1. RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY
Part No...., Module No....Lesson No
Module title
IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology
RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY
Part 16.1: Optimization of protection in fluoroscopy
Practical exercise
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Module…: (Add module number and title)
Lesson …: (Add session number and title)
Learning objectives: Upon completion of this lesson, the students will be able to: …
. (Add a list of what the students are expected to learn or be able to do upon completion of the session)
Activity: (Add the method used for presenting or conducting the lesson – lecture, demonstration, exercise, laboratory exercise, case study, simulation, etc.)
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IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

2. Part No...., Module No....Lesson No
Module title
Overview
To become familiar with quality control tests in fluoroscopy.
To measure the standard entrance dose rate to the patient
To assess the patient thickness variation effect on scattered radiation
Lecture notes: ( about 100 words)
Instructions for the lecturer/trainer
16.1: Optimization of protection in fluoroscopy
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

3. Part 16.1: Optimization of protection in fluoroscopy
Part No...., Module No....Lesson No
Module title
IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology
Part 16.1: Optimization of protection in fluoroscopy
Measurement of standard entrance dose rate
Part …: (Add part number and title)
Module…: (Add module number and title)
Lesson …: (Add session number and title)
Learning objectives: Upon completion of this lesson, the students will be able to: …
. (Add a list of what the students are expected to learn or be able to do upon completion of the session)
Activity: (Add the method used for presenting or conducting the lesson – lecture, demonstration, exercise, laboratory exercise, case study, simulation, etc.)
Duration: (Add presentation time or duration of the session – hrs)
Materials and equipment needed: (List materials and equipment needed to conduct the session, if appropriate)
References: (List the references for the session)
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

4. Fluoroscopy - Standard Dose Rate
Purpose :
Measurement of dose rate at the entrance of patient for different thickness
Effect on scattered radiation
Method :
Use different water equivalent absorber (acrylic, 20 cm for a standard patient) or copper sheets (2 mm for a standard patient
Place dosimeter on input (x-ray tube side) of absorber
16.1: Optimization of protection in fluoroscopy

5. Set-up for measurement of standard dose rate.
16.2: Optimization of protection in fluoroscopy

6. The ionization chamber should be protected pressure and possible malfunctioning. It should be in contact with the acrylic to include backscatter in the measurement.
16.2: Optimization of protection in fluoroscopy

7. Use 10 cm thickness of acrylic to simulate a thin patient
Use 10 cm thickness of acrylic to simulate a thin patient. The table to intensifier distance is 35 cm (this distance will be kept constant for the different patient thicknesses)
16.1: Optimization of protection in fluoroscopy

8. The chamber is easily centred using the fluoroscopic image
16.1: Optimization of protection in fluoroscopy

9. The entrance dose rate is 1.78 mGy/min.
16.1: Optimization of protection in fluoroscopy

10. The phantom thickness is now 20 cm.
16.1: Optimization of protection in fluoroscopy

11. The chamber now reads 8.85 mGy/min.
16.1: Optimization of protection in fluoroscopy

12. The patient entrance dose rate will increase.
If the distance between the input screen of the intensifier and the entrance of the patient is increased, i.e., extra 20 cm.
The patient entrance dose rate will increase.
16.1: Optimization of protection in fluoroscopy

13. Note: the chamber looks magnified (the intensifier is further away from the patient).
16.1: Optimization of protection in fluoroscopy

14. Before (intensifier-table distance: 35 cm)
Now (intensifier-table distance: 55 cm)
16.1: Optimization of protection in fluoroscopy

15. The entrance dose rate with the intensifier at 55 cm from the table is 17.9 mGy/min (to be compared with the previous value of 8.85 mGy/min).
16.1: Optimization of protection in fluoroscopy

16. Now the phantom thickness is increased up to 30 cm of acrylic.
16.1: Optimization of protection in fluoroscopy

17. 24.8 mGy/min (the reading was 8.85 with 20 cm thickness).
The patient entrance dose rate at the surface of the phantom increases to
24.8 mGy/min (the reading was 8.85 with 20 cm thickness).
16.1: Optimization of protection in fluoroscopy

18. The dose rate due to scatter radiation also increases with the patient thickness. For 30 cm acrylic, 3 mGy/h is measured close to the phantom.
16.1: Optimization of protection in fluoroscopy

19. 7 mGy/h. The patient entrance dose rate is now 59.6 mGy/min.
With the high contrast mode the dose rate for scatter radiation (30 cm acrylic), increases to
7 mGy/h. The patient entrance dose rate is now 59.6 mGy/min.
16.1: Optimization of protection in fluoroscopy

20. With 10 cm acrylic the dose rate due to scattered radiation is
0.2 mGy/h.
16.1: Optimization of protection in fluoroscopy

21. With 20 cm acrylic the dose rate due to scattered radiation is
1 mGy/h.
16.1: Optimization of protection in fluoroscopy

22. With 30 cm acrylic the dose rate due to scattered radiation is
3 mGy/h.
16.1: Optimization of protection in fluoroscopy

23. Note that with the extra thickness the image quality is extremely poor (the border of the chamber is hardly visible)
16.1: Optimization of protection in fluoroscopy

24. Fluoroscopy - Standard Dose Rate
Analysis :
should be < 25 mGy/min
Frequency :
acceptance, tube change
generator repair
intensifier repair
6 monthly
16.1: Optimization of protection in fluoroscopy

25. Where to Get More Information
Quality Control in Diagnostic Imaging, Gray JE, Winkler NT, Stears J, Frank ED. Available at no cost.
15.3: Optimization of protection in radiography