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 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Where to Get More Information Quality Control in Diagnostic Imaging, Gray JE, Winkler NT, Stears J, Frank ED. Available at no cost. http://www.diquad.com/QC%20Book.html 15.3: Optimization of protection in radiography