A fiber optic thermometer has a hollow body made of material of low thermal expansion and an optical fiber supported by a high thermal expansion intermediate support to form a cantilever section, a fiber optic splitter coupled to a first end of the optical fiber and a light source for directing light into the optical fiber via one branch of the optical splitter. A photodetector receives light conveyed through the optical fiber via the other branch of the optical splitter and measures intensity of the received light. A reflective target supported at a second end of the hollow body is axially aligned with the second end of the optical fiber at room temperature. Upon ambient temperature changes the cantilever section moves relative to the reflective target thereby changing the instantaneous intensity of light reflected by the target into the second end of the optical fiber and measured by the photodetector.

A bend information computation apparatus includes a light source, a first light guide, a detection target, a second light guide, a switching member, a driver, a detector, a generator, and a bend information arithmetic operator. The detector is configured to detect first and second spectrum change. The generator is configured to calculate, based on the second spectrum change, suppression information. The bend information arithmetic operator is configured to calculate change information based on the first spectrum change and the suppression information and to compute bend information based on the change information.

A bend information computation apparatus includes a light source, a first light guide, a detection target, a second light guide, a switching member, a driver, a detector, a generator, and a bend information arithmetic operator. The detector is configured to detect first and second spectrum change. The generator is configured to calculate, based on the second spectrum change, suppression information. The bend information arithmetic operator is configured to calculate change information based on the first spectrum change and the suppression information and to compute bend information based on the change information.

The application describes methods and apparatus for distributed fiber sensing, especially distributed acoustic/strain sensing. The method involves launching interrogating radiation in to an optical fiber and sampling radiation backscattered from within said fiber at a rate so as to acquire a plurality of samples corresponding to each sensing portion of interest. The plurality of samples are divided into separate processing channels and processed to determine a phase value for that channel. A quality metric is then applied to the processed phase data and the data combined to provide an overall phase value for the sensing portion based on the quality metric. The quality metric may be a measure of the degree of similarity of the processed data from the channels. The interrogating radiation may comprise two relatively narrow pulses separated by a relatively wide gap and the sampling rate may be set such that a plurality of substantially independent diversity samples are acquired.

The application describes methods and apparatus for distributed fiber sensing, especially distributed acoustic/strain sensing. The method involves launching at least first and second pulse pairs into an optical fiber, the first and second pulse pairs having the same frequency configuration as one another and being generated such that the phase relationship of the pulses of the first pulse pair has a predetermined relative phase difference to the phase relationship of the pulses of the second pulse pair. In one embodiment there is a frequency difference between the pulses in a pulse pair which is related to the launch rate of the pulse pairs. In another embodiment the phase difference between the pulses in a pair is varied between successive launches. In this way an analytic version of the backscatter interference signal can be generated within the baseband of the sensor.

A garment for real time detection of body deformation during an image scan includes a front portion, made of a compression material and having a plurality of fiber Bragg gratings (FBGs). The garment includes a plurality of light emitters, each light emitter configured to pulse light waves through a corresponding FBGs and a plurality of light sensors, each light sensor attached to a corresponding FBG and configured to receive pulsed light waves. A processor obtains data through a data acquisition module configured to receive from the light sensors peak wavelengths reflected by the FBG Based on the effective shifts of the Bragg wavelengths of the FBGs aligned along the cartesian coordinate system, the processor may correct acquired image data or re-direct an external beam treatment to compensate for body deformation during an image scan.

A method for compensating for dynamic changes in a body of a patient during a controlled interaction with the body includes acquiring data from at least one sensing device disposed on the body and detecting a change along at least one optical fiber of the sensing device caused by dynamic changes associated with the body during the controlled interaction. A respiratory gating signal is generated based on the change along the at least one optical fiber of the sensing device measured over time. The method further comprises controlling relative movement between the body and an interactive device in response to the respiratory gating signal to compensate for the dynamic changes associated with the body during the controlled interaction.

A method and system of compensating for body deformation during image acquisition or external beam treatment includes acquiring image data of a body and peak wavelength data from a plurality of fiber Bragg gratings (FBGs) disposed on the body aligned along a predetermined coordinate system on the body, such as a cartesian coordinate system. The method further comprises detecting effective shifts of the Bragg wavelengths of the FBGs caused by body deformation during image acquisition, and controlling the movement of the body through a cavity in a scanning device and controlling the acquisition of the image data or external beam treatment during body deformation based on the effective shifts of the Bragg wavelengths of the FBGs.

A method for compensating for dynamic changes in a body of a patient during a controlled interaction with the body includes acquiring data from at least one sensing device disposed on the body and detecting a change along at least one optical fiber of the sensing device caused by dynamic changes associated with the body during the controlled interaction. A respiratory gating signal is generated based on the change along the at least one optical fiber of the sensing device measured over time. The method further comprises controlling relative movement between the body and an interactive device in response to the respiratory gating signal to compensate for the dynamic changes associated with the body during the controlled interaction.

The application describes methods and apparatus for distributed fibre sensing, especially distributed acoustic/strain sensing. The method involves launching interrogating radiation in to an optical fibre and sampling radiation backscattered from within said fibre at a rate so as to acquire a plurality of samples corresponding to each sensing portion of interest. The plurality of samples are divided into separate processing channels and processed to determine a phase value for that channel. A quality metric is then applied to the processed phase data and the data combined to provide an overall phase value for the sensing portion based on the quality metric. The quality metric may be a measure of the degree of similarity of the processed data from the channels. The interrogating radiation may comprise two relatively narrow pulses separated by a relatively wide gap and the sampling rate may be set such that a plurality of substantially independent diversity samples are acquired.