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Long M, Albeshan S, Alashban Y, England A, Moore N, Young R, Bezzina P, McEntee MF. The effect of contact radiation shielding on breast dose during CT abdomen-pelvis: a phantom study. RADIATION PROTECTION DOSIMETRY 2023; 199:2104-2111. [PMID: 37551012 DOI: 10.1093/rpd/ncad218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 07/05/2023] [Accepted: 07/09/2023] [Indexed: 08/09/2023]
Abstract
This study aims to investigate if contact shielding reduces breast radiation dose during computed tomography (CT) abdomen-pelvis examinations using automatic tube current modulation to protect one of the four most radiosensitive organs during CT examinations. Dose measurements were taken with and without contact shielding across the anterior and lateral aspects of the breasts and with and without organ dose modulation (ODM) to quantify achievable dose reductions. Although there are no statistically significant findings, when comparing with and without shielding, the mean breast surface dose was reduced by 0.01 μSv without ODM (1.92-1.91 μSv, p = 0.49) and increased by 0.03 μSv with ODM (1.53-1.56 μSv, p = 0.44). Comparing with and without ODM, the mean breast surface dose was reduced by 0.35 μSv with shielding (1.91-1.56 μSv, p = 0.24) and by 0.39 μSv without shielding (1.92-1.53 μSv, p = 0.17). The addition of contact shielding does not provide significant breast surface radiation dose reduction during CT abdomen-pelvis.
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Affiliation(s)
- Maria Long
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
| | - Salman Albeshan
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, PO Box 145111, Riyadh 4545, Saudi Arabia
| | - Yazeed Alashban
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, PO Box 145111, Riyadh 4545, Saudi Arabia
| | - Andrew England
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
| | - Niamh Moore
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
| | - Rena Young
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
| | - Paul Bezzina
- Department of Radiography, Faculty of Health Sciences, University of Malta, Msida MSD 2080, Malta
| | - Mark F McEntee
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
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Saeedi-Moghadam M, Tayebi M, Chegeni N, Sina S, Kolayi T. Efficiency of non-lead and lead thyroid shields in radiation protection of CT examinations. Radiat Phys Chem Oxf Engl 1993 2021; 180:109265. [DOI: 10.1016/j.radphyschem.2020.109265] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Trožić Š, Mekiš N, Zalokar N. The efficiency of lead and non-lead shielding on breast dose in head CT. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2020; 40:816-826. [PMID: 32460255 DOI: 10.1088/1361-6498/ab96d5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The aim of the study was to assess the effect of the shielding material and its thickness on the measured skin dose to the breasts during the CT examination of the head. The helical and axial head CT was performed on an anthropomorphic phantom (PBU 60). Two types of shielding were tested-lead and non-lead (antimony-bismuth) shielding. Measurements with different thicknesses were performed and the shielding efficiency of the materials was compared. Skin dose to the breasts was measured with an educational direct dosimeter (EDD-30). The shielding efficiency during both scanning protocols indicated an increased dose reduction with the thicker equivalent thickness in both shielding materials. Dose reduction was the highest at 0.5 mm equivalent thickness for both materials; lead shielding reduced the dose by 91% and 83%, the antimony-bismuth shielding by 90% and 86%, during the axial and helical head CT protocols, respectively. Statistically significant differences were found between the materials of the same equivalent thickness (0.175, 0.25 and 0.5 mm) during the helical protocol in favor of the antimony-bismuth shielding. During the axial protocol there were no statistically significant differences. Shielding of radiosensitive organs can prevent unnecessary exposure of radiosensitive organs outside the primary beam. Due to the significant decrease in radiation dose to the breasts, and many other positive attributes, use of the antimony-bismuth shielding instead of the lead shielding should be considered, especially during the helical CT scan of the head.
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Affiliation(s)
- Šejla Trožić
- Faculty of Health Sciences, Medical Imaging and Radiotherapy Department, University of Ljubljana, Zdravstvena pot 5, Ljubljana 1000, Slovenia
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Zalokar N, Mekis N. Efficacy of breast shielding during head computed tomography examination. Radiol Oncol 2020; 55:116-120. [PMID: 33885233 PMCID: PMC7877269 DOI: 10.2478/raon-2020-0044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 06/16/2020] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Female breasts are exposed to scattered radiation regardless of not being included in the primary field during head CT. This study aimed to investigate whether the use of lead shielding is beneficial in dose reduction to the breasts during head CT. PATIENTS AND METHODS The study was performed in two different hospitals on two different CT units and included 120 patients. Half of the measurements (n = 60) was conducted without the use of lead shielding and the other half (n = 60) with the use of lead shielding of 0.5 mm equivalent thickness. RESULTS Significant skin dose reduction to the breasts during head CT in both hospitals with the use of lead shielding was discovered; 81% (338.2 ± 43.7 μGy to 64.3 ± 18.8 μGy) in Hospital A and 74% (from 253.1 ± 35.1 μGy to 65.3 ± 16.9 μGy) in Hospital B. CONCLUSIONS Considering the assumed carcinogenic effect of low doses of radiation, high frequency of the head CT scans and the significant reduction of radiation doses to the highly radiosensitive breasts, the use of lead shielding is highly recommendable.
