Staff Radiation Protection
in fluoroscopic procedures
1- Distance :
The intensity of scattered radiation is inversely proportional to the distance square . when the staff stand away from the patient during the radiation exposure , they get less scattered radiation.
2-Fluoroscopic Projection:
The scattered radiation is high near the area where the radiation incident . the tube positioning is highly significant in staff dose reduction the under couch tube position cause most of the scattered radiation to be towards the staff extremities . the overcoach position cause most of the scattered towards the sensitive organs (i.e eye ,...).
it is preferable to avoid the over coach position to protect the sensitive organs from the radiation hazard.
The lateral position is producing more scattered radiation due to higher patient thickness , and long beam pathway.
only 1-5 % of radiation transmit the patient body to the receptor side . it is preferable to stand at the receptor side in lateral position.
3-Shielding :
- Protective clothes
- Screen Shield
- Lead Curtains
Lead Apron efficiency :
- 0.25 mm -90 % dose reduction
- 0.35 mm -95 % dose reduction
- 0.5 mm -99 % dose reduction
Lead Suspended Screen
- Typically equivalent to 1 mm
- very effective if well positioned
The radiation exposure with and without lead suspended screen
- Without suspended screen 1.2 mSv/hr
- With suspended screen 50 uSv/hr
4-Patient size :
when patient size increase , the entrance dose increase , so the scattered radiation increase.
5-Field size :
scattered dose rate is higher , when the field size increase
6-Fluoroscopic Mode:
Changing from normal fluoroscopic mode to the high dose rate mode , increase the scattered radiation dose .
7-Grid
using grid leads to reduced the radiation intensity received by the detector ,which cause increasing the radiation intensity incident on the patient . the higher radiation incident on the patient , the higher scattered radiation
Summary
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