Radiographic imaging apparatus
Provided is a radiographic imaging apparatus capable of obtaining more suitable radiological images by reducing the influence of noise generated at a current detecting section which detects current carried by applying radiation. The radiographic imaging apparatus includes a plurality of radiation detection elements two-dimensionally arranged in each region defined by a scanning line and a signal line, a switch section the state of which is switched between on and off states depending on voltage applied to the connected scanning line, a scan drive means having a gate driver that applies on voltage and off voltage to the switch section through the scanning line and a power supply circuit that supplies on voltage and off voltage to the gate driver, a current detecting section for detecting current flowing between the power supply circuit and the gate driver or current flowing through the scanning line, and a control section for detecting at least the start of applying radiation on the basis of the value of the current detected by the current detecting section.
1. A radiographic imaging apparatus comprising:
a plurality of scanning lines;
a plurality of signal lines; arranged to cross each other;
a plurality of radiation detection elements two-dimensionally arranged in each region defined by the plurality of scanning lines and the plurality of signal lines;
a switch section which is arranged for each of the plurality of radiation detection elements and which is switched between on-state and off-state depending on a voltage applied to the connected scanning line, wherein an electric charge generated in the radiation detection element is maintained in the off-state and is released in the on-state;
a scan drive section having a gate driver that applies an on-voltage and an off-voltage to the switch section through the scanning line, and a power supply circuit that supplies said on-voltage and said off-voltage to the gate driver;
a current detecting section for detecting a current flowing between the power supply circuit and the gate driver or a current running through the scanning line; and
a control section for detecting at least a start of irradiation on a basis of a value of the current detected by the current detecting section.
2. The radiographic imaging apparatus of claim 1 , wherein the current detecting section comprises: a resistor serially connected to a connection line connecting between the power supply circuit and the gate driver; and a switch which enables establishing a short circuit between both terminals of the resistor, and wherein the resistor and the switch are configured so that when detecting the start of irradiation, the short circuit established by the switch is released, and in other case, the short circuit between the both terminals of the resistor is established by the switch.
3. The radiographic imaging apparatus of claim 2 , wherein the control section detects the start of irradiation when a current value detected by the current detecting section increases.
4. The radiographic imaging apparatus of claim 3 , wherein the control section identifies termination of the irradiation after a lapse of a predetermined time subsequent to detection of the start of irradiation following an increase in the current value detected by the current detecting section.
5. The radiographic imaging apparatus of claim 1 , wherein the control section detects the termination of irradiation when a current value detected by the current detecting section decreases.
6. The radiographic imaging apparatus of claim 5 , wherein the control section calculates a dosage of radiation irradiated based on a time interval from the start of irradiation to the termination of irradiation and a peak value of the current detected by the current detecting section.
7. The radiographic imaging apparatus of claim 5 , wherein the control section calculates a dosage of radiation irradiated as an integrated value of the current detected by the current detecting section during a time interval from the start of irradiation to the termination of irradiation.
8. The radiographic imaging apparatus of claim 5 , wherein the control section calculates a dosage of radiation irradiated as an integrated value of values subject to a band pass filtering processing is applied to the current detected by the current detecting section during a time interval from the start of irradiation to the termination of irradiation, and.
9. The radiographic imaging apparatus of claim 1 , wherein the switch section is maintained in the off-state when detecting the start of irradiation.
10. The radiographic imaging apparatus of claim 4 , wherein when detecting the start of irradiation, a voltage higher than a boundary voltage value by a predetermined value is applied to the switching section, wherein the boundary voltage value is a value of the applied voltage with which the off-state occurs when the applied voltage is reduced.