1. HEALTH CARE STATISTICS AND RESEARCH HEPR 410
Shawn Gross
HEALTH CARE STATISTICS AND RESEARCH
HEPR 410
Shawn Gross
HEALTH CARE STATISTICS AND RESEARCH
HEPR 410

2. Table of Contents Introduction Summary of Literature Conclusion
References
Table of contents

3. What do we know about x-rays?
We know x-rays are performed for many health care reasons, and we know x-rays come from the sun in the form of radiation.
General Knowledge

4. Introduction
The principle of radiation protection is that no practice involving exposure to radiation should occur unless it produces sufficient benefit to the exposed individual to offset the radiation risk to both the individual and the rest of the population.
As Low as Reasonably Achievable: There is not a safe dose of radiation.

5. Measuring radiation dosage
The scientific unit of measurement for radiation dose, commonly referred to as effective dose, is the millisiervert. Other radiation dose measurement units include rad, rem, roentgen, sievert, and gray.
Because different tissues and organs have varying sensitivity to radiation exposure, the actual radiation risk to different parts of the body from an x-ray procedure varies. The term effective dose is used when referring to the radiation risk averaged over the entire body.
The effective dose accounts for the different tissues exposed. More importantly, it allows for the comparison of risk and comparison to more familiar sources of exposure that range from natural background radiation to radiographic medical procedures.
How radiation dose is measured

6. Radiation from X-Rays and other Medical Tests
According to the American Nuclear Society, the following are the typical dose levels from various medical tests:
Extremity (arm, leg, etc) X-rays: 1 mrem
Dental X-ray: 1 mrem
Chest X-ray: 6 mrem
Nuclear Medicine (thyroid scan): 14 mrem
Neck/Skull X-ray: 20 mrem
Abdomen X-ray: 65 mrem
CAT Scan: 110 mrem
Upper GI X-ray: 245 mrem
Barium Enema: 405 mrem
Common radiographic procedures

7. Now looking at the other sources of radiation exposure.
You'll probably end up with around 300 mrem a year, perhaps more, if you take a lot of airplane flights.
Radon (radiation from the ground) about 100 mrem per year the largest single source of natural radiation.
Cosmic radiation (Sun): accounts for about 220 mrem per year.
As you can see, unless you have a lot of medical imaging procedures, you receive a lot more natural radiation per year compared to medical radiation levels.
Comparisons of everyday radiation to medical radiation

8. Summary of: Article I "Effects of AEC Chamber Selection."
“P” for the patient or problem: How necessary is shielding? What effects can a technologist have without shielding?
“I” for the intervention of interest: With or without shielding how much Compton scattering does organs and skin receive?
“C” for comparison, and:
“O” for outcome: Data and analysis supporting the effects of not proper shielding.

9. One way to reduce radiation exposure is by choosing the correct AEC chamber
The AEC supplies the cut-off signal to the generator, and thereby ensures an optimal and reproducible image quality, independent of the radiation quality, object density, and other factors.

10. This study provides information on selecting the correct AEC chambers to insure the ALARA principle.
Can we reduce patient dose by choosing the correct AEC chamber during x-rays?

11. Variables
Subjects
Dose Levels
AEC Selection
Radiographic Phantoms

12. Methods
A body phantom was positioned on the radiographic table with the central ray directed according to standard centering criteria. A 40inch source to image distance was used for the abdomen phantom. The central ray was directed perpendicular to the level of the iliac crest for the AP abdomen.
Multiple exposures were taken at each of the 3 AEC chamber configurations with the mA station and optimal kvp remaining constant for each exposure on each phantom.
The mean and standard deviation (SD) for each subset were calculated.

13. The AEC chamber selection producing the lowest dose on the AP abdomen is the two outside chambers with an OD(object distance) within the acceptable range.

14. Data For AP Abdomen
The dose level on the AP abdomen by selecting the 2 outside chambers(mean = mR) with an OD within the acceptable range (mean = 0.450).
This accounts for 2/3 decrease in radiation dose by choosing the correct AEC chambers.

15. Discussion
By choosing the correct chambers on the automatic entrance control feature we as radiographers can help to reduce patient exposure.

16. Summary of: Article II
“Reference Dose Levels for Patients Undergoing Diagnostic X-ray Examinations In Irish Hospitals.”

17. This article compares background radiation at hospitals that use strict QA programs to hospitals across the world who do not.

18. Variables
Subjects
Dose levels for x-rays of chest, abdomen, pelvis, and lumbar were used for the variables of this study.
Sixteen hospitals were chosen to represent 42% of the population. Ten patients for each exam was chosen to collect the dose levels. Each exam was performed in the same room with the same equipment. Each patient was an adult weighing near 70 kg.

19. Methods
Each exam had its own patient with their own dosimeter to collect the data for background reference dose levels(RDL). By using two sets of control dosimeters, any false reads were filtered out.

20. Entrance surface was used to determine the amount of radiation
Entrance surface was used to determine the amount of radiation. Dosimeters were kept with each patient’s file to collect the background dose level for each exam.

21. Results
ESD measurements were made on 884 dosimeters throughout the sixteen hospitals. A wide variation in background RDL was collected.
Chest PA: Min Mean Max Standard Dev. .13-Min/Max ratio 43
Abdominal: Min..5 –Mean4.75- Max Standard Dev.3.4 -Min/Max ratio37
PelvisAP: Min.1.2 –Mean5.63- Max Standard Dev.3.6 -Min/Max ratio22
LumbarAP: Min..27 –Mean6.47- Max Standard Dev.3.6 -Min/Max ratio75

22. With the exception of chest exams, background RDLs recorded an increase of 13% for lumbar x-ray dose and a decrease between 40% and 20% for the other exams. These variations show with a good QA program dose levels can dramatically be decreased.

23. Discussion
The hospitals that follow a strict QA program show a much smaller variation in dose levels compared to those who don’t.
To maintain the ALARA principle (As Low As Reasonably Achievable)dose level surveys should be conducted on a regular basis at all hospitals .

24. Conclusion
In order to reduce dose levels during radiographic examination and protect our patients and ourselves from over exposure, we need to follow basic radiation protection principles.

25. Resources
Hawkings, N. (2009). Effects of AEC Chamber Selection. RADIOLOGIC TECHNOLOGY, 80(5),
Johnston, D. A. (2000). Patients Undergoing Diagnostic X-ray Examinations In Irish Hospitals. Journal of Radiology, 73(4),
NRC. Nuclear Regulatory Commision. (2012, Mar. Th). Natural Background Sources Washington, DC: Office of Public Affairs. Retrieved July 2, 2012, from