Ok, so I finally got around to redoing my Medical Physics virtual CD jukebox properly so I’m not limited by the number of loopback devices. Works fabulously.
Now I have to figure out how to make it more convenient to search besides opening up the index page for each month’s issue. Since they’re all online now, there should be some way of crawling through the directory structure and indexing each of the PDF files. Googling returns a few possible solutions, but mostly for PDF files contained inside a webspace somewhere, which these are not. I suppose I could make them web accessible and index them using something like ht://dig or even have GoogleBot crawl it, but then I’d probably be violating some copyright rules. PDFSearch looks like it might have some potential, but looks a little cumbersome.
Guess I’ll just keep on looking.
What was that noise?
It was probably the cry of anguish from thousands of Canadians after the mens hockey team got shut out by the Russians in the quarter finals on Wednesday.
Bummer.
However, I am pleasantly surprised at how much curling action I’m seeing on TV this year. The Canadian women’s team took bronze yesterday (hooray!) and the men go for gold today. I’m kind of bummed I won’t be able to watch the Canadian men’s team going for gold though (it’s on at 11:30 this morning and I’ll be stuck at work). Guess I’ll have to settle for trying to catch highlights of the game.
Update: The men’s team took the gold!. Woohoo!
Blog archive ordering
Ok, so I’ve been blogging for a few years now, and reading a bunch of them in the meantime. This is something I’ve always wondered about: Why do people always sort their blog archives in reverse chronological order (newest to oldest)? For the main blog page it makes perfect sense to have the most recent post at the top. You don’t want to make readers have to scroll all the way to the bottom of the page to find the most recent entry. But for archives, IMO it makes very little sense. Think about it…sorting in reverse chronological order means the reader has to read through your blogging history from the bottom of the browser and scroll upwards. If an entry is longer than a screen length, then the reader has to scroll down to read the full entry, then scroll back up to find the next one.
Makes for lots of senseless scrolling. A much more logical way of reading blog archives would be sorted in chronological order (oldest to newest).
So why do people leave their blog archives like this? Just something they’ve never thought about? Because that’s the way it’s always been done? Something they can’t change? I can’t imagine any blogging software worth the bits it’s made from not giving the user at least that capability.
Bloggers, think about what you’re doing to your fellow readers!
First DR unit is in!
Did the acceptance testing of our first digital radiography unit a couple of days ago, a GE Revolution XR/d.
As imaging technology changes, I usually have to adapt my testing methods to fit. Some technologies render certain tests obsolete or irrelevant while other tests need to be modified, or the analysis changed. In the past, I’ve had to modify my test and analysis procedures for CR units and more recently multi-detector CT scanners.
This new DR unit was no exception. Being a digital unit, a few things went a little faster and easier. Images pop up within 15 seconds of the exposure, so a lot of time gets cut out waiting for the images to appear. The table detector is electronically coupled to the location of the tube and slides along as you move the tube along the table, so no need to fuss with centering the tube over the detector. The folks at GE were even kind enough to incorporate a patient entrance dose display and cumulative exposure counter on the workstation. For some reason though, they’ve apparently decided to forego any kind of exposure index indicator – some kind of indicator to the technologist that the x-ray exposure they just made falls within an acceptable range for image quality. At least there wasn’t one that I could find or that the service engineer knew about.
An exposure index is a very useful tool for providing feedback to the technologist. With conventional film/screen, the tech can easily see whether the exposure was too much or too little by how dark the developed film comes out. With digital imaging, there’s no relationship between the appearance of the image and exposure adequacy except in the appearance of noise. Almost all CR manufacturers have some form of exposure index that’s displayed to the tech. I’m puzzled as to why this GE DR unit doesn’t have anything. Maybe I’ll just have to dig deeper to find it.
The first problem this caused was just how to test the kV and thickness tracking for the phototimer. The phototimer is responsible for making sure the image receptor (film, CR cassette, DR receptor) gets enough radiation to produce an adequate image. For film, you measure the optical density (OD). With CR, I use whatever exposure index is provided by the CR vendor as an analog for OD. With this GE DR unit, there wasn’t anything immediately obvious to use. So after a bit of mucking around with the software to see what I could find, I eventually ended up using a central region of interest to get the mean pixel value from the raw unprocessed image and tracking that value.
Everything seemed to come out ok, although I have no feel for what an acceptable range would be. Something I’ll have to work out I suppose. In the meantime, this lack of any kind of exposure index seems like a potentially serious issue as far as providing feedback to the technologist.
The other new thing that needs to be done is the detector evaluation. These detectors need to be properly calibrated, and I’ll probably have to include procedures for verifying the calibration. Somewhere in the world of AAPM subcomittees and task groups, there was one putting out a report on testing CR and DR units, which is something I’ve been waiting a while for and is just what I need for this task. I didn’t see it on the list of active task groups, and last I heard the final report was coming RSN, so hopefully I’ll see something soon.
We’ve got a couple more DR rooms being installed in the next few months (hopefully), so I’ll have a chance to try out some new procedures in a little while.
Patent dreams
Had a very strange dream about patented things. I’m not entirely sure if it was actually a dream, or something I’m remembering from reading somewhere though.
So there I am having one of my ‘fly on the wall’ type dreams watching some guy talk to someone about computer related patents. He’s talking about one in particular, a patent for some kind of network router that he tried to build from the plans in the patent application. For some reason he couldn’t get it to work at all, so he was wondering what other kinds of ridiculous things had been granted patents, but didn’t work at all.
Then I woke up.
Very strange.