Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography

Li Tao; Henry M. Daghighian; Craig S. Levin

doi:10.1117/1.JMI.4.1.011010

1 February 2017 Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography

Li Tao, Henry M. Daghighian, Craig S. Levin

Author Affiliations +

Journal of Medical Imaging, Vol. 4, Issue 1, 011010 (February 2017). https://doi.org/10.1117/1.JMI.4.1.011010

Abstract

We compare the performance of two detector materials, cadmium telluride (CdTe) and bismuth silicon oxide (BSO), for optical property modulation-based radiation detection method for positron emission tomography (PET), which is a potential new direction to dramatically improve the annihilation photon pair coincidence time resolution. We have shown that the induced current flow in the detector crystal resulting from ionizing radiation determines the strength of optical modulation signal. A larger resistivity is favorable for reducing the dark current (noise) in the detector crystal, and thus the higher resistivity BSO crystal has a lower (50% lower on average) noise level than CdTe. The CdTe and BSO crystals can achieve the same sensitivity under laser diode illumination at the same crystal bias voltage condition while the BSO crystal is not as sensitive to 511-keV photons as the CdTe crystal under the same crystal bias voltage. The amplitude of the modulation signal induced by 511-keV photons in BSO crystal is around 30% of that induced in CdTe crystal under the same bias condition. In addition, we have found that the optical modulation strength increases linearly with crystal bias voltage before saturation. The modulation signal with CdTe tends to saturate at bias voltages higher than 1500 V due to its lower resistivity (thus larger dark current) while the modulation signal strength with BSO still increases after 3500 V. Further increasing the bias voltage for BSO could potentially further enhance the modulation strength and thus, the sensitivity.

Citation Download Citation

Li Tao, Henry M. Daghighian, and Craig S. Levin "Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography," Journal of Medical Imaging 4(1), 011010 (1 February 2017). https://doi.org/10.1117/1.JMI.4.1.011010

Received: 31 July 2016; Accepted: 12 January 2017; Published: 1 February 2017

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