Sunday, March 6, 2011

Shielding Issues


I have had a rough weekend.  I have been sick with a rather ugly cold, but I still had to work my two 12-hour shifts at the hospital.  I suffered through it though and will hopefully get to sleep it off tonight and tomorrow so I can get back into full swing before my next rotation starts on Tuesday...

I ran into an interesting situation today with a patient in the ER.  I had a female patient in her mid 20's, so I followed the standard protocol of finding out if she could be pregnant.  I asked her if there was any possibility she could be pregnant.  She simply responded with YES.  It turns out that she's a week late on her menstrual cycle.  She was in for a chest x-ray, so I stopped what I was doing and went back to visit the ER doctor who had ordered her x-ray.  He told me to shield her really well and make the images, so that's what I had to do.

I have issues with this decision.  In my humble opinion, shielding a patient for a chest x-ray has only minimal effect of keeping radiation away from the places you don't want it to go.  The central ray is not passing through the pelvic region, but a lot of scatter is.  The shielding I provided would have little or no effect on that scatter radiation passing from the chest region down through the pelvis.  I know that this scatter has changed direction at least 90 degrees for this to happen, and it loses a lot of energy in that process.  Losing energy in that direction also means that a larger majority of that scatter will be absorbed in the body rather than passing on through.  So what effect does the front, side, and rear shielding I provided for my potentially pregnant patient have since the radiation is coming from directly above? 

Tuesday, March 1, 2011

Lateral Knee X-ray

Here's one of my more common imaging errors in the world of x-ray. The lateral knee requires a lot of attention in the area of tube angle because of body habitus. When the patient has wide hips, more tube angle is required to get the knee perfectly lateral. In this image, I had the central ray positioned properly but not quite enough tube angle to get the joint space completely opened. The medial epicondyle should be almost perfectly superimposed over the lateral epicondyle. In my example here, it is not...

This image was also posted on for discussion.  If you haven't stopped by there yet, give it a look!