1. PET-utilized proton range verification using 13N signals
ICCR, London, United Kingdom
June 29, 2016
J Cho1, CH Min2, X Zhu3, G El Fakhri3, and H Paganetti3.
1 Department of Physics, Oklahoma State University, Stillwater, OK, USA
2 Department of Radiological Sciences, Yonsei University, South Korea
3 Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
PET imaging for proton therapy verification.
Please interrupt me anytime for questions.

2. Motivation Proton treatment Proton range verification using PET
Range uncertainty
Proton range verification using PET
PET signal uncertainty
The first motivation of my research is improving the current way of dose and range calculation as well as verification by providing tissue elemental composition.
The second motivation is on verifying the proton range with implantable dosimeters.
I was looking for some elements that are proton activated very strongly at very low proton energy and decay slowly so that we can observe the activation of these dosimeters as the sign of the proton distal end. By using these implantable dosimeters for proton range verification, we do not have to worry about first, biological diffusion, not activating at the very end of the proton range, also spending big bucks for in-room PET scanner.
Dose
PET
Parodi et al, NIH public access 2007

3. Motivation PET signals are time (delay & acquisition) dependent
Parodi et al, NIH public access 2007
Dose
PET
Motivation
PET signals are time (delay & acquisition) dependent
Investigate time dependence
Using ideal phantom situations free from biological washout
Feasibility of using 13N signals for proton range verification
The first motivation of my research is improving the current way of dose and range calculation as well as verification by providing tissue elemental composition.
The second motivation is on verifying the proton range with implantable dosimeters.
I was looking for some elements that are proton activated very strongly at very low proton energy and decay slowly so that we can observe the activation of these dosimeters as the sign of the proton distal end. By using these implantable dosimeters for proton range verification, we do not have to worry about first, biological diffusion, not activating at the very end of the proton range, also spending big bucks for in-room PET scanner.

4. Water or tissue-like phantoms
11C, 15O and 13N production in
Water or tissue-like phantoms
Attasasi et al PMB 2011

5. Experiment set-up
Zhu et al,
PMB 2011

6. PET acquisition for 30 min

7. Monte Carlo with no Gaussian convolution kernel
Attasasi et al PMB 2011

8. Gradient or slope profiles of first and last PET scans

9. Peak of subtracted gradients vs. proton range

10. Noise suppression using (x Depth2) weighting

11. Proton range from (Grad(10min)-Grad(3min)) x Depth2

12. Limitations and Future Direction
13N method is challenging for living patients.
Washout of 13N signals.
However, time and depth dependence of 11C, 13N and 15O could be used to interpret washout in patients and also to develop radioisotope dependent washout model.
There are much evidence for that each radioisotope biologically decay (or washout) at different rates.
So far, only organ specific washout models exist.
Our goal is developing a radioisotope dependent washout model.

13. Thank you.
Acknowledgement: Dr. Kira Grogg Funding: OSU A&S Academic Summer Research (ASR) & +1 Travel FY 2017 grant (PI: J. Cho), OSU Start-up grant (PI: J. Cho), and NIH R01EB and K07CA Hiring students: Author contact: