scholarly journals 3D Assessment of Endodontic Lesions with a Low-Dose CBCT Protocol

2020 ◽  
Vol 8 (2) ◽  
pp. 51 ◽  
Author(s):  
Marco Portelli ◽  
Angela Militi ◽  
Antonino Lo Giudice ◽  
Roberto Lo Giudice ◽  
Lorenzo Rustico ◽  
...  
Keyword(s):  
Image Quality ◽  
Low Dose ◽  
Organ Dose ◽  
Radiological Protection ◽  
Anthropomorphic Phantom ◽  
Organ Doses ◽  
Thermoluminescent Dosimeters ◽  
Lower Radiation Dose ◽  
Special Cases ◽  
Effective Doses

Background: Cone beam computed tomography (CBCT) is often used in different fields of dental science, especially in complex anatomical districts like the endodontic one. The aim of this study is to propose a low-dose CBCT protocol useful in cases of endodontic lesions. Methods: The device used was a MyRay Hyperion X9-11x5; the low dose setting of the machine was 90 Kv, 27 mAs, CTDI/Vol 2.89 mGy. The absorbed organ doses have been evaluated with an anthropomorphic phantom loaded with thermoluminescent dosimeters positioned at the level of sensitive organs like brain, bone marrow, salivary glands, thyroid, esophagus, oral mucosa, extrathoracic airways, and lymph nodes. Equivalent and effective doses have been calculated; the last one has been calculated using the recommendations approved by the Main Commission of ICRP (International Commission Radiological Protection) in March 2007. For the assessment of image quality, five senior clinicians, independent and experienced clinicians, were asked to state if CBCT scans were accurate enough to assess endodontic lesions. Results: The use of a low-dose CBCT acquisition produced the lowest organ dose (5.01 microSv) at the level of the esophagus. Image quality has been considered accurate enough for endodontic diagnostic needs. Conclusions: CBCT low-dose protocol can be used over the standard one in endodontic special cases because it provides a significantly lower radiation dose to the patients while ensuring good image quality. However, further studies are necessary to evaluate the opportunity of low-dose CBCT exams in endodontic clinical practice.

scholarly journals Feasibility of low-dose digital pulsed video-fluoroscopic swallow exams (VFSE): effects on radiation dose and image quality

2017 ◽  
Vol 58 (9) ◽  
pp. 1037-1044 ◽  
Author(s):  
Jakob Weiss ◽  
Mike Notohamiprodjo ◽  
Klement Neumaier ◽  
Minglun Li ◽  
Wilhelm Flatz ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Low Dose ◽  
Research Evaluation ◽  
Diagnostic Image Quality ◽  
Organ Doses ◽  
Dose Area Product ◽  
Thermoluminescent Dosimeters ◽  
Area Product

Background Fluoroscopy is a frequently used examination in clinical routine without appropriate research evaluation latest hardware and software equipment. Purpose To evaluate the feasibility of low-dose pulsed video-fluoroscopic swallowing exams (pVFSE) to reduce dose exposure in patients with swallowing disorders compared to high-resolution radiograph examinations (hrVFSE) serving as standard of reference. Material and Methods A phantom study (Alderson-Rando Phantom, 60 thermoluminescent dosimeters [TLD]) was performed for dose measurements. Acquisition parameters were as follows: (i) pVFSE: 76.7 kV, 57 mA, 0.9 Cu mm, pulse rate/s 30; (ii) hrVFSE: 68.0 kV, 362 mA, 0.2 Cu mm, pictures 30/s. The dose area product (DAP) indicated by the detector system and the radiation dose derived from the TLD measurements were analyzed. In a patient study, image quality was assessed qualitatively (5-point Likert scale, 5 = hrVFSE; two independent readers) and quantitatively (SNR) in 35 patients who subsequently underwent contrast-enhanced pVFSE and hrVFSE. Results Phantom measurements showed a dose reduction per picture of factor 25 for pVFSE versus hrVFSE images (0.0025 mGy versus 0.062 mGy). The DAP (µGym2) was 28.0 versus 810.5 (pVFSE versus hrVFSE) for an average examination time of 30 s. Direct and scattered organ doses were significantly lower for pVFSE as compared to hrVFSE ( P < 0.05). Image quality was rated 3.9 ± 0.5 for pVFSE versus the hrVFSE standard; depiction of the contrast agent 4.8 ± 0.3; noise 3.6 ± 0.5 ( P < 0.05); SNR calculations revealed a relative decreased of 43.9% for pVFSE as compared to hrVFSE. Conclusion Pulsed VFSE is feasible, providing diagnostic image quality at a significant dose reduction as compared to hrVFSE.

