Radiographic Technique Evaluation

1. Radiographic Technique Evaluation

2. Radiograph Evaluation • We understand how radiographs are made. • We understand how to develop our films to have a visible image. • Now we will learn how to evaluate the finished radiographic product. • The technician needs to have the ability to properly evaluate a radiograph. • If you don’t know what is good, then it will be hard to attain a good quality image on film. • Will help to minimize re-takes.

3. Assessing a Radiograph • Taking a second radiograph is unavoidable. • If you are able to realize what is wrong on the initial radiograph, you can make corrections so that the second attempt is the last attempt. • Radiographic quality depends on the technologist’s understanding of the concepts and variables that produce a good radiograph. • Quality radiographs are obtained by a understanding of the variables we have discussed so far.

4. Let’s Review • X-ray generation • mA is applied to the filament in the cathode. • This generates an electron cloud. • The electrons are moved to the target on the anode by kV. • The collision produces heat and x-radiation. • mAs controls the total number of x-rays produced. • kVp controls the penetrating power of the x-rays.

5. And more Review • Density and Contrast • Density is defined as amount of blackness of the radiograph. • Primarily affected by mAs. • Contrast is defined as the density differences between two areas of a finished radiograph. • Primarily affected by kVp.

6. Viewing a Radiograph • Should be viewed on an evenly lit view box in a semi-darkened room. • View box should be clean, and all light bulbs should be in working order.

7. Film View Position • Film position is also important. • Usually follow medical viewing protocol. • V/D or D/V anatomy should be placed on the top of the view screen. • Lateral views should be positioned to face viewer’s left with spine at the top.

8. Correct Lateral Positioning

9. Correct V/D positioning

10. Evaluation of Radiographic Technique • Ask two basic questions when evaluating a radiograph. • 1. Is the film too light or too dark? • 2. Is there proper penetration?

11. Is the film too light or too dark? • The more exposure, the blacker the film. • The less exposure, the lighter the film. • (opposite from photography). • Will most likely need to increase or decrease kVp or mAs. • To know which one to adjust, must answer second question.

12. Is there proper penetration? • If there is inappropriate penetration of the x-radiation, then the kVp should be changed. • If film is dark, should be decreased. • If film is light, should be increased. • If penetration of x-radiation is satisfactory, then mAs should be adjusted.

13. If film is too light Is the film under penetrated? If no: Increase mAs 30-50% If yes: Increase the kVp 10-15%

14. If film is too dark Is the film over penetrated? If yes: Decrease kVp by 10-15% If no: Decrease mAs by 30-50%.

15. What determines Adequate Penetration of X-rays? • When viewing an abdominal radiograph, should be able to see outlines of liver, spleen, kidneys and bowel. • Inadequate penetration has areas that appear almost completely white.

16. Not good penetration

17. Good Penetration

18. Too Dark Radiographs • If bone tissue is gray and there is not much contrast between the bone and adjacent soft tissue, there was too much penetration. • Decrease kVp by 10-15% • If bone tissue is relatively white as compared to surrounding tissues, then there was not too much penetration. • Decrease mAs 30-50%

19. Other Error Considerations • Exhausted chemicals • Poor development techniques • Darkroom issues • Not lightproof • Film issues