Repository logo
 
Publication

Are physical measures good indicators of image quality at low dose levels? A pilot study

2016Book part Open access
Simple item page
dc.contributor.authorLança, Luís
dc.contributor.authorAndersen, E. N.
dc.contributor.authorCarvalho, G.
dc.contributor.authorGerwen, M.
dc.contributor.authorJorge, José
dc.contributor.authorKleiker, M.
dc.contributor.authorMarkali, B.
dc.contributor.authorNightingale, P.
dc.contributor.authorHogg, Peter
dc.date.accessioned2016-06-29T14:36:14Z
dc.date.available2016-06-29T14:36:14Z
dc.date.issued2016
dc.description.abstractPurpose: To evaluate if physical measures of noise predict image quality at high and low noise levels. Method: Twenty-four images were acquired on a DR system using a Pehamed DIGRAD phantom at three kVp settings (60, 70 and 81) across a range of mAs values. The image acquisition setup consisted of 14 cm of PMMA slabs with the phantom placed in the middle at 120 cm SID. Signal-to-noise ratio (SNR) and Contrast-tonoise ratio (CNR) were calculated for each of the images using ImageJ software and 14 observers performed image scoring. Images were scored according to the observer`s evaluation of objects visualized within the phantom. Results: The R2 values of the non-linear relationship between objective visibility score and CNR (60kVp R2 = 0.902; 70Kvp R2 = 0.913; 80kVp R2 = 0.757) demonstrate a better fit for all 3 kVp settings than the linear R2 values. As CNR increases for all kVp settings the Object Visibility also increases. The largest increase for SNR at low exposure values (up to 2 mGy) is observed at 60kVp, when compared with 70 or 81kVp.CNR response to exposure is similar. Pearson r was calculated to assess the correlation between Score, OV, SNR and CNR. None of the correlations reached a level of statistical significance (p>0.01). Conclusion: For object visibility and SNR, tube potential variations may play a role in object visibility. Higher energy X-ray beam settings give lower SNR but higher object visibility. Object visibility and CNR at all three tube potentials are similar, resulting in a strong positive relationship between CNR and object visibility score. At low doses the impact of radiographic noise does not have a strong influence on object visibility scores because in noisy images objects could still be identified.pt_PT
dc.identifier.citationLança L, Andersen EN, Carvalho G, Gerwen v. M, Jorge J, Kleiker M, et al. Are physical measures good indicators of image quality at low dose levels? A pilot study. In: Hogg P, Blakeley C, Buissink C, editors. OPTIMAX 2015 – Multicultural team-based research in radiography: a holistic educational approach. Groningen: Hanze University of Applied Sciences; 2016. p. 128-42.pt_PT
dc.identifier.isbn9781907842771
dc.identifier.urihttp://hdl.handle.net/10400.21/6256
dc.language.isoengpt_PT
dc.peerreviewedyespt_PT
dc.publisherHanze University of Applied Sciencespt_PT
dc.relation.publisherversionhttp://usir.salford.ac.uk/38008/1/Ebook%20Hanze%202015.pdfpt_PT
dc.rights.urihttp://creativecommons.org/licenses/by-nc/4.0/pt_PT
dc.subjectRadiologypt_PT
dc.subjectImage qualitypt_PT
dc.subjectDosimetrypt_PT
dc.subjectX-raypt_PT
dc.titleAre physical measures good indicators of image quality at low dose levels? A pilot studypt_PT
dc.typebook part
dspace.entity.typePublication
oaire.citation.endPage142pt_PT
oaire.citation.startPage128pt_PT
oaire.citation.titleOPTIMAX 2015 – Multicultural team-based research in radiography: a holistic educational approachpt_PT
rcaap.rightsopenAccesspt_PT
rcaap.typebookPartpt_PT

Files

Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
Are physical measures good indicators of image quality at low dose levels.pdf
Size:
7.82 MB
Format:
Adobe Portable Document Format
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections

ESTeSL - Capítulos ou partes de livros