51
|
Carl B, Bopp M, Saß B, Pojskic M, Gjorgjevski M, Voellger B, Nimsky C. Reliable navigation registration in cranial and spine surgery based on intraoperative computed tomography. Neurosurg Focus 2019; 47:E11. [DOI: 10.3171/2019.8.focus19621] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 08/26/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVELow registration errors are an important prerequisite for reliable navigation, independent of its use in cranial or spinal surgery. Regardless of whether navigation is used for trajectory alignment in biopsy or implant procedures, or for sophisticated augmented reality applications, all depend on a correct registration of patient space and image space. In contrast to fiducial, landmark, or surface matching–based registration, the application of intraoperative imaging allows user-independent automatic patient registration, which is less error prone. The authors’ aim in this paper was to give an overview of their experience using intraoperative CT (iCT) scanning for automatic registration with a focus on registration accuracy and radiation exposure.METHODSA total of 645 patients underwent iCT scanning with a 32-slice movable CT scanner in combination with navigation for trajectory alignment in biopsy and implantation procedures (n = 222) and for augmented reality (n = 437) in cranial and spine procedures (347 craniotomies and 42 transsphenoidal, 56 frameless stereotactic, 59 frame-based stereotactic, and 141 spinal procedures). The target registration error was measured using skin fiducials that were not part of the registration procedure. The effective dose was calculated by multiplying the dose length product with conversion factors.RESULTSAmong all 1281 iCT scans obtained, 1172 were used for automatic patient registration (645 initial registration scans and 527 repeat iCT scans). The overall mean target registration error was 0.86 ± 0.38 mm (± SD) (craniotomy, 0.88 ± 0.39 mm; transsphenoidal, 0.92 ± 0.39 mm; frameless, 0.74 ± 0.39 mm; frame-based, 0.84 ± 0.34 mm; and spinal, 0.80 ± 0.28 mm). Compared with standard diagnostic scans, a distinct reduction of the effective dose could be achieved using low-dose protocols for the initial registration scan with mean effective doses of 0.06 ± 0.04 mSv for cranial, 0.50 ± 0.09 mSv for cervical, 4.12 ± 2.13 mSv for thoracic, and 3.37 ± 0.93 mSv for lumbar scans without impeding registration accuracy.CONCLUSIONSReliable automatic patient registration can be achieved using iCT scanning. Low-dose protocols ensured a low radiation exposure for the patient. Low-dose scanning had no negative effect on navigation accuracy.
Collapse
Affiliation(s)
- Barbara Carl
- 1Department of Neurosurgery, University of Marburg; and
| | - Miriam Bopp
- 1Department of Neurosurgery, University of Marburg; and
- 2Marburg Center for Mind, Brain and Behavior (MCMBB), Marburg, Germany
| | - Benjamin Saß
- 1Department of Neurosurgery, University of Marburg; and
| | - Mirza Pojskic
- 1Department of Neurosurgery, University of Marburg; and
| | | | | | - Christopher Nimsky
- 1Department of Neurosurgery, University of Marburg; and
- 2Marburg Center for Mind, Brain and Behavior (MCMBB), Marburg, Germany
| |
Collapse
|
52
|
Dual-Source Dual-Energy CT in Submandibular Sialolithiasis: Reliability and Radiation Burden. AJR Am J Roentgenol 2019; 213:1291-1296. [PMID: 31573848 DOI: 10.2214/ajr.19.21299] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE. This study aims to compare the diagnostic accuracy of virtual unenhanced CT images derived from dual-source dual-energy contrast-enhanced CT with that of standard unenhanced CT images for evaluation of sialolithiasis. MATERIALS AND METHODS. All dual-energy CT studies of the neck performed during the preceding 5 years were reviewed for submandibular gland calculi. Only patients who had unenhanced CT and contrast-enhanced CT performed as part of the same evaluation were included in this study. This review yielded 30 patients. Virtual unenhanced CT images were derived from the dual-energy dataset and compared with the true unenhanced CT images by two separate radiologists who assessed the total number of calculi encountered, their location, the largest dimension, and the attenuation of the calculi. The radiation burden incurred for true unenhanced CT and virtual unenhanced CT and the total radiation burden were calculated. RESULTS. Our analysis revealed that measurements of stone size showed good interobserver agreement. The mean stone size was 7.9 ± 5.9 (SD) mm on virtual unenhanced CT and 8.4 ± 5.9 mm on true unenhanced CT (range, 2.0-31.8 mm); the difference was statistically insignificant. The mean stone attenuation differed considerably (p < 0.01) between the virtual and true unenhanced CT images (494.8 ± 187.5 HU and 924.4 ± 374.9 HU, respectively), but correlated well. The mean radiation dose for a dual-phase IV contrast-enhanced CT study was 23.13 mGy (volume CT dose index). The mean dose was 10.93 mGy for the true unenhanced CT phase, thereby suggesting a 47.25% reduction in administered radiation dose when a single-phase contrast-enhanced CT study with virtual unenhanced image reconstructions is performed. CONCLUSION. Virtual unenhanced CT images derived from dual-source dual-energy CT scans of the neck provide accurate assessment of sialolithiasis akin to that provided by conventional CT protocols but at only a fraction of the radiation dosage.
Collapse
|
53
|
Yurt A, Özsoykal İ, Obuz F. Effects of the Use of Automatic Tube Current Modulation on Patient Dose and Image Quality in Computed Tomography. Mol Imaging Radionucl Ther 2019; 28:96-103. [PMID: 31507141 PMCID: PMC6746012 DOI: 10.4274/mirt.galenos.2019.83723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Objectives: The frequency of abdominal computed tomography examinations is increasing, leading to a significant level of patient dose. This study aims to quantify and evaluate the effects of automatic tube current modulation (ATCM) technique on patient dose and image quality in contrast-enhanced biphasic abdominal examinations. Methods: Two different scan protocols, based on constant tube current and ATCM technique, were used on 64 patients who visited our radiology department periodically. For three patient groups with different patient size, results from two protocols were compared with respect to patient dose and image quality. Dosimetric evaluations were based on the Computed Tomography Dose Index, dose length product, and effective dose. For the comparison of image qualities between two protocols, Noise Index (NI) and Contrast to Noise Ratio (CNR) values were determined for each image. Additionally, the quality of each image was evaluated subjectively by an experienced radiologist, and the results were compared between the two protocols. Results: Dose reductions of 31% and 21% were achieved by the ATCM protocol in the arterial and portal phases, respectively. On the other hand, NI exhibited an increase between 9% and 46% for liver, fat and aorta. CNR values were observed to decrease between 5% and 19%. All images were evaluated by a radiologist, and no obstacle limiting a reliable diagnostic evaluation was found in any image obtained by either technique. Conclusion: These results showed that the ATCM technique reduces patient dose significantly while maintaining a certain level of image quality.
Collapse
Affiliation(s)
- Ayşegül Yurt
- Dokuz Eylül University Faculty of Medicine, Department of Medical Physics, İzmir, Turkey
| | - İsmail Özsoykal
- Dokuz Eylül University Faculty of Medicine, Department of Medical Physics, İzmir, Turkey
| | - Funda Obuz
- Dokuz Eylül University Faculty of Medicine, Department of Radiology, İzmir, Turkey
| |
Collapse
|
54
|
Tzou DT, Zetumer S, Usawachintachit M, Taguchi K, Bechis SK, Duty BD, Harper JD, Hsi RS, Sorensen M, Sur RL, Reliford-Titus S, Chang HC, Isaacson D, Bayne DB, Wang ZJ, Stoller ML, Chi T. Computed Tomography Radiation Exposure Among Referred Kidney Stone Patients: Results from the Registry for Stones of the Kidney and Ureter. J Endourol 2019; 33:619-624. [PMID: 31030576 DOI: 10.1089/end.2019.0091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Purpose: Kidney stone patients routinely have CT scans during diagnostic work-up before being referred to a tertiary center. How often these patients exceed the recommended dose limits for occupational radiation exposure of >100 mSv for 5 years and >50 mSv in a single year from CT alone remains unknown. This study aimed to quantify radiation doses from CTs received by stone patients before their evaluation at a tertiary care stone clinic. Methods: From November 2015 to March 2017, consecutive new patients enrolled into the Registry for Stones of the Kidney and Ureter (ReSKU™) had the dose-length product of every available CT abdomen/pelvis within 5 years of their initial visit recorded, allowing for an effective dose (EDose) calculation. Multivariate logistic regression analysis identified factors associated with exceeding recommended dose limits. Models were created to test radiation reducing effects of low-dose and phase-reduction CT protocols. Results: Of 343 noncontrast CTs performed, only 29 (8%) were low-dose CTs (calculated EDose <4 mSv). Among 389 total patients, 101 (26%) and 25 (6%) had an EDose >20 mSv and >50 mSv/year, respectively. Increased body mass index, number of scans, and multiphase scans were associated with exceeding exposure thresholds (p < 0.01). The implementation of a low-dose CT protocol decreased the estimated number of scans contributing to overexposure by >50%. Conclusions: Stone patients referred to a tertiary stone center may receive excessive radiation from CT scans alone. Unnecessary phases and underutilization of low-dose CT protocols continue to take place. Enacting new approaches to CT protocols may spare stone patients from exceeding recommended dose limits.
