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Radiation dose and risk of exposure-induced death associated with common computed tomography procedures in Yazd Province. Eur J Radiol 2020; 126:108932. [DOI: 10.1016/j.ejrad.2020.108932] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 02/07/2020] [Accepted: 03/02/2020] [Indexed: 01/12/2023]
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2
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Sutanto H, Irdawati Y, Anam C, Fujibuchi T, Dougherty G, Hidayanto E, Arifin Z, Soedarsono JW, Bahrudin. An artifact-free thyroid shield in CT examination: a phantom study. Biomed Phys Eng Express 2020; 6:015029. [DOI: 10.1088/2057-1976/ab6ed1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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3
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European trends in radiology: investigating factors affecting the number of examinations and the effective dose. Radiol Med 2019; 125:296-305. [DOI: 10.1007/s11547-019-01109-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 11/13/2019] [Indexed: 12/24/2022]
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4
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Zhou Y, Scott A, Allahverdian J, Lee C, Kightlinger B, Azizyan A, Miller J. On the relationship of minimum detectable contrast to dose and lesion size in abdominal CT. Phys Med Biol 2015; 60:7671-94. [PMID: 26389637 DOI: 10.1088/0031-9155/60/19/7671] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
CT dose optimization is typically guided by pixel noise or contrast-to-noise ratio that does not delineate low contrast details adequately. We utilized the statistically defined low contrast detectability to study its relationship to dose and lesion size in abdominal CT. A realistically shaped medium sized abdomen phantom was customized to contain a cylindrical void of 4 cm diameter. The void was filled with a low contrast (1% and 2%) insert containing six groups of cylindrical targets ranging from 1.2 mm to 7 mm in size. Helical CT scans were performed using a Siemens 64-slice mCT and a GE Discovery 750 HD at various doses. After the subtractions between adjacent slices, the uniform sections of the filtered backprojection reconstructed images were partitioned to matrices of square elements matching the sizes of the targets. It was verified that the mean values from all the elements in each matrix follow a Gaussian distribution. The minimum detectable contrast (MDC), quantified by the mean signal to background difference equal to the distribution's standard deviation multiplied by 3.29, corresponding to 95% confidence level, was found to be related to the phantom specific dose and the element size by a power law (R^2 > 0.990). Independent readings on the 5 mm and 7 mm targets were compared to the measured contrast to the MDC ratios. The results showed that 93% of the cases were detectable when the measured contrast exceeds the MDC. The correlation of the MDC to the pixel noise and target size was also identified and the relationship was found to be the same for the scanners in the study. To quantify the impact of iterative reconstructions to the low contrast detectability, the noise structure was studied in a similar manner at different doses and with different ASIR blending fractions. The relationship of the dose to the blending fraction and low contrast detectability is presented.
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Garba I, Engel-Hills P, Davidson F, Tabari AM. Computed tomography dose index for head CT in northern Nigeria. RADIATION PROTECTION DOSIMETRY 2015; 165:98-101. [PMID: 25889610 DOI: 10.1093/rpd/ncv188] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Computed tomography dose index w and dose length product were recorded for the purpose of developing diagnostic reference levels (DRLs) for radiation dose optimisation. The study was conducted in three radiology departments with CT centres in Northern Nigeria. Data were collected from 54 consenting adult participants (weighing 70 kg ± 3) that had head CT scans. Analysis was done using SPSS version statistical software. A combined dose for the three centres was calculated and compared with the reported data from the international communities where there are established DRLs. Third quartile values of CTDIw and DLP were determined as 77 mGy and 985 mGy cm, respectively. Local DRLs that are significantly higher than most of the reported data in the literature have been established.