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Affiliation(s)
- Nika Zalokar
- University of Ljubljana, Faculty of Health Sciences, Medical Imaging and Radiotherapy Department, Ljubljana, Slovenia
| | - Nejc Mekis
- University of Ljubljana, Faculty of Health Sciences, Medical Imaging and Radiotherapy Department, Ljubljana, Slovenia
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Zalokar N, Mekiš N. A PHANTOM STUDY SHOWING THE IMPORTANCE OF BREAST SHIELDING DURING HEAD CT. RADIATION PROTECTION DOSIMETRY 2020; 188:464-469. [PMID: 31942634 DOI: 10.1093/rpd/ncz305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 11/25/2019] [Accepted: 12/24/2019] [Indexed: 06/10/2023]
Abstract
This study aimed to investigate the dose to the breasts during head computed tomography (CT) if lead shielding is used. The study was performed in two major hospitals using helical and axial protocols on an anthropomorphic phantom. Measurements were performed with and without the use of a lead shield of 0.5 mm equivalent density. The results showed a significant decrease in dose with the lead shielding in both hospitals. During the helical protocol, the use of shielding significantly reduced the dose by 96% in Hospital A and 82% in Hospital B. The dose reduction during axial protocol was also significant: 95% in Hospital A and 86% in Hospital B with lead shielding. Considering the significant dose reduction of 82% up to 96% during this study, we highly recommend the shielding of breasts regardless of the protocol used during head CT examinations.
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Affiliation(s)
- Nika Zalokar
- Faculty of Health Sciences, Medical imaging and radiotherapy department, University of Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia
| | - Nejc Mekiš
- Faculty of Health Sciences, Medical imaging and radiotherapy department, University of Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia
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Elshami W, Abuzaid MM, Tekin HO. Effectiveness of Breast and Eye Shielding During Cervical Spine Radiography: An Experimental Study. Risk Manag Healthc Policy 2020; 13:697-704. [PMID: 32636688 PMCID: PMC7335279 DOI: 10.2147/rmhp.s257185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/10/2020] [Indexed: 11/23/2022] Open
Abstract
Purpose This study assessed the effectiveness of breast and eye shielding and measured the radiation dose to radiosensitive tissues (eyes and breasts) due to scatter radiation during cervical spine X-ray radiography examinations. Methods Using an anthropomorphic phantom, the scattered radiation dose was measured before and after the placement of the lead shield over the eyes and breasts in the anteroposterior (AP) and left lateral projection. A regression formula was utilized to determine the exposure. Mean values and standard deviation of breasts and eyes doses were calculated. The paired two sample t-test was used to compare the recorded dose before and after shielding placement. Results Radiation shielding of eyes and breasts during AP cervical spine X-ray decreased radiation dose to the breasts by 99.9% and to the left and right eye by 91% and 89%, respectively. For the left lateral cervical spine X-ray, the radiation dose decreased by 26% and 31% for the left and right eye, respectively, and by 23% and 99% for the left and right breast, respectively. A significant difference was noted comparing the dose before and after the implementing shielding on the eye and breast. Conclusion According to the results presented, the dose is significantly reduced, especially considering that they are not in the area of interest but are exposed to scatter radiation.
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Affiliation(s)
- Wiam Elshami
- Medical Diagnostic Imaging Department, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Mohamed M Abuzaid
- Medical Diagnostic Imaging Department, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - H O Tekin
- Medical Diagnostic Imaging Department, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
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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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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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Baldeo C, Hritani A, Baldeo C, Percy R. Does chemo-radiation predispose to structural valve deterioration? Int J Cardiol 2016; 211:53-4. [PMID: 26974696 DOI: 10.1016/j.ijcard.2016.02.155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 02/29/2016] [Indexed: 10/22/2022]
Affiliation(s)
- Candice Baldeo
- University of Florida - Jacksonville, Internal Medicine Department, United States.
