I See the Light!
A recent article by Dr. Matt Wright of AnimalInsides.com entitled “Guide to
Almost all x-ray systems use a scintillator to convert x-rays to light. This is true for both film and digital systems (including CCD, CR and flat panel digital systems - except for Selenium-based flat panels). Traditionally, a Gadox (Gadolinium Oxide) screen has been used most often, and the reason for an upgrade to Cesium is related to reducing dose rather than improving image quality. A Cesium screen will generally deliver 25% to 50% more light than a good Gadox screen. Of course, both technologies vary from one brand to another in terms of quality.
Instead of going with a Cesium screen, our approach has been to offer a high end Gadox screen along with a very efficient lens system to maximize the light generated. Since our starting point provides x-ray imaging at a lower dose than that used with film, we question the viability for an end user of shopping the market for a Cesium screen to pursue additional reduction. Our standard digital sensor comes with a high-end Gadox screen, and replacing it with a Cesium screen, with the same resolution as the Gadox we use, would cost 2.5 times as much. Given usual manufacturer and distributor margins, the Cesium option could make the retail price almost 15% more expensive for the end user.
A good Cesium screen is available by special order. However, our internal tests show that, while this option for our system could reduce dose, it would deliver essentially the same image quality. Is it worth it?
Tagged Uncategorized | Comment now »
Too Much is a Good Thing!
When selecting a digital x-ray detector, a buyer usually assesses how each system relates to their current needs in terms of variables such as image quality, ease of use and price. System reliability and warranty are also important considerations, but it is often assumed that how a system performs today will be essentially how it performs in the years ahead. This overlooks the importance of the amount of data the hardware of a digital detector is capable of collecting now, even if it may be more power than is usable with the limitations of software available today - as good as it is. The unused power that a high quality digital system provides today will allow access to the significant benefits that future software development will deliver tomorrow. Buying too much horsepower for your new car doesn’t make sense with the direction of fuel prices. But, that’s not the case for a digital imaging system.
Tomorrow’s software enhancements will improve an existing digital system dramatically in areas such as soft tissue image quality, automatic measurement or sophisticated diagnostic supports. Yet to take advantage of these software features, the hardware must be capable of gathering enough information to support them, even though it can’t all be used today.
There are two specifications freely available in comparing digital sensors, whether they are flat panel or CCD based. These are resolution, measured in line pairs per millimeter (lp/mm), and the analog to digital signal conversion (ADC) measured in bits. The first relates to the fine detail available in the system while the second relates to the dynamic range. It is meaningless to promote high resolution if the dynamic range is insufficient for there to be enough contrast to see such resolution. Consider an upgrade from a 12 bit, 6 megapixel (MP) system to a 14 bit, 9 MP one. The 14 bit system will capture 6 times as much data for a computer to analyze than the 6 MP. If you were instead to move to a top of the line system with a 16 bit, 16 MP processor, you would have almost 43 times more information to work with. Pricing and system longevity become much more meaningful with this perspective.
Tagged Uncategorized | Comment now »
Buy Technology Now …….. or Wait?
Expanding practices are now very aware of the opportunity digital imaging provides versus film. They’ve seen first hand the high quality that’s available at very affordable prices, easily calculated the immediate economic benefits, heard colleagues confirm the positive impact on diagnoses, and they appreciate the important marketing impact technology can have for their services as well. But, it’s still difficult for some not to think that waiting “just a little longer” can get an even better payoff from tomorrow’s technology.
In making the buying decision, it is important not to confuse the hardware and software components of a digital x-ray system. Over the next several years, the cost to manufacture a high quality digital sensor is unlikely to come down significantly. From a hardware perspective, it makes little economic sense to delay. However, it is important to make sure your system will continue to be the one you want in the years ahead.
Some systems will suffer from x-ray damage over time and a resulting loss of image quality. Others will lose image quality or break down due to dust or condensation. A system should deliver consistent performance over time.
Another vital consideration is the capacity of a digital sensor to take advantage of the software enhancements coming to the market. These software enhancements will make the images even better and will provide tools to make a diagnosis easier and faster. Many systems on the market today do not provide the level of data required to truly make use of the software advances that are coming. An appreciation for the power of software in the future of digital imaging can have you saying “I wish I’d bought yesterday”.
Tagged Uncategorized | Comment now »
Digital in Practice
I certainly hope my perspectives on digital imaging do promote discussion among the wide spectrum of individuals involved in developing, designing and applying this science each day across every sector of health care. However, I also think that real case studies will pull a spotlight back on the objective of every one of us involved with digital x-ray – better diagnoses.
“Beezer, a 12 year old Boxer was presented for removal of an inflamed elbow skin mass. Before anesthesia on our older patients we insist on chest and abdomen x-rays. Beezer’s chest film revealed a large caudal lung mass. Surgery was canceled. Instead a fine needle aspiration of the mass was taken and submitted for pathology which came back as a malignant adendocarcinoma.
In this case the digital films were most diagnostic and contributory to Beezer’s case management”
Jan Bellows, DVM Dipl. AVDC
Tagged Uncategorized | Comment now »
Truth in Advertising
Astonishing, isn’t it? In the field of digital radiology, I’ve seen references to resolution specifications that are greater than what is mathematically possible based on the number of pixels and the size of the image. The phrase “specifications subject to change” was even included in one case; perhaps for legal reasons. Maybe those quoting the specifications know the truth, but then again, maybe they don’t.
