Impact on dose and image quality of a software-based scatter correction in mammography

2017 ◽  
Vol 59 (6) ◽  
pp. 649-656 ◽  
Author(s):  
Teresa Monserrat ◽  
Elena Prieto ◽  
Benigno Barbés ◽  
Luis Pina ◽  
Arlette Elizalde ◽  
...  
Keyword(s):  
Image Quality ◽  
Scatter Correction ◽  
Inverse Image ◽  
Clinical Image ◽  
Air Kerma ◽  
Average Glandular Dose ◽  
Standard Mode ◽  
Entrance Surface Air Kerma ◽  
Clinical Cases

Background In 2014, Siemens developed a new software-based scatter correction (Progressive Reconstruction Intelligently Minimizing Exposure [PRIME]), enabling grid-less digital mammography. Purpose To compare doses and image quality between PRIME (grid-less) and standard (with anti-scatter grid) modes. Material and Methods Contrast-to-noise ratio (CNR) was measured for various polymethylmethacrylate (PMMA) thicknesses and dose values provided by the mammograph were recorded. CDMAM phantom images were acquired for various PMMA thicknesses and inverse Image Quality Figure (IQFinv) was calculated. Values of incident entrance surface air kerma (ESAK) and average glandular dose (AGD) were obtained from the DICOM header for a total of 1088 pairs of clinical cases. Two experienced radiologists compared subjectively the image quality of a total of 149 pairs of clinical cases. Results CNR values were higher and doses were lower in PRIME mode for all thicknesses. IQFinv values in PRIME mode were lower for all thicknesses except for 40 mm of PMMA equivalent, in which IQFinv was slightly greater in PRIME mode. A mean reduction of 10% in ESAK and 12% in AGD in PRIME mode with respect to standard mode was obtained. The clinical image quality in PRIME and standard acquisitions resulted to be similar in most of the cases (84% for the first radiologist and 67% for the second one). Conclusion The use of PRIME software reduces, in average, the dose of radiation to the breast without affecting image quality. This reduction is greater for thinner and denser breasts.

Dosimetry and optimization in digital radiography based on the contrast-detail resolution

2018 ◽  
Vol 6 (3) ◽  
Author(s):  
Wilson Otto Gomes Batista ◽  
Alexandre Gomes De Carvalho
Keyword(s):  
Image Quality ◽  
Inverse Image ◽  
Point Of View ◽  
Complete Analysis ◽  
Portable Devices ◽  
Evaluation Tool ◽  
Air Kerma ◽  
Direct Radiography ◽  
Definition Of ◽  
Entrance Surface Air Kerma

Contrast-detail (C-D) curves are useful in evaluating the radiographic image quality in a global way. The objective of the present study was to obtain the C-D curves and the inverse image quality figure. Both of these parameters were used as an evaluation tool for abdominal and chest imaging protocols. The C-D curves were obtained with the phantom CDRAD 2.0 in computerized radiography and the direct radiography systems (including portable devices). The protocols were 90 and 102 kV in the range of 2 to 20 mAs for the chest and 80 kV in the range of 10 to 80 mAs for the abdomen. The incident air kerma values were evaluated with a solid state sensor. The analysis of these C-D curves help to identify which technique would allow a lower value of the entrance surface air kerma, Ke, while maintaining the image quality from the point of view of C-D detectability. The results showed that the inverse image quality figure, IQFinv, varied little throughout the range of mAs, while the value of Ke varied linearly directly with the mAs values. Also, the complete analysis of the curves indicated that there was an increase in the definition of the details with increasing mAs. It can be concluded that, in the transition phase for the use of the new receptors, it is necessary to evaluate and adjust the practised protocols to ensure, at a minimum, the same levels of the image quality, taking into account the aspects of the radiation protection of the patient.