Collapse
Affiliation(s)
- David T Tzou
- 1 Department of Urology, University of California, San Francisco, San Francisco, California.,2 Division of Urology, Department of Surgery, University of Arizona College of Medicine, Tucson, Arizona
| | - Samuel Zetumer
- 1 Department of Urology, University of California, San Francisco, San Francisco, California
| | - Manint Usawachintachit
- 1 Department of Urology, University of California, San Francisco, San Francisco, California.,3 Division of Urology, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, The Thai Red Cross Society, Bangkok, Thailand
| | - Kazumi Taguchi
- 1 Department of Urology, University of California, San Francisco, San Francisco, California.,4 Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Seth K Bechis
- 5 Department of Urology, University of California, San Diego, San Diego, California
| | - Brian D Duty
- 6 Department of Urology, Oregon Health & Science University, Portland, Oregon
| | - Jonathan D Harper
- 7 Department of Urology, University of Washington, Seattle, Washington
| | - Ryan S Hsi
- 8 Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Mathew Sorensen
- 7 Department of Urology, University of Washington, Seattle, Washington
| | - Roger L Sur
- 5 Department of Urology, University of California, San Diego, San Diego, California
| | | | - Helena C Chang
- 7 Department of Urology, University of Washington, Seattle, Washington
| | - Dylan Isaacson
- 1 Department of Urology, University of California, San Francisco, San Francisco, California
| | - David B Bayne
- 1 Department of Urology, University of California, San Francisco, San Francisco, California
| | - Zhen J Wang
- 9 Department of Radiology, University of California, San Francisco, San Francisco, California
| | - Marshall L Stoller
- 1 Department of Urology, University of California, San Francisco, San Francisco, California
| | - Thomas Chi
- 1 Department of Urology, University of California, San Francisco, San Francisco, California
| |
Collapse
|
55
|
Zhou DD, Sun P, Jia Z, Zhu W, Shi G, Kong B, Wang H, Zhang H. Multisection computed tomography: Results from a Chinese survey on radiation dose metrics. J Chin Med Assoc 2019; 82:155-160. [PMID: 30839508 DOI: 10.1097/jcma.0000000000000019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND As multisection spiral computed tomography (MSCT) have been extensively used, it is important to consider the amounts of doses the patients are exposed during a computed tomography (CT) examination. The aim of the current study was to summarize MSCT doses in Chinese patients to establish the diagnostic reference levels (DRLs). METHODS Radiation dose metrics were retrospectively collected from 164,073 CT examinations via the Radimetrics Enterprise Platform. Radiation dose metrics (volume CT dose index [CTDIvol], dose-length product [DLP], effective dose [ED], and organ dose) and size-specific dose estimate (SSDE) were calculated for adults and children based on anatomic area and scanner type. RESULTS The median CTDIvol and DLP values were highest in the head at 51.7 mGy (interquartile range [IQR], 33.2-51.7 mGy) and 906.5 mGy·cm (IQR, 582.4-1068.2 mGy·cm) and lowest in the chest at 7.9 mGy (IQR, 7.9-10.3 mGy) and 284.8 mGy·cm (IQR, 249.0-412.6 mGy·cm), respectively. The median SSDE values of chest and pelvis were 12.1 mGy (IQR, 10.8-14.1 mGy) and 36.3 mGy (IQR, 34.0-38.9 mGy), respectively. EDs for children were similar to adults except for an increased 1.5-, 0.77-, and 1.7-fold in the chest, neck, and pelvis, respectively (p < 0.001). Furthermore, radiation doses tended to increase with increasing slice number and decrease when exposure reduction techniques were used. CONCLUSION Our findings provide a basis for the evaluation of CT radiation doses and evidence for establishment of DRLs in China.
Collapse
Affiliation(s)
- Dan-Dan Zhou
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Pengfei Sun
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Zhifang Jia
- Department of Clinical Epidemiology, The First Hospital of Jilin University, Changchun, China
| | - Wanan Zhu
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Guang Shi
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Boyu Kong
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Haifeng Wang
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Huimao Zhang
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| |
Collapse
|
56
|
Xu J, He X, Xiao H, Xu J. Comparative Study of Volume Computed Tomography Dose Index and Size-Specific Dose Estimate Head in Computed Tomography Examination for Adult Patients Based on the Mode of Automatic Tube Current Modulation. Med Sci Monit 2019; 25:71-76. [PMID: 30604739 PMCID: PMC6327780 DOI: 10.12659/msm.913927] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 12/03/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The aim of this study was to compare the metrics of volume computed tomography index (CTDIvol) and size-specific dose estimate (SSDE), and quantity the differences in head CT examinations of adult patients. MATERIAL AND METHODS A total of 157 patients underwent head CT examination were enrolled in this retrospective study. Pearson correlation analysis and linear regression correlation analysis were performed to observe the correlation between the dose metrics of CTDIvol and SSDEaver versus tube current product (mAs) and water equivalent diameter (WED). Correlated factors of CTDIvol and SSDEaver were analyzed by multivariate linear stepwise regression analysis. RESULTS A sum of 4239 data settings were measured: slices with WED >16 cm was 71.05%, and the slices with f <1 was 72.64%. The average value of the absolute difference between WED and the diameter of AAPM head phantom was 2.24±1.42 cm. Statistically significant difference was found between the values of CTDIvol and SSDEaver (P=0.000). The dispersion degree of the CTDIvol values was greater than that of SSDEaver. Strong positive correlation was shown between CTDIvol and mAs (P=0.000), as well as CTDIvol and WED (P=0.000). Strong positive correlation was shown between SSDEaver and mAs (P=0.000), and moderate correlation for SSDEaver and WED (P=0.000). Both the metrics of mAs and WED were included in the multivariate linear stepwise regression equation to observe the effect of related factors on the value of SSDEaver. CONCLUSIONS SSDEaver with better representative can reproduce the radiation dosage of the specific adult patients in head CT examination.
