Patent Application
20140123388
This invention pertains to the field of positioning a patient into an initial setup position for multiple fractions of radiation therapy or diagnosis.
Modern diagnosis and radiation therapy machines have improved the quality of health care for miliions of patients. However, these machines are very expensive, and thus it is important to be able to move the patient into the identical initial setup position quickly when muitipte fractions are used. The present invention considerably speeds up this process, by (in one embodiment) using pointers, such as infrared pointers, corresponding detectors, and automated means to move the patient's couch into the initial setup position for each of a series of fractions.
Methods, apparati, and computer-readable media for automatically moving a patient (1) to an initial setup position. A method embodiment of the present invention entails the steps of pointing to at least one spot (8) on the body of the patient (1) when the patient (1) is located at the initial setup position at a first time point; recording spatial coordinate information for the at least one spot (8); and automatically moving the patient (1) to the initial setup position at a subsequent time point.
These and other more detailed and specific objects and features of the present invention are more fully disclosed in the following specification, reference being had to the accompanying drawings, in which:
As used herein, the following terms have the following meanings:
“Patient” means a human or other animal.
“Fraction” is a time period during which a dose of radiation therapy is administered to a patient 1, or, in the case where this term pertains to a diagnostic procedure rather than a therapeutic procedure, one of the times during which the diagnostic procedure is performed.
“Isocenter” is the intersection of the beam axis 5 and the gantry rotation axis 6.
“Initial setup position” is the location where the patient 1 is correctly positioned for the therapy or diagnosis. In the case where a tumor 13 is being treated, the tumor 13 is located at the isocenter 4 when the patient is at the initial setup position.
“Starting position” is a position where the patient 1 is initially located on couch 2 prior to therapy or diagnosis, prior to being moved to the initial setup position.
This invention can be used for diagnosis where there are multiple fractions, as well as for therapy. For example, the diagnosis can use ultrasound, magnetic resonance imaging, positron emission tomography, computed tomography, or any other imaging technique to diagnose a medical problem within a patient 1. However, for purposes of illustration only, the bulk of this written description discusses the case where the invention is used for radiation therapy, including image guided radiation therapy (IGRT). It will be understood by those of ordinary skill in the art that the detailed descriptions herein can be equally applied to fractionated diagnosis, mutatis mutandis.
The radiation therapy can be any type, including without limitation photon therapy, electron therapy, proton therapy, and heavy ion therapy.
One or more spots (marks) 8 are made on the surface of the patient's body 1 to assist in the automatic positioning. These one or more spots 8 are located in a known geometrical relationship with respect to the location of the tumor 13. The spots 8 are normally visible to the human eye, and may be, for example, marks made with a pen or Sharpie™. In one embodiment of the present invention, a pointer 7 is placed against the body 1 so that the tip 21 of the pointer (see
Tip 21 can be placed at spot(s) 8 manually by a human operator, or in another embodiment, pointer 7 can be coupled to a robotic arm (not iiiustrated) that is commanded by remote control to place pointer 7 in the proper location(s). The end of pointer 7 distal from tip 21 is affixed with one or several markers 9. In an embodiment in which pointer 7 is an infrared pointer, markers 9 can be sources of infrared luminosity which is detectable by one or more detection devices (cameras) 10 that are normally positioned at upper regions of the treatment room. Alternatively, as illustrated in
The reason for having more than one marker 9 is to provide for recordation of the angular orientation of pointer 7, which could not be achieved with the use of just one marker 9. The geometry of pointer 7 and markers 9 are known to the optical system command module 12. Therefore, command module 12 can calculate the location of pointer tip 21, based on the position and angular orientation of the markers 9.
Using more than one detection device 10, such as the two detection devices 10 that are illustrated in
In embodiments where pointer 7 is an illuminator, the light that is used for pointer 7 and detectors 10 can be light in any wavelength band anywhere from infrared to ultraviolet, inclusively. Visible light can be used, but is typically not used, because it might interfere with the ambient light in the treatment room. Other signaling can be used, such as a laser pointer 7 and a laser camera 10, which offers better resolution than with infrared pointers 7, but at higher cost.
