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Xin L, Zhuo W. Simulation of the shielding effect of lead apron undergoing chest CT scan. RADIATION PROTECTION DOSIMETRY 2024; 200:1554-1560. [PMID: 39540502 DOI: 10.1093/rpd/ncae041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/01/2024] [Accepted: 02/12/2024] [Indexed: 11/16/2024]
Abstract
Lead aprons are used to reduce radiation dose to patients. As the distance between the lead apron and the edge of the scan range increases, organ dose is expected to decrease, but with increasing scattered radiation dose in the body. By simulation, this work aims at estimate whether the organ dose increases due to the scattered radiation in the body with lead apron. A standard-sized male and a female phantom is used to simulate organ doses of chest scans in various lead apron shielding situations. Simulations in this work considered different distance between the edge of the 0.35-mm lead apron and the edge of the scan range. For the female phantom, the dose to the gonads was significantly reduced (56% on average), but not as much as men (78% on average). However, the amount of dose reduction is small for male and female phantoms (0.0082 mGy/100 mAs and 0.0160 mGy/100 mAs).
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Affiliation(s)
- Lin Xin
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
| | - Weihai Zhuo
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
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Kiapour M, Ebrahimnejad Gorji K, Mehraeen R, Ghaemian N, Niksirat Sustani F, Abedi-Firouzjah R, Shabestani Monfared A. Can Common Lead Apron in Testes Region Cause Radiation Dose Reduction during Chest CT Scan? A Patient Study. J Biomed Phys Eng 2021; 11:497-504. [PMID: 34458197 PMCID: PMC8385221 DOI: 10.31661/jbpe.v0i0.2104-1307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 05/31/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Computed tomography (CT) is a routine procedure for diagnosing using ionization radiation which has hazardous effects especially on sensitive organs. OBJECTIVE The aim of this study was to quantify the dose reduction effect of lead apron shielding on the testicular region during routine chest CT scans. MATERIAL AND METHODS In this measurement study, the routine chest CT examinations were performed for 30 male patients with common lead aprons folded and positioned in testis regions. The patient's mean body mass index (BMI) was 26.2 ± 4.6 kg/m2. To calculate the doses at testis region, three thermoluminescent dosimeters (TLD-100) were attached at the top surface of the apron as an indicator of the doses without shielding, and three TLDs under the apron for doses with shielding. The TLD readouts were compared using SPSS software (Wilcoxon test) version 16. RESULTS The radiation dose in the testicular regions was reduced from 0.46 ± 0.04 to 0.20 ± 0.04 mGy in the presence of lead apron shielding (p < 0.001), the reduction was equal to 56%. Furthermore, the heritable risk probability was obtained at 2.0 ×10-5 % and 4.6 ×10-5 % for the patients using the lead apron shield versus without shield, respectively. CONCLUSION Applying common lead aprons as shielding in the testis regions of male patients undergoing chest CT scans can reduce the radiation doses significantly. Therefore, this shield can be recommended for routine chest CT examinations.