A Virtual Image Chain for Perceived and Clinical Image Quality of Medical Display

2008 ◽  
Vol 4 (4) ◽  
pp. 356-368 ◽  
Author(s):  
CÉdric Marchessoux ◽  
Tom Kimpe ◽  
Tom Bert
Keyword(s):  
Image Quality ◽  
Clinical Image ◽  
Virtual Image

Influence of the characteristic curve on the clinical image quality of lumbar spine and chest radiographs

2004 ◽  
Vol 77 (915) ◽  
pp. 204-215 ◽  
Author(s):  
A Tingberg ◽  
C Herrmann ◽  
B Lanhede ◽  
A Almén ◽  
M Sandborg ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Image Quality ◽  
Characteristic Curve ◽  
Chest Radiographs ◽  
Clinical Image

scholarly journals Penerapan Teknik Parallel Imaging Pada Pesawat MRI 0,35 Tesla Untuk Optimalisasi Kualitas Informasi Anatomi Pada MRI Lumbal Pembobotan T1WI dan T2WI Potongan Sagital

2015 ◽  
Vol 1 (1) ◽  
pp. 19-22
Author(s):  
Gatot Murti Wibowo ◽  
Dartini Dartini ◽  
Hari Prayitno
Keyword(s):  
Image Quality ◽  
Parallel Imaging ◽  
Imaging Techniques ◽  
Spin Echo ◽  
Clinical Image ◽  
Good Imaging ◽  
Scan Time ◽  
Significant Difference ◽  
Lumbar Mri

Background : Parallel imaging is one of the MRI Scanning techniques used to reduce the overall scan time when the patients with unvoluntary movement being examined with a low magnetic field of 0,35 T.  This research aims to determine the difference between the clinical image quality of the conventional turbo spin echo (TSE) with mSENSE and that of the TSE with GRAPPA parallel imaging techniques from which resulting the MRI T1 and T2 Weighted Images (T1WI and T2WI) sagittal view of lumbar spines, and to define the techniques that clinically provide the most approriate anatomical information.Methods :  This experimental study is made performed by the MRI 0.35 T in which 10 patients who had hernia nucleus pulposus (HNP) desease participated in the experiments ramdomly. The appointed Radiologists blended in the image evaluation using an image checklist to assess the visualisation of anatomical organs on the resulted sagittal lumbar MRI T1WI and T2WI. The two non-parametric statistical tools, Friedman test and the post hoc Wilcoxon matched pairs test, is used to analyze all the data descriptively. Testing the resesearch hypotheses with 95% of confident interval is to proved the differences between resulted sagittal lumbar MRI T1WI and T2WI..Results : The results shown there is a significant difference on the image quality of anatomical information when conventional TSE, parallel imaging-mSENSE and -GRAPPA, with T1WI are applied in the imaging techniques. When those imaging techniques are employed to obtain T2WI, the result is not significant in  contrast.Conclusion : Good imaging techniques with adequate clinical image quality are ranked sequently as the conventional TSE, the  mSENSE and GRAPPA.

scholarly journals X-Rays through the Looking Glass: Mobile Imaging Dosimetry and Image Quality of Suspected COVID-19 Patients

2021 ◽  
Vol 46 (3) ◽  
pp. 120-126
Author(s):  
Alexandra Schelleman ◽  
Chris Boyd
Keyword(s):  
Image Quality ◽  
Scattered Radiation ◽  
X Rays ◽  
High Exposure ◽  
X Ray ◽  
Air Kerma ◽  
X Ray Imaging ◽  
Exposure Levels ◽  
Exposure Technique

Background: This paper aims to evaluate the clinical utility and radiation dosimetry, for the mobile X-ray imaging of patients with known or suspected infectious diseases, through the window of an isolation room. The suitability of this technique for imaging coronavirus disease 2019 (COVID-19) patients is of particular focus here, although it is expected to have equal relevance to many infectious respiratory disease outbreaks.Materials and Methods: Two exposure levels were examined, a “typical” mobile exposure of 100 kVp/1.6 mAs and a “high” exposure of 120 kVp/5 mAs. Exposures of an anthropomorphic phantom were made, with and without a glass window present in the beam. The resultant phantom images were provided to experienced radiographers for image quality evaluation, using a Likert scale to rate the anatomical structure visibility.Results and Discussion: The incident air kerma doubled using the high exposure technique, from 29.47 μGy to 67.82 μGy and scattered radiation inside and outside the room increased. Despite an increase in beam energy, high exposure technique images received higher image quality scores than images acquired using lower exposure settings.Conclusion: Increased scattered radiation was very low and can be further mitigated by ensuring surrounding staff are appropriately distanced from both the patient and X-ray tube. Although an increase in incident air kerma was observed, practical advantages in infection control and personal protective equipment conservation were identified. Sites are encouraged to consider the use of this technique where appropriate, following the completion of standard justification practices.

