Field of the Invention
The present invention relates to a radiographic image capture device, system, program storage medium and method, and in particular to a radiographic image capture device, system, program storage medium and method that captures a radiographic image expressing radiation passed through an imaging target site.
Description of the Related Art
Recently, radiation detectors such as Flat Panel Detectors (FPDs) are being implemented in which a radiation sensitive layer is disposed on a Thin Film Transistor (TFT) active matrix substrate and with which radiation can be converted directly into digital data. Radiographic image capture devices that employ such radiation detectors and can capture radiographic images expressing irradiated radiation are also being implemented. Radiation conversion methods used by radiation detectors employed in such radiographic image capture devices include indirect conversion methods, in which radiation is first converted into light with a scintillator and then the converted light is converted into electric charge with a semiconductor layer such as a photodiode, or direct conversion methods in which radiation is converted into electric charge with a semiconductor layer such as amorphous selenium. There are various materials that may be used in the semiconductor layer for each method.
In such radiographic image capture devices, if the radiographic image capture device itself can detect states such as initiation of radiation application, termination of radiation application, and an amount of radiation application, it becomes unnecessary to connect an image capture control device (referred to as a console) that performs overall control of the radiographic image capture device and the radiation source to the radiation source. Such a configuration is preferable from the perspective of simplifying the system configuration and simplifying control by the image capture control device.
An example of such technology related to radiographic image capture devices that can detect states of radiation application is disclosed in Japanese Patent No. 4217443. This radiographic image capture device includes a pixel area with plural pixels disposed on a substrate. Each pixel includes a phosphor material that converts incident radiation into visible light, a first photoelectric conversion element that converts the visible light into electrical signals, and a switching element that switches the output operations of the electrical signals from the photoelectric conversion element. Image data is generated based on the electrical signals output from the first photoelectric conversion elements. The radiographic image capture device includes a second photoelectric conversion element that detects the amount of incident radiation, and the switching elements and the second photoelectric conversion elements are disposed between the substrate and the first photoelectric conversion elements in the pixel area.
Japanese Patent No. 4217506 discloses a radiation imaging device having a conversion section provided with plural pixels, each having a first conversion element, wherein the conversion section is provided on the side of a substrate on which radiation is incident. The radiation imaging device outputs image data according to the amount of radiation incident to the conversion section. The radiation imaging device includes second conversion elements that detect at least one of a radiation application amount incident to the conversion section, the start and end of incidence of radiation to the conversion section. The second conversion elements are disposed between the first conversion elements of adjacent pixels in the conversion section on the side of the substrate on which radiation is incident. The second conversion elements have a width in one direction that is smaller than the pitch of the pixels.
However, in the above technologies, since the sensors for detecting radiation are embedded between the pixels for image generation, electric charges generated by photoelectric conversion are temporarily accumulated in these sensors. As a result, at least one of charge leakage (blooming) or induction charges due to floating capacitance may occur in the above technology, and this may cause deterioration in captured image quality. Such issues are more significant as the pixel pitch of the radiation detector is smaller.