| | - AbdulWahab Hritani
- University of Florida - Jacksonville, Internal Medicine Department, United States
| | | | - Robert Percy
- University of Florida - Jacksonville, Department of Cardiology, United States
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Kelaranta A, Ekholm M, Toroi P, Kortesniemi M. Radiation exposure to foetus and breasts from dental X-ray examinations: effect of lead shields. Dentomaxillofac Radiol 2015; 45:20150095. [PMID: 26313308 PMCID: PMC5083886 DOI: 10.1259/dmfr.20150095] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 08/13/2015] [Accepted: 08/26/2015] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Dental radiography may involve situations where the patient is known to be pregnant or the pregnancy is noticed after the X-ray procedure. In such cases, the radiation dose to the foetus, though low, needs to be estimated. Uniform and widely used guidance on dental X-ray procedures during pregnancy are presently lacking, the usefulness of lead shields is unclear and practices vary. METHODS Upper estimates of radiation doses to the foetus and breasts of the pregnant patient were estimated with an anthropomorphic female phantom in intraoral, panoramic, cephalometric and CBCT dental modalities with and without lead shields. RESULTS The upper estimates of foetal doses varied from 0.009 to 6.9 μGy, and doses at the breast level varied from 0.602 to 75.4 μGy. With lead shields, the foetal doses varied from 0.005 to 2.1 μGy, and breast doses varied from 0.002 to 10.4 μGy. CONCLUSIONS The foetal dose levels without lead shielding were <1% of the annual dose limit of 1 mSv for a member of the public. Albeit the relative shielding effect, the exposure-induced increase in the risk of breast cancer death for the pregnant patient (based on the breast dose only) and the exposure-induced increase in the risk of childhood cancer death for the unborn child are minimal, and therefore, need for foetal and breast lead shielding was considered irrelevant. Most important is that pregnancy is never a reason to avoid or to postpone a clinically justified dental radiographic examination.
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Affiliation(s)
- Anna Kelaranta
- Department of Physics, University of Helsinki, Helsinki, Finland
- HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Marja Ekholm
- Oral Radiology, Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Paula Toroi
- STUK—Radiation and Nuclear Safety Authority, Helsinki, Finland
| | - Mika Kortesniemi
- HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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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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Rizzo S, Origgi D, Brambilla S, De Maria F, Foà R, Raimondi S, Colombo N, Bellomi M. Radiation exposure of ovarian cancer patients: contribution of CT examinations performed on different MDCT (16 and 64 slices) scanners and image quality evaluation: an observational study. Medicine (Baltimore) 2015; 94:e765. [PMID: 25929914 PMCID: PMC4603053 DOI: 10.1097/md.0000000000000765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The objective of this study is to compare radiation doses given to ovarian cancer patients by different computed tomographies (CTs) and to evaluate association between doses and subjective and objective image quality.CT examinations included were performed either on a 16-slice CT, equipped with automatic z-axis tube current modulation, or on a 64-slice CT, equipped with z-axis, xy-axis modulation, and adaptive statistical iterative algorithm (ASIR). Evaluation of dose included the following dose descriptors: volumetric CT dose index (CTDIvol), dose length product (DLP), and effective dose (E). Objective image noise was evaluated in abdominal aorta and liver. Subjective image quality was evaluated by assessment of image noise, spatial resolution and diagnostic acceptability.Mean and median CTDIvol, DLP, and E; correlation between CTDIvol and DLP and patients' weight; comparison of objective noise for the 2 scanners; association between dose descriptors and subjective image quality.The 64-slice CT delivered to patients 24.5% lower dose (P < 0.0001) than 16-slice CT. There was a significant correlation between all dose descriptors (CTDIvol, DLP, E) and weight (P < 0.0001). Objective noise was comparable for the 2 CT scanners. There was a significant correlation between dose descriptors and image noise for the 64-slice CT, and between dose descriptors and spatial resolution for the 16-slice CT.Current dose reduction systems may reduce radiation dose without significantly affecting image quality and diagnostic acceptability of CT exams.