EVALUATION OF RADIATION DOSE FOR PATIENTS UNDERGOING MAMMOGRAPHY IN QATAR

2020 ◽  
Vol 189 (3) ◽  
pp. 354-361
Author(s):  
Huda AlNaemi ◽  
Antar Aly ◽  
Ahmed J Omar ◽  
Amal AlObadli ◽  
Olivera Ciraj-Bjelac ◽  
...  
Keyword(s):  
Patient Dose ◽  
Dose Assessment ◽  
Radiation Doses ◽  
Full Field ◽  
Average Value ◽  
Air Kerma ◽  
Full Field Digital Mammography ◽  
Gulf Countries ◽  
Average Glandular Dose ◽  
Entrance Surface Air Kerma

Abstract In the absence of information on radiation doses in mammography in the Gulf countries, this study was designed to assess patient dose in terms of entrance surface air kerma and average glandular dose (AGD) in three mammography units in Qatar that covers 21% of all mammography systems in the country. The study of 150 patients involving 600 projections indicated that the average value of AGD in patients was 2.2 mGy for cranio-caudal and 2.5 mGy for mediolateral-oblique views, respectively. Dose assessment was also performed for polymethyl methacrylate phantoms of thicknesses, ranging from 20 to 80 mm. Comparing the patient dose values with several other publications in literature for full-field digital mammography, our values are typically higher, which can be likely attributed to the larger compressed breast thickness.

Clinical Image Quality in Daily Practice of Breast Cancer Mammography Screening

2014 ◽  
Vol 65 (3) ◽  
pp. 199-206 ◽  
Author(s):  
Marie-Hélène Guertin ◽  
Isabelle Théberge ◽  
Michel-Pierre Dufresne ◽  
Hervé Tchala Vignon Zomahoun ◽  
Diane Major ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Image Quality ◽  
Confidence Interval ◽  
Breast Density ◽  
Risk Ratio ◽  
Daily Practice ◽  
Interrater Agreement ◽  
Clinical Image ◽  
Screening Mammograms

Objective To assess the quality of screening mammograms performed in daily practice in the Quebec Breast Cancer Screening Program. Subjects and Methods Clinical image quality of a random subsample of 197 screening mammograms performed in 2004-2005 was independently evaluated by 2 radiologists based on the criteria by Canadian Association of Radiologists (CAR). When disagreement occurred for overall judgement or positioning score, the mammograms were reviewed by a third radiologist. Cohen's kappas for interrater agreement were computed. Multivariable robust Poisson regression models were used to study associations of overall quality and positioning with body mass index (BMI) and breast density. Results The CAR criteria were not satisfied for 49.7% of the mammograms. Positioning was the quality attribute most often deficient, with 37.2% of mammograms failing positioning. Interrater agreement ranged from slight (kappa = 0.02 for compression and sharpness) to fair (kappa = 0.30 for exposure). For overall quality, women with a BMI ≥ 30 kg/m2 had a failure proportion of 67.5% compared with 34.9% for women with a BMI<25 kg/m2 (risk ratio 2.1 [95% confidence interval, 1.5-3.0]). For positioning, women with a BMI ≥ 30 kg/m2 had a failure proportion of 53.8% compared with 27.9% for women with a BMI < 25 kg/m2 (risk ratio 1.9 [95% confidence interval, 1.2-3.1]). Effects of breast density on image quality differed among radiologists. Conclusion Despite measures to ensure high-quality imaging, including CAR accreditation, approximately half of this random sample of screening mammograms failed the CAR quality standards. It would be important to define quality targets for screening mammograms carried out in daily practice to interpret such observations.

