JP2006158728A5

JP2006158728A5 -

Info

Publication number: JP2006158728A5
Application number: JP2004355758A
Authority: JP
Filing date: 2004-12-08
Publication date: 2008-01-31
Anticipated expiration: 2024-12-08

Claims

Radiation irradiating means for irradiating the subject with radiation;
Radiation detecting means in which a plurality of photoelectric conversion elements for converting radiation into electrical signals are arranged in a matrix;
Reading means for reading out the electrical signal from the radiation detection means;
Signal processing means for processing the electrical signal supplied from the reading means,
Subject photographing for irradiating radiation from the radiation irradiating means and detecting an electrical signal relating to a subject image based on the irradiated radiation, and acquiring offset data relating to the electrical signal without irradiating the radiation from the radiation irradiating means With offset shooting,
The signal processing means compares the amount of fluctuation of the offset data with a predetermined threshold value, and when the amount of fluctuation of the offset data is larger than the predetermined threshold value, the offset imaging is performed again, and the amount of fluctuation of the offset data Is smaller than a predetermined threshold, the subject imaging is continuously performed a plurality of times, and the subject irradiation image is corrected using the last offset data used for comparison, and the radiation irradiation period of the radiation irradiating means and A radiation imaging apparatus for controlling a reading cycle of the electrical signal from the radiation detection means.

The signal processing means includes storage means for storing a plurality of the offset data, acquires the offset data at a predetermined cycle, stores the offset data in the storage means, and based on the offset data stored in the storage means The radiation imaging apparatus according to claim 1, wherein the radiation irradiation period and the reading period are controlled in accordance with the obtained variation amount of the offset data.

The storage means includes first storage means for storing the odd-numbered offset data, and second storage means for storing the even-numbered offset data,
The radiation imaging apparatus according to claim 2, wherein the fluctuation amount of the offset data is a difference between the offset data stored in the first storage unit and the offset data stored in the second storage unit.

The signal processing unit includes a comparison unit that compares the change in the offset data with a predetermined threshold value, and controls the radiation irradiation period and the reading period according to a comparison result of the comparison unit. The radiation imaging apparatus according to any one of claims 1 to 3.

A plurality of combinations of the radiation irradiation period and the reading period are set, and the signal processing means includes the predetermined threshold value and the offset data provided for each combination of the radiation irradiation period and the reading period. The radiation imaging apparatus according to claim 1, wherein the radiation amount is compared with a fluctuation amount.

The readout means has drive means for driving and controlling the radiation detection means, and electrical signal readout means for reading out the electrical signal,
The signal processing means includes
The offset data is acquired at a predetermined cycle by the radiation detection means during a period in which no radiation is irradiated,
While calculating the difference of the acquired offset data to determine the amount of fluctuation of the offset data,
The radiation imaging apparatus according to claim 1, wherein the radiation irradiation period and the reading period are controlled according to a variation amount of the offset data.

The radiation imaging apparatus according to claim 1, wherein amorphous silicon is used as a material of the photoelectric conversion element.

The radiation imaging apparatus according to claim 7, wherein an MIS type photoelectric conversion element is used as the photoelectric conversion element.

It has a wavelength converter that performs wavelength conversion on radiation,
The radiation imaging apparatus according to claim 1, wherein a wave that has been wavelength-converted by the wavelength converter and output is incident on the photoelectric conversion element.

10. The radiation imaging apparatus according to claim 9, wherein the wavelength converter includes as a main component one selected from Gd ₂ O ₂ S, Gd ₂ O _3, and CsI.

The photoelectric conversion element has a function of absorbing radiation and converting it into an electrical signal, and the main material thereof is one selected from amorphous selenium, gallium arsenide, mercury iodide, and lead iodide. The radiation imaging apparatus according to claim 1, wherein:

A radiation imaging apparatus control method comprising radiation irradiating means for irradiating a subject with radiation, and radiation detecting means in which a plurality of photoelectric conversion elements for converting radiation into electrical signals are arranged in a matrix,
Performing a subject photographing in which radiation is emitted from the radiation irradiating means and an electric signal related to a subject image based on the irradiated radiation is detected by the radiation detecting means;
Applying predetermined processing to the electrical signal obtained by the subject photographing;
Performing offset imaging to obtain offset data related to the electrical signal without irradiating radiation from the radiation irradiating means;
The amount of fluctuation of the offset data acquired by the offset photographing is compared with a predetermined threshold, and when the amount of fluctuation of the offset data is larger than the predetermined threshold, the offset photographing is performed again, and the amount of fluctuation of the offset data Is smaller than a predetermined threshold value, the subject is continuously photographed a plurality of times, and the subject irradiation image is corrected using the last offset data used for comparison, and the radiation irradiation period of the radiation irradiating means and And a step of controlling a reading cycle of the electric signal from the radiation detecting means.

In order to cause a computer to execute a control method of a radiation imaging apparatus including radiation irradiation means for irradiating a subject with radiation and radiation detection means in which a plurality of photoelectric conversion elements for converting radiation into electrical signals are arranged in a matrix The program of
Performing subject imaging in which radiation is emitted from the radiation irradiating means and an electrical signal related to a subject image based on the irradiated radiation is detected by the radiation detecting means;
Applying predetermined processing to the electrical signal obtained by the subject photographing;
Performing offset imaging to obtain offset data related to the electrical signal without irradiating radiation from the radiation irradiating means;
The amount of fluctuation of the offset data acquired by the offset photographing is compared with a predetermined threshold, and when the amount of fluctuation of the offset data is larger than the predetermined threshold, the offset photographing is performed again, and the amount of fluctuation of the offset data Is smaller than a predetermined threshold value, the subject is continuously photographed a plurality of times, and the subject irradiation image is corrected using the last offset data used for comparison, and the radiation irradiation period of the radiation irradiating means and A program for causing a computer to execute a step of controlling a reading cycle of the electric signal from the radiation detecting means.

14. A computer-readable recording medium on which the program according to claim 13 is recorded.