Need tips on Portable AP Chests

Neverwinter27 · Joined: 25 Jun 2008 Posts: 28

Im a freshman in my rad program and I am planning on a competency for a port ap chest next week. Is there any tips you guys can give me on getting it done? Here is what I am going to do:

-Sit the patient up on the bed, and place the cassette 2'' crosswise above the shoulders
-sid would be up to the patient's legs and the tube would be angled about 15 degrees downwards and parallel to the sternum
-the top light would be at the edge of the patient's chin
-collimate to the cassette, patient holds breath on inhale

If there is an easier way to obtain the image, let me know, I would appreciate it, thanks.

btw whats the average technique for a ave adult? I'd go around 90@6.4

wildwestcats · Joined: 22 Feb 2008 Posts: 31 Location: Arizona

I think your technique is going to depend on what kind of system you are using, any protocols your facility may have in place and if you are using grid or non-grid. At my clinical site, 110 @ 6.4 is your basic chest technique for the portables, adjusting as needed for patient size, distance, pathology, etc.

954heat · Joined: 29 Sep 2007 Posts: 90 Location: south florida

yea that sounds good. but technique does vary depending on the site your at...at my first site it was about 85@ 3.2 but at my last site they wanted us to raise the mas and kvp up to increase the exposure index cuz it had to be around 2200. dont forget your marker too. oh make sure you keep the patients chin up they sometimes tend to drop there head down. and dont forget not all patients can sit up you may have to do it supine. also most patients should fit on one cassette but some may not. also good luck!

Neverwinter27 · Joined: 25 Jun 2008 Posts: 28

moohoohoohoohoohohoo tanks ;_;

metalfan · Joined: 27 Nov 2011 Posts: 11

Except for very thin people (or the young) using a grid will give you way better results than non grid. With a grid you should be using around 110kV like wildwestcats said. mAs will range from 3.4 up to around 12mAs depending on the patients body habitus. Somewhere around 4-6mAs for your average build male, 12 mAS for a very obese person.

If you are seeing a well defined T-spine, use a lower mAs next time. If costaphrenic angles are noisy(especially on women) or there is a large amount of noise centerally under the diaphragm, use a higher mAs next time.

As for positioning, you do yourself a lot of favours by not proceeding with the study until the patient is in the exact position that you want. Realign them so they arent lying diagonally across the bed. Move them up the bed so their bottom will be at the bed fold when it is raised. You will do far less repeats if you get the patient where you want them before you start setting up the image.

Caudual angulation is a good idea so long as you have a grid that will have vertical grid lines on the film orientation you are using. Actual degree of angulation is going to vary based on the patients posture.

"place the cassette 2'' crosswise above the shoulders" Try not to use soft tissue as positioning guides - they are not nearly as stationary and uniform as hard structures. If you use the shoulders as a positining guide then you will cut off the costaphrenic angles more often than you would be happy with. Over time you will try and position the film lower to stop cutting the angles off which will lead to you cutting the apices off.

Most females shoulders are less 'square' than males, thus on average the shoulders will be lower on females than males. Especially in the elderly, some patients shoulders are very high - to the point where a lateral c-spine would only see down to c3 or 4.

Check what vertebral level the AC joints are at over the next 20 or so CXR's you do - the shoulders are highly variable and thus not a good structure to use as a reliable guide for positioning. Vertebra prominens is a good structure to use for consistency and specificity. The relationship between the lungs and the ribs/spine is not very variable. Palpating the spinous process of C7 will give you a very accurate and consistent guide to where the apex of the lung is.

Ideally you could have the anatomically perfect patient and centre around midpoint of sternal angle and xiphoid process, however palpating those landmarks is highly inadvisable in certain situations - especially with male technicians and a young female patient.