Collapse
Affiliation(s)
- Jian Xu
- Department of Radiology, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, P.R. China
| | - Xiaolong He
- Department of Radiology, Quzhou People’s Hospital, Quzhou, Zhejiang, P.R. China
| | - Huawei Xiao
- Department of Radiology, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, P.R. China
| | - Jianguo Xu
- Department of Radiology, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, P.R. China
| |
Collapse
|
57
|
Hardy AJ, Bostani M, Hernandez AM, Zankl M, McCollough C, Cagnon C, Boone JM, McNitt-Gray M. Estimating a size-specific dose for helical head CT examinations using Monte Carlo simulation methods. Med Phys 2018; 46:902-912. [PMID: 30565704 DOI: 10.1002/mp.13301] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Size-specific dose estimates (SSDE) conversion factors have been determined by AAPM Report 204 to adjust CTDIvol to account for patient size but were limited to body CT examinations. The purpose of this work was to determine conversion factors that could be used for an SSDE for helical, head CT examinations for patients of different sizes. METHODS Validated Monte Carlo (MC) simulation methods were used to estimate dose to the center of the scan volume from a routine, helical head examination for a group of patient models representing a range of ages and sizes. Ten GSF/ICRP voxelized phantom models and five pediatric voxelized patient models created from CT image data were used in this study. CT scans were simulated using a Siemens multidetector row CT equivalent source model. Scan parameters were taken from the AAPM Routine Head protocols for a fixed tube current (FTC), helical protocol, and scan lengths were adapted to the anatomy of each patient model. MC simulations were performed using mesh tallies to produce voxelized dose distributions for the entire scan volume of each model. Three tally regions were investigated: (1) a small 0.6 cc volume at the center of the scan volume, (2) 0.8-1.0 cm axial slab at the center of the scan volume, and (3) the entire scan volume. Mean dose to brain parenchyma for all three regions was calculated. Mean bone dose and a mass-weighted average dose, consisting of brain parenchyma and bone, were also calculated for the slab in the central plane and the entire scan volume. All dose measures were then normalized by CTDIvol for the 16 cm phantom (CTDIvol,16 ). Conversion factors were determined by calculating the relationship between normalized doses and water equivalent diameter (Dw ). RESULTS CTDIvol,16 -normalized mean brain parenchyma dose values within the 0.6 cc volume, 0.8-1.0 cm central axial slab, and the entire scan volume, when parameterized by Dw , had an exponential relationship with a coefficient of determination (R2 ) of 0.86, 0.84, and 0.88, respectively. There was no statistically significant difference between the conversion factors resulting from these three different tally regions. Exponential relationships between CTDIvol,16 -normalized mean bone doses had R2 values of 0.83 and 0.87 for the central slab and for the entire scan volume, respectively. CTDIvol,16 -normalized mass-weighted average doses had R2 values of 0.39 and 0.51 for the central slab and for the entire scan volume, respectively. CONCLUSIONS Conversion factors that describe the exponential relationship between CTDIvol,16 -normalized mean brain dose and a size metric (Dw ) for helical head CT examinations have been reported for two different interpretations of the center of the scan volume. These dose descriptors have been extended to describe the dose to bone in the center of the scan volume as well as a mass-weighted average dose to brain and bone. These may be used, when combined with other efforts, to develop an SSDE dose coefficients for routine, helical head CT examinations.
Collapse
Affiliation(s)
- Anthony J Hardy
- Department of Radiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90024, USA.,Physics and Biology in Medicine Graduate Program, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90024, USA
| | - Maryam Bostani
- Department of Radiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90024, USA.,Physics and Biology in Medicine Graduate Program, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90024, USA
| | - Andrew M Hernandez
- Departments of Radiology and Biomedical Engineering, Biomedical Engineering Graduate Group, University of California Davis, Sacramento, CA, 95817, USA
| | - Maria Zankl
- Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Institute of Radiation Protection, Ingolstaedter Landstrasse 1, Neuherberg, 85764, Germany
| | | | - Chris Cagnon
- Department of Radiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90024, USA.,Physics and Biology in Medicine Graduate Program, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90024, USA
| | - John M Boone
- Departments of Radiology and Biomedical Engineering, Biomedical Engineering Graduate Group, University of California Davis, Sacramento, CA, 95817, USA
| | - Michael McNitt-Gray
- Department of Radiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90024, USA.,Physics and Biology in Medicine Graduate Program, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90024, USA
| |
Collapse
|
58
|
Frush DP. 'Here's looking at you, kid' … again? Revisiting multiphase CT in children. Pediatr Radiol 2018; 48:1711-1713. [PMID: 30178080 DOI: 10.1007/s00247-018-4248-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 08/24/2018] [Indexed: 11/25/2022]
Affiliation(s)
- Donald P Frush
- Department of Radiology, Duke University Medical Center, 1905 McGovern-Davison Children's Health Center, Durham, NC, 27710, USA.
| |
Collapse
|
59
|
Lee RK, Sun JY, Lockerby S, Soltycki E, Matalon T. Reducing Variability of Radiation Dose in CT: The New Frontier in Patient Safety. J Am Coll Radiol 2018; 15:1633-1641. [DOI: 10.1016/j.jacr.2017.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/20/2017] [Accepted: 10/03/2017] [Indexed: 10/18/2022]
|
60
|
Wang Y, Tancredi DJ, Miglioretti DL. Joint Indirect Standardization when Only Marginal Distributions are Observed in the Index Population. J Am Stat Assoc 2018; 114:622-630. [PMID: 31452558 PMCID: PMC6710018 DOI: 10.1080/01621459.2018.1506340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/01/2018] [Indexed: 10/28/2022]
Abstract
It is a common interest in medicine to determine whether a hospital meets a benchmark created from an aggregate reference population, after accounting for differences in distributions of multiple covariates. Due to the difficulties of collecting individual-level data, however, it is often the case that only marginal distributions of the covariates are available, making covariate-adjusted comparison challenging. We propose and evaluate a novel approach for conducting indirect standardization when only marginal covariate distributions of the studied hospital are known, but complete information is available for the reference hospitals. We do this with the aid of two existing methods: iterative proportional fit, which estimates the cells of a contingency table when only marginal sums are known, and synthetic control methods, which create a counterfactual control group using a weighted combination of potential control groups. The proper application of these existing methods for indirect standardization would require accounting for the statistical uncertainties induced by a situation where no individual-level data is collected from the studied population. We address this need with a novel method which uses a random Dirichlet parametrization of the synthetic control weights to estimate uncertainty intervals for the standard incidence ratio. We demonstrate our novel methods by estimating hospital-level standardized incidence ratios for comparing the adjusted probability of computed tomography examinations with high radiations doses, relative to a reference standard and we evalauate out methods in a simulation study.
Collapse
Affiliation(s)
- Yifei Wang
- Department of Radiology, University of California, San Francisco
| | | | | |
Collapse
|
61
|
Tanabe N, Oguma T, Sato S, Kubo T, Kozawa S, Shima H, Koizumi K, Sato A, Muro S, Togashi K, Hirai T. Quantitative measurement of airway dimensions using ultra-high resolution computed tomography. Respir Investig 2018; 56:489-496. [PMID: 30392536 DOI: 10.1016/j.resinv.2018.07.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/29/2018] [Accepted: 07/31/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND Quantitative measurement of airway dimensions using computed tomography (CT) is performed in relatively larger airways due to the limited resolution of CT scans. Nevertheless, the small airway is an important pathological lesion in lung diseases such as chronic obstructive pulmonary disease (COPD) and asthma. Ultra-high resolution scanning may resolve the smaller airway, but its accuracy and limitations are unclear. METHODS Phantom tubes were imaged using conventional (512 × 512) and ultra-high resolution (1024 × 1024 and 2048 × 2048) scans. Reconstructions were performed using the forward-projected model-based iterative reconstruction solution (FIRST) algorithm in 512 × 512 and 1024 × 1024 matrix scans and the adaptive iterative dose reduction 3D (AIDR-3D) algorithm for all scans. In seven subjects with COPD, the airway dimensions were measured using the 1024 × 1024 and 512 × 512 matrix scans. RESULTS Compared to the conventional 512 × 512 scan, variations in the CT values for air were increased in the ultra-high resolution scans, except in the 1024×1024 scan reconstructed through FIRST. The measurement error of the lumen area of the tube with 2-mm diameter and 0.5-mm wall thickness (WT) was minimal in the ultra-high resolution scans, but not in the conventional 512 × 512 scan. In contrast to the conventional scans, the ultra-high resolution scans resolved the phantom tube with ≥ 0.6-mm WT at an error rate of < 11%. In seven subjects with COPD, the WT showed a lower value with the 1024 × 1024 scans versus the 512 × 512 scans. CONCLUSIONS The ultra-high resolution scan may allow more accurate measurement of the bronchioles with smaller dimensions compared with the conventional scan.