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Affiliation(s)
- Mohammad Kiapour
- MSc, Student Research Committee, Babol University of Medical Sciences, Babol, Iran
| | - Kourosh Ebrahimnejad Gorji
- PhD, Department of Medical Physics Radiobiology and Radiation Protection, School of Medicine, Babol University of Medical Sciences, Babol, Iran
| | - Rahele Mehraeen
- MD, Department of Pediatric Radiology, Babol University of Medical Sciences, Babol, Iran
| | - Naser Ghaemian
- MD, Department of Radiology and Radiotherapy, School of Medicine, Babol University of Medical Sciences, Babol, Iran
| | - Fatemeh Niksirat Sustani
- MSc, Department of Medical Physics Radiobiology and Radiation Protection, School of Medicine, Babol University of Medical Sciences, Babol, Iran
| | - Razzagh Abedi-Firouzjah
- MSc, Department of Medical Physics Radiobiology and Radiation Protection, School of Medicine, Babol University of Medical Sciences, Babol, Iran
| | - Ali Shabestani Monfared
- PhD, Cancer Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
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Koo BY, Kong HJ. Development of an aperture-type radiation regulator for shielding against secondary radiation from x-ray tubes and collimators in computed tomography. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2019; 39:373-386. [PMID: 30602144 DOI: 10.1088/1361-6498/aafb96] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
During computed tomography (CT) scans, radiation scatters in all directions, increasing radiation exposure. In this study, an aperture-type radiation regulator was developed to provide shielding against secondary radiation from the x-ray tube and collimator in CT. To evaluate the usefulness of the developed aperture-type radiation regulator, (1) spatial dose distribution within the CT room was measured, (2) dose intensity at 1 m from the isocenter was compared, (3) absorbed dose in the nearby organs was evaluated using a human equivalent phantom, and (4) noise, CNR, and SNR were compared for assessment of image quality. The results showed that the developed aperture-type radiation regulator reduced the intensity of secondary radiation by approximately 25% in front of the gantry and 15% to the rear of the gantry. The maximum dose distribution on 10 μGy was reduced by approximately 18% in front of the gantry and 12% in the rear. In addition, when the neck and head were scanned, the absorbed dose in the chest decreased by 25% and 40%, respectively, and noise was reduced by 3.3%-4.5% for different phantoms. Evaluation of abdominal CT images showed 18% noise reduction, with 27% and 28% increases in the signal-to-noise and contrast-to-noise ratios, respectively. These results confirmed that the proposed aperture-type radiation regulator can reduce radiation exposure without affecting primary radiation that creates medical images. The results also confirmed that the radiation regulator effectively improves the quality of medical images.
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Affiliation(s)
- Bon-Yeoul Koo
- Department of Biomedical Engineering, Graduate School, Chungnam National University, Daejeon 35015, Republic of Korea
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Abstract
BACKGROUND The use of radiation protection equipment can reduce the radiation exposure of patients. OBJECTIVES The aim was to show which patient shields should be used for the different types of examination. METHODS The results of multiple studies were compiled and analyzed and recommendations made for the use of patient shields. The absolute dose values and the protective effect were considered. RESULTS Radiological protection should be used in many investigations; particularly in the case of CT investigations, a reasonable dose reduction potential exists due to the higher radiation dose. CONCLUSIONS Based on these recommendations, workflow changes in some types of investigation are expected due to the use of additional patient shields.
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Affiliation(s)
- M Fiebich
- Institut für Medizinische Physik und Strahlenschutz, Technische Hochschule Mittelhessen, Wiesenstr. 14, 35390, Gießen, Deutschland.
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Matyagin YV, Collins PJ. Effectiveness of abdominal shields in chest radiography: a Monte Carlo evaluation. Br J Radiol 2016; 89:20160465. [PMID: 27504913 PMCID: PMC5124812 DOI: 10.1259/bjr.20160465] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/26/2016] [Accepted: 08/05/2016] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The aims of this study were to assess the effectiveness of abdominal shields in reducing the dose to shielded organs during posteroanterior (PA) chest radiographic examinations, to evaluate the various factors contributing to the dose under the shield and to address the concern that internal scatter from the shield may lead to a dose increase to shielded organs. METHODS Monte Carlo simulations of radiographic exposures to a soft-tissue "patient" phantom of 80 × 34 × 24 cm were performed at the peak X-ray tube voltage of 100 kV. The abdominal shield was simulated as 0.5-mm lead with/without a 0.2-mm-thick plastic film cover. The shield-to-phantom spacing varied from 0 to 40 cm. RESULTS The dose to the phantom at different phantom depths and distances from the X-ray field edge was recorded. At the level of the uterus and ovaries (approximately 8-cm deep and 15 cm from the field of view), the dose reduction was approximately 0.035 µGy or 4%. A small dose increase (maximum: 0.4 µGy) to the phantom surface layer was also observed. CONCLUSION In general, there was a small dose reduction in regions protected by the shield. However, the overall risk benefit to a patient would be negligible. ADVANCES IN KNOWLEDGE Abdominal shields used during PA chest radiography provide a small dose reduction to organs at depth by removing the primary X-ray beam photons that are scattered in air, while giving a small increase in skin dose due to X-rays scattered from the abdominal shield internal surface.
