Mark V Dinsmore

US Patent:

6480568, Nov 12, 2002

Filed:

Jun 19, 2001

Appl. No.:

09/884561

Inventors:

Mark Dinsmore - Sudbury MA

Assignee:

Photoelectron Corporation - North Billerica MA

International Classification:

A61N 510

US Classification:

378 65, 378136

Abstract:

A miniaturized, optically driven therapeutic radiation source operates at significantly reduced power levels. The apparatus includes a laser-driven thermionic cathode, a target element, a probe assembly, and a laser source. The probe assembly includes an optical delivery structure, such as a fiber optic cable, that directs a laser beam from the laser source to impinge upon a surface of the thermionic cathode, heating the surface to a temperature sufficient to cause thermionic emission of electrons. The emitted electrons form an electron beam along a beam path. The target element is positioned in the beam path, and includes means for emitting therapeutic radiation, such as x-rays, in response to incident accelerated electrons from the electron beam. Reflector elements may be included to reflect unabsorbed laser radiation back to the thermionic cathode.

US Patent:

6480573, Nov 12, 2002

Filed:

Dec 4, 2001

Appl. No.:

10/005287

Inventors:

Mark Dinsmore - Sudbury MA

Assignee:

Photoelectron Corporation - North Billerica MA

International Classification:

H01J 3506

US Classification:

378136, 378119

Abstract:

A therapeutic radiation source includes a optically heated thermionic cathode that is shaped so as to maximize the coupling efficiency of the incident optical radiation to the thermionic cathode. A fiber optic cable directs a beam of radiation, having a power level sufficient to heat at east a portion of the electron-emissive surface to an electron emitting temperature, from a laser source onto the cathode. An electron beam generated by said cathode strikes a target which is positioned in its beam path and which emits therapeutic radiation in response to incident accelerated electrons from the electron beam. The thermionic cathode has a non-planar configuration, such as a conical shape and a concave shape, adapted to allow an incident ray of optical radiation to impinge upon, and undergo absorption from, a plurality of regions within the surface of the cathode in succession.

US Patent:

6493419, Dec 10, 2002

Filed:

Jun 19, 2001

Appl. No.:

09/884229

Inventors:

Mark Dinsmore - Sudbury MA

Assignee:

Photoelectron Corporation - North Billerica MA

International Classification:

A61N 510

US Classification:

378 65, 378121, 378136

Abstract:

A therapeutic radiation source includes a spiral-shaped, laser-heated thermionic cathode. A fiber optic cable directs a beam of radiation, having a power level sufficient to heat at least a portion of the electron-emissive surface to an electron emitting temperature, from a laser source onto the cathode. The cathode generates an electron beam along a beam path by thermionic emission, and strikes a target positioned in its beam path. The target includes radiation emissive material that emits therapeutic radiation in response to incident accelerated electrons from the electron beam. The spiral-shaped conductive element has a plurality of spaced apart turns, and is disposed in a vacuum. An interstitial spacing is defined between adjacent turns, so that heat transfer across the spacing between each adjacent turn is essentially eliminated, thereby substantially reducing heat loss in the cathode caused by thermal conduction.

US Patent:

6556651, Apr 29, 2003

Filed:

Apr 26, 2002

Appl. No.:

10/133103

Inventors:

Euan Thomson - Harvard MA
Mark Dinsmore - Sudbury MA

Assignee:

Photoelectron Corporation - North Billerica MA

International Classification:

A61N 510

US Classification:

378 65, 378134, 378136

Abstract:

A system for delivering therapeutic radiation, such as x-rays, to a treatment region includes a plurality of individually controllable therapeutic radiation sources. The therapeutic radiation sources are selectively and moveably disposed along one or more axes, or upon a two-dimensional surface, or within a three-dimensional volume, so as to form a one-dimensional or a multi-dimensional array. Each therapeutic radiation source includes an electron source for emitting electrons, and an associated target element adapted to emit therapeutic radiation in response to incident electrons. In one embodiment, each therapeutic radiation source is coupled to a distal end of an associated optical delivery structure, which is adapted to direct a beam of optical radiation to impinge upon a surface of the electron source so as to cause emission of electrons therefrom.