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Affiliation(s)
- Stefania Rizzo
- From the Department of Radiology, European Institute of Oncology, via Ripamonti 435, 20141 Milan (SR, MB), Department of Medical Physics, European Institute of Oncology, via Ripamonti 435, 20141 Milan (DO); Department of Health Sciences, University of Milan, via A.di Rudinì 8, 20142 Milan (SB, FDM, RF, MB); Department of Epidemiology and Biostatistics, European Institute of Oncology, via Ripamonti 435, 20141 Milan (SR); and Department of Gynecology, European Institute of Oncology, via Ripamonti 435, 20141 Milan, Italy (NC)
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Chung JJ, Cho ES, Kang SM, Yu JS, Kim DJ, Kim JH. Usefulness of a lead shielding device for reducing the radiation dose to tissues outside the primary beams during CT. Radiol Med 2014; 119:951-957. [PMID: 24903707 DOI: 10.1007/s11547-014-0421-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 02/17/2014] [Indexed: 12/20/2022]
Abstract
PURPOSE This study was done to investigate the efficacy of a lead shield in protecting the tissues outside the primary beams, such as the breast and thyroid, by measurement of the entrance skin dose during CT of the brain, neck, abdomen, and lumbar spine. MATERIALS AND METHODS Institutional Review Board approval was obtained. This study included 150 patients (male:female 25:125, age range 15-45 years). In females, brain, lumbar spine, and abdominal CT scans, pre-/post-contrast neck CT scans, and post-contrast liver dynamic CT scans were performed. In males, brain CT scans only were performed. Breast shielding was performed in all females, and thyroid shielding was conducted in patients with brain CT. During all CT studies, the left breast or left thyroid was shielded using a lead shield, and the contralateral side was left unshielded. Thus, each breast or thyroid measurement had its own control for the same demographic data. The efficacy of the shielding of both breasts and thyroids during CT was assessed. RESULTS During brain, abdominal, lumbar, pre-/post-contrast neck, and post-contrast liver dynamic CT, 33.5, 26.0, 17.4, 26.5, and 16.2 % of the breast skin dose were reduced, respectively. During brain CT, the thyroid skin dose was reduced by 17.9 % (females) and 20.6 % (males). There were statistically significant differences in the skin doses of shielded organs (p < 0.05). Breast shielding during neck and liver dynamic CT was the most effective compared with breast or thyroid shielding during other CT scans. CONCLUSIONS We recommend breast shielding during neck and liver dynamic CT in young female patients to avoid unnecessary radiation exposure.
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Affiliation(s)
- Jae-Joon Chung
- Department of Radiology and Research Institute of Radiological Science, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 135-720, Korea.
| | - Eun-Suk Cho
- Department of Radiology and Research Institute of Radiological Science, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 135-720, Korea
| | - Sung Min Kang
- Department of Radiology and Research Institute of Radiological Science, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 135-720, Korea
| | - Jeong-Sik Yu
- Department of Radiology and Research Institute of Radiological Science, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 135-720, Korea
| | - Dae Jung Kim
- Department of Radiology and Research Institute of Radiological Science, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 135-720, Korea.,Department of Radiology, CHA Bundang Medical Center, CHA University, Songnam, Korea
| | - Joo Hee Kim
- Department of Radiology and Research Institute of Radiological Science, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 135-720, Korea
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Goren AD, Prins RD, Dauer LT, Quinn B, Al-Najjar A, Faber RD, Patchell G, Branets I, Colosi DC. Effect of leaded glasses and thyroid shielding on cone beam CT radiation dose in an adult female phantom. Dentomaxillofac Radiol 2013; 42:20120260. [PMID: 23412460 DOI: 10.1259/dmfr.20120260] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES This study aims to demonstrate the effectiveness of leaded glasses in reducing the lens of eye dose and of lead thyroid collars in reducing the dose to the thyroid gland of an adult female from dental cone beam CT (CBCT). The effect of collimation on the radiation dose in head organs is also examined. METHODS Dose measurements were conducted by placing optically stimulated luminescent dosemeters in an anthropomorphic female phantom. Eye lens dose was measured by placing a dosemeter on the anterior surface of the phantom eye location. All exposures were performed on one commercially available dental CBCT machine, using selected collimation and exposure techniques. Each scan technique was performed without any lead shielding and then repeated with lead shielding in place. To calculate the percent reduction from lead shielding, the dose measured with lead shielding was divided by the dose measured without lead shielding. The percent reduction from collimation was calculated by comparing the dose measured with collimation to the dose measured without collimation. RESULTS The dose to the internal eye for one of the scans without leaded glasses or thyroid shield was 0.450 cGy and with glasses and thyroid shield was 0.116 cGy (a 74% reduction). The reduction to the lens of the eye was from 0.396 cGy to 0.153 cGy (a 61% reduction). Without glasses or thyroid shield, the thyroid dose was 0.158 cGy; and when both glasses and shield were used, the thyroid dose was reduced to 0.091 cGy (a 42% reduction). CONCLUSIONS Collimation alone reduced the dose to the brain by up to 91%, with a similar reduction in other organs. Based on these data, leaded glasses, thyroid collars and collimation minimize the dose to organs outside the field of view.
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Affiliation(s)
- A D Goren
- Department of Cariology and Comprehensive Care, New York University College of Dentistry, New York, NY 10010, USA.