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Affiliation(s)
- Yuri V Matyagin
- South Australian Medical Imaging, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Peter J Collins
- South Australian Medical Imaging, Royal Adelaide Hospital, Adelaide, SA, Australia
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Ferris H, Twomey M, Moloney F, O’Neill SB, Murphy K, O’Connor OJ, Maher M. Computed tomography dose optimisation in cystic fibrosis: A review. World J Radiol 2016; 8:331-341. [PMID: 27158420 PMCID: PMC4840191 DOI: 10.4329/wjr.v8.i4.331] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/15/2015] [Accepted: 01/19/2016] [Indexed: 02/06/2023] Open
Abstract
Cystic fibrosis (CF) is the most common autosomal recessive disease of the Caucasian population worldwide, with respiratory disease remaining the most relevant source of morbidity and mortality. Computed tomography (CT) is frequently used for monitoring disease complications and progression. Over the last fifteen years there has been a six-fold increase in the use of CT, which has lead to a growing concern in relation to cumulative radiation exposure. The challenge to the medical profession is to identify dose reduction strategies that meet acceptable image quality, but fulfil the requirements of a diagnostic quality CT. Dose-optimisation, particularly in CT, is essential as it reduces the chances of patients receiving cumulative radiation doses in excess of 100 mSv, a dose deemed significant by the United Nations Scientific Committee on the Effects of Atomic Radiation. This review article explores the current trends in imaging in CF with particular emphasis on new developments in dose optimisation.
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Manssor E, Abuderman A, Osman S, Alenezi SB, Almehemeid S, Babikir E, Alkhorayef M, Sulieman A. Radiation doses in chest, abdomen and pelvis CT procedures. RADIATION PROTECTION DOSIMETRY 2015; 165:194-198. [PMID: 25852181 DOI: 10.1093/rpd/ncv107] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Computed tomography (CT) scanning is recognised as a high-radiation dose modality and estimated to be 17 % of the radiological procedure and responsible for 70 % of medical radiation exposure. Although diagnostic X rays provide great benefits, their use involves some risk for developing cancer. The objectives of this study are to estimate radiation doses during chest, abdomen and pelvis CT. A total of 51 patients were examined for the evaluation of metastasis of a diagnosed primary tumour during 4 months. A calibrated CT machine from Siemens 64 slice was used. The mean age was 48.0 ± 18.6 y. The mean patient weight was 73.8 ± 16.1 kg. The mean dose-length product was 1493.8 ± 392.1 mGy cm, Volume CT dose index (CTDI vol) was 22.94 ± 5.64 mGy and the mean effective dose was 22.4 ± 5.9 mSv per procedure. The radiation dose per procedure was higher as compared with previous studies. Therefore, the optimisation of patient's radiation doses is required in order to reduce the radiation risk.
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Affiliation(s)
- E Manssor
- Radiology and Medical Imaging Department, Prince Sattam bin Abdulaziz University, College of Applied Medical Sciences, Alkharj, Saudi Arabia
| | - A Abuderman
- Basic Sciences Department, Sattam bin Abdulaziz University, College of Medicine, Alkharj, Saudi Arabia
| | - S Osman
- Radiology and Medical Imaging Department, Prince Sattam bin Abdulaziz University, College of Applied Medical Sciences, Alkharj, Saudi Arabia
| | - S B Alenezi
- Radiology Department, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - S Almehemeid
- Radiology Department, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - E Babikir
- Radiology Department, King Saud University, College of Applied Medical Science, Riyadh, Saudi Arabia
| | - M Alkhorayef
- Radiology Department, King Saud University, College of Applied Medical Science, Riyadh, Saudi Arabia
| | - A Sulieman
- Radiology and Medical Imaging Department, Prince Sattam bin Abdulaziz University, College of Applied Medical Sciences, Alkharj, Saudi Arabia
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Weber N, Monnin P, Elandoy C, Ding S. A model-based approach of scatter dose contributions and efficiency of apron shielding for radiation protection in CT. Phys Med 2015; 31:889-896. [PMID: 26112350 DOI: 10.1016/j.ejmp.2015.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 06/02/2015] [Accepted: 06/05/2015] [Indexed: 11/19/2022] Open
Abstract
Given the contribution of scattered radiations to patient dose in CT, apron shielding is often used for radiation protection. In this study the efficiency of apron was assessed with a model-based approach of the contributions of the four scatter sources in CT, i.e. external scattered radiations from the tube and table, internal scatter from the patient and backscatter from the shielding. For this purpose, CTDI phantoms filled with thermoluminescent dosimeters were scanned without apron, and then with an apron at 0, 2.5 and 5 cm from the primary field. Scatter from the tube was measured separately in air. The scatter contributions were separated and mathematically modelled. The protective efficiency of the apron was low, only 1.5% in scatter dose reduction on average. The apron at 0 cm from the beam lowered the dose by 7.5% at the phantom bottom but increased the dose by 2% at the top (backscatter) and did not affect the centre. When the apron was placed at 2.5 or 5 cm, the results were intermediate to the one obtained with the shielding at 0 cm and without shielding. The apron effectiveness is finally limited to the small fraction of external scattered radiation.
