1. Scatter Cloud of the C-arm

2. Objective
Investigate the radiation scatter during C-arm fluoroscopic examinations
Determine the best location for the radiographer to stand to achieve the lowest dose of radiation while performing radiographic procedures

3. Hypothesis Radiation scatter cloud is non-uniformly distributed
Scatter radiation would be higher under the examination table

4. “Scatter Cloud”
Risk
Radiation doses can vary widely
Although radiation exposure is a necessary risk, protection of staff and patients require a clear understanding of how the exposure radiates
The risk cannot be eliminated entirely
Quantifiable and reproducible radiation is created during fluoroscopic procedures
The outcome data resembles a “scatter cloud”
Room set up and imaging technique variables influence scatter radiation levels

5. Method
Digital imaging of an acrylic adult abdominal CT phantom was exposed at both anteroposterior and lateral projections

6. Method Dosimeters were positioned at different heights and distances
Height from the floor: 2 feet, 3 feet, 4 feet, and 5 feet
Distance from isocenter: 3 feet and 6 feet

7. Materials OEC 9900 Elite C-arm Acrylic Adult Abdominal CT Phantom
RaySafe™ i2 Dosimeters (4) and Software
IV Pole
Lead Aprons
Tape

8. Dosimeter
RaySafe™ i2 dosomiters visualize X-ray exposure in real-time and displays exposure values
Provides instant feedback to permit radiology staff to adjust their behavior to reduce unnecessary radiation exposure
Measurements are simultaneously stored for analysis for furthering new behaviors and allowing comparisons over time

9. Data Graph of C-Arm Scatter Cloud in AP Position
The scatter cloud was most intense at the 2 foot and 3 foot levels
The measured values at the 4 foot and 5 foot levels diminished to almost nothing
The greatest intensity of radiation was recorded at the tube end of the plane that passed through the tube and control portions of the C-Arm
Data
Graph of C-Arm Scatter Cloud in AP Position
*Due to physical limitations, measurements could not be taken at the 3-foot distance at the control end or the 5-foot distance at the image intensifier end in this orientation.

10. Data Graph of C-Arm Scatter Cloud in Lateral Position
The dose rate of the scatter cloud was most intense at the 2 foot and 3 foot levels
The measured values at the 4 foot and 5 foot levels diminished to almost nothing
The greatest intensity was to the left and right of the emitter at a distance of 3 feet away
*Room constraints prevented the placement of sensors at the 6-foot point on the tube end. The values for this position have been set to zero for graphing purposes.

11. Discussion
The results of our measurements appear to support the hypothesis that the scatter cloud produced by the C-Arm is non-uniform
The intensity of the dose rate diminished greatly from the 6 foot to the 3 foot mark
As anticipated based on the inverse square law

12. Discussion Dose rate was reduced greatly past the 3 foot height mark
perhaps due to the construction of the C-Arm and the phantom used.
Dose rate was particularly high near the tube end in the lateral orientation
The non-uniform nature of the scatter cloud is important
Knowledge of the areas of greater dose rate can help radiation workers determine where to position themselves while the C-Arm is being used

13. Conclusion
Our data and research indicates the best place for the radiographer to stand is behind the control end of the C-arm

14. Resources
Haqqani, O. P., Agarwal, P. K., Halin, N. M., & Iafrati, M. D. (2013). Defining the radiation “scatter cloud” in the interventional suite. Journal of Vascular Surgery, 58(5), doi: /j.jvs
Kim, K. P., & Miller, D. L. (2009, February). Minimising radiation exposure to physicians performing fluoroscopically guided cardiac catheterisation procedures: A review. Retrieved March 07, 2019, from
Manchikanti, L., Cash, K. A., Moss, T. L., Rivera, J., & Pampati, V. (2003, August 06). Risk of whole body radiation exposure and protective measures in fluoroscopically guided interventional techniques: A prospective evaluation. Retrieved March 07, 2019, from
Mitchell, F. P. (n.d.). Prevention of radiation injury from medical imaging ... Retrieved March 07, 2019, from
Software Used:
AutoCAD 2019 (Version P ) [Computer software]. (n.d.). Retrieved March 22, 2019, from
EZGIF Animated GIF editor and GIF maker. (n.d.). Retrieved March 22, 2019, from
Plot.ly. (n.d.). Retrieved March 22, 2019, from Online Graphing Application