scholarly journals Digital orthodontic radiographic set versus cone-beam computed tomography: an evaluation of the effective dose

2016 ◽  
Vol 21 (4) ◽  
pp. 66-72 ◽  
Author(s):  
Lillian Atsumi Simabuguro Chinem ◽  
Beatriz de Souza Vilella ◽  
Cláudia Lúcia de Pinho Maurício ◽  
Lucia Viviana Canevaro ◽  
Luiz Fernando Deluiz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
New York ◽  
Effective Dose ◽  
Cone Beam Computed Tomography ◽  
Cone Beam ◽  
Radiological Protection ◽  
Anthropomorphic Phantom ◽  
Thermoluminescent Dosimeters ◽  
Optimization Principle ◽  
Effective Doses

ABSTRACT Objective: The aim of this study was to compare the equivalent and effective doses of different digital radiographic methods (panoramic, lateral cephalometric and periapical) with cone-beam computed tomography (CBCT). Methods: Precalibrated thermoluminescent dosimeters were placed at 24 locations in an anthropomorphic phantom (Alderson Rando Phantom, Alderson Research Laboratories, New York, NY, USA), representing a medium sized adult. The following devices were tested: Heliodent Plus (Sirona Dental Systems, Bernsheim, Germany), Orthophos XG 5 (Sirona Dental Systems, Bernsheim, Germany) and i-CAT (Imaging Sciences International, Hatfield, PA, USA). The equivalent doses and effective doses were calculated considering the recommendations of the International Commission of Radiological Protection (ICRP) issued in 1990 and 2007. Results: Although the effective dose of the radiographic set corresponded to 17.5% (ICRP 1990) and 47.2% (ICRP 2007) of the CBCT dose, the equivalent doses of skin, bone surface and muscle obtained by the radiographic set were higher when compared to CBCT. However, in some areas, the radiation produced by the orthodontic set was higher due to the complete periapical examination. Conclusion: Considering the optimization principle of radiation protection, i-CAT tomography should be used only in specific and justified circumstances. Additionally, following the ALARA principle, single periapical radiographies covering restricted areas are more suitable than the complete periapical examination.

scholarly journals Image Quality and Patient-Specific Organ Doses in Stone Protocol CT: A Comparison of Traditional CT to Low Dose CT with Iterative Reconstruction

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Raghav Pai ◽  
Rishi Modh ◽  
Rebecca H. Lamoureux ◽  
Lori Deitte ◽  
David C. Wymer ◽  
...  
Keyword(s):  
Image Quality ◽  
Kidney Stone ◽  
Low Dose ◽  
Organ Dose ◽  
Patient Specific ◽  
Organ Doses ◽  
Low Dose Ct ◽  
Stone Burden ◽  
Stone Formers ◽  
Organ Specific

Objective. To compare organ specific radiation dose and image quality in kidney stone patients scanned with standard CT reconstructed with filtered back projection (FBP-CT) to those scanned with low dose CT reconstructed with iterative techniques (IR-CT). Materials and Methods. Over a one-year study period, adult kidney stone patients were retrospectively netted to capture the use of noncontrasted, stone protocol CT in one of six institutional scanners (four FBP and two IR). To limit potential CT-unit use bias, scans were included only from days when all six scanners were functioning. Organ dose was calculated using volumetric CT dose index and patient effective body diameter through validated conversion equations derived from previous cadaveric, dosimetry studies. Board-certified radiologists, blinded to CT algorithm type, assessed stone characteristics, study noise, and image quality of both techniques. Results. FBP-CT (n=250) and IR-CT (n=90) groups were similar in regard to gender, race, body mass index (mean BMI = 30.3), and stone burden detected (mean size 5.4 ± 1.2 mm). Mean organ-specific dose (OSD) was 54-62% lower across all organs for IR-CT compared to FBP-CT with particularly reduced doses (up to 4.6-fold) noted in patients with normal BMI range. No differences were noted in radiological assessment of image quality or noise between the cohorts, and intrarater agreement was highly correlated for noise (AC2=0.873) and quality (AC2=0.874) between blinded radiologists. Conclusions. Image quality and stone burden assessment were maintained between standard FBP and low dose IR groups, but IR-CT decreased mean OSD by 50%. Both urologists and radiologists should advocate for low dose CT, utilizing reconstructive protocols like IR, to reduce radiation exposure in their stone formers who undergo multiple CTs.