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Affiliation(s)
- N Weber
- University of Applied Sciences, Haute Ecole de Santé Vaud, Av. Beaumont 21, 1011 Lausanne, Switzerland; University Hospital of Lausanne (CHUV), Rue du Bugnon 46, 1011 Lausanne, Switzerland
| | - P Monnin
- University of Applied Sciences, Haute Ecole de Santé Vaud, Av. Beaumont 21, 1011 Lausanne, Switzerland
| | - C Elandoy
- University Hospital of Lausanne (CHUV), Rue du Bugnon 46, 1011 Lausanne, Switzerland
| | - S Ding
- University of Applied Sciences, Haute Ecole de Santé Vaud, Av. Beaumont 21, 1011 Lausanne, Switzerland.
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Kulkarni NM, Pinho DF, Kambadakone AR, Sahani DV. Emerging technologies in CT- radiation dose reduction and dual-energy CT. Semin Roentgenol 2014; 48:192-202. [PMID: 23796370 DOI: 10.1053/j.ro.2013.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Naveen M Kulkarni
- Massachusetts General Hospital, Division of Abdominal Imaging and Intervention, Boston, MA 02114, USA
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10
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Iball GR, Brettle DS. Organ and effective dose reduction in adult chest CT using abdominal lead shielding. Br J Radiol 2011; 84:1020-6. [PMID: 22011831 DOI: 10.1259/bjr/53865832] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The purpose of this study was to evaluate and compare organ and effective dose savings that could be achieved using conventional lead aprons and a new, custom-designed shield as out-of-plane shielding devices during chest CT scans. METHODS Thermoluminescent dosimeters were used to measure doses throughout the abdomen and pelvis during CT scans of the chest of a RANDO phantom. Dose measurements were made with no shielding, with lead aprons and with the new shield around the abdomen and pelvis in order to quantify the achievable organ and effective dose reductions. RESULTS Average dose savings in the 10 phantom sections ranged from 5% to 78% with the highest point dose saving of 93% being found in the mid-pelvis. When shielding was used, the maximum measured organ dose reduction was a 72% dose saving to the testes. Significant dose savings were found throughout the abdomen and pelvis, which contributed to an effective dose saving of 4% that was achieved over and above the dose savings obtained through conventional optimisation strategies. This could yield significant population dose savings and reductions in collective radiation risk. CONCLUSION In this study significant organ and effective dose reductions have been achieved through the use of abdominal shielding during chest CT examinations and it is therefore recommended that out-of-plane patient shielding devices should be used for all chest CT scans and potentially for every CT scan, irrespective of body part.
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Affiliation(s)
- G R Iball
- Department of Medical Physics & Engineering, Old Medical School, Leeds General Infirmary, Leeds, UK.
