Radiation detector and radiography method using the same

1. A radiography method using a radiation detector comprising a radiation detecting unit comprising a plurality of pixels arrayed in a matrix, wherein each pixel of the plurality of pixels is connected to a gate line of a plurality of gate lines, is connected to a data line of a plurality of data lines, and stores charges proportional to irradiation dose of radiation, the radiography method comprising:

(a) selecting at least one of the plurality of gate lines;

(b) selecting at least one of the plurality of data lines;

(c) reading out charges stored in at least one exposure detection pixel, and the plurality of pixels includes the at least one exposure detection pixel;

(d) setting a reference charge amount value by using a first charge amount of the charges read out from the at least one exposure detection pixel;

(e) removing charges stored in the plurality of pixels of the radiation detecting unit;

(f) selecting again the at least one of the plurality of gate lines and the at least one of the plurality of the data lines to detect exposure to radiation, and

determining whether or not the radiation detecting unit is exposed to radiation by comparing a second charge amount read out from the at least one exposure detection pixel with the reference charge amount value,

wherein, if it is determined that the radiation detecting unit is exposed to radiation, then the radiography method further comprises maintaining radiation exposure of the radiation detecting unit during a predetermined exposure time in order to store further charges to all the plurality of pixels, and then reading out charges stored in all the plurality of pixels for generating a radiographic image, by scanning all the plurality of pixels after the predetermined exposure time;

wherein, if it is determined that the radiation detecting unit is not exposed to radiation, then the radiography method further comprises generating a reset request signal for removing charges stored in the plurality of pixels of the radiation detecting unit;

wherein the radiography method further comprises correcting charge amount data of the at least one exposure detection pixel generated by charges read out from the at least one exposure detection pixel among the charges read out in all the plurality of pixels,

wherein determining whether or not the radiation detecting unit is exposed to radiation comprises reading out charges stored in the at least one exposure detection pixel, and is repetitively performed until before the exposure to radiation of the radiation detecting unit is determined, and

wherein, in correcting the charge amount data, a median value of charge amount data of pixels adjacent to the at least one exposure detection pixel is determined, and the charge amount data of the at least one exposure detection pixel is replaced with the median value to correct the charge amount data of the at least one exposure detection pixel.

2. The radiography method of claim 1 , further comprising:

setting the predetermined exposure time for which the radiation exposure of the radiation detecting unit is maintained.

3. The radiography method of claim 1 ,

wherein the radiation detecting unit is determined to have not been exposed to radiation when the charge amount being read out from the exposure detection pixel is smaller than the reference charge amount value, and

operations (e) and (f) are re-performed after determining that the radiation detecting unit is not exposed to radiation.

4. The radiography method of claim 3 ,

wherein the predetermined exposure time is longer than a period in which operations (e) and (f) are re-performed.

5. The radiography method of claim 1 ,

wherein the radiation detecting unit is determined to have been exposed to radiation when the second charge amount is equal to or greater than the reference charge amount value.

6. The radiography method of claim 1 ,

wherein, operations (e) and (f) are re-performed after determining that the radiation detecting unit is not exposed to radiation.