scholarly journals Assessment of Organ and Effective Doses Received by Paediatric Patients Undergoing Computed Tomography Examinations in Three Hospitals in Brazzaville, Congo Republic: An Urgent Necessity for Regulatory Control

2021 ◽  
pp. 527-550
Author(s):  
J. Bazoma ◽  
G. B. Dallou ◽  
P. Ondo Meye ◽  
C. Bouka Biona ◽  
Saïdou ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Absorbed Dose ◽  
Regulatory Control ◽  
Ct Scans ◽  
Radiological Protection ◽  
Age Group ◽  
Organ Doses ◽  
Paediatric Patients ◽  
Effective Doses

The present study aimed at estimating organ and effective doses from computed tomography (CT) scans of paediatric patients in three hospitals in Brazzaville, Congo Republic. A total of 136 data on paediatric patients, from 0.25 (3 months) to 15 years old, who underwent head, chest, abdomen – pelvis (AP) and chest – abdomen – pelvis (CAP) CT scans was considered. The approach followed in the present study to compute organ doses was to use pre-calculated volume CT dose index (CTDIvol) – and 100 milliampere-second (mAs) – normalized organ doses determined by Monte Carlo (MC) simulation. Effective dose were then derived using the international commission on radiological protection (ICRP) publications 60 and 103 formalism. For comparison purposes, effective dose were also computed using dose-length product (DLP) – to – effective dose conversion factors. A relatively high variation in organ and effective doses was observed in each age group due to the dependence of patient dose on the practice of technicians who perform the CT scan within the same facility or from one facility to another, patient size and lack of adequate training of technicians. In the particular case of head scan, the brain and the eye lens were delivered maximum absorbed doses of 991.81 mGy and 1176.51 mGy, respectively (age group 10-15 y). The maximum absorbed dose determined for the red bone marrow was 246.08 mGy (age group 1-5 y). This is of concern as leukaemia and brain tumours are the most common childhood cancers and as the ICRP recommended absorbed dose threshold for induction of cataract is largely exceeded. Effective doses derived from MC calculations and ICRP publications 60 and 103 tissues weighting factors showed a 0.40-17.61 % difference while the difference between effective doses derived by the use of k- factors and those obtained by MC calculations ranges from 0.06 to 224.87 %. The study has shown that urgent steps should be taken in order to significantly reduce doses to paediatric patients to levels observed in countries where dose reduction techniques are successfully applied.

Image Quality in Low-dose Multidetector Computed Tomography: A Pilot Study to Assess Feasibility and Dose Optimization in Whole-body Bone Imaging

2010 ◽  
Vol 61 (5) ◽  
pp. 258-264 ◽  
Author(s):  
Tadhg G. Gleeson ◽  
Brenda Byrne ◽  
Pat Kenny ◽  
Jason Last ◽  
Patricia Fitzpatrick ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Multidetector Computed Tomography ◽  
Low Dose ◽  
Interobserver Agreement ◽  
Skeletal Survey ◽  
Whole Body ◽  
Altman Plot ◽  
Low Dose Ct ◽  
Effective Doses

Objective To study the impact of dose parameters on image quality at whole-body low-dose multidetector computed tomography (CT) in an attempt to derive parameters that allow diagnostic quality images of the skeletal system without incurring significant radiation dose in patients referred for investigation of plasma cell dyscrasias. Methods By using a single cadaver, 14 different whole-body low-dose CT protocols were individually assessed by 2 radiologists, blinded to acquisition parameters (kVp and mAs, reconstruction algorithm, dose reduction software). Combinations of kVps that range from 80-140 kVp, and tube current time product from 14–125 mAs were individually scored by using a Likert scale from 1–5 in 4 separate anatomical areas (skull base, thoracic spine, pelvis, and distal femora). Correlation between readers scores and effective doses were obtained by using correlation coefficient statistical analysis, statistical significance was considered P < .01. Interobserver agreement was assessed by using a Bland and Altman plot. Interobserver agreement in each of the 4 anatomical areas was assessed by using kappa statistics. A single set of parameters was then selected for use in future clinical trials in a cohort of patients referred for investigation of monoclonal gammopathy, including multiple myeloma. Results Several sets of exposure parameters allowed low-dose whole-body CT to be performed with effective doses similar to skeletal survey while preserving diagnostic image quality. Individual reader's and average combined scores showed a strong inverse correlation with effective dose (reader 1, r = −0.78, P = .0001; reader 2, r = −0.75, P = .0003); average combined scores r = −0.81, P < .0001). Bland and Altman plot of overall scores shows reasonable interobserver agreement, with a mean difference of 1.055. Conclusion Whole-body low-dose CT can be used to obtain adequate CT image quality to assess normal osseous detail while delivering effective doses similar to those associated with conventional radiographic skeletal survey.