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11
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Chatterson LC, Leswick DA, Fladeland DA, Hunt MM, Webster ST. Lead versus Bismuth-Antimony Shield for Fetal Dose Reduction at Different Gestational Ages at CT Pulmonary Angiography. Radiology 2011; 260:560-7. [DOI: 10.1148/radiol.11101575] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Ott B, Stüssi A, Mini R. Effectiveness of protective patient equipment for CT: an anthropomorphic phantom study. RADIATION PROTECTION DOSIMETRY 2010; 142:213-221. [PMID: 20829205 DOI: 10.1093/rpd/ncq214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Protective patient equipment for CT examinations is not routinely provided. The aim of this study was to determine whether, and if so what, specific protective equipment is beneficial during CT scans. The absorbed organ doses and the effective doses for thorax, abdomen/pelvis and brain CT investigation with and without the use of protective patient equipment have been determined and compared. All measurements were carried out on modern multislice CT scanner using an anthropomorphic phantom and thermoluminescence dosemeters. The measurements show that protective equipment reduces the dose within the scattered beam area. The highest organ dose reduction was found in organs that protrude from the trunk like the testes or the female breasts that can largely be covered by the protective equipment. The most reduction of the effective dose was found in the male abdomen/pelvis examination (0.32 mSv), followed by the brain (0.11 mSv) and the thorax (0.06 mSv). It is concluded that the use of protective equipment can reduce the applied dose to the patient.
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Affiliation(s)
- Barbara Ott
- Department of Radiooncology, Division of Medical Radiation Physics, University Hospital of Berne, CH-3010 Bern, Switzerland.
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Singh S, Kalra MK, Hsieh J, Licato PE, Do S, Pien HH, Blake MA. Abdominal CT: Comparison of Adaptive Statistical Iterative and Filtered Back Projection Reconstruction Techniques. Radiology 2010; 257:373-83. [PMID: 20829535 DOI: 10.1148/radiol.10092212] [Citation(s) in RCA: 338] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Sarabjeet Singh
- Department of Radiology, Massachusetts General Hospital, 25 New Chardon St, Suite 400B, Boston, MA 02114, USA.
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Schindera S, Nauer C, Treier R, Trueb P, von Allmen G, Vock P, Szucs-Farkas Z. Strategien zur Reduktion der CT-Strahlendosis. Radiologe 2010; 50:1120, 1122-7. [DOI: 10.1007/s00117-010-2053-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Tsapaki V, Rehani M, Saini S. Radiation safety in abdominal computed tomography. Semin Ultrasound CT MR 2010; 31:29-38. [PMID: 20102693 DOI: 10.1053/j.sult.2009.09.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The rapid technological developments in computed tomography (CT) have enabled many new clinical applications in the abdominal region. Abdomen CT is considered as a high radiation dose examination due to the large number of radiosensitive organs in the field of view. CT radiation dose has received a lot of attention not only by the medical specialties and researchers, but also by patients and media. This article reviews the situation on radiation dose and risk and provides practical guidelines to effectively manage the radiation dose without losing the benefits and maintaining diagnostic confidence in CT procedures.
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Daniels C, Furey E. The Effectiveness of Surface Lead Shielding of Gonads Outside the Primary X-ray Beam. J Med Imaging Radiat Sci 2008; 39:189-191. [PMID: 31051779 DOI: 10.1016/j.jmir.2008.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 09/11/2008] [Accepted: 09/19/2008] [Indexed: 11/28/2022]
Affiliation(s)
- Cupido Daniels
- Department of Radiology, Dalhousie University, Halifax, Nova Scotia, Canada.
| | - Elizabeth Furey
- Department of Radiology, Dalhousie University, Halifax, Nova Scotia, Canada
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17
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Kennedy EV, Iball GR, Brettle DS. Investigation into the effects of lead shielding for fetal dose reduction in CT pulmonary angiography. Br J Radiol 2007; 80:631-8. [PMID: 17621603 DOI: 10.1259/bjr/31771954] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This work aims to determine whether lead shielding can be used to decrease the radiation dose to the fetus during CT scans for the diagnosis of pulmonary embolism during early stage pregnancy. An anthropomorphic phantom was modified to contain a 15 cc ionization chamber at the site of the uterus to enable fetal dose to be measured. The effects of a range of scan parameters, positioning of lead and thicknesses of lead were investigated. Fetal dose was lower with lower values of kV(p) and mAs. An increasing thickness of lead decreased the radiation dose to the uterus, as did increasing the proportion of the patient covered by the lead shielding. Fetal dose increased exponentially as the edge of the scan volume moved closer to the point of measurement. In no experiment was the dose to the fetus increased by the presence of the lead. It was found that the fetal radiation dose from a CT scan following a pulmonary embolism protocol can be effectively reduced by the use of lead shielding.
