US 5,027,818 AGranted

Dosimetric technique for stereotactic radiosurgery same

AssigneeUniversity of Florida

InventorsFrank J. Bova, William A. Friedman

Life of this patent

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Abstract

Stereotactic radiosurgery is facilitated by a technique for computing the doses at various points within the patient's body. In particular, the doses are computed at a relatively high density of points within a fine dose grid and at a relatively low density of points within a coarse dose grid. In that fashion, the user can quickly obtain necessary information about the radiation dose distribution before implementation of a proposed treatment plan. An advantageous technique of locating the intersection between the radiation beam and the contour or other surface of the patient is also provided. The method is especially well suited for use with a particular structure which allows one to utilize relatively narrow beam widths as a result of great mechanical accuracy.

Claims20

Dependent claims

A method for patient care comprising the steps of:

(a) localizing a target within a patient;
(b) subjecting the patient to an imaging system with a display to generate patient reference data in the form of x,y,z coordinates of the target and adjacent portions of the patient;
(c) supplying the patient reference data to a dosimetric computer connected to said display;
(d) inputting into the dosimetric computer a proposed plan for applying at least one beam of radiation to the patient from at least one source and from at least two different directions;
(e) selecting a plane of the patient for display of a distribution of radiation which would result from the proposed plan;
(f) displaying on said display a selected plane patient image corresponding to the selected plane by operation of the imaging system;
(g) determining the distribution of radiation within the selected plane by calculating the radiation dose at points spaced by distance D1 within a fine dose grid relatively close to the target and calculating the radiation dose at points spaced by distance D2, greater than D1, within a coarse dose grid outside said fine dose grid, the dosimetric computer performing the calculations for the radiation dose at a greater density of points in the fine dose grid and at a lower density of points in the coarse dose grid;
and
(h) displaying data on the display from the radiation dose calculations.

6 more elements

A method for patient care comprising the steps of:

(a) localizing a target within a patient;
(b) subjecting the patient to an imaging system with a display to generate patient reference data in the form of x,y,z coordinates of the target and adjacent portions of the patient;
(c) supplying the patient reference data to a dosimetric computer connected to said display;
(d) inputting into the dosimetric computer a proposed plan for applying at least one beam of radiation to the patient from at least one source and from at least two different directions;
wherein the proposed plan includes at least a first arc through which the beam is applied to the patient, said first arc being in a first arc plane, and wherein said inputting step includes the substeps of:
selecting the first arc plane;
displaying a first arc plane patient image corresponding to the first arc plane on the display;
creating a bit map of pixels on the display to said x,y,z coordinates of the patient reference data;
identifying each pixel which makes up an outside contour of the patient;
storing the beginning and end of the first arc;
drawing a line between the source at a given location and an isocenter within the target;
finding the intersection pixel of the line and the pixels corresponding to the outside contour;
referencing the bit map to identify the x,y,z coordinates of the intersection pixel as a beam entrance point;
repeating the drawing, finding, and referencing substeps to identify additional beam entrance points corresponding to different source locations;
and
storing the beam entrance points, these beam entrance points corresponding to the center of the beam at different source locations.

13 more elements

A method for patient care comprising the steps of:

(a) localizing a target within a patient;
(b) subjecting the patient to an imaging system with a display to generate patient reference data in the form of x,y,z coordinates of the target and adjacent portions of the patient;
(c) supplying the patient reference data to a dosimetric computer connected to said display;
(d) inputting into the dosimetric computer a proposed plan for applying at least one beam of radiation to the patient from at least one source and from at least two different directions;
(e) selecting a plane of the patient for display of a distribution of radiation which would result from the proposed plan;
(f) displaying on said display a patient image corresponding to the selected plane by operation of the imaging system;
(g) determining the distribution of radiation within the selected plane by calculating the radiation dose at points spaced by distance D1 within a fine dose grid relatively close to the target and calculating the radiation dose at points spaced by distance D2, greater than D1, within a coarse dose grid outside said fine dose grid, the dosimetric computer performing the calculations for the radiation dose at a greater density of points in the fine dose grid and at a lower density of points in the coarse dose grid;
and
(h) outputting data from the radiation dose calculations.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/353,816Filed 18 May 1989 · continuation in part
Priority: 3 Dec 1987
Granted: 2 Jul 1991
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

A61N 5/1049
Monitoring, verifying, controlling systems and methods: for verifying the position of the patient with respect to the radiation beam
A61N 5/10
Radiation therapy: x-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
A61N 5/103
X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy: treatment planning systems
A61N 5/1031
Treatment planning systems: using a specific method of dose optimization