Photon counting type image detector, X-ray diagnosis apparatus and X-ray computed tomography apparatus
View Patent ↗A photon counting type image detector has: a semiconductor cell that detects an X-ray photon; a charge amplifier that generates a plurality of electric pulses each being based on an electric charge collected in response to the detected X-ray photon; a comparator that discriminates a peak value of each of the electric pulses; a threshold logic circuit that performs control so as to count none of the peak-discriminated electric pulses corresponding to energy of characteristic X-rays produced in the semiconductor cell; and a counter that counts the discriminated electric pulses as controlled by the threshold logic circuit.
1. A photon counting type image detector comprising:
an X-ray detecting material configured to detect an X-ray photon;
a charge-to-voltage converter configured to generate a plurality of electric pulses each being based on an electric charge collected in response to the detected X-ray photon;
an energy discriminator configured to discriminate a peak value of each of the electric pulses;
a controller configured to perform control so as not to count a non-count pulse of the peak-discriminated electric pulses, the non-count pulse corresponding to energy of characteristic X-rays produced in the X-ray detecting material; and
a counter configured to count a count pulse of the peak-discriminated electric pulses, the count pulse being obtained by removing the non-count pulse from the peak-discriminated electric pulses.
2. An X-ray diagnosis apparatus having the photon counting type image detector according to claim 1 .
3. The X-ray diagnosis apparatus according to claim 2 , wherein
the controller performs control so as not to count the non-count pulses of the peak-discriminated electric pulses, the non-count pulses corresponding to the characteristic X-ray energy and corresponding to a difference between plural different energy values of characteristic X-rays produced in the X-ray detecting material.
4. The X-ray diagnosis apparatus according to claim 2 , further comprising:
an X-ray beam quality controller configured to control quality of the X-rays by controlling material of an anode of an X-ray tube, tube voltage to be applied to the X-ray tube and a quality filter put in front of the X-ray tube, wherein
the quality controller controls quality of the X-rays in such a way that lower limit energy in an X-ray spectrum of the X-rays is over double characteristic X-ray energy of the X-ray detecting material.
5. The X-ray diagnosis apparatus according to claim 2 , further comprising:
an X-ray beam quality controller configured to control quality of the X-rays by controlling material of an anode of an X-ray tube, tube voltage to be applied to the X-ray tube and a quality filter put in front of the X-ray tube, wherein
the quality controller controls quality of the X-rays, upon the X-ray detecting material being formed by a plurality of elements, in such a way that lower limit energy in an X-ray spectrum of the X-rays is over double a highest value of characteristic X-ray energy of the plural elements.
6. The X-ray diagnosis apparatus according to claim 2 , further comprising:
an X-ray beam quality controller configured to control quality of the X-rays by controlling material of an anode of an X-ray tube, tube voltage to be applied to the X-ray tube and a quality filter put in front of the X-ray tube, wherein
the quality controller controls quality of the X-rays, upon the characteristic X-ray energy including first characteristic X-ray energy and second characteristic X-ray energy which is lower than the first characteristic energy and no other characteristic X-ray energy being between the first characteristic X-ray energy and the second characteristic X-ray energy, in such a way that lower limit energy in an X-ray spectrum of the X-rays is over double the second characteristic X-ray energy and that upper limit energy in the X-ray spectrum equals the first characteristic X-ray energy and below.
7. The X-ray diagnosis apparatus according to claim 2 , further comprising:
an X-ray beam quality controller configured to control quality of the X-rays by controlling material of an anode of an X-ray tube, tube voltage to be applied to the X-ray tube and a quality filter put in front of the X-ray tube, wherein
the quality controller controls quality of the X-rays, upon the X-ray detecting material being formed by a plurality of elements, the characteristic X-ray energy including first characteristic X-ray energy and second characteristic X-ray energy which is lower than the first characteristic energy and no other characteristic X-ray energy being between the first characteristic X-ray energy and the second characteristic X-ray energy, in such a way that lower limit energy in an X-ray spectrum of the X-rays is over double a highest value of the second characteristic X-ray energy of the plural elements and that upper limit energy in the X-ray spectrum equals a lowest value of the first characteristic X-ray energy of the plural elements and below.
8. An X-ray computed tomography apparatus having the photon counting type image detector according to claim 1 .
9. The X-ray computed tomography apparatus according to claim 8 , wherein
the controller performs control so as not to count the non-count pulses of the peak-discriminated electric pulses, the non-count pulses corresponding to the characteristic X-ray energy and corresponding to a difference between plural different energy values of characteristic X-rays produced in the X-ray detecting material.
10. The X-ray computed tomography apparatus according to claim 8 , further comprising:
an X-ray beam quality controller configured to control quality of the X-rays by controlling material of an anode of an X-ray tube, tube voltage to be applied to the X-ray tube and a quality filter put in front of the X-ray tube, wherein
the quality controller controls quality of the X-rays in such a way that lower limit energy in an X-ray spectrum of the X-rays is over double characteristic X-ray energy of the X-ray detecting material.
11. The X-ray computed tomography apparatus according to claim 8 , further comprising:
an X-ray beam quality controller configured to control quality of the X-rays by controlling material of an anode of an X-ray tube, tube voltage to be applied to the X-ray tube and a quality filter put in front of the X-ray tube, wherein
the quality controller controls quality of the X-rays, upon the X-ray detecting material being formed by a plurality of elements, in such a way that lower limit energy in an X-ray spectrum of the X-rays is over double a highest value of characteristic X-ray energy of the plural elements.
12. The X-ray computed tomography apparatus according to claim 8 , further comprising:
an X-ray beam quality controller configured to control quality of the X-rays by controlling material of an anode of an X-ray tube, tube voltage to be applied to the X-ray tube and a quality filter put in front of the X-ray tube, wherein
the quality controller controls quality of the X-rays, upon the characteristic X-ray energy including first characteristic X-ray energy and second characteristic X-ray energy which is lower than the first characteristic energy and no other characteristic X-ray energy being between the first characteristic X-ray energy and the second characteristic X-ray energy, in such a way that lower limit energy in an X-ray spectrum of the X-rays is over double the second characteristic X-ray energy and that upper limit energy in the X-ray spectrum equals the first characteristic X-ray energy and below.
13. The X-ray computed tomography apparatus according to claim 8 , further comprising:
an X-ray beam quality controller configured to control quality of the X-rays by controlling material of an anode of an X-ray tube, tube voltage to be applied to the X-ray tube and a quality filter put in front of the X-ray tube, wherein
the quality controller controls quality of the X-rays, upon the X-ray detecting material being formed by a plurality of elements, the characteristic X-ray energy including first characteristic X-ray energy and second characteristic X-ray energy which is lower than the first characteristic energy and no other characteristic X-ray energy being between the first characteristic X-ray energy and the second characteristic X-ray energy, in such a way that lower limit energy in an X-ray spectrum of the X-rays is over double a highest value of the second characteristic X-ray energy of the plural elements and that upper limit energy in the X-ray spectrum equals a lowest value of the first characteristic X-ray energy of the plural elements and below.