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Affiliation(s)
- I Garba
- Department of Medical Radiography, Bayero University Kano, Kano, Kano State, Nigeria
| | - P Engel-Hills
- Department of Nursing and Radiography, Cape Peninsula University of Technology Cape Town, Cape Town, South Africa
| | - F Davidson
- Department of Nursing and Radiography, Cape Peninsula University of Technology Cape Town, Cape Town, South Africa
| | - A M Tabari
- Department of Radiology, Aminu Kano Teaching Hospital, Kano, Kano State, Nigeria
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The use of multi-detector computed tomography and ultrasonography for evaluation of pleural lesions. EGYPTIAN JOURNAL OF CHEST DISEASES AND TUBERCULOSIS 2015. [DOI: 10.1016/j.ejcdt.2014.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Eley KA, Watt-Smith SR, Golding SJ. "Black bone" MRI: a potential alternative to CT when imaging the head and neck: report of eight clinical cases and review of the Oxford experience. Br J Radiol 2013; 85:1457-64. [PMID: 23091288 DOI: 10.1259/bjr/16830245] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The potential risks associated with ionising radiation are well documented. We have previously reported the "black bone" MRI sequence, useful when imaging cortical bone. The objective of this paper is to report our initial experience of this technique in patients undergoing imaging of the head and neck region. METHODS Using the departmental database those patients having had "black bone" sequences of the head and neck performed as part of their MRI examination in the preceding 5 years were identified. The radiological reports were reviewed to identify those cases where "black bone" or conventional MRI sequences had been performed in place of the requested CT, and the patient medical records for these cases were reviewed. Medical record review was also conducted for those cases where it was considered that the pathological condition requiring imaging would ordinarily be investigated with CT. RESULTS The "black bone" sequence had been performed in 69 patients as part of routine MRI of the head and neck. Of these, 67% (n=46) were performed in combination with CT imaging, the majority of cases being primary tumours. In four cases, an MRI was performed in place of the requested CT scan. We present eight clinical cases illustrating the potential benefits of the "black bone" sequence. CONCLUSIONS "Black bone" MRI offers a radiation-free method of imaging the head and neck, and has been successfully utilised in a range of benign and malignant conditions affecting this region. Advances in knowledge Adoption of this approach, where feasible, would be a significant advance in radiation protection.
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Affiliation(s)
- K A Eley
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.
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Brady SL, Yee BS, Kaufman RA. Characterization of adaptive statistical iterative reconstruction algorithm for dose reduction in CT: A pediatric oncology perspective. Med Phys 2012; 39:5520-31. [PMID: 22957619 DOI: 10.1118/1.4745563] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
PURPOSE This study demonstrates a means of implementing an adaptive statistical iterative reconstruction (ASiR™) technique for dose reduction in computed tomography (CT) while maintaining similar noise levels in the reconstructed image. The effects of image quality and noise texture were assessed at all implementation levels of ASiR™. Empirically derived dose reduction limits were established for ASiR™ for imaging of the trunk for a pediatric oncology population ranging from 1 yr old through adolescence∕adulthood. METHODS Image quality was assessed using metrics established by the American College of Radiology (ACR) CT accreditation program. Each image quality metric was tested using the ACR CT phantom with 0%-100% ASiR™ blended with filtered back projection (FBP) reconstructed images. Additionally, the noise power spectrum (NPS) was calculated for three common reconstruction filters of the trunk. The empirically derived limitations on ASiR™ implementation for dose reduction were assessed using (1, 5, 10) yr old and adolescent∕adult anthropomorphic phantoms. To assess dose reduction limits, the phantoms were scanned in increments of increased noise index (decrementing mA using automatic tube current modulation) balanced with ASiR™ reconstruction to maintain noise equivalence of the 0% ASiR™ image. RESULTS The ASiR™ algorithm did not produce any unfavorable effects on image quality as assessed by ACR criteria. Conversely, low-contrast resolution was found to improve due to the reduction of noise in the reconstructed images. NPS calculations demonstrated that images with lower frequency noise had lower noise variance and coarser graininess at progressively higher percentages of ASiR™ reconstruction; and in spite of the similar magnitudes of noise, the image reconstructed with 50% or more ASiR™ presented a more smoothed appearance than the pre-ASiR™ 100% FBP image. Finally, relative to non-ASiR™ images with 100% of standard dose across the pediatric phantom age spectrum, similar noise levels were obtained in the images at a dose reduction of 48% with 40% ASIR™ and a dose reduction of 82% with 100% ASIR™. CONCLUSIONS The authors' work was conducted to identify the dose reduction limits of ASiR™ for a pediatric oncology population using automatic tube current modulation. Improvements in noise levels from ASiR™ reconstruction were adapted to provide lower radiation exposure (i.e., lower mA) instead of improved image quality. We have demonstrated for the image quality standards required at our institution, a maximum dose reduction of 82% can be achieved using 100% ASiR™; however, to negate changes in the appearance of reconstructed images using ASiR™ with a medium to low frequency noise preserving reconstruction filter (i.e., standard), 40% ASiR™ was implemented in our clinic for 42%-48% dose reduction at all pediatric ages without a visually perceptible change in image quality or image noise.
