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Neelam, that is very true. The 19" lcd we use is 1.3mp. GE lists this as non hi-res. We have twin portrait panels in chest clinic, ITU, etc. These require a (concurrent) twin lcd licence. If you go to 1.9mp ( 1600x 1200) this is classified as hi-res, although the GE data sheet refers to 2mp or above as hi-res, so in GE speak 1.9mp = 2.0mp. We are all used to inflation in this programme...
Ivan, we spent a good while looking at alternatives, and dont feel that there is a major difference between the 1.3mp web image and the 2 or 3mp dicom. This is viewing DR images produced by new ( philips ) DR chest units. There's a nice paper from Mass General saying something similar.
The GE clinician workstation does not support twin LCDs in the product that is in the national programme. The res of the twin lcds we use with the webamounts to a virtual screen of 2100 x 1200, which is around 3mp.
I suspect most of the chest guys would prefer this to a clinician workstation running a 1.9 mp ( 1600 x 1200 ) single panel, as the screen real estate is bigger... |
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| I do think it unhelpful for AGFA to label their images not suitable for diagnosis. There is no similar statement for GE, and our system is set for the web to display images 'as stored' What that means I am uncertain. GE web training can be done in an hour, but the clinician workstation is essentailly the same as the diagnostic workstation which takes most of a day.. this seems a major issue in roll-out |
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 James Steel
posted on Tuesday, October 31, 2006 - 09:39 am
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Peter,
I could be wrong but I think "As Stored" means what they were like when they hit PACS i.e. if you make any changes on the Radiologist workstations e.g. windowing or annotation, this is NOT displayed on the web. Pretty poo in my opinion!
James. |
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| Ivan Brown
posted on Tuesday, October 31, 2006 - 09:54 am
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Peter,
I agree that the GE Web does not carry a
"Not for diagnostic use" like the Agfa but the training literature issued to the IMandT training department for dissemination to users here did contain this warning and was a major issue in Southampton for some while.
Also if you view a CD burnt with the Web Viewer from the GE PACS at another site then unless this is loaded into a Diagnostic WS it will display the "Not for Diagnostic Use" warning. The GE WS are still locked out to prevent us loading CDs from other sites into them even though we have installed antivirus SW! |
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Peter and Ivan,
Agfa Web images do NOT carry this message "Not for diagnostic use", but the e-learning package does propagate this message actively.
I apologise if I have been mis-understood. |
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| The issue of monitor quality and its importance in diagnosis is uncertain. A recent study in the detection of wrist fractures ( Radiology 2005;237:872-877) failed to identify any significant benefit in using work station as opposed to PC monitors. This article makes the point that clinicians do not have to find a workstation monitor to confirm preliminary PC based findings - thereby increasing the number of areas where a primary diagnosis can be made. They also observed that non screen factors such as ambient light levels are very important. Further, if post processing tools are available on the PC these can help overcome areas of diagnostic uncertainty. In the light ( no pun ! ) of this one would have to question the necessity of expensive WS monitors (we have) and any comment such as "not for diagnostic use" utilised by manufacturers and applied to images also needs clarification. |
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| Ian Inglis
posted on Wednesday, November 01, 2006 - 07:09 pm
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I largely agree with Christopher's comments but have to add that the DICOM greyscale calibration of clinicians PCs is of much more significant value than this forum generally seems to give it credence for, especially as the cost for this calibration is trivial and also allows the maintaining of good QA.
DICOM calibration is at least and probably far more important than ambient light conditions under the vast majority of circumstances.
Ian |
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| > > > I agree entirely that calibration is vital Ian, but ambient lighting has been > shown to be an important determinant of diagnostic efficacy, particularly in > non-controlled environments with non-specialist reporters. Also it is > important to note that effective calibration relies on the measurement of > ambient lighting. > > Patrick C Brennan > > |
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| > > > I agree entirely that calibration is vital Ian, but ambient lighting has been > shown to be an important determinant of diagnostic efficacy, particularly in > non-controlled environments with non-specialist reporters. Also it is > important to note that effective calibration relies on the measurement of > ambient lighting. > > Patrick C Brennan > > |
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| Ian Inglis
posted on Thursday, November 02, 2006 - 12:15 pm
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Hi Patrick, it seems we are in general agreement however it is not correct to calibrate a PC/monitor and at the same time allow ambient light into the DICOM calibration with say a 'stand off' photometer if that is what you are suggesting.
DICOM greyscale calibration must be done using a photometer which touches the monitor screen and excludes ambient light. This is analogous with a diagnostic environment where the self calibrating diagnostic monitor calibrates itself by one of two methods. I attach a useful article by a monitor manufacturer.
In a diagnostic environment ambient light must be addressed as a separate entity, and the same applies to clinician PC/monitors.
This is the only way that a correct DICOM curve can be programmed in.
Ian |
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Dear all, someone has kindly noted that the RCR PACS group guidance on diagnostic display devices still has 'draft' in the heading, although they have been approved. To avoid confusion I've reposted the guidance below.
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| Can anyone tell me whether there are any guidelines on recommended ambient lighting for reporting digital images? |
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See the SIG guidance on QA of display devices http://www.pacsgroup.org.uk/forum/messages/419/17843.html
IPEM guidance is 15 lux.
In practice if you cannot see any reflections on the screen and you can see the 5% black box on the standard SMPTE/TG18QC test pattern, the ambient light level should not be an issue. |
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The importance of DICOM Calibration