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15
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The effect of breast shielding during lumbar spine radiography. Radiol Oncol 2013; 47:26-31. [PMID: 23450158 PMCID: PMC3573831 DOI: 10.2478/raon-2013-0004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 09/18/2012] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The aim of the study was to determine the influence of lead shielding on the dose to female breasts in conventional x-ray lumbar spine imaging. The correlation between the body mass index and the dose received by the breast was also investigated. MATERIALS AND METHODS Breast surface dose was measured by thermoluminescent dosimeters (TLD). In the first phase measurements of breast dose with and without shielding from lumbar spine imaging in two projections were conducted on an anthropomorphic phantom. In the second stage measurements were performed on 100 female patients, randomly divided into two groups of 50, with breast shielding only used in one group. RESULTS On average, breast exposure dose in lumbar spine imaging in both projections (anteroposterior (AP) and lateral) was found reduced by approximately 80% (p < 0,001) when shielding with 0.5 mm lead equivalent was used (from 0.45±0.25 mGy to 0.09±0.07 mGy on the right and from 0.26±0.14 mGy to 0.06±0.04 mGy on the left breast). No correlation between the body mass index (BMI) and the breast surface radiation dose was observed. CONCLUSIONS Although during the lumbar spine imaging breasts receive low-dose exposure even when shielding is not used, the dose can be reduced up to 80% by breast shielding with no influence on the image quality.
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Qu XM, Li G, Sanderink GCH, Zhang ZY, Ma XC. Dose reduction of cone beam CT scanning for the entire oral and maxillofacial regions with thyroid collars. Dentomaxillofac Radiol 2012; 41:373-8. [PMID: 22707330 DOI: 10.1259/dmfr/30200901] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The aim of this study was to evaluate the influence of thyroid collars on radiation dose during cone beam CT (CBCT) scanning. METHODS Average tissue-absorbed dose for a NewTom 9000 CBCT scanner (Quantitative Radiology, Verona, Italy) was measured using thermoluminescent dosemeter chips in a phantom. The scans were carried out with and without thyroid collars. Effective organ dose and total effective dose were derived using International Commission on Radiological Protection 2007 recommendations. RESULTS The effective organ doses for the thyroid gland and oesophagus were 31.0 µSv and 2.4 µSv, respectively, during CBCT scanning without a collar around the neck. When the thyroid collars were used loosely around the neck, no effective organ dose reduction was observed. When one thyroid collar was used tightly on the front of the neck, the effective organ dose for the thyroid gland and oesophagus were reduced to 15.9 µSv (48.7% reduction) and 1.4 µSv (41.7% reduction), respectively. Similar organ dose reduction (46.5% and 41.7%) was achieved when CBCT scanning was performed with two collars tightly on the front and back of the neck. However, the differences to the total effective dose were not significant among the scans with and without collars around the neck (p = 0.775). CONCLUSIONS Thyroid collars can effectively reduce the radiation dose to the thyroid and oesophagus if used appropriately.
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Affiliation(s)
- X M Qu
- Department of Oral and Maxillofacial Radiology, Peking University School, Beijing, China
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Korir GK, Wambani JS, Korir IK, Ochieng BO. Establishing the quality management baseline in the use of computed tomography machines in Kenya. J Appl Clin Med Phys 2012; 13:3457. [PMID: 22231208 PMCID: PMC5716130 DOI: 10.1120/jacmp.v13i1.3457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Revised: 09/08/2011] [Accepted: 09/09/2011] [Indexed: 11/23/2022] Open
Abstract
The objective of this study was to assess the level of compliance to quality assurance and image quality standards in computed tomography facilities in Kenyan hospitals. A quality assurance inspection and physical image quality assessment in eighteen representative computed tomography facilities were completed. A quantitative method was developed and used to score the results obtained from the physical image quality measurements using the American Association of Physicists in Medicine (AAPM) water phantom. Inspection was done in order to establish the level of compliance with internationally recognized standards such as those stipulated in the European Guidelines Quality Criteria for Computed Tomography and the International Basic Safety Standards for Protection against Ionizing Radiation. The overall findings placed the national quality management performance at 50±3%, while image quality and quality assurance performance were 61±3% and 37±3%, respectively. The quality assurance assessment benchmarked the country's level of quality management system compliance in diagnostic radiology. During accreditation appraisal, the scrutiny of scores from each stage in the medical imaging chain per facility will encourage continual implementation of the quality improvement process. PACS number: 87.57.C, 87.57.cf, 87.57.cj, 87.57.cm, 87.57.cp, 87.57.Q, 87.55.N
