - Juha Nikkinen
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
- Department of Oncology and Radiotherapy, Oulu University Hospital, Oulu, Finland
| | - Miika Tapio Nieminen
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Department of Radiology, Oulu University Hospital, Oulu, Finland
- Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
| |
Collapse
|
9
|
Abstract
Significant anxiety has been expressed by some over the radiation risks associated with computed tomography (CT), particularly when it applies to a screening examination such as CT colonography. These theoretic risks are far outweighed by the significant benefits colorectal cancer screening offers. Regardless of how significant the theoretic risk of CT radiation is in the older population, the ALARA principle maintains that radiation dose should be reduced to As Low As Reasonably Achievable. This article will discuss various strategies that may be utilized to reduce radiation dose and mitigate any increase in image noise that may occur.
Collapse
Affiliation(s)
- Kevin J Chang
- Department of Radiology, Newton-Wellesley Hospital, Brown University Alpert Medical School, 2014 Washington Street, Newton, MA 02462, USA.
| | - Judy Yee
- Department of Radiology, Montefiore Medical Center, Albert Einstein College of Medicine, 111 East 210th Street, Bronx, NY 10467, USA
| |
Collapse
|
10
|
Bonilha HS, Wilmskoetter J, Tipnis SV, Martin-Harris B, Huda W. EFFECTIVE DOSE PER UNIT KERMA-AREA PRODUCT CONVERSION FACTORS IN ADULTS UNDERGOING MODIFIED BARIUM SWALLOW STUDIES. RADIATION PROTECTION DOSIMETRY 2017; 176:269-277. [PMID: 28204745 PMCID: PMC5927331 DOI: 10.1093/rpd/ncx006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/04/2017] [Accepted: 01/16/2017] [Indexed: 05/31/2023]
Abstract
This study presents an investigation of adult effective dose (E) per unit Kerma-Area Product (KAP) in Modified Barium Swallow Study (MBSS) examinations. PC program for X-ray Monte Carlo (version 2.0.1) was used to calculate patient organ doses during MBSS examinations, which used combined to generate effective dose. Normalized patient doses were obtained by dividing the effective dose (mSv) by the incident KAP (Gy·cm2). Five standard projections were studied and the importance of X-ray beam size and in patient size (body mass index) were investigated. Lateral projections had an average E/KAP conversion factor of 0.19 ± 0.04 mSv/Gy·cm2. The average E/KAP was highest for upper gastrointestinal (GI) anterior-posterior projections (0.27 ± 0.04 mSv/Gy·cm2) and lowest for upper GI posterior-anterior projections (0.09 ± 0.03 mSv/Gy·cm2). E/KAP always increased with increasing filtration and/or X-ray tube voltage. Reducing the X-ray beam cross-sectional area increased the E/KAP conversion factors. Small patients have the E/KAP conversion factors that are twice those of a standard adult. Conversion factors for effective dose of adult patients undergoing MBSS examinations must account for X-ray beam projection, beam quality (kV and filtration), image size and patient size.
Collapse
Affiliation(s)
- Heather Shaw Bonilha
- Health Sciences and Research, Medical University of South Carolina
, 77 President St, MSC 700, Charleston, SC 29425-2503, USA
| | - Janina Wilmskoetter
- Health Sciences and Research, Medical University of South Carolina
, 77 President St, MSC 700, Charleston, SC 29425-2503, USA
| | - Sameer V Tipnis
- Department of Radiology and Radiological Science, Medical University of South Carolina, 96 Jonathan Lucas Street, MSC 323, Charleston, SC 29425-3230, USA
| | - Bonnie Martin-Harris
- Communication Sciences and Disorders, Northwestern University, 70 Arts Circle Drive, Evanston, IL 60208, USA
| | - Walter Huda
- Department of Radiology, Dartmouth-Hitchcock Medical Center, 1 Medical Center Dr, Lebanon, NH 03766, USA
| |
Collapse
|
11
|
Evaluation of a Net Dose-Reducing Organ-Based Tube Current Modulation Technique: Comparison With Standard Dose and Bismuth-Shielded Acquisitions. AJR Am J Roentgenol 2016; 206:1233-40. [DOI: 10.2214/ajr.15.15778] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
