METRONewsJuly 2013
Changing shot distance affects
the X-Ray image

Image Distortion


The goals of an X-Ray exposure include the presentation of an image that is properly exposed, contains sufficient diagnostic detail, and shows minimal distortion.  

Often called Focus Film Distances (FFD) and Source to Image-receptor Distance (SID), the X-Ray shot distance plays an important role in each.  

Proper exposure - One can increase or decrease the exposure making the image lighter or darker simply by changing the shot distance.  Moving further away will lighten the image.

Diagnostic detail - in digital X-Ray, a great X-Ray image contains "contrast" detail to visually isolate specific anatomy and related abnormalities while maintaining a smooth texture.  Often X-Ray images produced by under-powered generators lack detail and/or have a grainy texture.  By shortening the shot distance (FFD/SID), the exposure energy is intensified.  You can increase the MAS potential of a portable generator simply by moving it closer.  Setting your generator to output 2 MAS at 100cm will produce an 8 MAS equivalent at 50cm simply by the magnification caused by moving closer.  This move can help reduce the grainy look.  


Water Bottle Test Image distortion - there's a reason why X-Ray generators are normally positioned at least 100cm away from image receptor.   The lateral exposure of a dog's hip will present a larger hip socket diameter of the hip side that is closer to the  generator and a smaller socket diameter of the hip that is further away from the generator source. The shorter the distance, the greater the amount of visual magnification.  Also if the "hip" object is not at the center point of the X-Ray beam, the near view element (forward hip) can also appear out of position.  The X-Ray beam will project that object element away from center. (See illustration above.)


FFD-SID Test The two X-Ray images present effects of X-Ray (FFD/SID) on a digital image. The water bottle that is closer to the X-Ray source appears bigger than the water bottle that is further way. Using the shot distance of 100cm, the two bottles appear nearly the same size. At 50cm, the bottle that is closer to the generator appears much larger. 


With Equine X-Ray, the portable generator  is necessary and very effective with most all leg views.  When attempting to image the neck, spine and other very thick, dense shots, the portable needs to be on the high end of the power scale .  When using portable generators in Small Animal X-Ray, unit needs to have higher power capability to capture diagnostic images for any medium and large dogs.  Even with the tricks described above, the images may present too much distortion and still lack needed detail if using the entry-level portable generator.  


We are happy to help anyone who has X-Ray generator output questions or would like advice with X-Ray technique and image quality.  


Practice Spotlight 
Wyoming Equine | Equine Sports Medicine

Wyoming Equine-Dr ConnallyDr. Bruce Connally, DVM, MS has been using Metron Imaging Software since May 2012.  Upon returning to Wyoming to practice after seven years as an assistant professor at Colorado State University - College of Veterinary Medicine, he originally wasn't aware of Metron when he purchased his X-Ray system.  During his 30 years of clinical experience, he has used other X-Ray systems, however, Dr. Connally states "It is a very good product and they are the best images I have ever had."


Wyoming Equine is specifically Equine Sports Medicine, so in addition to diagnosing and treating injuries, he is also focused on prevention of those injuries.  Dr. Connally uses Metron with his X-Ray panel primarily for lameness and dental X-Rays. 


Dr. Connally states "I learned Metron on my own without much assistance and it was not hard to come up to speed."  He primarily uses Free Mark-Up in the Metron in his equine practice finding it very useful. He is also aware of the Guided Mark-Up for equine available in the Metron software.


Wyoming Equine Dr. Connally receives the Metron Support Services newsletters and reads them to learn more about the product and the new features coming.  In fact, METRONews is where he learned about the new Metron 7.07 release.


His mobile veterinary practice services equine athletes in his area and he often travels 75-150 miles to visit his patients.  The horse as an athlete is Dr. Connally's passion, both professionally and personally.  Learn more about Dr. Connally and his Wyoming Equine practice at the practice website or find him on  facebook. 


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In This Issue
Shot Distance & X-Ray Image Detail
Practice Spotlight: Wyoming Equine
July 4 Support Hours
METRONews Email Delivery
Your Support Website
Guided Mark-Up Tip


July 4 Support Hours
July 4
Metron Support Services will be closed Thursday, July 4 in observance of the Independence Day holiday. Limited support hours will be available Friday, July 5 9am-5pm. Regular business hours of 8am-6pm CST (M-F) will resume Monday, July 8.


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Did you know?

When you are doing Guided Mark-Up, instead of dragging the mouse across the screen to click on "Next Step >" you can just click the space bar.
Also, if you have questions while picking your points in the Guided Mark-Up process, clicking the space bar will bring up the "Help" section.
 Guided Markup Help



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