Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2001-10-18
2003-11-18
Shaw, Shawna J (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C128S920000
Reexamination Certificate
active
06650930
ABSTRACT:
TECHNICAL FIELD
The invention relates to radiotherapy dosimeter systems, especially of the kind which use a plurality of dosimeter sensors distributed in a region to be irradiated and means for monitoring radiation levels detected by the sensors.
BACKGROUND ART
Radiotherapy treatment of cancer patients involves the use of machines which produce high energy X-rays or high energy electrons. It is common practice to verify the radiation dose delivered to the patient with a dosimetry system such as the Thomson & Nielsen Patient Dose Verification System.
There are three different types of dosimetry system used in radiotherapy. These are based on (a) film or thermal luminescent dosimeters (TLD), (b) diodes and (c) MOSFETs. Diode and MOSFET systems use electronic dosimeter sensors together with electronic reading systems, whereas film or TLD use chemical or thermal methods of reading the detectors into an electronic reading system.
Since diode and MOSFET based dosimetry systems have the convenience of direct electronic reading of the dosimeters, they also have the potential advantage of direct data communication with computer systems. The person using a patient dosimetry system (usually a medical physicist, dosimetrist or therapist) requires the radiation dose information from the system to be in a format that is suitable for good quality assurance records.
The state of the art with patient dose verification systems is for the dose data to be presented in one of three formats—(a) on a display on the reading instrument, (b) on a print-out from the electronic reader or (c) on a computer screen. In the latter case, the information presented on the computer screen is in the form of numbers and, in some cases, graphs.
Thomson & Nielsen MOSFET dosimetry systems use Excel™ spreadsheets for this purpose. Sun Nuclear™ and Scanditronix™ have diode-based systems which use Windows™—based systems with numerical tables and graphs of data.
A disadvantage of these known systems is that it is not easy to confirm that the dose values measured were taken at the proper locations on the body of the patient.
SUMMARY OF INVENTION
An object of the present invention is to at least mitigate this disadvantage and to this end, there is provided a dosimetry system having means for displaying a representation of the body, e,g., a patient, to be irradiated, showing specific locations of radiation sensors in relation to the body.
According to one aspect of the present invention, there is provided a dosimetry system comprising display means; display control means for controlling the display means to provide, simultaneously, a display image comprising a representation of at least a portion of a body to be irradiated and a plurality of graphics artefacts each comprising a sensor icon representing a respective one of a plurality of radiation sensors to be positioned in, on or adjacent said body during subsequent irradiation of the body, and a corresponding identifier; user-operable means for controlling the display control means to relocate, selectively, some or all of the sensor icons at respective positions on or adjacent said body image, said positions corresponding to positions on, in or adjacent said body at which the sensors themselves are to be positioned during subsequent irradiation of the body, and outputting to one or both of storage means and recording means a record of the displayed image showing the body image and graphics artefacts with the sensor portions positioned as relocated.
Preferably, the display system is arranged to display the representations, prior to irradiation, with the sensor location artefacts and sensor identifiers and, after irradiation, with the measured doses associated with each sensor.
Preferably, the display system provides for adjustment of the sensor location artefacts prior to the irradiation, to select desired locations, and then may provide for printing of the representations, showing the sensor location artefacts, prior to irradiation, thus allowing the print-out to be used by an operator as a guide when positioning the sensors.
A method of determining locations of radiation sensors in, on or adjacent a body during subsequent irradiation thereof by a radiation therapy system, comprising the steps of:
(I) displaying on a display device, simultaneously, a representation of at least a portion of the body to be irradiated, and a plurality of graphics artefacts each representing a respective one of a plurality of radiation sensors to be positioned in, on or adjacent said body during subsequent irradiation of the body, each graphics artefact comprising a sensor icon and a sensor identifier;
(ii)controlling the display means to relocate, selectively, some or all of the sensor icons of the graphics arrefacts at respective positions on or adjacent said representation, said positions corresponding to positions on, in or adjacent said body at which the radiation sensors represented by the selected sensor icons are to be positioned during subsequent irradiation of the body, and
(iii) outputting to one or both of storage means and recording means a record of the displayed representation and graphics anefacts with the sensor icons in their relocated positions.
Embodiments of the invention advantageously enable the physicist to plan the locations where dose measurements are required, ensure that the dosimeters are placed according to plan, and confirm that the body (patient) has received the correct dose to the correct location according to the plan.
Yet another advantageous feature is that the one or more representations of the body, together with the preselected dosimeter sensor locations, may be printed prior to patient treatment so as to facilitate correct positioning of the dosimeter sensors in the correct anatomical positions by the medical personnel performing the radiotherapy procedure.
Advantageously, embodiments of the present invention may provide real-time display of data from the dosimetry system reader.
Another advantageous feature is that the patent's treatment information may be readily recorded (e.g. patient's name, identification of radiotherapy machine used, energy of the machine).
The one or more representations used to indicate the positions of the dosimeter sensors on the body, e.g. on the patient's anatomy, may comprise standard line drawings or custom images, such as scanned photographs or digital camera images. In the latter cases, the use of actual images of the body facilitates proper location of the sensors.
Another advantageous feature of embodiments of the present invention which use a computer display is that the software may calculate the radiation dose using the data input from the reading instrument and any calibration or correction factors previously input by the physicist, typically following a previous calibration of the dosimetry system in a known manner. The software then may compare the dose calculations with predetermined target doses and indicate, conveniently by highlighting in the display, any deviation for corrective action.
A further feature of embodiments of the present invention is the capability to view, print or electronically save the final report with all the relevant dosimetry data collected during the patient's treatment.
According to a third aspect of the invention there is provided software for interfacing a plurality of dosimeter sensors and a reader to a microcomputer or personal computer to provide for the display of an image or other representation of the body/patient and the locations of the sensors in relation to the body, in a system according to the first aspect.
REFERENCES:
patent: 5621779 (1997-04-01), Hughes et al.
patent: 5923724 (1999-07-01), Soukal
patent: 6266453 (2001-07-01), Hibbard et al.
patent: 6398710 (2002-06-01), Ishikawa et al.
patent: 6405072 (2002-06-01), Cosman
patent: 1362679 (1974-08-01), None
Adams Thomas
Shaw Shawna J
Thomson & Nielsen Electronics Ltd.
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