12
|
Martin CJ, Abuhaimed A, Sankaralingam M, Metwaly M, Gentle DJ. Organ doses can be estimated from the computed tomography (CT) dose index for cone-beam CT on radiotherapy equipment. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2016; 36:215-229. [PMID: 26975735 DOI: 10.1088/0952-4746/36/2/215] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Cone beam computed tomography (CBCT) systems are fitted to radiotherapy linear accelerators and used for patient positioning prior to treatment by image guided radiotherapy (IGRT). Radiotherapists' and radiographers' knowledge of doses to organs from CBCT imaging is limited. The weighted CT dose index for a reference beam of width 20 mm (CTDIw,ref) is displayed on Varian CBCT imaging equipment known as an On-Board Imager (OBI) linked to the Truebeam linear accelerator. This has the potential to provide an indication of organ doses. This knowledge would be helpful for guidance of radiotherapy clinicians preparing treatments. Monte Carlo simulations of imaging protocols for head, thorax and pelvic scans have been performed using EGSnrc/BEAMnrc, EGSnrc/DOSXYZnrc, and ICRP reference computational male and female phantoms to derive the mean absorbed doses to organs and tissues, which have been compared with values for the CTDIw,ref displayed on the CBCT scanner console. Substantial variations in dose were observed between male and female phantoms. Nevertheless, the CTDIw,ref gave doses within ±21% for the stomach and liver in thorax scans and 2 × CTDIw,ref can be used as a measure of doses to breast, lung and oesophagus. The CTDIw,ref could provide indications of doses to the brain for head scans, and the colon for pelvic scans. It is proposed that knowledge of the link between CTDIw for CBCT should be promoted and included in the training of radiotherapy staff.
Collapse
Affiliation(s)
- Colin J Martin
- Department of Clinical Physics, University of Glasgow, Glasgow, UK
| | | | | | | | | |
Collapse
|
13
|
Huda W, Tipnis SV. Doses metrics and patient age in CT. RADIATION PROTECTION DOSIMETRY 2016; 168:374-380. [PMID: 25977348 DOI: 10.1093/rpd/ncv310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Accepted: 03/27/2015] [Indexed: 06/04/2023]
Abstract
The aim of this study was to investigate how effective dose and size-specific dose estimate (SSDE) change with patient age (size) for routine head and abdominal/pelvic CT examinations. Heads and abdomens of patients were modelled as a mass-equivalent cylinder of water corresponding to the patient 'effective diameter'. Head CT scans were performed at CTDIvol(S) of 40 mGy, and abdominal CT scans were performed at CTDIvol(L) of 10 mGy. Values of SSDE were obtained using conversion factors in AAPM Task Group Report 204. Age-specific scan lengths for head and abdominal CT scans obtained from the authors' clinical practice were used to estimate the dose-length product for each CT examination. Effective doses were calculated from previously published age- and sex-specific E/DLP conversion factors, based on ICRP 103 organ-weighting factors. For head CT examinations, the scan length increased from 15 cm in a newborn to 20 cm in adults, and for an abdominal/pelvic CT, the scan length increased from 20 cm in a newborn to 45 cm in adults. For head CT scans, SSDE ranged from 37.2 mGy in adults to 48.8 mGy in a newborn, an increase of 31 %. The corresponding head CT effective doses range from 1.4 mSv in adults to 5.2 mSv in a newborn, an increase of 270 %. For abdomen CT scans, SSDE ranged from 13.7 mGy in adults to 23.0 mGy in a newborn, an increase of 68 %. The corresponding abdominal CT effective doses ranged from 6.3 mSv in adults to 15.4 mSv in a newborn, an increase of 140 %. SSDE increases much less than effective dose in paediatric patients compared with adults because it does not account for scan length or scattered radiation. Size- and age-specific effective doses better quantify the total radiation received by patients in CT by explicitly accounting for all organ doses, as well as their relative radio sensitivity.