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Affiliation(s)
- S L Brady
- Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA.
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Brady Z, Ramanauskas F, Cain TM, Johnston PN. Assessment of paediatric CT dose indicators for the purpose of optimisation. Br J Radiol 2012; 85:1488-98. [PMID: 22844033 DOI: 10.1259/bjr/28015185] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES To establish local diagnostic reference levels (LDRLs) at the Royal Children's Hospital (RCH) Melbourne, Parkville, Australia, for typical paediatric CT examinations and compare these with international diagnostic reference levels (DRLs) to benchmark local practice. In addition, the aim was to develop a method of analysing local scan parameters to enable identification of areas for optimisation. METHODS A retrospective audit of patient records for paediatric CT brain, chest and abdomen/pelvis examinations was undertaken. Demographic information, examination parameters and dose indicators--volumetric CT dose index (CTDI(vol)) and dose-length product (DLP)--were collected for 220 patients. LDRLs were derived from mean survey values and the effective dose was estimated from DLP values. The normalised CTDI(vol) values, mAs values and scan length were analysed to better identify parameters that could be optimised. RESULTS The LDRLs across all age categories were 18-45 mGy (CTDI(vol)) and 250-700 mGy cm (DLP) for brain examinations; 3-23 mGy (CTDI(vol)) and 100-800 mGy cm (DLP) for chest examinations; and 4-15 mGy (CTDI(vol)) and 150-750 mGy cm (DLP) for abdomen/pelvis examinations. Effective dose estimates were 1.0-1.6 mSv, 1.8-13.0 mSv and 2.5-10.0 mSv for brain, chest and abdomen/pelvis examinations, respectively. CONCLUSION The RCH mean CTDI(vol) and DLP values are similar to or lower than international DRLs. Use of low-kilovoltage protocols for body imaging in younger patients reduced the dose considerably. There exists potential for optimisation in reducing body scan lengths and justifying the selection of reference mAs values. The assessment method used here proved useful for identifying specific parameters for optimisation. Advances in knowledge Assessment of individual CT parameters in addition to comparison with DRLs enables identification of specific areas for CT optimisation.
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Affiliation(s)
- Z Brady
- Applied Physics, RMIT University, Melbourne, VIC, Australia.
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10
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Survey of computed tomography technique and radiation dose in Sudanese hospitals. Eur J Radiol 2011; 80:e544-51. [DOI: 10.1016/j.ejrad.2010.12.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 12/17/2010] [Indexed: 11/23/2022]
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Dougeni E, Faulkner K, Panayiotakis G. A review of patient dose and optimisation methods in adult and paediatric CT scanning. Eur J Radiol 2011; 81:e665-83. [PMID: 21684099 DOI: 10.1016/j.ejrad.2011.05.025] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Revised: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 12/14/2022]
Abstract
An increasing number of publications and international reports on computed tomography (CT) have addressed important issues on optimised imaging practice and patient dose. This is partially due to recent technological developments as well as to the striking rise in the number of CT scans being requested. CT imaging has extended its role to newer applications, such as cardiac CT, CT colonography, angiography and urology. The proportion of paediatric patients undergoing CT scans has also increased. The published scientific literature was reviewed to collect information regarding effective dose levels during the most common CT examinations in adults and paediatrics. Large dose variations were observed (up to 32-fold) with some individual sites exceeding the recommended dose reference levels, indicating a large potential to reduce dose. Current estimates on radiation-related cancer risks are alarming. CT doses account for about 70% of collective dose in the UK and are amongst the highest in diagnostic radiology, however the majority of physicians underestimate the risk, demonstrating a decreased level of awareness. Exposure parameters are not always adjusted appropriately to the clinical question or to patient size, especially for children. Dose reduction techniques, such as tube-current modulation, low-tube voltage protocols, prospective echocardiography-triggered coronary angiography and iterative reconstruction algorithms can substantially decrease doses. An overview of optimisation studies is provided. The justification principle is discussed along with tools that assist clinicians in the decision-making process. There is the potential to eliminate clinically non-indicated CT scans by replacing them with alternative examinations especially for children or patients receiving multiple CT scans.
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Affiliation(s)
- E Dougeni
- Imaging Physics and Radiation Safety Section, Regional Medical Physics Department, Freeman Hospital, Freeman Road, Newcastle Upon Tyne NE7 7DN, UK.