Collapse
Affiliation(s)
- Naoya Tanabe
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Tsuyoshi Oguma
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Susumu Sato
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Takeshi Kubo
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Satoshi Kozawa
- Division of Clinical Radiology Service, Kyoto University Hospital, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Hiroshi Shima
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Koji Koizumi
- Division of Clinical Radiology Service, Kyoto University Hospital, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Atsuyasu Sato
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Shigeo Muro
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Kaori Togashi
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Toyohiro Hirai
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| |
Collapse
|
62
|
Navigation-Supported Stereotaxy by Applying Intraoperative Computed Tomography. World Neurosurg 2018; 118:e584-e592. [DOI: 10.1016/j.wneu.2018.06.246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 12/22/2022]
|
63
|
Radiation dose reduction in myocardial perfusion imaging single-photon emission computed tomography/computed tomography using a dose-tracking software. Nucl Med Commun 2018; 39:894-900. [DOI: 10.1097/mnm.0000000000000895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
64
|
Clerkin C, Brennan S, Mullaney LM. Establishment of national diagnostic reference levels (DRLs) for radiotherapy localisation computer tomography of the head and neck. Rep Pract Oncol Radiother 2018; 23:407-412. [PMID: 30190653 PMCID: PMC6107902 DOI: 10.1016/j.rpor.2018.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 05/11/2018] [Accepted: 07/21/2018] [Indexed: 11/28/2022] Open
Abstract
AIM The aim of this research is to establish if variation exists in the dose delivered for head and neck (HN) localisation computed tomography (CT) imaging in radiation therapy (RT); to propose a national diagnostic reference levels (DRLs) for this procedure and to make a comparison between the national DRL and a DRL of a European sample. BACKGROUND CT has become an indispensable tool in radiotherapy (RT) treatment planning. It is a requirement of legislation in many countries that doses of ionising radiation for medical exposures be kept 'As Low As Reasonably Achievable'. There are currently no dose guidelines for RT localisation CT of the HN. MATERIALS AND METHODS All RT departments in Ireland and a sample of European departments were surveyed. Dose data on CT dose length product (DLP); dose index volume (CTDIvol); current time product; tube voltage and scan length was acquired for ten average-sized HN patients from each department. DRLs were proposed for DLP and CTDIvol using the rounded 75th percentile of the distribution of the means. RESULTS 42% of Irish departments and one European department completed the survey. Significant variation was found in the mean DLP, CTDIvol and scan lengths across the Irish departments. The proposed Irish DRL is 882 mGy cm and 21 mGy and the European department DRL is 816 mGy cm and 21 mGy, for DLP and CTDIvol, respectively. CONCLUSIONS Variation exists in doses used for HN RT localisation CT. DRLs have been proposed for comparison purposes with the aim of dose optimisation.
Collapse
Affiliation(s)
- Celine Clerkin
- Applied Radiation Therapy Trinity Research Group, Discipline of Radiation Therapy, School of Medicine, Trinity College Dublin, Ireland
| | - Sinead Brennan
- Department of Radiation Oncology, St Luke's Radiation Oncology Network at St Luke's Hospital, Dublin 6, Ireland
| | - Laura M. Mullaney
- Applied Radiation Therapy Trinity Research Group, Discipline of Radiation Therapy, School of Medicine, Trinity College Dublin, Ireland
| |
Collapse
|
65
|
Leukaemia risk associated with low-dose radiation. LANCET HAEMATOLOGY 2018; 5:e324-e325. [PMID: 30026009 DOI: 10.1016/s2352-3026(18)30106-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 06/24/2018] [Indexed: 10/28/2022]
|
66
|
Ekpo EU, Adejoh T, Akwo JD, Emeka OC, Modu AA, Abba M, Adesina KA, Omiyi DO, Chiegwu UH. Diagnostic reference levels for common computed tomography (CT) examinations: results from the first Nigerian nationwide dose survey. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2018; 38:525-535. [PMID: 29376504 DOI: 10.1088/1361-6498/aaaaf8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
PURPOSE To explore doses from common adult computed tomography (CT) examinations and propose national diagnostic reference levels (nDRLs) for Nigeria. MATERIALS AND METHODS This retrospective study was approved by the Nnamdi Azikiwe University and University Teaching Hospital Institutional Review Boards (IRB: NAUTH/CS/66/Vol8/84) and involved dose surveys of adult CT examinations across the six geographical regions of Nigeria and Abuja from January 2016 to August 2017. Dose data of adult head, chest and abdomen/pelvis CT examinations were extracted from patient folders. The median, 75th and 25th percentile CT dose index volume (CTDIvol) and dose-length-product (DLP) were computed for each of these procedures. Effective doses (E) for these examinations were estimated using the k conversion factor as described in the ICRP publication 103 (EDLP = k × DLP). RESULTS The proposed 75th percentile CTDIvol for head, chest, and abdomen/pelvis are 61 mGy, 17 mGy, and 20 mGy, respectively. The corresponding DLPs are 1310 mGy.cm, 735 mGy.cm, and 1486 mGy.cm respectively. The effective doses were 2.75 mSv (head), 10.29 mSv (chest), and 22.29 mSv (abdomen/pelvis). CONCLUSION Findings demonstrate wide dose variations within and across centres in Nigeria. The results also show CTDIvol comparable to international standards, but considerably higher DLP and effective doses.
Collapse
Affiliation(s)
- Ernest U Ekpo
- Faculty of Health Sciences, The University of Sydney, Discipline of Medical Radiation Sciences, Cumberland Campus, 75 East Street, Lidcombe, NSW 2141, Australia
| | | | | | | | | | | | | | | | | |
Collapse
|
67
|
National survey on dose data analysis in computed tomography. Eur Radiol 2018; 28:5044-5050. [DOI: 10.1007/s00330-018-5408-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 01/04/2023]
|
68
|
Preoperative 3-Dimensional Angiography Data and Intraoperative Real-Time Vascular Data Integrated in Microscope-Based Navigation by Automatic Patient Registration Applying Intraoperative Computed Tomography. World Neurosurg 2018; 113:e414-e425. [DOI: 10.1016/j.wneu.2018.02.045] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/04/2018] [Accepted: 02/06/2018] [Indexed: 11/23/2022]
|
69
|
Varghese B, Kandanga I, Puthussery P, Vijayan D, Babu SPH, Aneesh MK, Noufal M, Binu EV, Babu AC, James SM, Kumar S. Radiation dose metrics in multidetector computed tomography examinations: A multicentre retrospective study from seven tertiary care hospitals in Kerala, South India. Indian J Radiol Imaging 2018; 28:250-257. [PMID: 30050252 PMCID: PMC6038221 DOI: 10.4103/ijri.ijri_394_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Presently, computed tomography (CT) is the most important source of medical radiation exposure. CT radiation doses vary considerably across institutions depending on the protocol and make of equipment. India does not yet have national or region-specific CT diagnostic reference levels. AIM To evaluate radiation doses of consecutive multidetector CT (MDCT) examinations based on anatomic region, performed in 1 month, collected simultaneously from seven tertiary care hospitals in Kerala. SETTINGS AND DESIGN Descriptive study. MATERIALS AND METHODS We collected the CT radiation dose data of examinations from the seven collaborating tertiary care hospitals in Kerala, performed with MDCT scanners of five different makes. The data included anatomic region, number of phases, CT dose index (CTDIvol), dose-length product (DLP), and effective dose (ED) of each examinations and patient demographic data. STATISTICAL ANALYSIS We calculated the 25th, 50th, and 75th percentiles of the CTDIvol, DLP, and ED according to anatomic region. We made descriptive comparisons of these results with corresponding data from other countries. RESULTS Of 3553 patients, head was the most frequently performed examination (60%), followed by abdomen (19%). For single-phase head examinations, 75th percentile of CTDIvol was 68.1 mGy, DLP 1120 mGy-cm, and ED 2.1 mSv. The 75th percentiles of CTDIvol, DLP, and ED for single-phase abdomen examinations were 10.6, 509.3, and 7.7, and multiphase examinations were 14.6, 2666.9, and 40.8; single-phase chest examinations were 23.4, 916.7, and 13.38, and multiphase examinations were 19.9, 1737.6, and 25.36; single-phase neck were 24.9, 733.6, and 3.814, and multiphase neck were 24.9, 2076, and 10.79, respectively. CONCLUSION This summary CT radiation dose data of most frequently performed anatomical regions could provide a starting point for institutional analysis of CT radiation doses, which in turn leads to meaningful optimization of CT.