US Patent:

6658086, Dec 2, 2003

Filed:

Jun 19, 2002

Appl. No.:

10/175164

Inventors:

Mark Dinsmore - Sudbury MA

Assignee:

Carl Zeiss - Oberkochen

International Classification:

A61N 510

US Classification:

378 65, 378119

Abstract:

A miniaturized, optically driven, therapeutic radiation source is disclosed in which the voltage gradient between a high electron accelerating voltage and the ground potential can be controlled. The electron source and the target element are disposed within a capsule which defines a substantially evacuated region extending along an electron beam axis. The inner surface of the capsule is coated with a weakly conductive or semiconductive coating, so that a substantially uniform voltage gradient is maintained within the evacuated capsule. In this way, the chances of electric flashover or breakdown are reduced. Also, secondary emissions of electrons striking the inner wall of the capsule are reduced. X-ray production efficiency is optimized by maximizing the percentage of electrons propagated directly to the target.

US Patent:

6721392, Apr 13, 2004

Filed:

Dec 4, 2001

Appl. No.:

10/005289

Inventors:

Mark Dinsmore - Sudbury MA

Assignee:

Carl-Zeiss-Stiftung - Okerkochen

International Classification:

A61N 510

US Classification:

378 65, 378119

Abstract:

A minaturized tharapeutic radiation source includes a optically driven thermionic cathode having an electron-emissive surface, and a non-planar, x-ray emissive target. A fiber optic cable directs a beam of optical radiation, having a power level sufficient to heat at least a portion of the electron-emissive surface to an electron emitting temperature, from a laser source onto the cathode. An electron beam emitted from said cathode strikes the target, positioned in the electron beam path. The target includes a thin film of x-ray emissive material, adapted to emit therapeutic radiation in response to incident accelerated electrons from the electron beam, and a support structure made of x-ray transmissive material. The target has a non-planar configuration, such as a conical shape or a hemispherical shape, designed to produce a more uniform and intense radiation pattern around the target.

US Patent:

6728335, Apr 27, 2004

Filed:

Apr 26, 2002

Appl. No.:

10/133048

Inventors:

Euan Thomson - Harvard MA
Mark Dinsmore - Sudbury MA

Assignee:

Carl-Zeiss-Stiftung - Oberkochen

International Classification:

A61N 510

US Classification:

378 65, 378 64, 378 92, 378124, 378134, 600 2, 600 3

Abstract:

A controller is provided for selectively and independently control each of a plurality of therapeutic radiation sources arranged along an array. The controller is operable to selectively generate therapeutic radiation at selected time intervals and at selected intensities. The controller includes intensity control circuitry for controlling the intensity of the therapeutic radiation generated by each therapeutic radiation source. The controller also includes duration control circuitry for controlling the duration of the therapeutic radiation generated by each therapeutic radiation source. The controller may also include a mechanical introducer for inserting the array into a treatment region, and for withdrawing the array from the treatment region.

US Patent:

6856668, Feb 15, 2005

Filed:

Apr 26, 2002

Appl. No.:

10/133079

Inventors:

Euan Thomson - Harvard MA, US
Mark Dinsmore - Sudbury MA, US

Assignee:

Carl Zeiss AG - Oberkochen

International Classification:

A61N005/10

US Classification:

378 65, 378 64, 604 20

Abstract:

A method is provided for treating a tumor by pre-irradiation. The location, size, and shape of the tumor is identified. A region that includes the tumor as well as a surrounding portion most likely to contain residual tumorous cells is identified. The identified region is irradiated with therapeutic radiation, such as x-rays, prior to surgical removal of the tumor. The tumor is removed after irradiation of the identified region, leaving only the pre-irradiated surrounding portion. The risk of recurrence of tumorous growth after resection of the tumor may be significantly reduced.