Do low dose CT-KUBs really expose patients to more radiation than plain abdominal radiographs?

2021 ◽  
pp. 039156032199444
Author(s):  
Bob Yang ◽  
Noorunisa Suhail ◽  
Johan Marais ◽  
James Brewin
Keyword(s):  
Effective Dose ◽  
Low Dose ◽  
Lower Sensitivity ◽  
Radiological Protection ◽  
High Radiation ◽  
Single Centre ◽  
Low Dose Ct ◽  
Abdominal Radiographs ◽  
Effective Doses ◽  
Average Effective Dose

Background: Urolithiasis patients often require frequent urinary tract imaging, leading to high radiation exposure. CT Kidney-Ureter-Bladder (CT-KUB) is the gold standard in urolithiasis detection, however it is thought to harbour significant radiation load. Urologists have therefore utilised abdominal radiographs (XR-KUB) as an alternative, though with markedly lower sensitivity and specificity. We present the first contemporary UK study comparing the effective doses of XR-KUBs with low dose CT-KUBs. Method: Fifty-three patients were retrospectively identified in a single centre who underwent both a XR-KUB and a CT-KUB in 2018. Effective-Dose was measured by converting the recorded ‘Dose Area/Length Product’ via the International Commission on Radiological Protection formula. Results: The average effective dose of XR-KUBs and low dose CT-KUBs were 5.10 mSv and 5.31 mSv respectively. Thirty-four percent (18/53) of patients had a XR-KUBs with a higher effective dose than their low dose CT-KUB. Patients with higher Weight, BMI and AP diameter had higher effective doses for both their XR and low dose CT-KUBs. All patients in our study weighing over 92 kg or with a BMI greater than 32 had a XR-KUBs with a higher effective dose than their low dose CT-KUB. Conclusion: This data supports moving away from XR-KUBs for the investigation of urolithiasis, particularly in patients with a high BMI.

Radiation exposure and establishment of diagnostic reference levels of whole-body low-dose CT for the assessment of multiple myeloma with second- and third-generation dual-source CT

2021 ◽  
pp. 028418512110032
Author(s):  
Sebastian Zensen ◽  
Denise Bos ◽  
Marcel Opitz ◽  
Johannes Haubold ◽  
Michael Forsting ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Low Dose ◽  
Whole Body ◽  
Third Generation ◽  
Dual Source Ct ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Organ Doses ◽  
Dual Source ◽  
Effective Doses

Background In the assessment of diseases causing skeletal lesions such as multiple myeloma (MM), whole-body low-dose computed tomography (WBLDCT) is a sensitive diagnostic imaging modality, which has the potential to replace the conventional radiographic survey. Purpose To optimize radiation protection and examine radiation exposure, and effective and organ doses of WBLDCT using different modern dual-source CT (DSCT) devices, and to establish local diagnostic reference levels (DRL). Material and Methods In this retrospective study, 281 WBLDCT scans of 232 patients performed between January 2017 and April 2020 either on a second- (A) or third-generation (B) DSCT device could be included. Radiation exposure indices and organ and effective doses were calculated using a commercially available automated dose-tracking software based on Monte-Carlo simulation techniques. Results The radiation exposure indices and effective doses were distributed as follows (median, interquartile range): (A) second-generation DSCT: volume-weighted CT dose index (CTDIvol) 1.78 mGy (1.47–2.17 mGy); dose length product (DLP) 282.8 mGy·cm (224.6–319.4 mGy·cm), effective dose (ED) 1.87 mSv (1.61–2.17 mSv) and (B) third-generation DSCT: CTDIvol 0.56 mGy (0.47–0.67 mGy), DLP 92.0 mGy·cm (73.7–107.6 mGy·cm), ED 0.61 mSv (0.52–0.69 mSv). Radiation exposure indices and effective and organ doses were significantly lower with third-generation DSCT ( P < 0.001). Local DRLs could be set for CTDIvol at 0.75 mGy and DLP at 120 mGy·cm. Conclusion Third-generation DSCT requires significantly lower radiation dose for WBLDCT than second-generation DSCT and has an effective dose below reported doses for radiographic skeletal surveys. To ensure radiation protection, DRLs regarding WBLDCT are required, where our locally determined values may help as benchmarks.