Collapse
Affiliation(s)
- Binoj Varghese
- Department of Radiodiagnosis, Amala Institute of Medical Sciences, Thrissur, Kerala, India
| | - Indu Kandanga
- Department of Radiodiagnosis, Amala Institute of Medical Sciences, Thrissur and University Hospital of North Durham, Durham, United Kingdom
| | - Paul Puthussery
- Department of Radiodiagnosis, Govt Medical College, Thrissur, Kerala, India
| | - Dhanesh Vijayan
- Department of Radiodiagnosis, Travancore Medical College Hospital, Kollam, Kerala, India
| | - S P Harish Babu
- Department of Radiodiagnosis, Baby Memorial Hospital, Kozhikode, Kerala, India
| | - M K Aneesh
- Department of Radiodiagnosis, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
| | | | - E V Binu
- Department of Radiodiagnosis, Daya Hospital, Thrissur, Kerala, India
| | - Arun C Babu
- Department of Radiodiagnosis, Amala Institute of Medical Sciences, Thrissur, Kerala, India
| | - Sheen M James
- Department of Radiodiagnosis, Amala Institute of Medical Sciences, Thrissur, Kerala, India
| | - Siva Kumar
- Department of Radiodiagnosis, Amala Institute of Medical Sciences, Thrissur, Kerala, India
| |
Collapse
|
70
|
Govani SM, Higgins PDR, Rubenstein JH, Stidham RW, Waljee AK. CT utilization abruptly increases at age 18 among patients with inflammatory bowel diseases in the hospital. PLoS One 2018; 13:e0195022. [PMID: 29596461 PMCID: PMC5875842 DOI: 10.1371/journal.pone.0195022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 03/15/2018] [Indexed: 12/17/2022] Open
Abstract
Objectives Patients with inflammatory bowel disease(IBD) are frequently exposed to computed tomography (CT). Each CT exposes patients to radiation that cumulatively could increase the risk of malignancy, particularly in younger patients. We aim to study the effect of age on CT use in IBD patients seen in the Emergency Department (ED) or the hospital. Methods We conducted a retrospective cohort study of IBD patients identified in Truven Health Marketscan databases between 2009–2013. The main outcome was use of CT during an ED or inpatient visit. Effect of age on CT use was characterized using logistic regression accounting for important covariables. Results There were 66,731 patients with IBD with 144,147 ED or inpatient visits in this cohort with a diagnosis code of IBD. At first visit, 5.8% percent were below age 18. CT was utilized in 26.6% of visits. In multivariable analysis, adjusting for medications, recent surgery, and gender, patients 18–35 were more likely to undergo CT (OR 2.35, 95%CI: 2.20–2.52) compared to those <18. Examining patients only between 16 and 19, the odds of an 18 or 19-year-old undergoing CT is significantly higher than a 16 or 17-year-old (OR 1.96, 95%CI: 1.71–2.24). Conclusions Patients with IBD undergo CT more than a quarter of the time in the ED or inpatient setting. Pediatric providers limit radiation exposure among those <18 while adult providers are not as cautious with radiation exposure for the young adult population. Increased awareness of the risks of cumulative radiation exposure in the young adult population is needed.
Collapse
Affiliation(s)
- Shail M. Govani
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States of America
- South Texas Veterans Healthcare System, San Antonio, Texas, United States of America
- UT Health San Antonio, San Antonio, Texas, United States of America
- * E-mail:
| | - Peter D. R. Higgins
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States of America
| | - Joel H. Rubenstein
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States of America
- South Texas Veterans Healthcare System, San Antonio, Texas, United States of America
| | - Ryan W. Stidham
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States of America
| | - Akbar K. Waljee
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States of America
- VA Center for Clinical Management Research, VA Ann Arbor Health Care System, Ann Arbor, Michigan, United States of America
| |
Collapse
|
71
|
Using the American College of Radiology Dose Index Registry to Evaluate Practice Patterns and Radiation Dose Estimates of Pediatric Body CT. AJR Am J Roentgenol 2018; 210:641-647. [DOI: 10.2214/ajr.17.18122] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
72
|
Boos J, Kröpil P, Bethge OT, Aissa J, Schleich C, Sawicki LM, Heinzler N, Antoch G, Thomas C. ACCURACY OF SIZE-SPECIFIC DOSE ESTIMATE CALCULATION FROM CENTER SLICE IN COMPUTED TOMOGRAPHY. RADIATION PROTECTION DOSIMETRY 2018; 178:8-19. [PMID: 28541574 DOI: 10.1093/rpd/ncx069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 05/15/2017] [Indexed: 06/07/2023]
Abstract
To evaluate the accuracy of size-specific dose estimate (SSDE) calculation from center slice with water-equivalent diameter (Dw) and effective diameter (Deff). A total of 1812 CT exams (1583 adult and 229 pediatric) were included in this retrospective study. Dw and Deff were automatically calculated for all slices of each scan. SSDEs were calculated with two methods: (1) from the center slice; and (2) from all slices of the volume, which was regarded as the reference standard. Impact of patient weight, height and body mass index (BMI) on SSDE accuracy was assessed. The mean difference between overall SSDE and the center slice approach ranged from 2.0 ± 1.7% (range: 0-15.5%) for pediatric chest to 5.0 ± 3.2% (0-17.2%) for adult chest CT. Accuracy of the center slice SSDE approach correlated with patient size (BMI: r = 0.15-0.43; weight r = 0.26-0.49) which led to SSDE overestimation in small and underestimation in large patients. SSDE calculation using the center slice leads to an error of 2-5%; however, SSDE is underestimated in large patients and overestimation in small patients.
Collapse
Affiliation(s)
- Johannes Boos
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| | - Patric Kröpil
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| | - Oliver Th Bethge
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| | - Joel Aissa
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| | - Christoph Schleich
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| | - Lino Morris Sawicki
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| | - Niklas Heinzler
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| | - Christoph Thomas
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany
| |
Collapse
|
73
|
Transatlantic Comparison of CT Radiation Doses in the Era of Radiation Dose-Tracking Software. AJR Am J Roentgenol 2017; 209:1302-1307. [PMID: 28898129 DOI: 10.2214/ajr.17.18087] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study is to compare diagnostic reference levels from a local European CT dose registry, using radiation-tracking software from a large patient sample, with preexisting European and North American diagnostic reference levels. MATERIALS AND METHODS Data (n = 43,761 CT scans obtained over the course of 2 years) for the European local CT dose registry were obtained from eight CT scanners at six institutions. Means, medians, and interquartile ranges of volumetric CT dose index (CTDIvol), dose-length product (DLP), size-specific dose estimate, and effective dose values for CT examinations of the head, paranasal sinuses, thorax, pulmonary angiogram, abdomen-pelvis, renal-colic, thorax-abdomen-pelvis, and thoracoabdominal angiogram were obtained using radiation-tracking software. Metrics from this registry were compared with diagnostic reference levels from Canada and California (published in 2015), the American College of Radiology (ACR) dose index registry (2015), and national diagnostic reference levels from local CT dose registries in Switzerland (2010), the United Kingdom (2011), and Portugal (2015). RESULTS Our local registry had a lower 75th percentile CTDIvol for all protocols than did the individual internationally sourced data. Compared with our study, the ACR dose index registry had higher 75th percentile CTDIvol values by 55% for head, 240% for thorax, 28% for abdomen-pelvis, 42% for thorax-abdomen-pelvis, 128% for pulmonary angiogram, 138% for renal-colic, and 58% for paranasal sinus studies. CONCLUSION Our local registry had lower diagnostic reference level values than did existing European and North American diagnostic reference levels. Automated radiation-tracking software could be used to establish and update existing diagnostic reference levels because they are capable of analyzing large datasets meaningfully.
Collapse
|
74
|
Pyfferoen L, Mulkens TH, Zanca F, De Bondt T, Parizel PM, Casselman JW. Benchmarking adult CT-dose levels to regional and national references using a dose-tracking software: a multicentre experience. Insights Imaging 2017; 8:513-521. [PMID: 28884462 PMCID: PMC5621994 DOI: 10.1007/s13244-017-0570-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 08/16/2017] [Accepted: 08/16/2017] [Indexed: 11/21/2022] Open
Abstract
Objectives To benchmark CT-dose data for standard adult CT studies to regional and national reference levels using a dose-tracking system. Methods Data from five CT systems from three hospitals were collected over a 1- to 2.5-year period (2012–2014), using the same type of dose management system. Inclusion criteria were adult patients and standard CT-head, CT-abdomen-pelvis, CT-thorax, CT-lumbar spine, CT-pulmonary embolism, CT-cervical spine and CT-thorax-abdomen studies, with one helical scan. Volumetric CT-dose index (CTDIvol), dose length product (DLP) and scan length from 31,709 scans were analysed statistically. Results After dose optimisation CTDIvol and DLP values were below the national diagnostic reference levels (DRLs) for all CT studies and for all systems investigated. Mostly no significant differences were found between CTDIvol and DLP levels (p values ≥ 0.01) of CT studies performed on different scanners within the same hospital. Significant dose differences (p values < 0.01) were instead observed among hospitals for comparable CT studies. Dose level range and scan length differences for similar CT studies were revealed. Conclusions Dose-tracking systems help to reduce CT-dose levels below national DRLs. However, dose and protocol data comparison between and within hospitals has the potential to further reduce variability in dose data of standard adult CT studies. Key Points • Retrospective three-centre study on dose levels of standard adult CT procedures. • Dose-tracking systems help hospitals to stay below national dose reference levels. • Dose-tracking systems help to align CT dose levels between scanners within hospitals. • Benchmarking shows CT dose level variability for similar examinations in different hospitals. • Differences in dose level range/scan length for similar CT studies are revealed. Electronic supplementary material The online version of this article (10.1007/s13244-017-0570-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Lotte Pyfferoen
- Department of Radiology, AZ Sint-Jan Brugge-Oostende AV, Ruddershove 10, 8000, Brugge, Belgium.