In still other embodiments, ultrasound or RF (radio frequency radiation) can be used in lieu of optical pointing. For ultrasound, transmitters or transponders are located on or proximate to the patient 1, and corresponding ultrasound detection devices 10 are used to receive the ultrasound radiation. For RF, transmitters or active or passive transponders are located on or proximate to the patient 1, and corresponding RF detection devices 10 are used to receive the RF radiation. These transmitters and transponders can remain on the patient 1 over the course of multiple fractions. These transmitters and transponders do not have to be located along the beam axis 5, as long as there is a known geometrical relationship between the transmitters and transponders, and the location of the tumor 13. Thus, the transmitters and transponders do not have to be affixed to the patient 1, but rather can be merely proximate to the patient 1.
In an alternative embodiment, a pointer 7 is not used, but rather an optical marker (which can be infrared or ultraviolet, active or passive) is placed temporarily on the patient's body 1 for the setup, the whole fraction, multiple fractions, or the entire course of treatment.
In yet another alternative embodiment, the location of the initial setup position is determined not by a pointer but rather in a three-dimensional planning process that is performed prior to the first treatment fraction. In this embodiment, command module 12 can readily obtain enough information to enable module 12 to position couch 2 (and therefore patient 1) with all six of the aforesaid degrees of freedom.
This invention can be used in conjunction with image guided radiation therapy (IGRT), in which X-rays or other images are taken when the patient 1 is in the initial setup position, or close thereto. These images are then matched with reference images for fine-tuning the initial setup position. This can be done remotely and/or automatically.
Whatever type of signaling is used, the position information obtained by the at least one detection device 10 is fed to command module 12, which is coupled to the detector(s) 10 and also has access to a prestored representation of the three-dimensional coordinates of the treatment room. Then, command module 12, taking into account the known geometrical relationship between the at least one spot 8 and the location of the tumor 13, calculates, typically in a fixed three-dimensional coordinate system that is correlated with the three-dimensional coordinates of the treatment room, a three-dimensional vector representing where couch 2 needs to be moved in order to place the patient 1 into the initial setup position for fractions other than the first fraction. Using these calculations, command module 12 sends appropriate commands to at least one motor 14 associated with couch 2 to cause couch 2 to automatically place the patient in the initial setup position for said subsequent fraction.
Command module 12 can comprise any combination of hardware, firmware, and/or software. Any such software modules located within command module 12 can be resident on one or more computer-readable media, such as at least one hard disk, floppy disk, optical disk, DVD, etc., containing computer program instructions needed or useful to carry out the above-described calculations and to perform the above-described commands.
With respect to the present invention, the gating system uses one or several optical scanning detectors 61 that detect the above-described motion on the surface of the patient's body 1. Detectors 61 constantly scan a projected grid (or other pattern) on said surface 1 in three dimensions, calculate three-dimensional differences of patient position with respect to time, and give a pseudo three-dimensional representation to a human operator on a two-dimensional display. The gating system is calibrated to room coordinates, as are embodiments of the present invention that are described above. The results of the scan of the patient's surface 1 performed by detectors 61 can be displayed in near realtime on one or more displays that are coupled to the detectors 61. These displays can be located inside and/or outside the treatment room.
The gating system uses mathematical correlation models to correlate between the motion of the patient's surface 1 and the motion of the tumor 13. Such correlation models are defined and/or verified during treatment planning and/or prior to each fraction, and are used to inform the operator of the treatment control system when the patient's breathing has moved tumor 13 to the point where tumor 13 is too far out of position for safe and/or effective therapy. Typically, the information given to the operator has a resolution of about 2 mm and covers the whole body 1. When the tumor 13 is too far out of position, the gating system either sends an alarm to the operator, or automatically activates a switch to shut off or pause the flow of radiation emanating from the gantry 22, 31.
One way in which the present invention can be used with the gating system is for command module 12 to convey to the gating system where the spots 8 and/or the markers of the gating system are, thereby telling the gating system what locations it should be monitoring, and how this monitoring is proceeding. Additionally, command module 12 performs the duties described above regarding determining where the patient 1 needs to be moved in order for the patient 1 to be in the initial setup position, and issuing appropriate commands to motors(s) 14.
The above description is included to illustrate the operation of preferred embodiments, and is not meant to limit the scope of the invention. The scope of the invention is to be limited only by the following claims. From the above description, many variations will be apparent to one skilled in the art that would yet be encompassed by the spirit and scope of the present invention.