scholarly journals Patients Radiation Risks from Computed Tomography Lymphography

2020 ◽  
Vol 10 ◽  
pp. 46 ◽  
Author(s):  
Abdullah Almujally ◽  
Abdelmoneim Sulieman ◽  
Fabrizio Calliada
Keyword(s):  
Computed Tomography ◽  
Clinical Indication ◽  
Radiological Protection ◽  
Organ Doses ◽  
Radiation Induced Cancer ◽  
Radiation Induced ◽  
Patient Doses ◽  
Effective Doses ◽  
The Mean ◽  
Ct Lymphography

Objectives: This study aims to first measure patient doses during computed tomography (CT) chest, abdomen, and extremities procedures for evaluation lymphedema, and second to estimate the radiation dose-related risks during the procedures. Material and Methods: Radiation effective doses from CT lymphography procedures quantified using CT machines from different vendors. After the calibration of CT systems, the data collected for a total of 28 CT lymphography procedures. Effective and organ doses extrapolated using national radiological protection software based on Monte Carlo simulation. Results: The mean patient doses for chest and abdomen procedures in term of CTDIvol (mGy) and DLP (mGy.cm) are 10.0 ± 3 and 425 ± 222 and 24 ± 12 and 1118 ± 812 for CT 128 and CT 16 slice, respectively. The mean DLP (mGy.cm) for extremities was 320 ± 140 and 424 ± 212 for CT 128 and CT 16 slice, in that order. Conclusion: Patients’ dose showed significant differences due to variation in the scan length and clinical indication. Organs lay in the primary beam received high radiation doses especially in the chest region which increases the probability of radiation-induced cancer. The current patient’s doses are higher compared to the previous studies.

THE IMPACT OF OBESITY ON ABDOMINAL CT RADIATION DOSE AND IMAGE QUALITY

2018 ◽  
Vol 185 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Abdulaziz A Qurashi ◽  
Louise A Rainford ◽  
Khalid M Alshamrani ◽  
Shane J Foley
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Organ Dose ◽  
Oxide Semiconductor ◽  
Obese Patients ◽  
Dose Length Product ◽  
Organ Doses ◽  
The Impact

Abstract The aim of this study was to evaluate how iterative reconstruction can compensate for the noise increase in low radiation dose abdominal computed tomography (CT) technique for large size patients and the general impact of obesity on abdominal organ doses and image quality in CT. An anthropomorphic phantom layered with either none or a single layer of 3-cm- thick circumferential animal fat packs to simulate obese patients was imaged using a 128MDCT scanner. Abdominal protocols (n = 12) were applied using automatic tube current modulation (ATCM) with various quality reference mAs (150, 200, 250 and 300). kVs of 100, 120 and 140 were used for each mAs selection. Metal oxide semiconductor field effect transistor dosimeters (MOSFET) measured internal organ dose. All images produced were reconstructed with filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE) (3, 4 and 5) and objective noise was measured within three regions of interest at the level of L4–L5. Organ doses varied from 0.12 to 41.9 mGy, the spleen received the highest doses for both phantom sizes. Compared to the phantom simulating average size, the obese phantom was associated with up to twofold increase in delivered mAs, dose length product (DLP) and computed tomography dose index (CTDIvol) for the matched mAs selection (p < 0.05). However, organ dose increased by 50% only. The use of 100 kV resulted in a 40% lower dose (p < 0.05) compared to 120 kV and the associated noise increase was improved by SAFIRE (5) use, which resulted in 60% noise reduction compared to FBP (p < 0.05). When combined with iterative reconstruction, low kV is feasible for obese patients to optimise radiation dose and maintain objective image quality.

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