Digital Imaging

Dr. Don Johnson

Director Sports Medicine Clinic Carleton University

Assistant Professor of Orthopedic Surgery University of Ottawa

donnie@carletonsportsmed.com

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What is it?

Digital imaging is the process of acquiring a photographic image into your computer without traditional photographic film.

The following will be a practical discussion of digital imaging. It is a system that works for me, but there are many other ways it could be done. The importance of digital imaging was brought home to me again after recently finishing writing a book chapter, I realized how archaic and labor intensive the production of camera ready 5X7 black and white photos can be. It would be much simpler to send the entire manuscript to the publisher in a digital format. The second scene that struck me was when visiting Wake Forest University as a visiting professor, I saw all the medical students carrying a laptop and palmpilot. There was not a textbook in sight. This should be a wake up call for the traditional publishers.

This paper is on stll imaging only, for video click here

 

How do you do it?

With digital cameras, and scanners

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Digital cameras are the easiest way to get photos in the OR, of patients in the clinic, and x-rays. I use the Olympus C2500 to shoot x-rays on the view box, to capture close ups in the OR and to record clinical examination of patients in the clinic. The high resolution image of the camera is 1700x1400 or 2.5 million pixels. This is about 900 KB in JPEG format. The camera has a Smart media and compact flash card slots, 32 Mb smart media card, and I carry 2 of them to give me 100 high resolution photos (each card holds 50 photos). The card then fits into a pc card adapter, that you open on the computer as another drive. The 50 photos are dragged and dropped into a folder on your hard disc. These photo are then dropped on to an editing program called PhotoIntern, where they are cropped, adjusted for brightness, sized, if for the internet (640X480), named, saved as a JPEG (250 kb) and placed in suitable folders on the hard drive. PhotoIntern can catalogue the folder with an album of thumbnails. This allows easy retrieval of the images when you go to this folder again.

The Nikon coolpix 900 is camera with similar resolution. The essentials to get in a digital camera are:

High resolution – at least 1288X1924 or 1.4 million pixels

Close up or macro capabilities - Olympus 10" and Nikon 3"

Zoom lens

Removal flash cards – to allow downloading without a cord connection

These cameras come with PhotoDeluxe, a scaled down version of PhotoShop. I prefer to use PhotoIntern, see below.

Is the picture quality the same as a slide from a 35 mm camera? No, but it is sufficient for most orthopedic applications. Below are examples of an intra-operative photo and an x-ray, both taken with the Olympus digital camera.

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I use a Umax flatbed scanner to scan large photos. The photo is acquired by PhotoDeluxe, manipulated by the program, and saved as a JPEG.

I also use a Canon slide scanner to scan into the same PhotoDeluxe program my favorite clinical slides. These are named and saved in the appropriate folder on my server hard drive. The Nikon slide scanner is faster, but more expensive. The Canon connects on a scssi fast connection. The parallel port connection scanners are too slow.

I also use a Sony digital capture system to acquire photos from my arthroscopic camera at the time of surgery. These are saved as JPEG’s in the same fashion as above. Both Linvatec and Stryker offer systems to integrate the capture of arthroscopy images from their digital camera systems. These programs also use PhotoIntern. An additional program Rec room will allow you to drag and drop the digital images into a operative note based on a macro.

Image Format

The common file format's are:

.bmp 
.JPEG
.GIF
.tiff.

My preference is to use JPEG. They will import into PowerPoint, word, and .html. They are compressed files, take less space on your computer, and will lose some quality if you need to print large 8X10 photos. This is rare to have to print large pictures, and thus JPEG is the most versatile format.

Now I have plenty of photos, what do I do with them?

I use them in presentations such as PowerPoint,

I insert them in FrontPage for my web site.

I use them to illustrate articles (in word documents) that I write for the Practical Arthroscopy newsletter.

To give a slide show on a large screen TV of my latest trip.

 

The file system

The first step is to be well organized on your computer. After you start to collect some images, you will want to retrieve them easily. Start by giving the image a name that identifies the slide. For example in the arthroscopy slides below, you can see that I called the images, acl_chronic_tear. I then put it in a folder called arthroscopy and a subfolder called ACL. The folders called ‘new’ are to download digital images that I collect during the day, and don’t have time to immediately edit them. After they are edited, they are moved to the appropriate folder.

This file directory is the mirror of my LAN server, where the pictures are ultimately stored. I started with zip and jaz discs, but quickly ran out of space. I then connected all my computers together with a Ethernet and PCMCIA cards to a 24 gig NT server. But even this storage bin is quickly filling up!

The arthroscopy directory

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PhotoIntern

This is the best all around editing and archiving program. I had been using several programs, PhotoShop, PhotoDeluxe, LightView pro and image access pro to do what PhotoIntern does. This is an illustration of the album of acl arthroscopy images.

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X-rays

It is important to keep the x-rays organized as well. The file system on your computer should look like this. This one is from my laptop, but I keep a mirror on my desktop and my server. The photos are periodically removed from the laptop and desktop to the server.

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The PhotoIntern Album for xrays-knee-acl. When I open the folder of acl knee x-rays, I click on the PhotoIntern album, locate the exact photo I want, and import it into my document.

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There are several programs that will do almost the same. These are LightView Pro, Image access Pro, PhotoShop, and PhotoDeluxe.