scholarly journals Pelvis imaging: Achieving dose reduction with different patient positions

2019 ◽  
Vol 34 (4) ◽  
pp. 375-383
Author(s):  
Anja Resnik ◽  
Janez Zibert ◽  
Nejc Mekis
Keyword(s):  
Image Quality ◽  
Effective Dose ◽  
Signal To Noise Ratio ◽  
Absorbed Dose ◽  
Field Size ◽  
Optimal Position ◽  
Dose Area Product ◽  
Significant Difference ◽  
Noise Ratio ◽  
Area Product

The purpose of this research was to determine how dose area product, effective dose, absorbed doses to specific organs, and image quality changed according to different automatic exposure control positions in pelvis imaging. The research was carried out in two parts. The study was conducted on an anthropomorphic phantom and 200 patients referred to pelvic imaging. We measured the dose area product, field size, height, and mass. Then we calculated the effective dose and absorbed dose for individual organs accordingly. Lateral ionizing cells were first positioned in line with the iliac crests (head towards position) and subsequently, with the femoral neck (head away position). All the images were independently evaluated by three radiologists using ViewDEX and objective image analysis was performed measuring contrast-to-noise ratio and signal-to-noise ratio. We found no significant differences in the Siemens Luminos unit in any of the inspected parameters. However, there was a significant difference in dose area product (37.3 %), effective dose (35.7 %) and average absorbed dose to selected individual organs (36.7 %) when the head away position of the patient was used and the image quality increased. Based on these results, we can propose that the optimal position of the patient regarding the ionizing cells is the head away position.

LUMBAR SPINE RADIOGRAPHY: LOWER ORGAN DOSE WITH THE USE OF PA PROJECTION

2019 ◽  
Vol 186 (4) ◽  
pp. 507-512
Author(s):  
Erna Alukić ◽  
Nejc Mekiš
Keyword(s):  
Lumbar Spine ◽  
Effective Dose ◽  
Organ Dose ◽  
Field Size ◽  
Organ Doses ◽  
Dose Area Product ◽  
Spine Radiography ◽  
Spine Imaging ◽  
Significant Difference ◽  
Area Product

Abstract The purpose of the research was to determine the effect of the posteroanterior (PA) patient position in lumbar spine imaging on effective dose and the absorbed organ dose. The study was performed on 100 patients that were referred to the lumbar spine radiography that were divided into two equal groups of 50. Body Mass Index, Dose Area Product (DAP), exposure index (EXI), tube time-current (mAs), image field size and the source-patient distance were acquired for each patient. The entrance surface dose (ESD), the effective dose and the absorbed organ doses were calculated. There was no statistically significant difference in the BMI and EXI between the AP and PA projection. The results showed a significant reduction of ESD by 33% and the effective dose by 53% when the PA projection was used. Furthermore, there was a 64% average reduction of the absorbed organ doses to the selected organs.

OPTIMAL COLLIMATION SIGNIFICANTLY IMPROVES LUMBAR SPINE RADIOGRAPHY

2020 ◽  
Vol 189 (4) ◽  
pp. 420-427
Author(s):  
Anamaria Pazanin ◽  
Damijan Skrk ◽  
Jessica C O'Driscoll ◽  
Mark F McEntee ◽  
Nejc Mekis
Keyword(s):  
Lumbar Spine ◽  
Image Quality ◽  
Absorbed Dose ◽  
Field Size ◽  
Organ Doses ◽  
Dose Area Product ◽  
Spine Radiography ◽  
Spine Imaging ◽  
Radiosensitive Organs ◽  
Area Product

Abstract Purpose To determine the influence of optimal collimation during lumbar spine radiography on radiation dose and image quality. Material and methods 110 lumbar spine patients were split into two groups—the first imaged with standard collimation and the second with optimal collimation. Body mass index, image field size, exposure conditions and dose area product were measured. Effective and absorbed organ doses were calculated. Image quality was assessed. Results Optimal collimation reduced the primary field by up to 40%. The effective dose was reduced by 48% for the AP projection, while no differences were found for the LAT projection due to incorrect positioning of the central beam with standard collimation. The absorbed dose to selected radiosensitive organs decreased by 41 and 10% in the AP and LAT projections, respectively. Image quality for the LAT projection improved by 24% and maintained for the AP projection. Conclusion Optimal collimation in lumbar spine imaging significantly influences patient exposure to radiation.