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12
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Tsalafoutas IA. The impact of overscan on patient dose with first generation multislice CT scanners. Phys Med 2011; 27:69-74. [DOI: 10.1016/j.ejmp.2010.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Revised: 02/08/2010] [Accepted: 03/07/2010] [Indexed: 11/30/2022] Open
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Tsalafoutas IA, Metallidis SI. A method for calculating the dose length product from CT DICOM images. Br J Radiol 2010; 84:236-43. [PMID: 21081566 DOI: 10.1259/bjr/37630380] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The dosimetric calculations in CT examinations are currently based on two quantities: the volume weighted CT dose index (CTDI(vol)) and the dose-length product (DLP). The first quantity is dependent on the exposure factors, scan field of view, collimation and pitch factor selections, whereas the second is additionally dependent on the scan length. METHODS In this study a method for the calculation of these quantities from digital imaging and communication in medicine (DICOM) CT images is presented that allows an objective audit of patient doses. This method was based on software that has been developed to enable the automatic extraction of the DICOM header information of each image (relating to the parameters that affect the aforementioned quantities) into a spreadsheet with embedded functions for calculating the contribution of each image to the CTDI(vol) and DLP values. The applicability and accuracy of this method was investigated using data from actual examinations carried out in three different multislice CT scanners. These examinations have been performed with the automatic exposure control systems activated, and therefore the tube current and tube loading values varied during the scans. RESULTS The calculated DLP values were in good agreement (±5%) with the displayed values. The calculated average CDTI(vol) values were in similar agreement with the displayed CTDI(vol) values but only for two of the three scanners. In the other scanner the displayed CTDI(vol) values were found to be overestimated by about 25%. As an additional application of this method the differences among the tube modulation techniques used by the three CT scanners were investigated. CONCLUSION This method is a useful tool for radiation dose surveys.
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Affiliation(s)
- I A Tsalafoutas
- Medical Physics Department, Agios Savvas Hospital, 171 Alexandras Avenue, 115 22, Athens, Greece.
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Tsalafoutas IA, Koukourakis GV. Patient dose considerations in computed tomography examinations. World J Radiol 2010; 2:262-8. [PMID: 21160666 PMCID: PMC2999328 DOI: 10.4329/wjr.v2.i7.262] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 06/18/2010] [Accepted: 06/25/2010] [Indexed: 02/06/2023] Open
Abstract
Ionizing radiation is extensively used in medicine and its contribution to both diagnosis and therapy is undisputable. However, the use of ionizing radiation also involves a certain risk since it may cause damage to tissues and organs and trigger carcinogenesis. Computed tomography (CT) is currently one of the major contributors to the collective population radiation dose both because it is a relatively high dose examination and an increasing number of people are subjected to CT examinations many times during their lifetime. The evolution of CT scanner technology has greatly increased the clinical applications of CT and its availability throughout the world and made it a routine rather than a specialized examination. With the modern multislice CT scanners, fast volume scanning of the whole human body within less than 1 min is now feasible. Two dimensional images of superb quality can be reconstructed in every possible plane with respect to the patient axis (e.g. axial, sagital and coronal). Furthermore, three-dimensional images of all anatomic structures and organs can be produced with only minimal additional effort (e.g. skeleton, tracheobronchial tree, gastrointestinal system and cardiovascular system). All these applications, which are diagnostically valuable, also involve a significant radiation risk. Therefore, all medical professionals involved with CT, either as referring or examining medical doctors must be aware of the risks involved before they decide to prescribe or perform CT examinations. Ultimately, the final decision concerning justification for a prescribed CT examination lies upon the radiologist. In this paper, we summarize the basic information concerning the detrimental effects of ionizing radiation, as well as the CT dosimetry background. Furthermore, after a brief summary of the evolution of CT scanning, the current CT scanner technology and its special features with respect to patient doses are given in detail. Some numerical data is also given in order to comprehend the magnitude of the potential radiation risk involved in comparison with risk from exposure to natural background radiation levels.
