dc.contributor.author | Lança, Luis | |
dc.contributor.author | Andersen, Erik Normann | |
dc.contributor.author | Carvalho, G. | |
dc.contributor.author | von Gerwen, M. | |
dc.contributor.author | Jorge, Jose | |
dc.contributor.author | Kleiker, M. | |
dc.contributor.author | Markali, Benedicte | |
dc.contributor.author | Nightingale, P. | |
dc.contributor.author | Hogg, Peter | |
dc.date.accessioned | 2017-01-30T10:05:15Z | |
dc.date.accessioned | 2017-03-13T10:28:25Z | |
dc.date.available | 2017-01-30T10:05:15Z | |
dc.date.available | 2017-03-13T10:28:25Z | |
dc.date.issued | 2016 | |
dc.identifier.citation | Lança L, Andersen EN, Carvalho G, von Gerwen, Jorge J, Kleiker, Markali B, Nightingale P, Hogg P: Are physical measures good indicators of image quality at low dose levels? A pilot study. In: Hogg P, Blakeley, Buissink C. OPTIMAX 2015 : Multicultural team-based research in radiography, a holistic educational approach. , 2016. University of Salford p. 128-142 | language |
dc.identifier.isbn | 978-1-907842-77-1 | |
dc.identifier.uri | https://hdl.handle.net/10642/4216 | |
dc.description.abstract | Purpose:
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-to-
noise 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 R
2
values of the non-linear relationship between objective visibility
score and CNR (60kVp R
2
= 0.902; 70Kvp R
2
= 0.913; 80kVp R
2
= 0.757) demonstrate
a better fit for all 3 kVp settings than the linear R
2
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. | language |
dc.language.iso | en | language |
dc.publisher | University of Salford | language |
dc.rights | CC-BY-NC-SA | language |
dc.title | Are physical measures good indicators of image quality at low dose levels? A pilot study | language |
dc.title.alternative | OPTIMAX 2015 : Multicultural team-based research in radiography, a holistic educational approach. | language |
dc.type | Chapter | |
dc.type | Peer reviewed | language |
dc.date.updated | 2017-01-30T10:05:15Z | |
dc.description.version | publishedVersion | language |
dc.identifier.cristin | 1440899 | |
dc.source.isbn | 978-1-907842-77-1 | |