| | - Tom H Mulkens
- Department of Radiology, H. Hart Hospital, Mechelsestraat 24, 2500, Lier, Belgium
| | - Federica Zanca
- GE Healthcare, DoseWatch, Rue de la Minière 283, 78530, Buc, France.,Imaging and Pathology Department, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Timo De Bondt
- Department of Radiology, Antwerp University Hospital and University of Antwerp, Wilrijkstraat 10, 2650, Antwerp, Belgium
| | - Paul M Parizel
- Department of Radiology, Antwerp University Hospital and University of Antwerp, Wilrijkstraat 10, 2650, Antwerp, Belgium
| | - Jan W Casselman
- Department of Radiology, AZ Sint-Jan Brugge-Oostende AV, Ruddershove 10, 8000, Brugge, Belgium
| |
Collapse
|
75
|
Kovacs WC, Yao J, Bluemke DA, Folio LR. Opportunities to Reduce CT Radiation Exposure, Experience Over 5 Years at the NIH Clinical Center. RADIATION PROTECTION DOSIMETRY 2017; 175:482-492. [PMID: 28096313 PMCID: PMC5927337 DOI: 10.1093/rpd/ncw377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 12/05/2016] [Accepted: 12/10/2016] [Indexed: 06/06/2023]
Abstract
Our current study was undertaken in order to compare CT exposures during various dose-reduction initiatives at the National Institutes of Health Clinical center, to show trends in exposure reduction over a 5-y period, and to provide benchmarks that other facilities may use. Using an in-house extraction tool (Radiation Exposure Extraction Engine), we derived CT exposure data from Digital Imaging and Communications in Medicine (DICOM) headers over 5 y. We present parameters used and compare most common exams between 2010 and 2015. During a period of exposure-reduction initiatives, data of 79 396 exams from nine CT scanners on 87 scan protocols were analyzed. Adult chest exposures were reduced 53% and chest, abdomen and pelvis exams were reduced 43% (p < 0.001). Only extremity exams did not show significantly reduced exposure. Collecting data over several years allowed us to confirm and compare several initiatives. We demonstrated significant exposure reductions during continued reduction efforts on common exams. Our results may provide benchmarks for similar centers.
Collapse
Affiliation(s)
- William C. Kovacs
- Diagnostic Radiology Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Jianhua Yao
- Diagnostic Radiology Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - David A. Bluemke
- Diagnostic Radiology Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Les R. Folio
- Diagnostic Radiology Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
76
|
Demb J, Chu P, Nelson T, Hall D, Seibert A, Lamba R, Boone J, Krishnam M, Cagnon C, Bostani M, Gould R, Miglioretti D, Smith-Bindman R. Optimizing Radiation Doses for Computed Tomography Across Institutions: Dose Auditing and Best Practices. JAMA Intern Med 2017; 177:810-817. [PMID: 28395000 PMCID: PMC5818828 DOI: 10.1001/jamainternmed.2017.0445] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
IMPORTANCE Radiation doses for computed tomography (CT) vary substantially across institutions. OBJECTIVE To assess the impact of institutional-level audit and collaborative efforts to share best practices on CT radiation doses across 5 University of California (UC) medical centers. DESIGN, SETTING, AND PARTICIPANTS In this before/after interventional study, we prospectively collected radiation dose metrics on all diagnostic CT examinations performed between October 1, 2013, and December 31, 2014, at 5 medical centers. Using data from January to March (baseline), we created audit reports detailing the distribution of radiation dose metrics for chest, abdomen, and head CT scans. In April, we shared reports with the medical centers and invited radiology professionals from the centers to a 1.5-day in-person meeting to review reports and share best practices. MAIN OUTCOMES AND MEASURES We calculated changes in mean effective dose 12 weeks before and after the audits and meeting, excluding a 12-week implementation period when medical centers could make changes. We compared proportions of examinations exceeding previously published benchmarks at baseline and following the audit and meeting, and calculated changes in proportion of examinations exceeding benchmarks. RESULTS Of 158 274 diagnostic CT scans performed in the study period, 29 594 CT scans were performed in the 3 months before and 32 839 CT scans were performed 12 to 24 weeks after the audit and meeting. Reductions in mean effective dose were considerable for chest and abdomen. Mean effective dose for chest CT decreased from 13.2 to 10.7 mSv (18.9% reduction; 95% CI, 18.0%-19.8%). Reductions at individual medical centers ranged from 3.8% to 23.5%. The mean effective dose for abdominal CT decreased from 20.0 to 15.0 mSv (25.0% reduction; 95% CI, 24.3%-25.8%). Reductions at individual medical centers ranged from 10.8% to 34.7%. The number of CT scans that had an effective dose measurement that exceeded benchmarks was reduced considerably by 48% and 54% for chest and abdomen, respectively. After the audit and meeting, head CT doses varied less, although some institutions increased and some decreased mean head CT doses and the proportion above benchmarks. CONCLUSIONS AND RELEVANCE Reviewing institutional doses and sharing dose-optimization best practices resulted in lower radiation doses for chest and abdominal CT and more consistent doses for head CT.
Collapse
Affiliation(s)
- Joshua Demb
- Department of Epidemiology and Biostatistics, University of California, San Francisco
| | - Philip Chu
- Department of Radiology, University of California, San Francisco
| | - Thomas Nelson
- Department of Radiology, University of California, San Diego
| | - David Hall
- Department of Radiology, University of California, San Diego
| | - Anthony Seibert
- Department of Public Health Sciences, UC Davis, and Kaiser Permanente Washington Health Research Institute, Kaiser Foundation Health Plan of Washington
| | - Ramit Lamba
- Department of Public Health Sciences, UC Davis, and Kaiser Permanente Washington Health Research Institute, Kaiser Foundation Health Plan of Washington
| | - John Boone
- Department of Public Health Sciences, UC Davis, and Kaiser Permanente Washington Health Research Institute, Kaiser Foundation Health Plan of Washington
| | - Mayil Krishnam
- Department of Radiology, University of California, Irvine
| | | | - Maryam Bostani
- Department of Radiology, University of California, Los Angeles
| | - Robert Gould
- Department of Radiology, University of California, San Francisco
| | - Diana Miglioretti
- Department of Public Health Sciences, UC Davis, and Kaiser Permanente Washington Health Research Institute, Kaiser Foundation Health Plan of Washington
| | | |
Collapse
|
77
|
Ghetti C, Ortenzia O, Palleri F, Sireus M. Definition of Local Diagnostic Reference Levels in a Radiology Department Using a Dose Tracking Software. RADIATION PROTECTION DOSIMETRY 2017; 175:38-45. [PMID: 27614299 DOI: 10.1093/rpd/ncw264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 08/05/2016] [Indexed: 06/06/2023]
Abstract
Dose optimization in radiological examinations is a mandatory issue: in this study local Diagnostic Reference Levels (lDRLs) for Clinical Mammography (MG), Computed Tomography (CT) and Interventional Cardiac Procedures (ICP) performed in our Radiology Department were established. Using a dose tracking software, we have collected Average Glandular Dose (AGD) for two clinical mammographic units; CTDIvol, Size-Specific Dose Estimate (SSDE), Dose Length Product (DLP) and total DLP (DLPtot) for five CT scanners; Fluoro Time, Fluoro Dose Area Product (DAP) and total DAP (DAPtot) for two angiographic systems. Data have been compared with Italian Regulation and with the recent literature. The 75th percentiles of the different dosimetric indices have been calculated. Automated methods of radiation dose data collection allow a fast and detailed analysis of a great amount of data and an easy determination of lDRLs for different radiological procedures.
