Varian Medical Systems, Inc.

Varian Associates, Inc.

Varian Medical Systems Technologies, Inc.

Stanley Woodrow Johnsen

Edward J Seppi

Richard E Colbeth

John Milan Pavkovich

Edward G Shapiro

Peter Munro

Raymond Denzil McIntyre

Marcel R Marc

Michelangelo Delfino

A multi-mode cone beam computed tomography radiotherapy simulator and treatment machine is disclosed. The radiotherapy simulator and treatment machine both include a rotatable gantry on which is positioned a cone-beam radiation source and a flat panel imager. The flat panel imager captures x-ray image data to generate cone-beam CT volumetric images used to generate a therapy patient position setup and a treatment plan.

Multi-mode cone beam CT radiotherapy simulator and treatment machine with a flat panel imager

A multi-mode cone beam computed tomography radiotherapy simulator and radiotherapy treatment machine is disclosed. The radiotherapy simulator and radiotherapy treatment machine both include a rotatable gantry on which is positioned a cone-beam radiation source and a flat panel imager. The flat panel imager captures x-ray image data to generate cone-beam CT volumetric images used to generate a therapy patient position setup and a treatment plan.

A flexible multi-leaf collimator for electron radiotherapy is provided, where the leaves are not a single rigid component, but are configured in a manner that curves away from the patient to provide greater clearance. The invention includes a plurality of flexible assemblies, at least one guide supporting the assemblies, and a plurality of assembly drivers. The driver engages the assembly and moves the assembly along the guide. The assembly has an extended state and a retracted state relative to the guide, such that when in the extended state the assembly is held in the aperture plane and when in the retracted state the assembly conforms along the guide. When in the extended state the assemblies are disposed as a treatment aperture.

Multileaf collimator for electron radiotherapy

A multi-leaf collimator includes a number of independently adjustable leaves. Adjacent leaves overlap to prevent an incident beam of radiation from passing through a gap between them. The overlapping portions of the leaves are made of a first material, while the non-overlapping portions of the leaves are made of a second, different material.

Multi-leaf collimator with leaves formed of different materials

A method of using a radiation system having a multileaf collimator ('MLC') to adjust for unevenness in the radiation emitted by the system is disclosed. By appropriately controlling the MLC in accordance with the invention the system can be operated without a flattening filter. In addition, the invention allows the system user to vary the radiation beam energy in the course of a single treatment, without the need to use or change flattening filters. A map of the uneven radiation beam intensity in the treatment area is obtained, and the map information is combined with a treatment plan to control movement of the leaves of the MLC such that each area receives the correct radiation dose.

Radiation therapy system and method of using the same

An apparatus and method for irradiating target objects, especially medical stents for in vivo implantation. A linear accelerator provides a high energy electron beam that impinges upon and is received by an x-ray conversion target. The x-ray conversion target is activated by either a static or dynamically moveable electron beam to generate and emit an x-ray flux so as to efficiently intercept the target object. The x-ray flux is directed to the target object for a desired time period and is of sufficiently high energy to efficiently impart radioactive properties to the target object. Alternatively, the target object is positioned within the path of the x-ray flux or is translated within the path during irradiation. Mechanical transport assemblies such as a carousel, rotational and/or linear translator and/or movement tube system also may be provided.

Method and apparatus for producing radioactive materials for medical treatment using x-rays produced by an electron accelerator

Information on radiation dosage from segmented ionization chambers can be incomplete due to the existence of insensitive regions of the chamber. By measuring the total current to the high voltage power supply, the total ionization current including that in the insensitive areas can be estimated, thereby providing a measure of the dosage to the insensitive areas.

Method of measuring total ionization current in a segmented ionization

A beam of charged particles is scattered by a thin foil and the flux at two angles .theta..sub.1 and .theta..sub.2, is sampled to yield an exponential function of the respective energy difference, E(.theta..sub.2)-E(.theta..sub.1). For .theta..sub.1 =0.degree., a signal representative of the energy stability of the beam is obtained and compared with a reference to form an error signal for application to the accelerator for stabilizing the beam energy and/or providing an energy interlock.

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Palo Alto, CA, United States of America

Stanley Woodrow Johnsen