Clinical Image Quality and Sensitivity in an Organized Mammography Screening Program

2018 ◽  
Vol 69 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Isabelle Théberge ◽  
Marie-Hélène Guertin ◽  
Nathalie Vandal ◽  
Jean-Marc Daigle ◽  
Michel-Pierre Dufresne ◽  
...  
Keyword(s):  
Image Quality ◽  
Quality Evaluation ◽  
Screening Program ◽  
Clinical Image ◽  
Breast Cancers ◽  
Canadian Association ◽  
Screening Mammograms ◽  
Screening Sensitivity ◽  
Adjusted Sensitivity

Purpose The study sought to examine the association between clinical image quality of mammograms and screening sensitivity. Methods Four radiologists evaluated the clinical image quality of 374 invasive screen-detected cancers and 356 invasive interval breast cancers for which quality evaluation of screening mammograms could be assessed from cancers diagnosed among participants in the Quebec Breast Cancer Screening Program in 2007. Quality evaluation was based on the Canadian Association of Radiologists accreditation criteria, which are similar to those of the American College of Radiology. The association between clinical quality and screening sensitivity was assessed by logistic regression. Adjusted sensitivity and adjusted sensitivity ratios were obtained through marginal standardization. No institutional review board approval was required. Results A proportion of 28% (206 of 730) of screening mammograms had lower overall quality for the majority of assessments. Positioning was the quality attribute that was the most frequently deficient. The 2-year screening sensitivity reached 68%. Sensitivity of screening was not statistically associated with the overall quality (ratio of 2-year sensitivity = 1.03; 95% confidence interval: 0.93-1.15) or with any quality attributes (positioning, exposure, compression, sharpness, artifacts, contrast). Results were similar for the 1-year sensitivity. Conclusions Although not all mammograms in the Quebec screening program met the optimum quality required by the Canadian Association of Radiologists or American College of Radiology accreditation, the screening mammograms produced in this population-based organized screening program reached a high enough level of quality so that the remaining variation in quality is too little to impair screening sensitivity.

scholarly journals Retinal Optical Quality of Multifocal Refractive and Monofocal Intraocular Lenses

Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 559
Author(s):  
Francesco D’Oria ◽  
Ali Nowrouzi ◽  
Jorge L. Alio del Barrio ◽  
Francesco Versaci ◽  
Jorge L. Alio
Keyword(s):  
Image Quality ◽  
Quality Parameters ◽  
Optical Quality ◽  
Intraocular Lenses ◽  
Clinical Image ◽  
Control Group ◽  
Strehl Ratio ◽  
Group 2 ◽  
Group B

(1) Background: This study aimed to evaluate and compare the clinical optical image quality following implantation with different premium IOLs by the analysis of the point spread function (PSF) Strehl ratio using a Pyramidal WaveFront-based sensor (PWS) aberrometer at two different pupil sizes. (2) Methods: This study included 96 eyes of 70 patients implanted with: (1) 19 AcrySof SA60AT (control group); (2) 24 LENTIS Mplus LS-313 MF30; (3) 33 LENTIS Mplus LS-313 MF15; and (4) 20 Precizon Presbyopic. Main outcome measures were PSF Strehl ratio, PSF Strehl ratio excluding second-order aberrations (PSFw2), total root-mean-square (RMS), and low- and high-order aberrations’ RMS measured by PWS aberrometer. Results: SA60AT had the highest significant PSFw2 Strehl ratio at both 3- and 4-mm pupil size (0.41 ± 0.11 and 0.28 ± 0.07) followed by LENTIS Mplus 15 (group C, 0.35 ± 0.1 and 0.21 ± 0.06) and a near tie between LENTIS MPLUS 30 (group B, 0.27 ± 0.08 and 0.18 ± 0.06) and Precizon Presbyopic (group D, 0.27 ± 0.07 and 0.17 ± 0.04). MPlus MF15 was found to be significantly better than MPlus MF30 at both 3.00 mm (p < 0.0001) and 4.00 mm (p = 0.002). (4) Conclusions: The PSFw2 represents a new tool to objectively evaluate the far distance retinal image quality of multifocal IOLs, and the far distance clinical image quality parameters measured by PWS aberrometer differed significantly according to the technology of the implanted lens.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

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