Stereotactic Therapy System

Abstract

A fiducial marker system ( 210 a - c ) comprises a first unit and a second unit. The first unit is patient affixable and comprises a partly spherical inner surface having a first center point that is adapted to receive a touch probe measurement head for measuring the spatial position of the center point. The second unit is releasably attachable to an outer surface of the first unit, and has a second center point, wherein the first center point and the second center point are substantially identical when the second unit is attached to the first unit. For stereotactic therapy, a patient is imaged with the first and second unit assembled. Then the second unit is detached. A stereotactic frame ( 300 ) is attached to the first units via arms. Thus frameless imaging is provided in a frame based stereotactic surgery system with high precision. Repeated assembly of the frame ( 300 ) to the first units, remaining in the patient, provides advantageous fractionized stereotactic radiotherapy.

1 . In a framebased stereotactic therapy system, a stereotactic frame comprising a base unit and a plurality of adjustable arms mounted to said base unit, wherein a mounting unit is provided at an end portion of said arms that is arranged for releasably mounting each of said arms, and thus said stereotactic frame, to an outer surface of patient affixed first fiducial marker units of a fiducial marker system, such that said base unit of said stereotactic frame has a spatial relationship to said first fiducial marker units and thus, when said first fiducial marker units are secured in relation to a boney anatomical structure of a patient, a fixed spatial relationship to said patient, wherein said arms comprise lockable freely pivotable joints arranged to be locked after mounting each of said arms to said first fiducial marker units by said mounting units. 
     
     
         2 . The stereotactic frame of  claim 1 , wherein each or any of said arms are arranged to freely rotate around said first fiducial marker units when mounted thereto. 
     
     
         3 . The stereotactic frame of  claim 1 , wherein said end portion of said arms is provided with an opening for access of a measurement arm to the first fiducial marker unit when said adjustable arm is mounted to the fiducial marker unit for measuring the spatial position of the fiducial marker unit when said arms, and said frame are mounted thereto. 
     
     
         4 . The stereotactic frame of  claim 3 , whereby an inner surface of said first unit is accessible via said opening to receive said external measuring device to measure a spatial position of a first center point of said first fiducial marker unit by said external measuring device. 
     
     
         5 . The stereotactic frame of  claim 1 , wherein said stereotactic frame comprises predefined surface marks adapted to be measured by an external measuring device for determining the position of the stereotactic frame. 
     
     
         6 . The stereotactic frame of  claim 1 , wherein said stereotactic frame comprises a further arm to be attached to a cervical vertebra. 
     
     
         7 . The stereotactic frame of  claim 1 , wherein said stereotactic frame is of a carbon fiber reinforced plastic material. 
     
     
         8 . A framebased stereotactic therapy system comprising at least three fiducial marker systems having said first units secured in relation to a boney anatomical structure of a patient,
 and said second units releasably mounted to said first unit for frameless imaging of said patient,   and a stereotactic frame, attached to said first units of said fiducial marker systems via a plurality of adjustable arms for a session of said framebased stereotactic therapy of said patient, wherein said second units are detached from said first units for said framebased stereotactic therapy.   
     
     
         9 . The framebased stereotactic therapy system of  claim 8 , wherein said stereotactic frame is adapted to be removed and repositioned onto the patient for subsequent framebased stereotactic therapy sessions, using the same first units left secured in said relation to said boney anatomical structure of said patient. 
     
     
         10 . The framebased stereotactic therapy system of  claim 8 , wherein said frame is adapted to remain mounted to the patient only during the actual therapy session. 
     
     
         11 . The framebased stereotactic therapy system of  claim 8 , wherein registration of a position of said first units of said fiducial marker systems, which are secured to said patient is provideable by frameless imaging by a CT or MR imager, at a first point in time, when said second units are releasably mounted to said first unit; and
 wherein registration of a position of said fiducial marker systems is as well provideable by an external measuring device, such as a touch probe based measuring device, at a second point in time, different from said first point in time, when said second units are detached from said first units and said stereotactic frame is mounted to said first units of said fiducial marker systems.   
     
     
         12 . The framebased stereotactic therapy system of  claim 11 , wherein registration of a position of said stereotactic frame in relation to said first units is provideable by said external measuring device for subsequent fractionated treatment sessions when said stereotactic frame is removed and repositioned onto the patient for subsequent framebased stereotactic therapy sessions of said fractionated treatment. 
     
     
         13 . A method of conducting stereotactic therapy comprising:
 acquiring image data of a portion of a patient's body;   generating a patient coordinate system that defines the spatial location of said portion of said patient's body in said patient coordinate system;   mounting a frame externally to said portion of a patient's body;   generating a frame coordinate system that defines the spatial location of said frame in said frame coordinate system;   correlating said patient coordinate system with said frame coordinate system; and   performing stereotactic therapy.