CALIBRATION METHOD FOR RADIATION DETECTOR, AND PARTICLE THERAPY SYSTEM

• US 20130221213A1
• Filed: 02/25/2013
• Published: 08/29/2013
• Est. Priority Date: 02/29/2012
• Status: Active Grant

• Current Assignee: Hitachi High -Tech Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: TAKAYANAGI, Taisuke, NISHIUCHI, Hideaki, FUJII, Yusuke, TADOKORO, Masahiro, SAKAE, Takeji, TERUNUMA, Toshiyuki
• Granted Patent: US 9,188,685 B2
• Time in Patent Office: Days
• US Class Current: 250/252.1
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/1048 Monitoring, verifying, controlling systems and methods
• CPC Class Codes: A61N 5/1075 for testing, calibrating, or quality assurance of the radiation treatment apparatus
• CPC Class Codes: G01T 1/29 Measurement performed on radiation beams, e.g. position or section of the beam; Measurement of spatial distribution of radiation
• CPC Class Codes: G01T 7/005 calibration techniques stabilization of spectrometer G01T1/40

Abstract

A stacked type of radiation detector and a calibration method that enables the radiation detector to correct variations in sensor-specific output easily and within a short time, without using a water-phantom dose detector. The radiation detector is equipped with a sensor section including a plurality of sensors arranged in layers in a traveling direction of a particle beam. A dummy absorber has water-equivalent thickness equal to an average water-equivalent thickness of the sensors. A signal-processing unit calculates sensor-specific calibration coefficients using a measurement result obtained during irradiation of the radiation detector with the radiation when electrical signals developed in each sensor are measured, and a measurement result obtained during irradiation of the radiation detector with the radiation when the sensor section is moved in the traveling direction of the radiation, then the dummy absorber is set in place, and electrical signals developed in each sensor are measured.

Claims

8-1. The radiation detector according to claim 2, further comprising:

a range shifter; and

a range shifter driving control device for driving the range shifter;

wherein the dummy absorber driving control section is the range shifter driving control device; and

wherein the range shifter driving control device drives the dummy absorber in addition to the range shifter.

9-2. A particle therapy system with the radiation detector of claim 2, wherein

the integrated extraction dose value is acquired by a dose monitor equipped on a particle beam irradiation apparatus of the particle therapy system.

11. A calibration method for a radiation detector including a sensor section having radiation sensors stacked one another, the method comprising:

acquiring a first measurement result by measuring radiation passing through the sensor section;

placing, at an anterior position in a direction of measurement by the sensor section, with the anterior position corresponding to a position at the line where the radiation propagates, a dummy absorber having water-equivalent thickness equal to average water-equivalent thickness of the stacked radiation sensors;

moving the sensor section through a distance equal to average thickness of the stacked radiation sensors, in a traveling direction of the radiation, at the line where the radiation propagates;

acquiring a second measurement result by measuring the radiation passing through the sensor section after passing through the absorber; and

calculating calibration coefficients for each of the radiation sensors, from the first measurement result, the second measurement result, and an integrated extraction dose of the radiation extracted during the acquisition of the first measurement result and the second measurement result.

12. A calibration method for a radiation detector including a sensor section having radiation sensors stacked one another, the method comprising:

placing, at an anterior position in a direction of measurement by the sensor section, with the anterior position corresponding to a position at the line where radiation propagates, a dummy absorber having water-equivalent thickness equal to average water-equivalent thickness of the stacked radiation sensors;

acquiring a first measurement result by measuring the radiation passing through the sensor section after passing through the absorber;

removing the dummy absorber from the line where the radiation propagates;

moving the sensor section through a distance equal to average thickness of the stacked radiation sensors, in a traveling direction of the radiation, at the line where the radiation propagates;

acquiring a second measurement result by measuring the radiation passing through the sensor section; and

calculating calibration coefficients for each of the radiation sensors, from the first measurement result, the second measurement result, and an integrated extraction dose of the radiation extracted during the acquisition of the first measurement result and the second measurement result.