Collapse
Affiliation(s)
- Walter Huda
- Department of Radiology and Radiological Science, MUSC, 96 Jonathan Lucas St, MSC 323, Charleston, SC 29425-3230, USA
| | - Sameer V Tipnis
- Department of Radiology and Radiological Science, MUSC, 96 Jonathan Lucas St, MSC 323, Charleston, SC 29425-3230, USA
| |
Collapse
|
14
|
Hazards of Ionizing Radiation and Its Impact on Neurosurgical Practice. World Neurosurg 2016; 86:42-3. [DOI: 10.1016/j.wneu.2015.09.092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 09/28/2015] [Indexed: 11/17/2022]
|
15
|
Patient radiation biological risk in computed tomography angiography procedure. Saudi J Biol Sci 2016; 24:235-240. [PMID: 28149156 PMCID: PMC5272934 DOI: 10.1016/j.sjbs.2016.01.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/02/2016] [Accepted: 01/05/2016] [Indexed: 11/22/2022] Open
Abstract
Computed tomography angiography (CTA) has become the most valuable imaging modality for the diagnosis of blood vessel diseases; however, patients are exposed to high radiation doses and the probability of cancer and other biological effects is increased. The objectives of this study were to measure the patient radiation dose during a CTA procedure and to estimate the radiation dose and biological effects. The study was conducted in two radiology departments equipped with 64-slice CT machines (Aquilion) calibrated according to international protocols. A total of 152 patients underwent brain, lower limb, chest, abdomen, and pelvis examinations. The effective radiation dose was estimated using ImPACT scan software. Cancer and biological risks were estimated using the International Commission on Radiological Protection (ICRP) conversion factors. The mean patient dose value per procedure (dose length product [DLP], mGy·cm) for all examinations was 437.8 ± 166, 568.8 ± 194, 516.0 ± 228, 581.8 ± 175, and 1082.9 ± 290 for the lower limbs, pelvis, abdomen, chest, and cerebral, respectively. The lens of the eye, uterus, and ovaries received high radiation doses compared to thyroid and testis. The overall patient risk per CTA procedure ranged between 15 and 36 cancer risks per 1 million procedures. Patient risk from CTA procedures is high during neck and abdomen procedures. Special concern should be provided to the lens of the eye and thyroid during brain CTA procedures. Patient dose reduction is an important consideration; thus, staff should optimize the radiation dose during CTA procedures.
Collapse
|
16
|
Sookpeng S, Martin CJ, Gentle DJ. Influence of CT automatic tube current modulation on uncertainty in effective dose. RADIATION PROTECTION DOSIMETRY 2016; 168:46-54. [PMID: 25628455 DOI: 10.1093/rpd/ncu374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/29/2014] [Indexed: 06/04/2023]
Abstract
Computed tomography (CT) scanners are equipped with automatic tube current modulation (ATCM) systems that adjust the current to compensate for variations in patient attenuation. CT dosimetry variables are not defined for ATCM situations and, thus, only the averaged values are displayed and analysed. The patient effective dose (E), which is derived from a weighted sum of organ equivalent doses, will be modified by the ATCM. Values for E for chest-abdomen-pelvis CT scans have been calculated using the ImPACT spreadsheet for patients on five CT scanners. Values for E resulting from the z-axis modulation under ATCM have been compared with results assessed using the same effective mAs values with constant tube currents. Mean values for E under ATCM were within ±10 % of those for fixed tube currents for all scanners. Cumulative dose distributions under ATCM have been simulated for two patient scans using single-slice dose profiles measured in elliptical and cylindrical phantoms on one scanner. Contributions to the effective dose from organs in the upper thorax under ATCM are 30-35 % lower for superficial tissues (e.g. breast) and 15-20 % lower for deeper organs (e.g. lungs). The effect on doses to organs in the abdomen depends on body shape, and they can be 10-22 % higher for larger patients. Results indicate that scan dosimetry parameters, dose-length product and effective mAs averaged over the whole scan can provide an assessment in terms of E that is sufficiently accurate to quantify relative risk for routine patient exposures under ATCM.