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Affiliation(s)
- Geoffrey K. Korir
- Department of Physics and Applied Physics; University of Massachusetts Lowell; Lowell MA 01854 USA
| | | | - Ian K. Korir
- National Nuclear Regulator; Centurion 0157 South Africa
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18
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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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19
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Yadav P, Kozak K, Tolakanahalli R, Ramasubramanian V, Paliwal BR, Welsh JS, Rong Y. Adaptive planning using megavoltage fan-beam CT for radiation therapy with testicular shielding. Med Dosim 2011; 37:157-62. [PMID: 21925866 DOI: 10.1016/j.meddos.2011.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 04/26/2011] [Accepted: 06/10/2011] [Indexed: 11/26/2022]
Abstract
This study highlights the use of adaptive planning to accommodate testicular shielding in helical tomotherapy for malignancies of the proximal thigh. Two cases of young men with large soft tissue sarcomas of the proximal thigh are presented. After multidisciplinary evaluation, preoperative radiation therapy was recommended. Both patients were referred for sperm banking and lead shields were used to minimize testicular dose during radiation therapy. To minimize imaging artifacts, kilovoltage CT (kVCT) treatment planning was conducted without shielding. Generous hypothetical contours were generated on each "planning scan" to estimate the location of the lead shield and generate a directionally blocked helical tomotherapy plan. To ensure the accuracy of each plan, megavoltage fan-beam CT (MVCT) scans were obtained at the first treatment and adaptive planning was performed to account for lead shield placement. Two important regions of interest in these cases were femurs and femoral heads. During adaptive planning for the first patient, it was observed that the virtual lead shield contour on kVCT planning images was significantly larger than the actual lead shield used for treatment. However, for the second patient, it was noted that the size of the virtual lead shield contoured on the kVCT image was significantly smaller than the actual shield size. Thus, new adaptive plans based on MVCT images were generated and used for treatment. The planning target volume was underdosed up to 2% and had higher maximum doses without adaptive planning. In conclusion, the treatment of the upper thigh, particularly in young men, presents several clinical challenges, including preservation of gonadal function. In such circumstances, adaptive planning using MVCT can ensure accurate dose delivery even in the presence of high-density testicular shields.
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Affiliation(s)
- Poonam Yadav
- Department of Human Oncology, University of Wisconsin, Madison, Madison, WI, USA
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Breast Surface Radiation Dose During Coronary CT Angiography: Reduction by Breast Displacement and Lead Shielding. AJR Am J Roentgenol 2011; 197:367-73. [DOI: 10.2214/ajr.10.4569] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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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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22
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Radiation dose for routine clinical adult brain CT: Variability on different scanners at one institution. AJR Am J Roentgenol 2010; 195:433-8. [PMID: 20651201 DOI: 10.2214/ajr.09.3957] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to determine, using an anthropomorphic phantom, whether patients are subject to variable radiation doses based on scanner assignment for routine CT of the brain. MATERIALS AND METHODS Twenty metal oxide semiconductor field effect transistor dosimeters were placed in the brain of a male anthropomorphic phantom scanned three times with a routine clinical brain CT protocol on four scanners from one manufacturer in four configurations and on one 64-MDCT scanner from another manufacturer. Absorbed organ doses were measured for skin, cranium, brain, lens of the eye, mandible, and thyroid. Effective dose was calculated on the basis of the dose-length product recorded on each scanner. RESULTS Organ dose ranges were as follows: cranium, 2.57-3.47 cGy; brain, 2.34-3.78 cGy; lens, 2.51-5.03 cGy; mandible 0.17-0.48 cGy; and thyroid, 0.03-0.28 cGy. Statistically significant differences between scanners with respect to dose were recorded for brain and lens (p < 0.05). Absorbed doses were lowest on the single-detector scanner. In the comparison of MDCT scanners, the highest doses were found on the 4-MDCT scanner and the dual-source 64-MDCT scanner not capable of gantry tilt. Effective dose ranged from 1.22 to 1.86 mSv. CONCLUSION According to the phantom data, patients are subject to different organ doses in the lens and brain depending on scanner assignment. At our institution with existing protocols, absorbed doses at brain CT are lowest with the single-detector CT scanner, followed by MDCT scanners capable of gantry tilt. On scanners without gantry tilt, CT of the brain should be performed with careful head positioning and shielding of the orbits. These precautions are especially true for patients who need repeated scanning and for pediatric patients.
