Technical Tips We May Have Forgotten

There are many reasons why x-ray films may lack the quality you expect. The least likely reason is the x-ray machine. Most of the time, it is the fault of the "technician," and we all know who that is.

You should treat your x-ray unit and dark room like a radiology department. We all have front desk procedures, reporting procedures, and billing procedures, so why not radiography procedures? The key to obtaining quality x-rays is consistency. Once good procedures are established, it only requires that those procedures are followed every time an x-ray is taken.

Here are a few useful recommendations:

1. Have the calibration checked on your x-ray unit periodically (every 2-3 years).

    

2. Warm up the x-ray tube before taking films. This will extend the life of your tube.

    

3. Have a regular schedule for cleaning your cassettes (every 2-3 months for most offices). The busier the office, the more frequent the cleaning. Commercial cleaners are best, but make sure you don't scratch the screens.

    

4. Chemistry in the processor should be changed at the very least every month. The more films taken, the more frequently it should be changed. The chemicals do degrade, so don't think you can just change them whenever.

    

5. Clean the roller in the processor at least daily. Don't use anything abrasive.

    

6. If you have an older processor, "feed" it films daily to keep the chemistry renewed.

    

7. If you are still using tanks, change the fresh water every day. The developer and fixer should be clear. Don't wait until they're black to change them.

    

8. Check your darkroom for light leaks at least once a year. The caulking dries up and ceiling tiles can shift.

    

9. Keep a log with the patient's measurements and techniques used. If this begins to change, it can indicate a problem with the x-ray unit.

    

10. For lateral lumbar x-rays, take two measurements: one at the waist and one at the hips, particularly with females. The median between the two should be the measurement used to calculate the technical factors. If the difference between the two measurements is greater than 6cm, plan on taking a lateral L5-S1 spot.

11. Remember to move the tube closer to the bucky one inch for every five degrees of tube tilt to maintain the original film focal distance. (I bet some of us have forgotten that one).

12. Identify the film. Proper identification includes:

• patient's name
• patient's age/sex, or date of birth
• exam date
• exam location
• right or left marker

  These are the techniques I use for spinal views:

View	Distance	kVp	Angle	Central Ray
C-Spine
APOM	40"	70	none	uvula
AP	40"	70	15 up	C4
Lateral	72"	70	none	C4
Flex/extend	72"	70	none	C4
Pillar	40"	70	35 down	C4
Oblique	72"	70	15 up or down	C4
Swim Lateral	40"	80	5 down	C7
T-Spine
AP	40"	80	none	T6
Lateral	40"	80	none	T6
L-Spine
AP	40"	80	none	L3-4
Lateral	40"	90+	none	L3-4
Oblique	40"	80+	none	2" above crest and 2" below medial ASIS
AP L5-S1	40"	80	20-30 up	between pubes and ASIS
Lateral L5-S1	40"	90+	none	2" below crest
Sacrum
AP	40"	80	15 up	between pubes and ASIS
Lateral	40"	90+	none	through ASIS
Sacroiliac
AP	40"	90	35 up	between pubes and ASIS
Lateral	40"	90+	none	same
Coccyx
AP	40"	80	10 down	2" above pubes
Lateral	40"	80	none	4" below crest

For more positioning techniques, refer to the Atlas of Radiographic Positioning by Sharon Jaeger,DC,DACBR.