October 2001 Bulletin

Buying digital camera? Check pixels, memory

Orthopaedists recording pre-, postop exams and intraoperative images

By Reid L. Stanton

Images have always been indispensable to orthopaedic education and practice. Today, digital cameras have made acquiring and sharing orthopaedic images both handy and economical.

Like digital watches, personal computers and wireless phones, the capabilities of digital cameras are expanding as the prices are dropping. Nevertheless, before you begin shopping for a digital camera, you should consider the kinds of pictures you will want to take, where you will shoot them and how you will use them.

Several uses for digital cameras in orthopaedics include recording physical examinations (both pre- and postop), diagnostic images and intraoperative photographs. George W. Wood II, MD, associate professor, University of Tennessee, Campbell Clinic, has become an avid digital photographer. He has taken more than 9,000 photographs of patients, X-rays, and doctors worldwide.

Don Johnson, MD, assistant professor of orthopedic surgery, University of Ottawa, agrees that the digital camera is an excellent tool. "The essential characteristics of a digital camera for orthopaedic surgeons include high resolution (1700x 1400 pixels or higher), the ability to do close-ups, a zoom lens, and removable memory cards," says Dr. Johnson.

If you’re in the market for a digital camera, your most important consideration should be image quality. Image quality is affected most by the technology used to capture the digital image. Select a digital camera that uses CCD (charge-coupled device) technology rather than CMOS (Complementary Metal-Oxide Semiconductor). CCD costs more, but is definitely the superior technology today.

Image quality also depends on capturing images at high resolution: the higher the maximum resolution rating the better the picture quality. Many digital cameras are rated or promoted based on their megapixel resolutions. A megapixel equals one million pixels. You’ll want a camera with a rating of at least 2.4 megapixels.

Look for a camera that has removable memory. If you only have built in memory, and you fill it up, you will have to download the images before you can take more pictures. Removable memory cards permit you to reload in the field.

The two most popular types of memory cards are SmartMedia and Compact Flash solid-state cards. They come in various storage capacities, rated in megabytes. Keep in mind these cards are not interchangeable. In addition, if you buy removable memory cards, you will need PC card adapter.

According to Michael L. Pearl, MD, shoulder and elbow staff surgeon at Kaiser Permanente in Los Angeles, "It’s very important to have an LCD (liquid crystal display) monitor that swivels. Other kinds of cameras require that your eye (head and body) be in the appropriate position to view from the correct angle. For example, the LCD monitor permits me to float the camera over the wound in the operating room and to get to the right height of an X-ray viewbox. A tilting LCD simply makes it easier to get the images you want."

Look for a camera that can accept rechargeable batteries and purchase a battery charger. Digital cameras drain batteries quickly, especially if you use the LCD viewfinder.

Often, digital cameras come with a serial port and a cable that connects to your personal computer’s serial port. Serial ports are notoriously slow, so you may want to make sure your camera has a USB port. A USB port will provide a simple and faster way to get your pictures out of your camera and into your computer.

Beyond the essentials, there are a great many options and add-ons for your digital camera, such as a built-in flash, extra flash memory cards, an AC adapter and much more. If you are looking for the highest high-tech, you might want an Ira (Infrared Data Association) port so you can beam your images to your computer.

Many digital cameras come with image editing software, which you’ll need if you want to make any changes to your images. With the right software, you can easily remove patient identifiers from any image—such as an X-ray—that you plan to make public in papers or presentations.

Reid Stanton is manager, electronic media, in the AAOS department of electronic media, evaluation and course operations.

Computer Link welcomes suggestions about future topics for the column and questions about the use of computers in orthopaedic practice. Send your suggestions to the Bulletin at AAOS, 6300 N. River Rd., Rosemont, Ill. 60018.

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