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Golding SJ. Radiation Exposure in CT: What Is the Professionally Responsible Approach? Radiology 2010; 255:683-6. [DOI: 10.1148/radiol.10100449] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Dose reduction in multislice CT by means of bismuth shields: results of in vivo measurements and computed evaluation. Radiol Med 2009; 115:152-69. [DOI: 10.1007/s11547-009-0469-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Accepted: 09/15/2008] [Indexed: 10/20/2022]
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Livingstone RS, Dinakaran PM. Regional survey of CT dose indices in India. RADIATION PROTECTION DOSIMETRY 2009; 136:222-227. [PMID: 19687133 DOI: 10.1093/rpd/ncp160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study intends to evaluate the current level of computed tomography (CT) scanner doses installed in a region in India. In-site CT dose measurement was performed for 127 CT scanners in a region in India. CT dose index (CTDI) was measured using a 10 cm3 pencil ion chamber and 32-cm polymethyl methacrylate body phantom. The CT numbers and image noise were measured for the phantom using software available on each CT scanner. Of the 127 CT scanners, 13 were conventional, 53 helical single-section, 44 multidetector row CT (MDCT) and 17 refurbished machines. The mean-weighted CTDI (CTDI(w)) values calculated using standard exposure parameters for conventional, conventional refurbished, single-section helical scanner (SSHS), refurbished SSHS and MDCT scanners were 7.5, 6.53, 6.8, 6.6 and 7.04 mGy. Twenty-seven CT scanners had deranged CT numbers. Periodic quality assurance and regional dose surveys would be beneficial to set up regional reference levels in India.
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Muhogora WE, Ahmed NA, Beganovic A, Benider A, Ciraj-Bjelac O, Gershan V, Gershkevitsh E, Grupetta E, Kharita MH, Manatrakul N, Milakovic M, Ohno K, Ben Omrane L, Ptacek J, Schandorf C, Shabaan MS, Stoyanov D, Toutaoui N, Wambani JS, Rehani MM. Patient doses in CT examinations in 18 countries: initial results from International Atomic Energy Agency projects. RADIATION PROTECTION DOSIMETRY 2009; 136:118-126. [PMID: 19687134 DOI: 10.1093/rpd/ncp144] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The purpose of this prospective study at 73 facilities in 18 countries in Africa, Asia and Eastern Europe was to investigate if the CT doses to adult patients in developing countries are higher than international standards. The dose assessment was performed in terms of weighted computed tomography dose index (CTDIw) and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. Except in one case, the mean CTDIw values were below diagnostic reference level (DRL) while for DLP, 17 % of situations were above DRLs. The resulting CT images were of adequate quality for diagnosis. The CTDIw and DLP data presented herein are largely similar to those from two recent national surveys. The study has shown a stronger need to create awareness and training of radiology personnel as well as monitoring of radiation doses in many developing countries so as to conform to the ALARA principle.
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Affiliation(s)
- W E Muhogora
- Tanzania Atomic Energy Commission, PO Box 743, Arusha, Tanzania
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Gleeson TG, Moriarty J, Shortt CP, Gleeson JP, Fitzpatrick P, Byrne B, McHugh J, O'Connell M, O'Gorman P, Eustace SJ. Accuracy of whole-body low-dose multidetector CT (WBLDCT) versus skeletal survey in the detection of myelomatous lesions, and correlation of disease distribution with whole-body MRI (WBMRI). Skeletal Radiol 2009; 38:225-36. [PMID: 19009290 DOI: 10.1007/s00256-008-0607-4] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 10/05/2008] [Accepted: 10/07/2008] [Indexed: 02/02/2023]
Abstract
AIM The aim of the study is to assess the feasibility of whole-body low-dose computed tomography (WBLDCT) in the diagnosis and staging of multiple myeloma and compare to skeletal survey (SS), using bone marrow biopsy and whole-body magnetic resonance imaging (WBMRI; where available) as gold standard. MATERIALS AND METHODS Patients referred over an 18-month period for investigation of suspected multiple myeloma or restaging of myeloma were randomized to undergo one of two WBLDCT protocols using high kVp, low mAs technique (140 kVp, 14 mAs; or 140 kVp, 25 mAs). Recent WBMRI scans were reviewed in 23 cases. Each imaging modality was assessed by two radiologists in consensus and scored from 0-3 (0 = normal, 1 = 1-4 lesions, 2 = 5-20 lesions, 3 >or= 20 lesions/diffuse disease) in ten anatomical areas. Overall stage of disease, image quality score, and the degree of confidence of diagnosis were recorded. Diagnostic accuracy of skeletal survey and WBLDCT were determined using a gold standard of bone marrow biopsy and distribution of disease was compared to WBMRI. RESULTS Thirty-nine patients were evaluated. WBLDCT identified more osteolytic lesions than skeletal survey with a greater degree of diagnostic confidence and led to restaging in 18 instances (16 upstaged, two downstaged). In those with recent WBMRI, distribution of disease on WBLDCT showed superior correlation with WBMRI when compared with SS. Overall reader impression of stage on WBLDCT showed significant correlation with WBMRI (kappa = 0.454, p < 0.05). WBLDCT provided complementary information to WBMRI in nine patients with normal marrow signal following treatment response, but which were shown to have diffuse residual cortical abnormalities on CT. CONCLUSION WBLDCT at effective doses lower than previously reported, is superior to SS at detecting osteolytic lesions and at determining overall stage of multiple myeloma, and provides complementary information to WBMRI.