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Affiliation(s)
- E V Kennedy
- Academic Unit of Medical Physics, University of Leeds, UK
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Abstract
Computed Tomography (CT) examinations have rapidly increased in number over the last few years due to recent advances such as the spiral, multidetector-row, CT fluoroscopy and Positron Emission Tomography (PET)-CT technology. This has resulted in a large increase in collective radiation dose as reported by many international organisations. It is also stated that frequently, image quality in CT exceeds the level required for confident diagnosis. This inevitably results in patient radiation doses that are higher than actually required, as also stressed by the US Food and Drug Administration (FDA) regarding the CT exposure of paediatric and small adult patients. However, the wide range in exposure parameters reported, as well as the different CT applications reveal the difficulty in standardising CT procedures. The purpose of this paper is to review the basic CT principles, outline the recent technological advances and their impact in patient radiation dose and finally suggest methods of radiation dose optimisation.
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Dauer LT, Casciotta KA, Erdi YE, Rothenberg LN. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans. BMC Med Imaging 2007; 7:5. [PMID: 17367529 PMCID: PMC1831769 DOI: 10.1186/1471-2342-7-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Accepted: 03/16/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0-15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. METHODS The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. RESULTS The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. CONCLUSION Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.
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Affiliation(s)
- Lawrence T Dauer
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
| | - Kevin A Casciotta
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
| | - Yusuf E Erdi
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
| | - Lawrence N Rothenberg
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
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Abstract
World wide, the number of CT studies in children and the radiation exposure by CT increases. The same energy dose has a greater biological impact in children than in adults, and scan parameters have to be adapted to the smaller diameter of the juvenile body. Based on seven rules, a practical approach to paediatric CT is shown: Justification and patient preparation are important steps before scanning, and they differ from the preparation of adult patients. The subsequent choice of scan parameters aims at obtaining the minimal signal-to-noise ratio and volume coverage needed in a specific medical situation; exposure can be divided in two aspects: the CT dose index determining energy deposition per rotation and the dose-length product (DLP) determining the volume dose. DLP closely parallels the effective dose, the best parameter of the biological impact. Modern scanners offer dose modulation to locally minimise exposure while maintaining image quality. Beyond the selection of the physical parameters, the dose can be kept low by scanning the minimal length of the body and by avoiding any non-qualified repeated scanning of parts of the body. Following these rules, paediatric CT examinations of good quality can be obtained at a reasonable cost of radiation exposure.
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Affiliation(s)
- Peter Vock
- Department of Radiology, University Hospital Inselspital, 3010, Bern, Switzerland.
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Hohl C, Mahnken AH, Klotz E, Das M, Stargardt A, Mühlenbruch G, Schmidt T, Günther RW, Wildberger JE. Radiation Dose Reduction to the Male Gonads During MDCT: The Effectiveness of a Lead Shield. AJR Am J Roentgenol 2005; 184:128-30. [PMID: 15615962 DOI: 10.2214/ajr.184.1.01840128] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Our study was designed to quantify the effect of a standard gonad shield on the testicular radiation exposure due to scatter during routine abdominopelvic MDCT. SUBJECTS AND METHODS Routine abdominopelvic MDCT was performed in 34 patients with gonadal lead shielding and 32 patients without this shielding; the testes were not exposed to the direct beam during the examination. We estimated the testicular dose administered with thermoluminescent dosimetry, taking into account each patient's body weight and body mass index (BMI). RESULTS With a 1-mm lead shield, the mean testicular dose was reduced from 2.40 to 0.32 mSv, a reduction of 87%. The difference was found to be statistically significant (p < 0.0001). No correlation between testicular dose and body weight or BMI was found. CONCLUSION Shielding the male gonads reduces the testicular radiation dose during abdominopelvic MDCT significantly and can be recommended for routine use.
