X-ray dose detector based on color changing of light-emitting polymer–metal complex hybrid material.

Abstract

We report on the design, fabrication and performance of a poly (2-methoxy-5(2_-ethylhexyloxy)- p-phenylenevinylene)/tris-(8-hydroxyquinoline)aluminum (MEH-PPV/Alq3) X-ray dose detector for improving safety for cancer patients shortly before radiation therapy. The detector consists of an inexpen-sive (<US$ 1) organic device that is irreversibly color changing from red, to yellow, to green and measures the delivered dose from the radiation beams of a linear accelerator (6 MV) in the range of 0–40 Gy. The effect of radiation on the optical properties of MEH-PPV/Alq3 was described and we observed a strong correlation between the photoemission spectrum of Alq3 and the photoemission and absorption spectra of MEH-PPV degraded by radiation. A series of tests was conducted on the performance of the organic detector in measuring depth-dose distribution of photon beams in a water phantom and demonstrating linearity in the shift of PL and absorption as functions of the dose. These results have enabled the qual-itative and quantitative analysis of how the radiation instability of optical properties of MEH-PPV/Alq3 can be used to develop an innovative organic device for radiation therapy.