Method and apparatus for computing tomographic scans

Details Method and apparatus for computing tomographic scans Method and apparatus for computing tomographic scans

1992-03-11

1994-04-26

Envall, Jr., Roy N.

Boots, shoes, and leggings

378 14, G06F 1500

Patent

active

053072642

ABSTRACT:
Apparatus and method for mounting on an existing x-ray simulator and calculating a back projected computed tomographic image. The detector array is linear and outputs signals from the photodiodes mounted therein to a preprocessor for smoothing, correcting and filtering and subsequent processing to transform the signal from that produced by an x-ray originating from a fan beam source, e.g., in a polar coordinate system, into the signal which would have been produced by a detector in an array on which a parallel beam is incident on a Cartesian coordinate system. The transformed data is converted to a gray scale value for a picture element having a specific position in the Cartesian coordinate system and output to an appropriate display. Data is taken at each incremental angle as the beam source and detector array rotate around a target object.
The method of reconstructing this back projected image involves correcting and smoothing the output signals, scaling those corrected and smoothed signals, and convolving the scaled signals into data characterizing the ray which is incident on each individual detector element into the equivalent intensity data had the incident ray originated from a parallel beam source. Also provided are methods for correcting the data for incorrect detector reading and for displacement of the detector array resulting from the off-center rotation of either or both of the x-ray source or the detector array.

REFERENCES:
patent: 3867634 (1975-02-01), Hounsfield
patent: 4149247 (1979-04-01), Pavkovich et al.
patent: 4212062 (1980-07-01), Kohno et al.
patent: 4365339 (1982-12-01), Pavkovich et al.
patent: 4570224 (1986-02-01), Shimoni et al.
patent: 4580219 (1986-04-01), Pelc et al.
patent: 4703424 (1987-10-01), Gullberg et al.
patent: 4707822 (1987-11-01), Hopkinson et al.
patent: 4740896 (1988-04-01), Horiba et al.
patent: 4769757 (1988-09-01), Horiba et al.
patent: 4812983 (1989-03-01), Gullberg et al.
patent: 4894775 (1990-01-01), Kritchman et al.
patent: 4979111 (1990-12-01), Nishimura
patent: 5051904 (1991-09-01), Griffith
patent: 5099846 (1992-03-01), Hardy
R. G. Waggener, et al., "Hybrid reconstruction algorithm for x-ray computed tomography", 16 Med. Phys. (1989).
M. Hamron (Ed.), "Simulator as `Mini-CT` treatment control," CART News No. 8 (1987).
C. Perez and L. Brady, "Principles in radiologic physics, densimetry, and treatment planning," in Principles and Practice of Radiation Oncology, Philadelphia: J. B. Lippencott Co. (1987).
H. Peng and H. Stark, Direct Fourier reconstruction in fan beam tomography, MI-6 IEEE Transactions on Medical Imaging 209-219 (1987).
G. Kowalski, "Suppression of ring artifacts in CT fan beam scanners", NS-25 IEEE Transactions on Nuclear Science 1111-1116 (1978).

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