Can SGRT Serve as an Added Safety Barrier for 3D Bolus in the Clinic

Christopher Kutyreff,
PhD Therapeutic Medical Physics Resident
Mayo Clinic Phoenix

1. ©2024 Mayo Foundation for Medical Education and Research | slide-1

2. ©2024 Mayo Foundation for Medical Education and Research | slide-2
SURFACE-GUIDED RADIOTHERAPY AS AN ADDED SAFETY BARRIER FOR 3D BOLUS IN THE CLINIC
PRESENTED BY: C. KUTYREFF, PHD
US SGRT CONFERENCE, 2024

3. ©2024 Mayo Foundation for Medical Education and Research | slide-3
DISCLOSURES
•I have nothing to disclose

4. ©2024 Mayo Foundation for Medical Education and Research | slide-4
OUTLINE
•Background
•Study Aim
•Methods
•Results
•Challenges
•Conclusions

5. ©2024 Mayo Foundation for Medical Education and Research | slide-5
BACKGROUND
192419801995
“Bolus Alba”SuperflabCustom-milled wax

6. ©2024 Mayo Foundation for Medical Education and Research | slide-6
BACKGROUND
Image Credit: Hobbis, D, et al (2024). Comprehensive clinical implementation, workflow, and FMEA of custom silicone
bolus cast from 3D printed molds **Under Review**

7. ©2024 Mayo Foundation for Medical Education and Research | slide-7
STUDY AIM
•We have VisionRT SGRT system
•We have in-house 3D bolus fabrication workflow
Can we use SGRT as an additional safety barrier in 3D bolus treatments?

8. ©2024 Mayo Foundation for Medical Education and Research | slide-8
METHODS – SIMULATION

9. ©2024 Mayo Foundation for Medical Education and Research | slide-9
•Mould is created from the bolus DICOM file
• (one edge cropped)
•Mould is 3D printed and glued together
•Silicone is mixed and poured into the mould
•Final bolus is removed from the mould and cleaned up for use
METHODS – BOLUS FABRICATION
Image Credit: J. Smetanick. 2023. Comprehensive Bolus Instructions

10. ©2024 Mayo Foundation for Medical Education and Research | slide-10
METHODS – VRT SETUP SURFACES

11. ©2024 Mayo Foundation for Medical Education and Research | slide-11
METHODS – PHANTOM SETUP

12. ©2024 Mayo Foundation for Medical Education and Research | slide-12
METHODS – BOLUS SETUP

13. ©2024 Mayo Foundation for Medical Education and Research | slide-13
METHODS – SIMULATED AIR GAP TEST

14. ©2024 Mayo Foundation for Medical Education and Research | slide-14
METHODS – TRANSLATIONAL OFFSET TESTS

15. ©2024 Mayo Foundation for Medical Education and Research | slide-15
METHODS – ROTATIONAL OFFSET TESTS

16. ©2024 Mayo Foundation for Medical Education and Research | slide-16
RESULTS – BOLUS THICKNESS TESTS
Bolus Thickness
(cm)
Vrt
(cm)
0.30.02
0.50.02
0.70.05
10.04

17. ©2024 Mayo Foundation for Medical Education and Research | slide-17
RESULTS – TRANSLATIONAL OFFSET TESTS
Bolus
Thickness (cm)
Measured Lateral
Shifts (cm)
Average Difference
(cm)
0.3-0.80.70.25
0.5-0.760.850.20
0.7-1.031.10.07
1-1.051.080.07
*1 cm lateral shift applied

18. ©2024 Mayo Foundation for Medical Education and Research | slide-18
RESULTS – TRANSLATIONAL OFFSET TESTS
Bolus Thickness
(cm)
Measured Longitudinal
Shifts (cm)
Average
Difference (cm)
0.3-0.20.60.6
0.5-0.170.80.52
0.7-0.130.80.54
1-10.920.04
*1 cm longitudinal shift applied

19. ©2024 Mayo Foundation for Medical Education and Research | slide-19
RESULTS – ROTATIONAL OFFSET TESTS
Bolus
Thickness (cm)
Baseline
Rotation (deg)
5° applied15° applied
0.30.32.03.6
0.5-0.21.31.7
0.70.33.78.8
1-0.25.112.8
*5 and 15 degree rotations applied

20. ©2024 Mayo Foundation for Medical Education and Research | slide-20
RESULTS – QUALITATIVE BOLUS PLACEMENT

21. ©2024 Mayo Foundation for Medical Education and Research | slide-21
RESULTS – QUALITATIVE BOLUS PLACEMENT

22. ©2024 Mayo Foundation for Medical Education and Research | slide-22
RESULTS – QUALITATIVE BOLUS PLACEMENT

23. ©2024 Mayo Foundation for Medical Education and Research | slide-23
CHALLENGES – BOLUS OPTICAL PROPERTIES

24. ©2024 Mayo Foundation for Medical Education and Research | slide-24
CHALLENGES – ROI VS QUANTITATIVE RESULTS
ROI = Bolus + 6 mmROI = Bolus edgesROI = Bolus - 6 mm

25. ©2024 Mayo Foundation for Medical Education and Research | slide-25
CHALLENGES – BOLUS THICKNESS VS. QUANTIFICATION
Bolus
Thickness
(cm)
Average
Difference
(cm)
0.30.25
0.50.20
0.70.07
10.07
Lateral Offset
Bolus
Thickness
(cm)
Average
Difference
(cm)
0.30.6
0.50.52
0.70.54
10.04
Longitudinal Offset
Bolus
Thickness
(cm)
5°
applied
15°
applied
0.32.03.6
0.51.31.7
0.73.78.8
15.112.8
Rotational Offset

26. ©2024 Mayo Foundation for Medical Education and Research | slide-26
CHALLENGES – ANATOMICAL INFORMATION

27. ©2024 Mayo Foundation for Medical Education and Research | slide-27
CONCLUSIONS
•Proof-of-concept results suggest that VisionRT SGRT system can:
•reliably detect simulated air gaps of 1 mm
•reliably quantify bolus thickness discrepancies
•semi-quantitatively report lateral bolus displacement
•semi-quantitatively report longitudinal bolus displacement
•semi-quantitatively report rotational bolus displacement
•is more accurate when using bolus > 3 mm thick
•be used as an added safety barrier in the clinic

28. ©2024 Mayo Foundation for Medical Education and Research | slide-28
FUTURE WORK
•Explore quantitative ability versus room lighting
•Explore quantitative ability versus ROI definition
•Explore differences between infrared and optical systems in our clinic
•Explore possibility of adding “setup features” to be removed before
treatment

29. ©2024 Mayo Foundation for Medical Education and Research | slide-29
THANK YOU FOR YOUR ATTENTION!
•Grateful to our group for all the
support:
•Courtney Buckey, PhD
•Mike Armstrong
•Riley Tegtmeier, MS
•Suzanne Chungbin, MS
•Jennifer Smetanick
•Yi Rong, PhD
Questions?