Collapse
Affiliation(s)
- C Ghetti
- Department of Medical Physics, University Hospital of Parma, Italy
| | - O Ortenzia
- Department of Medical Physics, University Hospital of Parma, Italy
| | - F Palleri
- Department of Medical Physics, University Hospital of Parma, Italy
| | - M Sireus
- Department of Physics, University of Cagliari, Italy
| |
Collapse
|
78
|
Variability in Radiation Dose From Repeat Identical CT Examinations: Longitudinal Analysis of 2851 Patients Undergoing 12,635 Thoracoabdominal CT Scans in an Academic Health System. AJR Am J Roentgenol 2017; 208:1285-1296. [DOI: 10.2214/ajr.16.17070] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
79
|
Radiation dose-reduction strategies in thoracic CT. Clin Radiol 2017; 72:407-420. [DOI: 10.1016/j.crad.2016.11.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/31/2016] [Accepted: 11/14/2016] [Indexed: 01/08/2023]
|
80
|
Liang CR, Chen PXH, Kapur J, Ong MKL, Quek ST, Kapur SC. Establishment of institutional diagnostic reference level for computed tomography with automated dose-tracking software. J Med Radiat Sci 2017; 64:82-89. [PMID: 28247587 PMCID: PMC5454333 DOI: 10.1002/jmrs.210] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 11/26/2022] Open
Abstract
Introduction The aim of this study was to establish institutional diagnostic reference levels (DRLs) by summarising doses collected across the five computed tomography (CT) system in our institution. Methods CT dose data of 15940 patients were collected retrospectively from May 2015 to October 2015 in five institutional scanners. The mean, 75th percentile and 90th percentile of the dose spread were calculated according to anatomic region. The common CT examinations such as head, chest, combined abdomen/pelvis (A/P), and combined chest/abdomen/pelvis (C/A/P) were reviewed. Distribution of CT dose index (CTDIvol), dose‐length product (DLP) and effective dose (ED) were extracted from the data for single‐phasic and multiphasic examinations. Results The institutional DRL for our CT units were established as mean (50th percentile) of CTDIvol (mGy), DLP (mGy.cm) and ED (mSv) for single and multiphasic studies using the dose‐tracking software. In single phasic examination, Head: (49.0 mGy), (978.0 mGy.cm), (2.4 mSv) respectively; Chest: (6.0 mGy), (254.0 mGy.cm), (4.9 mSv) respectively; CT A/P (10.0 mGy), (514.0 mGy.cm), (8.9 mSv) respectively; CT C/A/P (10.0 mGy), (674.0 mGy.cm), (11.8 mSv) respectively. In multiphasic studies: Head (45.0 mGy), (1822.0 mGy.cm), (5.0 mSv) respectively; Chest (8.0 mGy), (577.0 mGy.cm), (10.0 mSv) respectively; CT A/P: (10.0 mGy), (1153.0 mGy.cm), (20.2 mSv) respectively; CT C/A/P: (11.0 mGy), (1090.0 mGy.cm), (19.2 mSv) respectively. Conclusions The reported metrics offer a variety of information that institutions can use for quality improvement activities. The variations in dose between scanners suggest a large potential for optimisation of radiation dose.
Collapse
Affiliation(s)
- Chong R Liang
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Priscilla X H Chen
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Jeevesh Kapur
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Michael K L Ong
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Swee T Quek
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Subhash C Kapur
- Department of Diagnostic Imaging, National University Hospital, Singapore
| |
Collapse
|
81
|
The evolution of radiation dose over time: Measurement of a patient cohort undergoing whole-body examinations on three computer tomography generations. Eur J Radiol 2017; 86:63-69. [DOI: 10.1016/j.ejrad.2016.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/24/2016] [Accepted: 11/01/2016] [Indexed: 11/23/2022]
|
82
|
Harbron R. What do recent epidemiological studies tell us about the risk of cancer from radiation doses typical of diagnostic radiography? Radiography (Lond) 2016. [DOI: 10.1016/j.radi.2016.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
83
|
Smith-Bindman R, Wang Y, Yellen-Nelson TR, Moghadassi M, Wilson N, Gould R, Seibert A, Boone JM, Krishnam M, Lamba R, Hall DJ, Miglioretti DL. Predictors of CT Radiation Dose and Their Effect on Patient Care: A Comprehensive Analysis Using Automated Data. Radiology 2016; 282:182-193. [PMID: 27438166 DOI: 10.1148/radiol.2016151391] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Purpose To determine patient, vendor, and institutional factors that influence computed tomography (CT) radiation dose. Materials and Methods The relevant institutional review boards approved this HIPAA-compliant study, with waiver of informed consent. Volume CT dose index (CTDIvol) and effective dose in 274 124 head, chest, and abdominal CT examinations performed in adult patients at 12 facilities in 2013 were collected prospectively. Patient, vendor, and institutional characteristics that could be used to predict (a) median dose by using linear regression after log transformation of doses and (b) high-dose examinations (top 25% of dose within anatomic strata) by using modified Poisson regression were assessed. Results There was wide variation in dose within and across medical centers. For chest CTDIvol, overall median dose across all institutions was 11 mGy, and institutional median dose was 7-16 mGy. Models including patient, vendor, and institutional factors were good for prediction of median doses (R2 = 0.31-0.61). The specific institution where the examination was performed (reflecting the specific protocols used) accounted for a moderate to large proportion of dose variation. For chest CTDIvol, unadjusted median CTDIvol was 16.5 mGy at one institution and 6.7 mGy at another (adjusted relative median dose, 2.6 mGy [95% confidence interval: 2.5, 2.7]). Several variables were important predictors that a patient would undergo high-dose CT. These included patient size, the specific institution where CT was performed, and the use of multiphase scanning. For example, while 49% of patients (21 411 of 43 696) who underwent multiphase abdominal CT had a high-dose examination, 8% of patients (4977 of 62 212) who underwent single-phase CT had a high-dose examination (adjusted relative risk, 6.20 [95% CI: 6.17, 6.23]). If all patients had been examined with single-phase CT, 69% (18 208 of 26 388) of high-dose examinations would have been eliminated. Patient size, institutional-specific protocols, and multiphase scanning were the most important predictors of dose (change in R2 = 8%-32%), followed by manufacturer and iterative reconstruction (change in R2, 0.2%-15.0%). Conclusion CT doses vary considerably within and across facilities. The primary factors that influenced dose variation were multiphase scanning and institutional protocol choices. It is unknown if the variation in these factors influenced diagnostic accuracy. © RSNA, 2016.
Collapse
Affiliation(s)
- Rebecca Smith-Bindman
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Yifei Wang
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Thomas R Yellen-Nelson
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Michelle Moghadassi
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Nicole Wilson
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Robert Gould
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Anthony Seibert
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - John M Boone
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Mayil Krishnam
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Ramit Lamba
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - David J Hall
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| | - Diana L Miglioretti
- From the Department of Radiology and Biomedical Imaging (R.S., M.M., N.W., R.G.), Department of Epidemiology and Biostatistics (R.S.), and Philip R. Lee Institute for Health Policy Studies (R.S.), University of California, San Francisco, 350 Parnassus Ave, Suite 307C, San Francisco, CA 94143-0336; Division of Biostatistics, Department of Public Health Sciences (Y.W., D.L.M.), and Department of Radiology (A.S., J.M.B., R.L.), University of California, Davis, Davis, Calif; Department of Radiology, University of California, San Diego, San Diego, Calif (T.R.Y., D.J.H.); Department of Radiological Sciences, University of California, Irvine, Orange County, Calif (M.K.); and Group Health Research Institute, Group Health Cooperative, Seattle, Wash (D.L.M.)
