1. PEDIATRIC RADIOGRAPHY

2. The Role of The Radiographer in Dose Reduction for Paediatrics
Cynthia Cowling ACR, B.Sc. M.Ed
Director of Education ISRRT
Development Leader, Radiation Sciences
Central Queensland University, Australia 2 2

3. Outline Traditional role and techniques Role in CT Dose Reduction
Implications for Interventional
Dose implications in the move from Analog to digital
Some specialized activities 3 3

4. Use of restraining devices Response to verbal direction
The pediatric patient always presents with unique problems for the radiographer
Keeping still
Use of restraining devices
Response to verbal direction
Use of shielding
Role of the family

5. Use immobilization devices judiciously
Capture the attention
of the child 5 5

6. Other Devices Tape (be careful not to hurt skin) Sheets, towels
Sandbags
Radiolucient sponges
Compression bands
Stockinettes
Ace bandages

7. Radiation Protection ALARA Proper immobilization Short exposure time
Limited views
Close collimation
Lead aprons and half shields

8. Differences children and adults
Mental development
Chest and abdomen the same circumference in NB
Pelvis - mostly cartilage
Abdominal organs higher in infants than older children
Hard to find ASIS or Iliac Crest in young child, can center 1 inch above umbilicus (bellybutton)
Exposure made as baby takes a breath to let out a cry

9. Dose reduction in CT Use
Radiologists and radiographers must create
an essential partnership
It is the Radiographer who UNDERSTANDS
and OPERATES the equipment
All CT sites should
cooperate;
start reduction and
validate results 9 9

10. Essential features Dose should be age and weight specific
Dose should be customized to pathology
Number of follow ups should be scrutinized
Software features should be used if possible
Image enhancement
Modulation of mAs 10 10

11. Working with the radiologist, the radiographer…
Starts with standard protocol and then reduces to provide acceptable image
Screens all requests, re protocol and suitability of request
Attempts to narrow down area of interest 11 11

12. Interventional Procedures
Increased because of immediate risk benefit for child (not undergoing surgery)
However, not much consideration given to long term stochastic effects 12 12

13. Collaboration makes a huge difference
Example from Hospital for Sick Children, Toronto Canada
In Angio CT the TEAM was able to reduce dose from 3 mSev to 0.8 mSev as standard for typical Angio CT exam for child 13 13

14. Dose Optimization in CT
kVp – decrease kVp, decrease dose, increase image noise, non-linear
Ex. 140 kVp kVp dose by 78% (Siegel M et al, 2004)
mAs – decrease mAs, decrease dose, increase noise, linear
Ie. Halve mAs, Halve dose
Pitch, length of scan, gantry cycle time

15. Cardiac Angiography CT Protocol
Weight-based protocol
IV injection of contrast
Set parameters:
Tube Voltage: 80 kVp
Gantry Rotation Time 0.4 s
Pitch 0.9
Variable parameters: Vary mAs According to body weight
- <5 kg: 70 mAs [Newborn phantom]
kg: 80 mAs [1-, 5-year old phantom]
kg: 90 mAs [10-year old phantom]
- >50 kg: 100 mAs
Scan Coverage
Only area of interest

16. Conclusions
New protocol/equipment exposes patients to less radiation than previous set-up
Doses are less than 1 mSv across all phantoms ~75% decrease from previous protocol
Images are of diagnostic quality
Project is a good illustration of the utility we have at Sick Kids -> Easily determine radiation risk from various procedures with in-house equipment

17. Moving Forward This study was a general view of the exam
Study Clinical assessments to:
Collect data on what scans are used to diagnosis for
Percentage diagnosis yield
Percentage of cases that would have benefitted from lower/higher dose
Can we tighten dose optimization further

18. Other Areas attempting dose reduction Scoliosis series18 18

19. EOS
1- Takes two simultaneous digital planar radiographs in the standing position with very low dose : 2D
EOS 2D
2- Creates a three dimensional bone envelope weight bearing image : 3D
sterEOS 3D 19

