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

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 inexpensive (<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 qualitative 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.