| |
Collapse
|
84
|
Westermaier T, Linsenmann T, Homola GA, Loehr M, Stetter C, Willner N, Ernestus RI, Solymosi L, Vince GH. 3D rotational fluoroscopy for intraoperative clip control in patients with intracranial aneurysms--assessment of feasibility and image quality. BMC Med Imaging 2016; 16:30. [PMID: 27094510 PMCID: PMC4837534 DOI: 10.1186/s12880-016-0133-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 04/12/2016] [Indexed: 12/29/2022] Open
Abstract
Background Mobile 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. In this series, the image quality and value of intraoperative 3D fluoroscopy with intravenous contrast agent for the evaluation of aneurysm occlusion and vessel patency after clip placement was assessed in patients who underwent surgery for intracranial aneurysms. Materials and methods Twelve patients were included in this retrospective analysis. Prior to surgery, a 360° rotational fluoroscopy scan was performed without contrast agent followed by another scan with 50 ml of intravenous iodine contrast agent. The image files of both scans were transferred to an Apple PowerMac® workstation, subtracted and reconstructed using OsiriX® free software. The procedure was repeated after clip placement. Both image sets were compared for assessment of aneurysm occlusion and vessel patency. Results Image acquisition and contrast administration caused no adverse effects. Image quality was sufficient to follow the patency of the vessels distal to the clip. Metal artifacts reduce the assessability of the immediate vicinity of the clip. Precise image subtraction and post-processing can reduce metal artifacts and make the clip-site assessable and depict larger neck-remnants. Conclusion This technique quickly supplies images at adequate quality to evaluate distal vessel patency after aneurysm clipping. Significant aneurysm remnants may be depicted as well. As it does not require visual control of all vessels that are supposed to be evaluated intraoperatively, this technique may be complementary to other intraoperative tools like indocyanine green videoangiography and micro-Doppler, especially for the assessment of larger aneurysms. At the momentary state of this technology, it cannot replace postoperative conventional angiography. However, 3D fluoroscopy and image post-processing are young technologies. Further technical developments are likely to result in improved image quality.
Collapse
Affiliation(s)
- Thomas Westermaier
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany.
| | - Thomas Linsenmann
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - György A Homola
- Department of Neuroradiology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Mario Loehr
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Christian Stetter
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Nadine Willner
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Ralf-Ingo Ernestus
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Laszlo Solymosi
- Department of Neuroradiology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Giles H Vince
- Abteilung für Neurochirurgie, Klinikum Klagenfurt, Feschnigstraße 11, 9020, Klagenfurt am Woerthersee, Austria
| |
Collapse
|
85
|
Abstract
The past decade has seen a significant growth in diagnostic CT imaging as a direct result of the clinical value provided by CT imaging. At the same time, many new techniques and resources are now available to make CT imaging safe. This article presents the basics of CT dosimetry and their usage in clinical practices, methods to implement CT dose reduction, followed by a summary of legislation, and guidelines related to patient safety in diagnostic CT imaging. Also, CT radiation dose diagnostic reference levels from published regional and national surveys are reviewed and applied in a CT dose tracking and monitoring program.
Collapse
Affiliation(s)
- Zheng Feng Lu
- Department of Radiology, University of Chicago, 5841 S Maryland Avenue, MC 2026, Chicago, IL, 60637, USA.
| | - Stephen Thomas
- Department of Radiology, University of Chicago, 5841 S Maryland Avenue, MC 2026, Chicago, IL, 60637, USA
| |
Collapse
|
86
|
Weisenthal SJ, Folio L, Kovacs W, Seff A, Derderian V, Summers RM, Yao J. Open-Source Radiation Exposure Extraction Engine (RE3) with Patient-Specific Outlier Detection. J Digit Imaging 2015; 29:406-19. [PMID: 26644157 DOI: 10.1007/s10278-015-9852-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
We present an open-source, picture archiving and communication system (PACS)-integrated radiation exposure extraction engine (RE3) that provides study-, series-, and slice-specific data for automated monitoring of computed tomography (CT) radiation exposure. RE3 was built using open-source components and seamlessly integrates with the PACS. RE3 calculations of dose length product (DLP) from the Digital imaging and communications in medicine (DICOM) headers showed high agreement (R (2) = 0.99) with the vendor dose pages. For study-specific outlier detection, RE3 constructs robust, automatically updating multivariable regression models to predict DLP in the context of patient gender and age, scan length, water-equivalent diameter (D w), and scanned body volume (SBV). As proof of concept, the model was trained on 811 CT chest, abdomen + pelvis (CAP) exams and 29 outliers were detected. The continuous variables used in the outlier detection model were scan length (R (2) = 0.45), D w (R (2) = 0.70), SBV (R (2) = 0.80), and age (R (2) = 0.01). The categorical variables were gender (male average 1182.7 ± 26.3 and female 1047.1 ± 26.9 mGy cm) and pediatric status (pediatric average 710.7 ± 73.6 mGy cm and adult 1134.5 ± 19.3 mGy cm).
Collapse
Affiliation(s)
- Samuel J Weisenthal
- National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Clinical Image Processing Service (CIPS), 10 Center Drive, Bethesda, MD, 20892-1182, USA.,University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY, 14642, USA
| | - Les Folio
- National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Clinical Image Processing Service (CIPS), 10 Center Drive, Bethesda, MD, 20892-1182, USA
| | - William Kovacs
- National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Clinical Image Processing Service (CIPS), 10 Center Drive, Bethesda, MD, 20892-1182, USA
| | - Ari Seff
- National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Clinical Image Processing Service (CIPS), 10 Center Drive, Bethesda, MD, 20892-1182, USA
| | - Vana Derderian
- National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Clinical Image Processing Service (CIPS), 10 Center Drive, Bethesda, MD, 20892-1182, USA
| | - Ronald M Summers
- National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Clinical Image Processing Service (CIPS), 10 Center Drive, Bethesda, MD, 20892-1182, USA
| | - Jianhua Yao
- National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Clinical Image Processing Service (CIPS), 10 Center Drive, Bethesda, MD, 20892-1182, USA.
| |
Collapse
|
87
|
Matsunaga Y, Kawaguchi A, Kobayashi K, Kobayashi M, Asada Y, Minami K, Suzuki S, Chida K. Effective radiation doses of CT examinations in Japan: a nationwide questionnaire-based study. Br J Radiol 2015; 89:20150671. [PMID: 26647804 PMCID: PMC4985214 DOI: 10.1259/bjr.20150671] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/28/2015] [Accepted: 12/07/2015] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVE The aims of this study were to estimate the effective radiation doses from CT examinations of both adults and children in Japan and to study the impact of various scan parameters on the effective doses. METHODS A questionnaire, which contained detailed questions on the CT scan parameters employed, was distributed to 3000 facilities throughout Japan. For each scanner protocol, the effective doses for head (non-helical and helical), chest and upper abdomen acquisitions were estimated using ImPACT CT Patient Dosimetry Calculator software v. 1.0.4 (St George's Hospital, London, UK). RESULTS The mean effective doses for chest and abdominal examinations using 80-110 kV were significantly lower than those using 120 kV. However, there was no statistically significant difference in the mean effective doses for head scans between facilities employing 80-110 kV and 120 kV. In chest and abdominal examinations, the mean effective doses using CT scanners from Western manufacturers [Siemens (Forchheim, Germany), Philips (Eindhoven, Netherlands) and GE Medical Systems (Milwaukee, WI)] were significantly lower than those of examinations using Japanese scanners [Hitachi (Kashiwa, Japan) and Toshiba (Otawara, Tochigi, Japan)], except for in paediatric chest examinations. CONCLUSION The mean effective doses for adult head, chest and abdominal CT examinations were 2.9, 7.7 and 10.0 mSv, respectively, whereas the corresponding mean effective doses for paediatric examinations were 2.6, 7.1 and 7.7 mSv, respectively. ADVANCES IN KNOWLEDGE Facilities using CT scanners by Western manufacturers commonly adopt low-tube-voltage techniques, and low-tube-voltage CT may be useful for reducing the radiation doses to the patients, particularly for the body region.
Collapse
Affiliation(s)
- Yuta Matsunaga
- Department of Imaging, Nagoya Kyoritsu Hospital, Nagoya, Japan
- Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Ai Kawaguchi
- Graduate School of Medicine, Tohoku University, Sendai, Japan
- Department of Radiology, Toyota Memorial Hospital, Toyota, Japan
| | - Kenichi Kobayashi
- Department of Radiology, Fujita Health University Hospital, Toyoake, Japan
| | | | - Yasuki Asada
- School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Kazuyuki Minami
- School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Shoichi Suzuki
- School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Koichi Chida
- Graduate School of Medicine, Tohoku University, Sendai, Japan
| |
Collapse
|