Proton Computed

TomographyNicole Hoffmann

Introduction

Radiation therapy◦ Common and effective

Photons damage everything◦ Detrimental to healthy tissue

Dose plot and irradiation damages

Overview

Proton therapy is a popular and effective treatment option◦ Maximize radiation dose to tumor

◦ Minimize radiation dose to healthy tissue

How do we make this process better? First center in Loma Linda, CA, 1990 Worked with Dr. Zutshi

Background

Why would anyone use pCT? X-ray CT uses photons, causing 3 to 5

percent range errors More dangerous near vital organs Potential pCT benefits◦ Fewer range errors by using same

particle

◦ Planning and treatment with protons

Methods

Protons are charged

Multiple Coulomb Scattering

Calculations

◦ Trajectory (fiber tracker)

◦ Residual energy (scintillator stack)

◦ Estimation of path length and density

The detector was built as a collaboration between

Delhi, Fermilab, and NIU.

Fiber Tracker and Scintillator Stack

SiPMs

Silicon photomultipliers

◦ Protons pass through fibers

◦ Each pixel operates as a digital device

◦ Scintillation light

◦ Converts photons to current

◦ Analog output

Single Photo Electron Spectrum

Detector

Methods

Performance plots Approximation of proton path◦ MCS and trajectories

◦ Most likely path algorithm

◦ Shows error

◦ Calculated with residual energies

B. Erdelyi

Results

Detector is finished Undergoing testing to confirm pCT

benefits Compare to X-Ray CT◦ Accuracy

◦ Non-medical applications

◦ Not affected by implants

◦ Less radiation during scan

Conclusions

Significance◦ Changes cancer treatment

◦ Less detrimental to patient health

Compared to X-Ray CT

◦ Benefits are being investigated

Future Directions

Where do we go next?◦ Confirm positive benefits of pCT

◦ Further improve the detector

◦ Commercialize for clinical settings

Acknowledgments

Warrenville Proton Center Department of Defense Research Rookies University of Delhi Fermilab