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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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25
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Nauer CB, Kellner-Weldon F, Von Allmen G, Schaller D, Gralla J. Effective doses from scan projection radiographs of the head: impact of different scanning practices and comparison with conventional radiography. AJNR Am J Neuroradiol 2008; 30:155-9. [PMID: 18768713 DOI: 10.3174/ajnr.a1293] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE For CT scan planning, scan projection radiographs (SPR) are used. Tube tension and current for head SPR can be reduced to a minimum because of the small head diameter and because only high-contrast structures need to be visualized for planning. The goal of this study was to investigate SPR of the head in respect to effective doses, the influence of dose-reduction measures, and comparison with conventional x-ray. MATERIALS AND METHODS Entrance doses for default and minimal settings were measured on a LightSpeed Ultra CT scanner and on conventional x-ray equipment. Effective doses for different scanning fields of the head were calculated for an adult, a 10-year-old child, and a neonate by using the commercially available software PCXMC. RESULTS Depending on projection and technique, SPR effective doses for adults were 1.9-27.7 muSv; for the 10-year-old child, 2.1-31.1 muSv; and for the neonate, 5.2-97.2 muSv. Doses with the tube under the table were 1.3-3.4 times lower. Doses for conventional radiography were higher than SPR doses for adults and partially lower for children. CONCLUSIONS Depending on the scanning technique, effective doses for head SPR can differ up to 17-fold. The dose is significantly reduced by lowering tube voltage and current, by positioning the tube under the table, and by keeping the thyroid out of the scan or by protecting it with a lead collar. Compared with the conventional x-ray technique, SPR doses tend to be lower due to x-ray beam characteristics.
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Affiliation(s)
- C B Nauer
- Institute for Diagnostic and Interventional Neuroradiology, University Hospital and University of Berne, Berne, Switzerland.
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26
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Ngaile JE, Uiso CBS, Msaki P, Kazema R. Use of lead shields for radiation protection of superficial organs in patients undergoing head CT examinations. RADIATION PROTECTION DOSIMETRY 2008; 130:490-498. [PMID: 18375945 DOI: 10.1093/rpd/ncn095] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Head computed tomography examinations are often accompanied with unnecessary irradiation of superficial organs that are rarely the main target for the investigation. The aim of this work is to demonstrate that lead shields could be effectively used to protect superficial organs without compromising image quality where superficial organ itself is not a target and that the irradiation of the superficial organ is unavoidable. The objective was achieved by first assessing the image quality using phantom measurements made with and without lead shielding in order to determine optimal shielding thickness for patient applications. The entrance surface doses (ESDs) to superficial organs of sixty patients were measured using LiF-thermoluminescent dosemeters without, with one layer, or with two layers of lead shields. Phantom studies demonstrated that the use of modified lead shields of up to 0.25 mm thickness could be used without significant effect on the image quality for central and posterior regions. In these studies, lead shields of 0.25 mm thickness reduce the ESDs to the lens of the eyes and thyroid by 44 and 51%, respectively. The image quality reduction by eye shields was significant to the anterior (i.e. orbital) region but marginal to the central and posterior regions (cerebrum). In view of the above, the use of modified lead shields could reduce the dose to the superficial organs considerably without significantly compromising image quality.
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Affiliation(s)
- J E Ngaile
- Radiation Control Directorate, Tanzania Atomic Energy Commission, PO Box 743, Arusha, Tanzania.
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27
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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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28
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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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Gaeta M, Minutoli F, Vinci S, Salamone I, D'Andrea L, Bitto L, Magaudda L, Blandino A. High-Resolution CT Grading of Tibial Stress Reactions in Distance Runners. AJR Am J Roentgenol 2006; 187:789-93. [PMID: 16928946 DOI: 10.2214/ajr.05.0303] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was twofold: to determine whether asymptomatic distance runners exhibit cortical tibial abnormalities on CT and to determine the diagnostic accuracy of CT in athletes with medial tibial stress syndrome. MATERIALS AND METHODS A cross-sectional study with high-resolution CT of both tibiae was performed on 41 subjects: 20 asymptomatic distance runners, 11 distance runners with unilateral or bilateral pain due to medial tibial stress syndrome (14 painful tibiae), and 10 volunteers not involved in a sport. The group was composed of 13 women and 28 men, ranging in age from 18 to 26 years. A total of 82 tibiae, 14 painful and 68 painless, were evaluated. On the basis of CT findings, tibiae were classified in three groups, and correlation between CT classification and symptoms was made. RESULTS Among distance runners, the presence of CT abnormalities was found in 14 (100%) of 14 painful tibiae in patients with medial tibial stress syndrome and in 8 (16.6%) of 48 painless tibiae. The difference was statistically significant (p < 0.001, Fisher's exact test). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT in diagnosing medial tibial stress syndrome were 100%, 88.2%, 63.6%, 100%, and 90.2%, respectively. CONCLUSION High-resolution CT has high diagnostic accuracy in depicting medial tibial stress syndrome. Cortical abnormalities can also be seen in some asymptomatic distance runners.