Minimizing table time in patients with claustrophobia using focused ferumoxytol-enhanced MR angiography (f-FEMRA): a feasibility study

2021 ◽  
Vol 94 (1125) ◽  
pp. 20210430
Author(s):  
Puja Shahrouki ◽  
Kim-Lien Nguyen ◽  
John M. Moriarty ◽  
Adam N. Plotnik ◽  
Takegawa Yoshida ◽  
...  
Keyword(s):  
Image Quality ◽  
Mr Angiography ◽  
Signal To Noise Ratio ◽  
Diagnostic Image Quality ◽  
Diagnostic Confidence ◽  
Motion Artefact ◽  
Scan Time ◽  
Wilcoxon Rank Sum Test ◽  
Significant Difference ◽  
Noise Ratio

Objectives: To assess the feasibility of a rapid, focused ferumoxytol-enhanced MR angiography (f-FEMRA) protocol in patients with claustrophobia. Methods: In this retrospective study, 13 patients with claustrophobia expressed reluctance to undergo conventional MR angiography, but agreed to a trial of up to 10 min in the scanner bore and underwent f-FEMRA. Thirteen matched control patients who underwent gadolinium-enhanced MR angiography (GEMRA) were identified for comparison of diagnostic image quality. For f-FEMRA, the time from localizer image acquisition to completion of the angiographic acquisition was measured. Two radiologists independently scored images on both f-FEMRA and GEMRA for arterial and venous image quality, motion artefact and diagnostic confidence using a 5-point scale, five being best. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the aorta and IVC were measured. The Wilcoxon rank-sum test, one-way ANOVA with Tukey correction and two-tailed t tests were utilized for statistical analyses. Results: All scans were diagnostic and assessed with high confidence (scores ≥ 4). Average scan time for f-FEMRA was 6.27 min (range 3.56 to 10.12 min), with no significant difference between f-FEMRA and GEMRA in diagnostic confidence (4.86 ± 0.24 vs 4.69 ± 0.25, p = 0.13), arterial image quality (4.62 ± 0.57 vs 4.65 ± 0.49, p = 0.78) and motion artefact score (4.58 ± 0.49 vs 4.58 ± 0.28, p > 0.99). f-FEMRA scored significantly better for venous image quality than GEMRA (4.62 ± 0.42 vs 4.19 ± 0.56, p = 0.04). CNR in the IVC was significantly higher for steady-state f-FEMRA than GEMRA regardless of the enhancement phase (p < 0.05). Conclusions: Comprehensive vascular MR imaging of the thorax, abdomen and pelvis can be completed in as little as 5 min within the magnet bore using f-FEMRA, facilitating acceptance by patients with claustrophobia and streamlining workflow. Advances in knowledge: A focused approach to vascular imaging with ferumoxytol can be performed in patients with claustrophobia, limiting time in the magnet bore to 10 min or less, while acquiring fully diagnostic images of the thorax, abdomen and pelvis.

Absorbed dose and image quality in examinations of the colon with digital and analogue techniques

1997 ◽  
Vol 38 (6) ◽  
pp. 1010-1014 ◽  
Author(s):  
J. Persliden ◽  
P. Larsson ◽  
B. Norén ◽  
S. Wirell
Keyword(s):  
Image Quality ◽  
Absorbed Dose ◽  
Image Intensifier ◽  
Incident Radiation ◽  
Conventional Technique ◽  
Digital System ◽  
Digital Technique ◽  
Significant Difference ◽  
Total Examination Time ◽  
Area Product

Purpose: Image quality and the absorbed dose to the patient are issues of primary interest in the change-over from the conventional analogue technique to the digital technique in the examination of the colon by means of fluoroscopy. the aim of this study was to compare the incident radiation and to evaluate the image quality in two different X-ray equipment types, one digital and one analogue Material and Methods: A kerma-area product meter was used to measure the incident radiation to the patient. Both fluoroscopy and total-examination times were measured as was the number of images. an evaluation of image quality was made and statistically analysed Results and Conclusion: No significant difference in the irradiation dose was observed between the two techniques. the fluoroscopy time was significantly lower with the conventional technique but the total-examination time decreased by 18% with the digital technique. the total number of images taken was higher with the digital technique (25 images compared to 19) owing to the limited field of the image intensifier. Significantly more noise and less sharpness were observed with the digital system but there was no significant difference in contrast or image quality in the various anatomical structures. Although the change-over to the digital system produced a reduction in sharpness and an increase in noise, and no significant dose saving was measured, the digital system was faster to work with and could well be used for diagnostic purposes