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Affiliation(s)
- T G Gleeson
- Department of Radiology and Diagnostic Imaging, Mater Misericordiae University Hospital, Eccles St., Dublin 7, Ireland.
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ARTHURS OJ, YATES SJ, SET PAK, GIBBONS DA, DIXON AK. Evaluation of image quality and radiation dose in adolescent thoracic imaging: 64-slice is preferable to 16-slice multislice CT. Br J Radiol 2009; 82:157-61. [DOI: 10.1259/bjr/52970138] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Shrimpton PC, Hillier MC, Lewis MA, Dunn M. National survey of doses from CT in the UK: 2003. Br J Radiol 2007; 79:968-80. [PMID: 17213302 DOI: 10.1259/bjr/93277434] [Citation(s) in RCA: 411] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A review of patient doses from CT examinations in the UK for 2003 has been conducted on the basis of data received from over a quarter of all UK scanners, of which 37% had multislice capability. Questionnaires were employed to collect scan details both for the standard protocols established at each scanner for 12 common types of CT examination on adults and children, and for samples of individual patients. This information was combined with published scanner-specific CT dose index (CTDI) coefficients to estimate values of the standard dose indices CTDI(w) and CTDI(vol) for each scan sequence. Knowledge of each scan length allowed assessment of the dose-length product (DLP) for each examination, from which effective doses were then estimated. When compared with a previous UK survey for 1991, wide variations were still apparent between CT centres in the doses for standard protocols. The mean UK doses for adult patients were in general lower by up to 50% than those for 1991, although doses were slightly higher for multislice (4+) (MSCT) relative to single slice (SSCT) scanners. Values of CTDI(vol) for MSCT were broadly similar to European survey data for 2001. The third quartile values of these dose distributions have been used to derive UK national reference doses for examinations on adults (separately for SSCT and MSCT) and children as initial tools for promoting patient protection. The survey has established the PREDICT (Patient Radiation Exposure and Dose in CT) database as a sustainable national resource for monitoring dose trends in CT through the ongoing collation of further survey data.
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Affiliation(s)
- P C Shrimpton
- Radiation Protection Division, Health Protection Agency, Chilton, Didcot, Oxon OX11 0RQ, UK.
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Heaney DE, Norvill CAJ. A Comparison of reduction in CT dose through the use of gantry angulations or bismuth shields. ACTA ACUST UNITED AC 2006; 29:172-8. [PMID: 16845922 DOI: 10.1007/bf03178890] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study investigated the effect of gantry angulation and eye shielding on radiation dose to the eye lens during brain Computed Tomography (CT), and secondly the effectiveness of thyroid and breast bismuth shielding during routine neck and chest CT. An anthropomorphic 'Rando' phantom was scanned at three commonly used gantry angles using this centre's normal adult brain protocol, and for normal adult neck and chest protocols. Bismuth shields were placed over the appropriate organs and dose measured using thermoluminescent dosimeters (TLD). Angling the gantry along the supraorbital meatal plane could reduce the dose by approximately 88% relative to the hard palate and Reid's base line protocols. Bismuth eye shields reduce dose by up to 48% when using either of the first two angles but gave no significant reduction in the supra-orbital plane. Reduction in thyroid dose for neck and chest scans were 55% and 47% respectively, and dose reduction in breast was 23%. We thus conclude that angling the gantry to avoid the orbits is the more effective method of reducing radiation dose to the eyes, with single use bismuth shields to be used where this is not feasible. Thyroid and breast shields should be used where the resultant artefact is not detrimental to image quality.
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Affiliation(s)
- D E Heaney
- Medical Imaging Department, Prince of Wales Hospital, Sydney, Australia
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