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Affiliation(s)
- Michele Gaeta
- Graduating Course of Motor and Sport Sciences, University of Messina, 98100 Messina, Italy
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30
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Williams L, Adams C. Computed tomography of the head: An experimental study to investigate the effectiveness of lead shielding during three scanning protocols. Radiography (Lond) 2006. [DOI: 10.1016/j.radi.2005.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Geleijns J, Salvadó Artells M, Veldkamp WJH, López Tortosa M, Calzado Cantera A. Quantitative assessment of selective in-plane shielding of tissues in computed tomography through evaluation of absorbed dose and image quality. Eur Radiol 2006; 16:2334-40. [PMID: 16604323 DOI: 10.1007/s00330-006-0217-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 01/26/2006] [Accepted: 02/27/2006] [Indexed: 10/24/2022]
Abstract
This study aimed at assessment of efficacy of selective in-plane shielding in adults by quantitative evaluation of the achieved dose reduction and image quality. Commercially available accessories for in-plane shielding of the eye lens, thyroid and breast, and an anthropomorphic phantom were used for the evaluation of absorbed dose and image quality. Organ dose and total energy imparted were assessed by means of a Monte Carlo technique taking into account tube voltage, tube current, and scanner type. Image quality was quantified as noise in soft tissue. Application of the lens shield reduced dose to the lens by 27% and to the brain by 1%. The thyroid shield reduced thyroid dose by 26%; the breast shield reduced dose to the breasts by 30% and to the lungs by 15%. Total energy imparted (unshielded/shielded) was 88/86 mJ for computed tomography (CT) brain, 64/60 mJ for CT cervical spine, and 289/260 mJ for CT chest scanning. An increase in image noise could be observed in the ranges were bismuth shielding was applied. The observed reduction of organ dose and total energy imparted could be achieved more efficiently by a reduction of tube current. The application of in-plane selective shielding is therefore discouraged.
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Affiliation(s)
- J Geleijns
- Radiology Department, Leiden University Medical Center, Albinusdreef 2, 2333, ZA Leiden, The Netherlands.
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Tsiklakis K, Donta C, Gavala S, Karayianni K, Kamenopoulou V, Hourdakis CJ. Dose reduction in maxillofacial imaging using low dose Cone Beam CT. Eur J Radiol 2005; 56:413-7. [PMID: 15978765 DOI: 10.1016/j.ejrad.2005.05.011] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 05/13/2005] [Accepted: 05/18/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES (a) To measure the absorbed dose at certain anatomical sites of a RANDO phantom and to estimate the effective dose in radiographic imaging of the jaws using low dose Cone Beam computed tomography (CBCT) and (b) to compare the absorbed and the effective doses between thyroid and cervical spine shielding and non-shielding techniques. STUDY DESIGN Thermoluminescent dosimeters (TLD-100) were placed at 14 sites in a RANDO phantom, using a Cone Beam CT device (Newtom, Model QR-DVT 9000, Verona, Italy). Dosimetry was carried out applying two techniques: in the first, there was no shielding device used while in the second one, a shielding device (EUREKA!, TRIX) was applied for protection of the thyroid gland and the cervical spine. Effective dose was estimated according to ICRP(60) report (E(ICRP)). An additional estimation of the effective dose was accomplished including the doses of the salivary glands (E(SAL)). A Wilcoxon Signed Ranks Test was used for statistical analysis. RESULTS In the non-shielding technique the absorbed doses ranged from 0.16 to 1.67 mGy, while 0.32 and 1.28 mGy were the doses to the thyroid and the cervical spine, respectively. The effective dose, E(ICRP), was 0.035 mSv and the E(SAL) was 0.064 mSv. In the shielding technique, the absorbed doses ranged from 0.09 to 1.64 mGy, while 0.18 and 0.95 mGy were the respective values for the thyroid and the cervical spine. The effective dose, E(ICRP), was 0.023 mSv and E(SAL) was 0.052 mSv. CONCLUSIONS The use of CBCT for maxillofacial imaging results in a reduced absorbed and effective dose. The use of lead shielding leads to a further reduction of the absorbed doses of thyroid and cervical spine, as well as the effective dose.
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Affiliation(s)
- Kostas Tsiklakis
- Department of Oral Diagnosis and Oral Radiology, School of Dentistry, University of Athens, Greece.
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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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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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