20. Scanning process Collimated detector Collimated X Ray beam scanning
linear detector
Linear scanning of a fan-shaped collimated X ray beam
from 5 cm to 180 cm (whole body)
No vertical divergence of X rays
No scatter detect
SNR increased
Allows for lower dose ++

21. Dose & Image quality Current practice :
- Scattered radiation accounts for more than 80% of the X-ray flux passing through the patient
- This noise reduces detectability and therefore a higher dose is required to maintain image quality
Clinical impact of dose :
M. Doody et. Al., « Breast Cancer Mortality After Diagnostic Radiography », Spine, Vol. 25, No 16, pp
Retrospective study on mortality due to breast cancer (women followed for scoliosis using spine X-Rays) :
5466 women followed between 1912 and Average of 25 radiographs (~0.11 Gy)
=> Risk of death due to breast cancer is 69% higher than what is encountered in general population.
In a linear scanner such as EOS, the detector geometry prevents more than 99.9% of the scattered radiation from entering the detector
EOS allows for a dose reduction up to 10 times compared to CR 21 21

22. Low dose & High Image Quality
Fuji
EOS
EOS requires less dose (Montreal study on spine)
100%
11%
EOS lowers dose by over 89%
Dose reduction x9…
…With improved or equivalent image quality (97%)
High dynamic of image (16 bits, > Levels of Gray).
Digital images, DICOM format
Single exposure for multiple exams
Pixel size 254µm
EOS
Non EOS/Dose x10 22

23. Why Low Dose? Slot Scanning Technology
No scatter detected, Noise suppressed
 Allows for Lower Dose
Charpak Nobel Prize Winning Detector
Detector amplification : Photon gaz cascade,
 High gain signal, sensitivity maximized
Automatic internal gain adjustment
Dynamic range outperform other digital imaging technology (30,000 gray levels)
Available for any patient! 23

24. Analog to Digital, Dose implications
Requires changes to radiographer’s knowledge base
Radiographers ｗork practice must change to ensure high quality images
Must be more aware of dose since automation and image acquisition does not provide feedback in image production especially key effects of mAs and kVp
Radiographer must work as part of Team to ensure adherence to ALARA
QC always critical 24 24

25. Cont.. Positioning can be more critical, aligning to detectors
Manual techniques may be required to produce optimum quality
Post processing as a method of enhancing image should be discouraged
Exposure creep must be avoided (any more than 4% unacceptable)
ADVANTAGE provides statistical evidence of exposure factors and dose 25 25

26. How the profession can improve dose reduction
Increase awareness through membership in initiatives such as Image Gently
Provide retraining opportunities
Make use of publications such as ICRP
Participate in Clinical Audits
Actively work collaboratively with radiologists and physicians 26 26

27. For Example
In Ontario, Canada, Radiographers are regulated by the College of Medical Radiation Technologists of Ontario (CMRTO) and
Healing Arts Radiation Protection Act (HARP) which controls and identifies who can order and operate x ray equipment 27 27

28. Recommendations
HARP should require that prescribing or requesting a CT be permitted only by individuals who have appropriate clinical knowledge and training in radiation protection
All persons operating CT equipment or devices take a radiation safety course documented by a certificate of credentials
200% increase in CTs in Ontario between 28 28

29. Enhancing Radiation Protection in Computed Tomography for Children
Module two
Image Gently 29 29

30. ＴＷＯ KEY　POINTS
TEAMWORK
TRAINING
TEAMWORK 30 30

31. Many Thanks and Acknowledgements to
Image Gently- Alliance for Radiation Safety in Pediatric Imaging
American Society of Radiologic Technologists-ASRT
Ellen Charkot, Director Imaging Services Hospital for Sick Children, Toronto Canada
Lori Boyd, Director of Policy College of Medical Radiation Technologists of Ontario, Canada (CMRTO)
Marie De La Simone, biospace med, Paris France
International Society of Radiographers and Radiological Technologists (ISRRT)
Maria del Rosario Perez, WHO 31 31