X-ray CT apparatus
View Patent ↗An X-ray CT apparatus is provided with an X-ray tube current modulation pattern calculation means that calculates an X-ray tube current modulation pattern based on a 3-dimensional model of an object calculated based on a scanogram image of the object, start-up shape acquisition means that acquires a start-up shape of CT values of a predetermined region of the object or CT value time differences after injecting contrast agent into the object, time contrast curve prediction means that predicts a time contrast curve indicative of a time sequential change of contrast in a diagnostic portion of the object at each slice position at a scan time based on the acquired start-up shape of the CT values or CT value time differences, object 3-dimensional model modification means that modifies a 3-dimensional model of the object based on the predicted time contrast curve, and X-ray tube electric current modulation pattern modification means that modifies the X-ray tube electric current modulation pattern based on the modified 3-dimensional model of the object.
1. An X-ray CT apparatus comprising:
an X-ray source configured to irradiate an X-ray while rotating around an object to be examined;
an X-ray detector disposed facing the X-ray source placing the object therebetween, configured to detect the X-ray dose transmitted through the object;
image reconstruction means configured to reconstruct a tomographic image of the object based on the detected X-ray dose;
display means configured to display the tomographic image,
characterized in further comprising:
X-ray tube current modulation pattern calculation means configured to calculate the X-ray tube current modulation pattern based on a 3-dimensional model of the object calculated based on a scanogram image of the object;
start-up shape acquisition means configured to acquire a start-up shape of the CT values or the CT value time difference in a predetermined region of the object after injecting contrast agent into the object;
time contrast curve prediction means configured to predict a time contrast curve indicating time series variation of the contrast in a diagnostic region of the object with respect to each slice position upon scanning, based on the start-up shape of the acquired CT values or the CT value time difference;
object 3-dimensional model modification means configured to modify the 3-dimensional model of the object based on the predicted time contrast curve; and
X-ray tube current modulation pattern modification means configured to modify the X-ray tube current modulation pattern based on the modified object 3-dimensional model.
2. The X-ray CT apparatus according to claim 1 , wherein the start-up shape acquisition means acquires a start-up shape of the CT values or the CT value time difference by executing monitoring scan in the upstream position of a diagnostic region of the object.
3. The X-ray CT apparatus according to claim 2 , the time contrast curve prediction means has standard data of the time contrast curve, and predicts the time contrast curve by modifying the standard data of the time contrast curve based on information on irradiation condition of the X-ray and/or information on the object.
4. The X-ray CT apparatus according to claim 2 , wherein the X-ray tube current modulation pattern calculation means or the X-ray tube current modulation pattern modification means calculates or modifies the X-ray tube current modulation pattern based on the set image target value.
5. The X-ray CT apparatus according to claim 2 , wherein the X-ray tube current modulation pattern calculation means or the X-ray tube current modulation pattern modification means determines an X-ray tube current amplitude or an X-ray tube current maximum value based on the X-ray tube voltage to be applied to the X-ray source.
6. The X-ray CT apparatus according to claim 1 , the time contrast curve prediction means has standard data of the time contrast curve, and predicts the time contrast curve by modifying the standard data of the time contrast curve based on information on irradiation condition of the X-ray and/or information on the object.
7. The X-ray CT apparatus according to claim 6 , wherein the X-ray tube current modulation pattern calculation means or the X-ray tube current modulation pattern modification means calculates or modifies the X-ray tube current modulation pattern based on the set image target value.
8. The X-ray CT apparatus according to claim 6 , wherein the X-ray tube current modulation pattern calculation means or the X-ray tube current modulation pattern modification means determines an X-ray tube current amplitude or an X-ray tube current maximum value based on the X-ray tube voltage to be applied to the X-ray source.
9. The X-ray CT apparatus according to claim 1 , wherein the X-ray tube current modulation pattern calculation means or the X-ray tube current modulation pattern modification means calculates or modifies the X-ray tube current modulation pattern based on the set image target value.
10. The X-ray CT apparatus according to claim 9 , wherein the X-ray tube current modulation pattern calculation means or the X-ray tube current modulation pattern modification means determines an X-ray tube current amplitude or an X-ray tube current maximum value based on the X-ray tube voltage to be applied to the X-ray source.
11. The X-ray CT apparatus according to claim 1 , wherein the X-ray tube current modulation pattern calculation means or the X-ray tube current modulation pattern modification means determines an X-ray tube current amplitude or an X-ray tube current maximum value based on the X-ray tube voltage to be applied to the X-ray source.