Occupational radiation safety in Radiological imaging 1) There is increased use of radiation-based medical imaging globally, but many staff lack proper training in radiation safety techniques. 2) Workers in cardiology cath labs receive the highest radiation doses, followed by radiology cath labs and other interventional procedures. Prolonged fluoroscopic screening can lead to hair loss and cataracts in interventionalists. 3) Basic principles of radiation safety include minimizing time, maximizing distance, and using shielding. Monitoring staff doses with dosimeters and following safety protocols helps ensure doses are as low as reasonably achievable.

1. Occupational radiation safety
in Radiological imaging
Dr Roshan S Livingstone
Associate Professor
Department of Radiology
Christian Medical College, Vellore

2. Concerns
• Increased use of man-made radiation globally
• Increase in the purchase of radiation based high-end modalities
• Lack of orientation/training of staff – technique and radiation safety
• Lack of awareness among the staff and public

3. Occupational radiation workers
order of dose severity
• Cardiology cath lab
• Radiology cath lab
• Endovascular surgery – operation theatre
• Operation theatre procedures (ortho, uro..)
• Barium and ERCP (Radiology and Gastro)
• Conventional Radiography (Radiology)
• Dental
• Lithotripsy
• Mobile radiography
• Dual energy xray absorptiometry (DEXA)
• CT

4. OUTLINE
• Factors influencing radiation dose to staff in Radiology
• Principles of radiation safety
• Monitoring radiation dose to staff and radiation safety accessories
• Conclusion

5. Early x-ray imaging
• Discovery of x-rays by Wilhelm C Roentgen in 1895
• Medical imaging specialty to visualize internal anatomy
of a human body without surgical exploration.
• Early imaging modalities
• Fluorescent screens
• Film-screen cassettes
• Image intensifier
• CT scanner

6. Early days

7. Factors influencing radiation dose to staff from
x-ray modalities

8. Scatter radiation
• When x-rays enter through
the body surface most of the
energy is absorbed by tissues
while some amount is
scattered from the body
surface (eg., patient).
• Staff are are exposed to these
scatter (secondary) radiations.
Most of a operator’s occupational exposure comes from scatter radiation
Using radiation safety accessories will effectively lower operator’s occupational exposure.

9. Loss of hair among interventionalists
• Duration of fluoroscopic
screening – reduce
wherever possible
Courtesy: Wagner, Biomed Imaging Interv J 2007
Wiper et al., Heart, 91 (11); 1432, 2005
Loss of hair among
interventionalists from cath labs
Ill-effects

10. Cataract among interventionalists
• Eye lens opacities and cataracts among
interventionalists working in catheterization labs
for several years.
• Cumulative median values of lens doses were
estimated at 6.0 Sv for cardiologists and 1.5 Sv
for associated medical personnel.
Vano E et al., Radiat Res.Oct;174(4):490-5, 2010
Ill-effects

11. Work practices
• Tube Angulation
• Steep angulations –
LAO 45o CAU 35o
• Demands more
radiation for imaging
• Increases staff dose
• Increases patient dose
Less radiation dose More radiation dose
Factors influencing radiation dose to staff

12. Work practices..
X-ray
tube
X-ray
tube
Image
detector
The distance between
patient and image
detector should be
minimum and
maximum between
patient and the source.
Image
detector
Low dose
High dose
Factors influencing radiation dose to staff

13. Work practices..
• Collimation
• Radiation beam should
be collimated along the
region of interest to
reduce scatter and
improve image quality
Collimated beam
Less scatter
More scatter
Factors influencing radiation dose to staff

14. Work practices…
• Excessive use of image
magnification increases
radiation doses
• Use image magnification modes
judiciously
Normal view Magnified view
Factors influencing radiation dose to staff

15. Work practices..
• Use of radiation safety accessories is
mandatory in all x-ray rooms
• Lead rubber aprons / lead free aprons
• Lead goggles
• Thyroid shield
• Ceiling mounted lead glass
• Lead drapes
• Shield barrier
Factors influencing radiation dose to staff

16. Basic principles of radiation protection

17. Time
• Radiation dose is directly proportional to
time of x-ray exposure.
• Examination time should be minimum
• Lesser the time spent lesser is the dose.
• Increasing the screening time will increase the radiation dose
• Do not depress the footswitch continually for long periods;
• Use last image hold options
• Use pulsed fluoroscopy modes

18. • Radiation dose is inversely
proportional to the square of
the distance.
• Increasing the distance
reduces the dose effectively.
• Do not put your arm under
the primary beam
Source
64 units of
intensity
16 units of
intensity
4 units of
intensity
2 units of
intensity
Distance

19. • Shielding is warranted for all
staff working in radiation
areas.
• Use of lead aprons (0.25-
0.5mm), ceiling mounted lead
barriers, lead glass goggles,
lead drapes.
• Always work behind the
barriers .
Shielding

20. Practice: As Low As Reasonably Achievable principle
Am I
protected?

21. MONITORING STAFF DOSES AND
SAFETY ACCESSORIES

22. Radiation dose monitoring
• Thermo-Luminescent Dosimeters
• Real-time monitoring devices
• Pocket dosimeters
• Area surveillances using survey meters
Survey meter
Real time monitoring

23. INSTRUCTION TO USERS -
Do’S
• Use TLD card of the valid service period
• Handle the TLD badge with care
• Store the badge in a radiation free place when not in use
• Report any unusual radiation incident to your Supervisor/RSO/
Head of the Institution
• Return the TLD card on or before 5th of every fourth month
(quarter)

24. Don’ts…
• Don’t wear the TLD badge outside
the apron
• Don’t leave the TLD badge in the
washing machine or in the vicinity
of hot plate, ovens
• Don’t leave the badge in the
radiation area when it is not in use
• Don’t share your TLD badge with
someone else. Your badge is your
own

25. Ceiling mounted lead glass
There can be a reduction of
about 50% of dose savings
to the operator with the use
of articulated lead screen
between the patient and the
operator

26. Safety accessories (fixed/movable) in cath lab
With the use of 0.5 and 1
mm over-couch and
under-couch shielding, it
is possible to reduce the
mean operator radiation
exposure to 14% and 6%,
respectively

27. Other personal safety accessories
Implementation

28. Periodic screening of aprons

29. Awareness among patients and public

30. Follow low dose protocols for angiography procedures to avoid
complication
(a) 6-8 weeks after multiple coronary angiography and angioplasty procedures.
(b) 16-21 weeks
(c) 18-21 months after the procedures showing tissue necrosis .
(d) Close-up photograph of the lesion shown in (c).
(e) Photograph after skin grafting.
(d) (e)
(a) (c)(b)
(Photographs courtesy of T. Shope & ICRP).

31. Radiation Dose in MDCT
Y Imanishi et al. Eur Radiol (2005) 15:41-46

32. Patient relatives waiting inside the x-ray rooms should
be avoided
50 mR/hr

33. CONCLUSION
• Use radiation safety accessories when required.
• Use personal monitoring devices
• Follow the basic principles of radiation safety
• Follow radiation dose reduction techniques
• Radiation safety awareness and training program

34. For safe practice of radiation in health care
ALARA is still “WAY FORWARD”

35. Thank You