The Influence of Alteration of kVp and mAs towards the Image Quality of Acrylic Using CBCT

2019 ◽  
Vol 829 ◽  
pp. 252-257
Author(s):  
Azhari ◽  
Yohanes Hutasoit ◽  
Freddy Haryanto
Keyword(s):  
Image Quality ◽  
Signal To Noise Ratio ◽  
Region Of Interest ◽  
Signal To Noise ◽  
Bite Block ◽  
Significant Difference ◽  
Noise Ratio ◽  
Post Hoc ◽  
Radiograph Image

CBCT is a modernized technology in producing radiograph image on dentistry. The image quality excellence is very important for clinicians to interpret the image, so the result of diagnosis produced becoming more accurate, appropriate, thus minimizing the working time. This research was aimed to assess the image quality using the blank acrylic phantom polymethylmethacrylate (PMMA) (C­5H8O2)n in the density of 1.185 g/cm3 for evaluating the homogeneity and uniformity of the image produced. Acrylic phantom was supported with a tripod and laid down on the chin rest of the CBCT device, then the phantom was fixed, and the edge of the phantom was touched by the bite block. Furthermore, the exposure of the X-ray was executed toward the acrylic phantom with various kVp and mAs, from 80 until 90, with the range of 5 kV and the variation of mA was 3, 5, and 7 mA respectively. The time exposure was kept constant for 25 seconds. The samples were taken from CBCT acrylic images, then as much as 5 ROIs (Region of Interest) was chosen to be analyzed. The ROIs determination was analyzed by using the ImageJ® software for recognizing the influence of kVp and mAs towards the image uniformity, noise and SNR. The lowest kVp and mAs had the result of uniformity value, homogeneity and signal to noise ratio of 11.22; 40.35; and 5.96 respectively. Meanwhile, the highest kVp and mAs had uniformity value, homogeneity and signal to noise ratio of 16.96; 26.20; and 5.95 respectively. There were significant differences between the image uniformity and homogeneity on the lowest kVp and mAs compared to the highest kVp and mAs, as analyzed with the ANOVA statistics analysis continued with the t-student post-hoc test with α = 0.05. However, there was no significant difference in SNR as analyzed with the ANOVA statistic analysis. The usage of the higher kVp and mAs caused the improvement of the image homogeneity and uniformity compared to the lower kVp and mAs.

scholarly journals Feasibility study of using simultaneous multi-slice RESOLVE diffusion weighted imaging to assess parotid gland tumors: comparison with conventional RESOLVE diffusion weighted imaging

2020 ◽  
Author(s):  
Jia-Suo Jiang ◽  
Liu-Ning Zhu ◽  
Qian Wu ◽  
Yi Sun ◽  
Wei Liu ◽  
...  
Keyword(s):  
Image Quality ◽  
Parotid Gland ◽  
Diffusion Weighted Imaging ◽  
Signal To Noise Ratio ◽  
Anatomical Structure ◽  
Parotid Gland Tumors ◽  
Diffusion Weighted ◽  
Scan Time ◽  
Significant Difference ◽  
Noise Ratio

Abstract Background To evaluate the feasibility of using simultaneous multi-slice (SMS) readout segmentation of long variable echo-trains (RESOLVE) diffusion-weighted imaging (DWI) to assess parotid gland tumors, compared with conventional RESOLVE DWI Methods From September 2018 to December 2018, 20 consecutive patients with parotid tumors who underwent MRI scan for pre-surgery evaluation were enrolled. SMS-RESOLVE DWI and conventional RESOLVE DWI were scanned with matched imaging parameters, respectively. The scan time of two DWI sequences was recorded. Qualitative (anatomical structure differentiation, lesion display, artifact, and overall image quality) and quantitative (apparent diffusion coefficient, ADC; ratio of signal-to-noise ratio, SNR ratio; ratio of contrast-to-noise ratio, CNR ratio) assessments of image quality were performed, and compared between SMS-RESOLVE DWI and conventional RESOLVE DWI. Paired t-test was used for statistical analyses. Results The scan time was 3 minutes and 41 seconds for SMS-RESOLVE DWI, and 5 minutes and 46 seconds for conventional RESOLVE DWI. SMS-RESOLVE DWI produced similar qualitative image quality with RESOLVE DWI (anatomical structure differentiation, P = 0.164; lesion display, P = 0.193; artifact, P = 0.330; overall image quality, P = 0.083). Meanwhile, there were no significant difference on ADCLesion (P = 0.298), ADCMasseter (P = 0.122), SNR ratio (P = 0.584) and CNR ratio (P = 0.217) between two DWI sequences. Conclusion Compared with conventional RESOLVE DWI, SMS-RESOLVE DWI could provide comparable image quality using markedly reduced scan time. SMS could increase the clinical usability of RESOLVE technique for DWI of parotid gland.