Collapse
Affiliation(s)
- S Sookpeng
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand
| | - C J Martin
- Department of Clinical Physics, University of Glasgow, Glasgow G12 8QQ, UK
| | - D J Gentle
- Health Physics, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH, UK
| |
Collapse
|
17
|
Yao H, Huda W, Mah E, He W. Review of Kerma-Area Product and total energy incident on patients in radiography, mammography and CT. RADIATION PROTECTION DOSIMETRY 2015; 163:251-260. [PMID: 24821931 DOI: 10.1093/rpd/ncu157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study estimated the energy incident on patients in radiography, mammography and CT using data related to X-ray beam quantity and quality. The total X-ray beam quantity is the average Air Kerma multiplied by the X-ray beam area and expressed as the Kerma-Area Product (Gy cm(-2)). The X-ray beam quality primarily depends on the target material (and anode angle), X-ray voltage (and ripple) as well as X-ray beam filtration. For any X-ray spectra, dividing total energy (fluence × mean energy) by the X-ray beam Kerma-Area Product yields the energy per Kerma-Area Product value (ε/KAP). Published data on X-ray spectra characteristics and energy fluence per Air Kerma conversion factors were used to determine ε/KAP factors. In radiography, ε/KAP increased from 6 mJ Gy(-1) cm(-2) at the lowest X-ray tube voltage (50 kV) to 25 mJ Gy(-1) cm(-2) at the highest X-ray tube voltage (140 kV). ε/KAP values ranged between 1 and 5 mJ Gy(-1) cm(-2) in mammography and between 24 and 42 mJ Gy(-1) cm(-2) in CT. Changes in waveform ripple resulted in variations in ε/KAP of up to 15 %, similar to the effect of changes resulting in the choice of anode angle. For monoenergetic X-ray photons, there was a sigmoidal-type increase in ε/KAP from 2 mJ Gy(-1) cm(-2) at 20 keV to 42 mJ Gy(-1) cm(-2) at 80 keV. However, between 80 and 150 keV, the ε/KAP shows variations with changing photon energy of <10 %. Taking the average spectrum energy to consist of monoenergetic X rays generally overestimates the true value of ε/KAP. This study illustrated that the energy incident on a patient in any area of radiological imaging can be estimated from the total X-ray beam intensity (KAP) when X-ray beam quality is taken into account. Energy incident on the patient can be used to estimate the energy absorbed by the patient and the corresponding patient effective dose.
Collapse
Affiliation(s)
- Hai Yao
- Department of Bioengineering, Clemson-MUSC Bioengineering Program, Clemson University, Charleston, SC 29425, USA
| | - Walter Huda
- Department of Radiology and Radiological Science, Medical University of South Carolina (MUSC), Charleston, SC 29425, USA
| | - Eugene Mah
- Department of Radiology and Radiological Science, Medical University of South Carolina (MUSC), Charleston, SC 29425, USA
| | - Wenjun He
- Department of Bioengineering, Clemson-MUSC Bioengineering Program, Clemson University, Charleston, SC 29425, USA
| |
Collapse
|
18
|
|
19
|
Lima F, Ding D, Goetz W, Yang AJ, Baulch JE. High LET (56)Fe ion irradiation induces tissue-specific changes in DNA methylation in the mouse. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:266-77. [PMID: 24723241 DOI: 10.1002/em.21832] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 07/12/2013] [Accepted: 11/15/2013] [Indexed: 05/15/2023]
Abstract
DNA methylation is an epigenetic mechanism that drives phenotype and that can be altered by environmental exposures including radiation. The majority of human radiation exposures occur in a relatively low dose range; however, the biological response to low dose radiation is poorly understood. Based on previous observations, we hypothesized that in vivo changes in DNA methylation would be observed in mice following exposure to doses of high linear energy transfer (LET) (56) Fe ion radiation between 10 and 100 cGy. We evaluated the DNA methylation status of genes for which expression can be regulated by methylation and that play significant roles in radiation responses or carcinogenic processes including apoptosis, metastasis, cell cycle regulation, and DNA repair (DAPK1, EVL, 14.3.3, p16, MGMT, and IGFBP3). We also evaluated DNA methylation of repeat elements in the genome that are typically highly methylated. No changes in liver DNA methylation were observed. Although no change in DNA methylation was observed for the repeat elements in the lungs of these same mice, significant changes were observed for the genes of interest as a direct effect and a delayed effect of irradiation 1, 7, 30, and 120 days post exposure. At delayed times, differences in methylation profiles among genes were observed. DNA methylation profiles also significantly differed based on dose, with the lowest dose frequently affecting the largest change. The results of this study are the first to demonstrate in vivo high LET radiation-induced changes in DNA methylation that are tissue and locus specific, and dose and time dependent.
Collapse
Affiliation(s)
- Florence Lima
- Division of Nephrology, Bone and Mineral Metabolism, University of Kentucky, Lexington, Kentucky
| | | | | | | | | |
Collapse
|
20
|
Sookpeng S, Martin CJ, Gentle DJ, Lopez-Gonzalez MR. Relationships between patient size, dose and image noise under automatic tube current modulation systems. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2014; 34:103-123. [PMID: 24334678 DOI: 10.1088/0952-4746/34/1/103] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Automatic tube current modulation (ATCM) systems are now used for the majority of CT scans. The principles of ATCM operation are different in CT scanners from different manufacturers. Toshiba and GE scanners base the current modulation on a target noise setting, while Philips and Siemens scanners use reference image and reference mAs concepts respectively. Knowledge of the relationships between patient size, dose and image noise are important for CT patient dose optimisation. In this study, the CT patient doses were surveyed for 14 CT scanners from four different CT scanner manufacturers. The patient cross sectional area, the tube current modulation and the image noise from the CT images were analysed using in-house software. The Toshiba and GE scanner results showed that noise levels are relatively constant but tube currents are dependent on patient size. As a result of this there is a wide range in tube current values across different patient sizes, and doses for large patients are significantly higher in these scanners. In contrast, in the Philips and Siemens scanners, tube currents are less dependent on patient size, the range in tube current is narrower, and the doses for larger patients are not as high. Image noise is more dependent on the patient size.
