Correction Of Collimator Aperture Using A Shift-Variant Deconvolution Filter In Gamma Camera Emission CT

Koichi Ogawa; Seungkuen Paek; Masato Nakajima; Shin'ichi Yuta; Atsushi Kubo; Shozo Hashimoto

doi:10.1117/12.968702

27 June 1988 Correction Of Collimator Aperture Using A Shift-Variant Deconvolution Filter In Gamma Camera Emission CT

Koichi Ogawa, Seungkuen Paek, Masato Nakajima, Shin'ichi Yuta, Atsushi Kubo, Shozo Hashimoto

Proceedings Volume 0914, Medical Imaging II; (1988) https://doi.org/10.1117/12.968702
Event: Medical Imaging II, 1988, Newport Beach, CA, United States

Abstract

We propose a new method which enables improved spatial resolution of a reconstructed image from a gamma camera emission CT(SPECT). SPECT images are blurred due to the effect of the collimator aperture. The blur effect changes with the geometrical structure of the collimator and with the distance between the rotational center of the gamma camera and the collimator surface. The acquired projection, affected by the collimator aperture, can be assumed to be the convolution of the ideal projection by the shift-variant blur functions. So the measured projection will be represented as a weighted summation of neighboring ideal projections of different angles and positions. From this standpoint, the blur function can be defined as a function of a common spatial frequency in the Fourier domain. Hence the deconvolution of the measured projection was circularly processed in the frequency domain. The effectiveness of the method was proven by simulations involving various aperture angles and the distances between the collimator surface and the rotational center.

Citation Download Citation

Koichi Ogawa, Seungkuen Paek, Masato Nakajima, Shin'ichi Yuta, Atsushi Kubo, and Shozo Hashimoto "Correction Of Collimator Aperture Using A Shift-Variant Deconvolution Filter In Gamma Camera Emission CT", Proc. SPIE 0914, Medical Imaging II, (27 June 1988); https://doi.org/10.1117/12.968702

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