Dual-stage positioning system

Abstract

A positioning system for positioning a patient support in an imaging device is disclosed herein. The positioning system includes a fine positioning subsystem coupled to the patient support and adapted to position the patient support with fine precision along the X-axis; and a coarse positioning subsystem coupled to the fine positioning subsystem and adapted to position the patient support with coarse precision along the X-axis. In an embodiment, the fine positioning subsystem and the coarse positioning subsystem are a dual-stage drive positioning system, with the first drive including a screw mechanism and the second drive including a prime mover. In an embodiment, a programmer is provided for configuring the fine positioning subsystem to align the patient support based on a velocity profile.

1 . A positioning system for positioning a patient support in an imaging device comprising:
 a fine positioning subsystem coupled to the patient support, adapted for positioning the patient support with fine precision; and   a coarse positioning subsystem coupled to the fine positioning subsystem, adapted for positioning the patient support with coarse precision,   wherein the fine positioning subsystem and the coarse positioning subsystem are configured to position the patient support along an X-axis.   
     
     
         2 . The positioning system as in  claim 1 , wherein the fine positioning subsystem is configured to position the patient support with micrometer precision, and the coarse positioning subsystem is configured to position the patient support with millimeter precision. 
     
     
         3 . The positioning system as in  claim 1 , wherein the fine positioning subsystem is configured to position the patient support with a precision of one micrometer for a range of 0-300 micrometers along the X-axis. 
     
     
         4 . The positioning system as in  claim 1 , wherein the coarse positioning subsystem is configured to position the patient support with a precision of one millimeter for a range of 0-2000 millimeters along the X-axis. 
     
     
         5 . The positioning system as in  claim 1 , wherein the fine positioning subsystem comprises a screw drive mechanism operating in a closed loop. 
     
     
         6 . The positioning system as in  claim 5 , wherein the screw drive mechanism includes a screw arrangement and an electric motor coupled to the screw arrangement and configured to drive the screw arrangement. 
     
     
         7 . The positioning system as in  claim 6 , wherein the screw drive mechanism is coupled to the patient support through a fine feed. 
     
     
         8 . The positioning system as in  claim 1 , wherein the coarse positioning subsystem is configured to be a prime mover operating in a closed loop. 
     
     
         9 . The positioning system as in  claim 8 , wherein the coarse positioning subsystem includes a screw drive mechanism, hydraulic drive mechanism or belt drive mechanism. 
     
     
         10 . The positioning system as in  claim 1 , wherein the fine positioning subsystem is coupled to the coarse positioning subsystem through a coarse feed. 
     
     
         11 . The positioning system as in  claim 1 , wherein the imaging device is one of a computed tomography device, a positron emission tomography device, a magnetic resonance imaging device, an ultrasound imaging device and an X-ray device. 
     
     
         12 . A positioning system with a dual-stage drive assembly for an imaging device, comprising:
 (a) a patient support capable of moving along an X-axis;   (b) a first drive coupled to the patient support, adapted for fine positioning of the patient support with fine precision along the X-axis; and   (c) a second drive coupled to the first drive, adapted for coarse positioning of the patient support with coarse precision along the X-axis.   
     
     
         13 . The positioning system as in  claim 12 , wherein the first drive is configured to position the patient support with micrometer precision, and the second drive is configured to position the patient support with millimeter precision. 
     
     
         14 . The positioning system as in  claim 12 , wherein the patient support includes a carrier and at least two pairs of elongated rails. 
     
     
         15 . The positioning system as in  claim 12 , wherein the first drive is configured to position the patient support with a precision of one micrometer for a range of 0-300 micrometer. 
     
     
         16 . The positioning system as in  claim 12 , wherein the first drive includes a screw drive mechanism operating in a closed loop. 
     
     
         17 . The positioning system as in  claim 16 , wherein the screw drive mechanism includes a screw arrangement coupled to the patient support and an electric motor coupled to the screw arrangement. 
     
     
         18 . The positioning system as in  claim 17 , further comprising a programmer for configuring the electric motor to position the patient support based on a velocity profile. 
     
     
         19 . The positioning system as in  claim 18 , wherein the velocity profile includes mapping of velocity of the patient support in the imaging device over volume of a scanned object. 
     
     
         20 . The positioning system as in  claim 12 , wherein the second drive is configured to be a prime mover operating in a closed loop. 
     
     
         21 . A method of positioning a patient in an imaging device comprising the steps of:
 (a) aligning a patient table along an X-axis using a coarse positioning subsystem;   (b) fine tuning the alignment of the patient table with fine precision along the X-axis using a fine positioning subsystem;   (c) actuating the fine positioning subsystem to align the patient table using a velocity profile; and   (d) adjusting the position of the patient table using the velocity profile.   
     
     
         22 . The method as in  claim 21 , wherein the velocity profile includes mapping of velocity of the patient table passing through a scanning beam in the imaging device over volume of a scanned object.