Collapse
Affiliation(s)
- S Sookpeng
- Health Physics, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH, UK. Department of Clinical Physics, University of Glasgow, Glasgow G12 8QQ, UK
| | | | | | | |
Collapse
|
21
|
Optimization of computed tomography (CT) arthrography of hip for the visualization of cartilage: an in vitro study. Skeletal Radiol 2014; 43:169-78. [PMID: 24281772 DOI: 10.1007/s00256-013-1759-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 10/11/2013] [Accepted: 10/13/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We sought to optimize the kilovoltage, tube current, and the radiation dose of computed tomographic arthrography of the hip joint using in vitro methods. MATERIALS AND METHODS A phantom was prepared using a left femoral head harvested from a patient undergoing total hip arthroplasty and packed in a condom filled with iodinated contrast. The right hip joint of a cadaver was also injected with iodinated contrast. The phantom and the cadaver were scanned using different values of peak kilovoltage (kVp) and tube current (milliamp seconds, mAs). Three different regions of interest (ROI) were drawn in the cartilage, subchondral bone plate, and intraarticular contrast. The attenuation values, contrast/noise ratio (CNR), and effective dose were calculated. Two independent observers classified the quality of the contrast-cartilage interface and the cartilage-subchondral bone plate interface as (1) diagnostic quality or (2) nondiagnostic quality. RESULTS Contrast, cartilage, and subchondral bone plate attenuation values decreased at higher kVp. CNR increased with both kVp and mAs. The qualitative analysis showed that in both phantom and cadaver, at 120 kVp and 50 mAs, the contrast-cartilage and cartilage-subchondral bone plate interfaces were of diagnostic quality, with an effective dose decreased to 0.5 MSv. CONCLUSIONS The absolute effective dose is not directly related to the quality of images but to the specific combination of kVp and mAs used for image acquisition. The combination of 120 kVp and 50 mAs can be suggested to decrease the dose without adversely affect the visibility of cartilage and subchondral bone plate.
Collapse
|
22
|
Oh JS, Koea JB. Radiation risks associated with serial imaging in colorectal cancer patients: Should we worry? World J Gastroenterol 2014; 20:100-109. [PMID: 24415862 PMCID: PMC3885998 DOI: 10.3748/wjg.v20.i1.100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/31/2013] [Accepted: 08/09/2013] [Indexed: 02/06/2023] Open
Abstract
To provide an overview of the radiation related cancer risk associated with multiple computed tomographic scans required for follow up in colorectal cancer patients. A literature search of the PubMed and Cochrane Library databases was carried out and limited to the last 10 years from December 2012. Inclusion criteria were studies where computed tomographic scans or radiation from other medical imaging modalities were used and the risks associated with ionizing radiation reported. Thirty-six studies were included for appraisal with no randomized controlled trials. Thirty-four of the thirty-six studies showed a positive association between medical imaging radiation and increased risk of cancer. The radiation dose absorbed and cancer risk was greater in children and young adults than in older patients. Most studies included in the review used a linear, no-threshold model to calculate cancer risks and this may not be applicable at low radiation doses. Many studies are retrospective and ensuring complete follow up on thousands of patients is difficult. There was a minor increased risk of cancer from ionizing radiation in medical imaging studies. The radiation risks of low dose exposure (< 50 milli-Sieverts) are uncertain. A clinically justified scan in the context of colorectal cancer is likely to provide more benefits than harm but current guidelines for patient follow up will need to be revised to accommodate a more aggressive approach to treating metastatic disease.