scholarly journals New patient-controlled abdominal compression method in radiography: radiation dose and image quality

2018 ◽  
Vol 7 (5) ◽  
pp. 205846011877286 ◽  
Author(s):  
Oili Piippo-Huotari ◽  
Eva Norrman ◽  
Agneta Anderzén-Carlsson ◽  
Håkan Geijer
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Prone Position ◽  
Quality Criteria ◽  
Abdominal Compression ◽  
Radiographic Images ◽  
Dose Area Product ◽  
Similar Dose ◽  
Significant Difference ◽  
Area Product

Background The radiation dose for patients can be reduced with many methods and one way is to use abdominal compression. In this study, the radiation dose and image quality for a new patient-controlled compression device were compared with conventional compression and compression in the prone position . Purpose To compare radiation dose and image quality of patient-controlled compression compared with conventional and prone compression in general radiography. Material and Methods An experimental design with quantitative approach. After obtaining the approval of the ethics committee, a consecutive sample of 48 patients was examined with the standard clinical urography protocol. The radiation doses were measured as dose-area product and analyzed with a paired t-test. The image quality was evaluated by visual grading analysis. Four radiologists evaluated each image individually by scoring nine criteria modified from the European quality criteria for diagnostic radiographic images. Results There was no significant difference in radiation dose or image quality between conventional and patient-controlled compression. Prone position resulted in both higher dose and inferior image quality. Conclusion Patient-controlled compression gave similar dose levels as conventional compression and lower than prone compression. Image quality was similar with both patient-controlled and conventional compression and was judged to be better than in the prone position.

scholarly journals Evaluation of dose parameters defining the probability of deterministic effects in the skin of patients undergoing interventional radiological examinations

2020 ◽  
Vol 13 (3) ◽  
pp. 77-86
Author(s):  
S. S. Sarycheva
Keyword(s):  
Absorbed Dose ◽  
Dose Assessment ◽  
Field Size ◽  
Skin Dose ◽  
Operation Technique ◽  
Representative Point ◽  
High Dose ◽  
Dose Area Product ◽  
Area Product ◽  
Radiological Examinations

The study is devoted to the assessment of dose parameters determine the probability of deterministic effects in the skin for patients undergoing high-dose interventional radiological examinations. Particular attention is paid to the analysis of the geometry of the absorbed dose distribution over the patient’s skin for the main types of interventional examinations. The aim of this study was to clarify the methodology for assessment of the maximum absorbed dose in the patients’ skin, taking into account new data. The data collection was carried out in nine city hospitals from Sankt-Petersburg; detailed information about more than 400 procedures was obtained. The data about operation technique for the main types of interventional examinations, physical, technical, geometric and dosimetric parameters for each procedure were registered. Based on the statistical data on distribution of geometric procedure parameters (fields size and projections) possible localizations and values of the absorbed dose in certain areas of the patients’ skin were determined. An updated methodology for skin dose assessment based on the recorded dosimetric value of dose area product considering the radiation fields size was presented. As an alternative, an estimation of the maximum skin dose based on the cumulative air kerma at the patient’s reference point – «representative» point for the patient’s skin considering the tube rotation was proposed. This method does not require the information on used field size. The conservative conversion coefficients from the measured dosimetric values to the peak skin dose and trigger values to prevent deterministic effects in the patients’ skin were calculated.

scholarly journals Evaluation of Patient's Dose and Estimate of Cancer Risk in Electrophysiology Studies and Ablation in Cath Lab Center of Afshar Hospital, Yazd, Iran