And it goes on… Advertising 16 bit sampling is fair, but to say that it results in 65,536 shades of gray is inaccurate since this number is the theory, not the reality. Even high quality systems will have noise that reduces this theoretical number significantly. 16 bit sampling is certainly better than 14 bit (16,384 shades in theory) because much of the 14 bit is also not usable. Unfortunately, here we have a situation where an important system spec is lost to marketing sizzle. At least, I have not seen any advertising claim more than is scientifically possible.
And while we are at it, what about those film speed comparisons? There are no accepted comparisons between digital sensors and film speed. This leaves marketers to claim whatever they wish, and some seem to do just that.
The solution is for an independent physicist to be motivated to step forward and propose valid measurements for digital radiology specifications. Some specs, such as the number of megapixels or the number of bit sampling, are accurate. However, since these metrics do not provide the complete picture, it remains important for a buyer to look at the images taken by the system.
Tagged Uncategorized | Comment now »
Thoughts on RSNA
I am just back from the RSNA (Radiological Society of North America) convention in
Our company chose not to set-up a booth this year, although a partner, AFP Imaging did promote our new digital x-ray sensor as part of their display. It left us free to work the convention and establish many effective meetings. It proved to be a great show, and one important supplier we met with, who was without a booth this year, felt exactly the same way.
How much marketing glitz is good for a company’s bottom line? Of course, we need some. But in the end, I am betting that producing the right quality product for users and effectively explaining its features will do more to attract new customers and grow profitability than competing for the most floor space, elevation and lighting - somewhat meaningless objectives.
Tagged Uncategorized | Comment now »
Medical Records – What a Change!
From an early age, my mother gave me an interest in medical records (she was President of the Canadian Medical Records Librarians Association when they received their official government charter many years ago). Technology could make our lives easier in this area, yet it can become very complicated.
Recently I reviewed our 26 page DICOM conformance statement; developed so our data can be effectively shared. It was like reading another language. An engineer explained the difference between “big endian” and “little endian”; to me a useless fact that I can use to pretend I have more intelligence than I do. What is important are the results it gives.
If it were easy to take advantage of IT for medical records, President Bush’s goal of full adoption by 2014, of a measure to enhance Medicare payments for going paperless, would be much sooner. Incentives are in place to get it moving, but implementation cost remains a significant hurdle http://www.chicagotribune.com/features/lifestyle/health/chi-wed_doctors1031oct31,1,7769214.story.Major company CIOs talk about the difficulties connected with moving to electronic records due to issues much more involved than those we encounter in our DICOM work http://www.informationweek.com/blog/main/archives/2007/09/health_care_cio.html. But it is happening. For instance, Microsoft recently bought another company specifically to take advantage of the business opportunity involved http://www.eweek.com/article2/0,1895,2208998,00.asp
Teleradiology is growing, including important gains in the veterinary and chiropractic fields. This is good, especially since we do not need to know anything about the “little endian”.
Published by John Brooks on November 5th, 2007Tagged Uncategorized | 1 Comment »
Let’s Talk About Reliability
It’s easy to focus on image quality. You can look at images and see product specifications. Reliability is much more difficult to assess. It is a fair question to ask: “How is your cooling system designed?”
Tagged Uncategorized | Comment now »
Do You Know What I Want?
To most companies it is obvious what their customers want. Yet when we look at product failures, the obvious might be wrong. Recently a blog by Macadamian Technologies’ Matt Hately crossed my desk that mentioned ImaSight as a favorite example of involving customers early on in the product development cycle. As the blog suggests, what appeared to me to be the obvious step in product design may not be the norm.
The thermostat in my house is so complicated that most of its features are useless. This is an extreme example, but many products could benefit from early involvement with customers. It is easy to blame the engineers. We can call them nerds who are out of touch with normal people, but I suspect the real problem is management. Tight timelines, demand for more features and an assumption that customer involvement is unnecessary are likely to blame. Sometimes it is the little things that a customer will point out. As Michelangelo said so long ago “Trifles make perfection and perfection is no trifle”.
Tagged Uncategorized | Comment now »
Dynamic Range: Beyond the Limitations of Film
With a film based x-ray system, getting the right exposure is key to obtaining a good image. The dynamic range of a digital x-ray system allows great latitude in the technique used, thereby avoiding the need for retakes. The elimination of most retakes is a major consideration when a purchaser decides to upgrade from film to digital. This is important, but it is still thinking along the lines of film.
The dynamic range of a good digital system offers more benefits. Working with veterinarians, we find they like to scroll through various x-ray absorption levels. The best level to view soft tissues will be different than the best level to view bones. They are looking at more than a static image, yet using information taken from a single exposure.
Dynamic range is a function of the signal to noise ratio. The purchaser of a digital system typically compares different products using product specs and static images, but does not have information on dynamic range. About all a purchaser can do is to view an image scrolled through various absorption levels. We’re working to promote measures that truly focus on quality from the user’s perspective.
Published by John Brooks on August 31st, 2007Tagged Uncategorized | 2 Comments »