Collapse
|
23
|
Abstract
Patients, referring physicians, the media, and government agencies have all expressed concern over the risks of medical radiation, particularly as it relates to CT. This concern is particularly paramount when associated with a screening examination such as CT colonography. These theoretical risks must be weighed realistically against the substantial benefits of colon cancer screening as well as against the risks inherent in the major alternative screening option, optical colonoscopy. When put into perspective, the risk-benefit ratio is highly in favor of the performance of CT colonography. Nevertheless, in following the ALARA principle, there is an ever increasing armamentarium of options that can be employed in the pursuit of CT radiation dose reduction, all of which can be used in many synergistic combinations allowing for dose reduction while simultaneously preserving image quality and minimizing image noise. After a brief tutorial on estimating radiation dose, various strategies will be discussed including reductions in tube current and tube voltage as well as the use of automatic dose modulation and iterative reconstruction. Other practical considerations will also be reviewed including proper patient isocentering, optimization of colonic insufflation to minimize additional decubitus scans, proper choice of scan volumes to avoid overranging, and variation of slice thickness and window width to minimize perceived image noise. Finally, a strategy for how to incrementally introduce these methods as well as a way to compare dose reduction efforts across institutions throughout the country will be offered.
Collapse
|
24
|
|
25
|
Kepros JP, Opreanu RC, Samaraweera R, Briningstool A, Morrison CA, Mosher BD, Schneider P, Stevens P. Whole body imaging in the diagnosis of blunt trauma, ionizing radiation hazards and residual risk. Eur J Trauma Emerg Surg 2012; 39:15-24. [PMID: 26814919 DOI: 10.1007/s00068-012-0201-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 06/06/2012] [Indexed: 02/06/2023]
Abstract
Ever since the introduction of radiographic imaging, its utility in identifying injuries has been well documented and was incorporated in the workup of injured patients during advanced trauma life support algorithms [American College of Surgeons, 8th ed. Chicago, 2008]. More recently, computerized tomography (CT) has been shown to be more sensitive than radiography in the diagnosis of injury. Due to the increased use of CT scanning, concerns were raised regarding the associated exposure to ionizing radiation [N Engl J Med 357:2277-2284, 2007]. During the last several years, a significant amount of research has been published on this topic, most of it being incorporated in the BEIR VII Phase 2 report, published by the National Research Council of the National Academies [National Academy of Sciences, Washington DC, 2006]. The current review will analyze the scientific basis for the concerns over the ionizing radiation associated with the use of CT scanning and will examine the accuracy of the typical advanced trauma life support work-up for diagnosis of injuries.
Collapse
Affiliation(s)
- J P Kepros
- Department of Surgery, College of Human Medicine, Michigan State University, 1215 East Michigan Avenue, Suite 655, Lansing, MI, 48912, USA. .,Trauma and Surgical Critical Care, Sparrow Hospital, Lansing, MI, USA.
| | - R C Opreanu
- Department of Surgery, College of Human Medicine, Michigan State University, 1215 East Michigan Avenue, Suite 655, Lansing, MI, 48912, USA.
| | - R Samaraweera
- Department of Radiology, Sparrow Hospital, Lansing, MI, USA
| | - A Briningstool
- Emergency Department, Sparrow Hospital, Lansing, MI, USA
| | - C A Morrison
- Department of Surgery, College of Human Medicine, Michigan State University, 1215 East Michigan Avenue, Suite 655, Lansing, MI, 48912, USA.,Trauma and Surgical Critical Care, Sparrow Hospital, Lansing, MI, USA
| | - B D Mosher
- Department of Surgery, College of Human Medicine, Michigan State University, 1215 East Michigan Avenue, Suite 655, Lansing, MI, 48912, USA.,Trauma and Surgical Critical Care, Sparrow Hospital, Lansing, MI, USA
| | - P Schneider
- Department of Surgery, College of Human Medicine, Michigan State University, 1215 East Michigan Avenue, Suite 655, Lansing, MI, 48912, USA.,Trauma and Surgical Critical Care, Sparrow Hospital, Lansing, MI, USA
| | - P Stevens
- Trauma and Surgical Critical Care, Sparrow Hospital, Lansing, MI, USA
| |
Collapse
|
26
|
Cohen MD. CT radiation dose reduction: can we do harm by doing good? Pediatr Radiol 2012; 42:397-8. [PMID: 22302318 DOI: 10.1007/s00247-011-2315-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 11/18/2011] [Indexed: 01/05/2023]
Affiliation(s)
- Mervyn D Cohen
- Department of Radiology, Riley Hospital for Children, Indiana University, 702 Barnhill Drive, Indianapolis, IN 46202, USA.
| |
Collapse
|