2020 ◽  
Author(s):  
Fatollah Bouzarjomehri ◽  
Fereshteh Omidvar ◽  
Mohammad Hossein Zare ◽  
Mashallah Nakhaeine Nejad
Keyword(s):  
Cancer Risk ◽  
Effective Dose ◽  
Absorbed Dose ◽  
Image Intensifier ◽  
Time Range ◽  
Cross Sectional ◽  
Dose Area Product ◽  
The Mean ◽  
Area Product ◽  
Risk Of Cancer

Introduction: Today electrophysiology studies and ablation have been developed due to increasing arrhythmias disorder of heart. In these diagnostic – treatments methods, the use of fluoroscopy can be causes patient radiation dose, therefore evaluation of patient's absorbed dose is necessary to protection of the radiation. The aim of this study was to evaluate the absorbed dose in patients undergoing electrophysiology and cardiac ablation and to estimate their risk of cancer in Yazd Afshar Hospital. Methods: This study was a cross-sectional study. In this study, the mean absorbed dose of referral patients for electrophysiology studies and ablation had been measured in the cat. Lab of Afshar Hospital, Yazd. The dosimeter had been used in this research was KAP meter, the M4 DIAMENTOR made in Germany that was able to measure dose-area product and time of the fluoroscopy. The patient effective dose was calculated by the PCXMC software from dose-area product. Results: The mean dose-area in ablation and electrophysiology studies was respectively 153.34±105.32 and 5.62 14.88 Gy.cm2 and the radiation time range was recorded 3.32 to 68.65 minutes and 1.03 to 6.28 minutes, respectively. The mean effective dose of ablation and electrophysiology studies were respectively 16.38 and 1.65 mSv. The cancer risk per ten thousands of patients, who were under the ablation and electrophysiology examinations were estimated 13 and 1.3 people, respectively. Conclusion: Increasing of patient dose due to ablation in this study relation to the other studies can be due to long old of image intensifier device.

scholarly journals Intervariability in radiographic parameters and general evaluation of a low-dose fluoroscopic technique in patients with idiopathic scoliosis

2021 ◽  
Vol 10 (9) ◽  
pp. 205846012110432
Author(s):  
Christian Wong ◽  
Jens Adriansen ◽  
Jytte Jeppsen ◽  
Andreas Balslev-Clausen
Keyword(s):  
Image Quality ◽  
Idiopathic Scoliosis ◽  
Low Dose ◽  
Signal To Noise Ratio ◽  
Radiographic Images ◽  
Dose Area Product ◽  
General Evaluation ◽  
Radiographic Parameters ◽  
Cobb’S Angle ◽  
Noise Ratio

Background Radiographic images in adolescent idiopathic scoliosis (AIS) have a potential radiation-induced oncogenic effect; thus lowering radiation dose by using fluoroscopic imaging technique of low-dose fluoroscopic technique (LFT) which might be relevant for clinical evaluation. Purpose To compare radiographs of LFT with gold standard radiographs for AIS ordinary radiographic technique (ORT). Material and Methods Image quality was evaluated for LTF and ORT of a child phantom and two 3D-printed models (3DPSs) of AIS. We measured the primary physical characteristics of noise, contrast, spatial resolution, signal-to-noise ratio, and contrast-to-noise ratio. Three independent evaluators assessed the radiographs by observer-based methods of image criteria (ICS) and visual grading analysis(VGAS). Radiation doses were evaluated by the dose-area-product (DAP) of the 25 phantom radiographs. Reliability and agreement of Cobb’s angle (CA) and other radiographic parameters were evaluated on the 3DPSs and reliability on 342 LFT. Results The average noise and contrast were approximately 15-fold higher for LFT. SNR and CNR were similar. Overall, ICS and VGAS were 3-fold higher for ORT than for LFT for L3 and similar for Th6. Reliability and agreement were good for the experimental LFT, and the interclass correlation coefficient for CA was 0.852 for the clinical LFT. The average DAP and effective dose for LFT were 8-fold lower than those for ORT. Conclusion In conclusion, LFT is reliable for CA measurements and is thus useful for clinical outpatient follow-up evaluation. Even though the image quality is lower for LFT than ORT, the merits are the substantially reduced radiation and a lowered malignancy risk without compromising the measurement of Cobb’s angle, thus following the principles of ALARA.

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