A New Tool for Real-Time Monitoring of Photon-Beam Irradiation Using Positron Production in Radiotherapy
A method for monitoring the real-time irradiation field and irradiation dose of energetic photons has been developed for use in cancer radiotherapy that uses photoproduced positrons. A new detector system consisting of a pair of collimators and a fast crystal scintillator was designed and fabricated...
Saved in:
| Published in: | Japanese Journal of Applied Physics Vol. 50; no. 9; pp. 098005 - 098005-2 |
|---|---|
| Main Authors: | , , , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
The Japan Society of Applied Physics
01-09-2011
|
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | A method for monitoring the real-time irradiation field and irradiation dose of energetic photons has been developed for use in cancer radiotherapy that uses photoproduced positrons. A new detector system consisting of a pair of collimators and a fast crystal scintillator was designed and fabricated. It was successfully operated to confirm the irradiation field by real-time measurements of counting rates, which were found to be proportional to the intensity of the photon beam. These results indicate that this method can be used to monitor the irradiation field as well as the irradiation dose. |
|---|---|
| Bibliography: | Experimental layout. The photon beam irradiated an acrylic target and produced annihilation photons. One of the photons passed through two collimators to hit an array of eight counters, each of which is a Pr:LuAg crystal scintillator ($12\,\text{mm$\phi$}\times 10\,\text{mm$^{\text{t}}$}$) viewed by a photon-counting head (Hamamatsu Photonics H6780-06). Fabricated PEV camera in the setup. The photon beam descended from the linac to the target placed on the patient couch. A 2nd collimator is enclosed in the PEV camera. Background-subtracted dose-rate dependence of counting rates of a Pr:LuAG counter as a function of the axial position, where zero is the center of the irradiation field from $-5$ to +5 cm. The counting rates were measured at 0, 100, and 200 MU, and they were found to be proportional to the MU values. The widths of both distributions at 100 and 200 MU (solid circles) represent the size of the irradiation field. |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.1143/JJAP.50.098005 |