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Affiliation(s)
- Christian Hohl
- Department of Diagnositc Radiology, University of Technology of Aachen, Paulwelsstrasse 30, Aachen D-52057, Germany.
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Kalra MK, Maher MM, Rizzo S, Kanarek D, Shepard JAO, Shephard JAO. Radiation exposure from chest CT: issues and strategies. J Korean Med Sci 2004; 19:159-66. [PMID: 15082885 PMCID: PMC2822293 DOI: 10.3346/jkms.2004.19.2.159] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Accepted: 03/15/2004] [Indexed: 01/13/2023] Open
Abstract
Concerns have been raised over alleged overuse of CT scanning and inappropriate selection of scanning methods, all of which expose patients to unnecessary radiation. Thus, it is important to identify clinical situations in which techniques with lower radiation dose such as plain radiography or no radiation such as MRI and occasionally ultrasonography can be chosen over CT scanning. This article proposes the arguments for radiation dose reduction in CT scanning of the chest and discusses recommended practices and studies that address means of reducing radiation exposure associated with CT scanning of the chest.
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Affiliation(s)
- Mannudeep K Kalra
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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Kalra MK, Maher MM, Toth TL, Hamberg LM, Blake MA, Shepard JA, Saini S. Strategies for CT radiation dose optimization. Radiology 2004; 230:619-28. [PMID: 14739312 DOI: 10.1148/radiol.2303021726] [Citation(s) in RCA: 670] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Recent technologic advances have markedly enhanced the clinical applications of computed tomography (CT). While the benefits of CT exceed the harmful effects of radiation exposure in patients, increasing radiation doses to the population have raised a compelling case for reduction of radiation exposure from CT. Strategies for radiation dose reduction are difficult to devise, however, because of a lack of guidelines regarding CT examination and scanning techniques. Various methods and strategies based on individual patient attributes and CT technology have been explored for dose optimization. It is the purpose of this review article to outline basic principles of CT radiation exposure and emphasize the need for CT radiation dose optimization based on modification of scanning parameters and application of recent technologic innovations.
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Affiliation(s)
- Mannudeep K Kalra
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, White 270-E, 55 Fruit St, Boston, MA 02114, USA
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Brnić Z, Vekić B, Hebrang A, Anić P. Efficacy of breast shielding during CT of the head. Eur Radiol 2003; 13:2436-40. [PMID: 12827426 DOI: 10.1007/s00330-003-1945-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2002] [Revised: 12/18/2002] [Accepted: 03/17/2003] [Indexed: 11/26/2022]
Abstract
In light of increasing frequency of CT examinations in the past decades, the aims of this prospective study were to investigate scatter radiation breast exposure in head CT and its dependence upon body constitution, and to assess the efficacy of lead shielding as a means of breast dose reduction. In 49 women referred to head CT for objective medical reasons one breast was covered with lead apron during CT scanning. Radiation doses were measured by use of thermoluminescent dosimeters, at skin of both breasts and over the apron. The doses were then compared as well as correlated to body mass index and meatus acusticus externus-to-dosimeter distance, respectively. Average exposure at the skin of the unshielded breast was 0.28 mGy (range 0.15-0.41 mGy), compared with 0.13 mGy (range 0.05-0.29 mGy) at the shielded breast. The doses showed a mean reduction by 57% due to lead shielding. At least half of breast exposure was imparted to the breast from outside, whereas the remainder results from internal scatter. The higher the body mass index, the higher the percentage of internal scatter in total breast dose. Although the level of scatter radiation to the breast is generally low during head CT examination, the use of lead cover enables recognizable further reduction of the exposure, and is recommended as a feasible and effective procedure of breast protection during CT of the head.
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Affiliation(s)
- Z Brnić
- Department of Diagnostic and Interventional Radiology, University Hospital Merkur, Zajceva 19, 10000, Zagreb, Croatia.
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