Determining PET scanning time

1. A method for determining PET scanning time, comprising:

performing a CT scan with a CT device to obtain a CT image of a subject;

dividing the CT image into multiple single-bed CT images according to bed information corresponding to different positional segments of multiple beds of a PET scan, wherein each of the multiple single-bed CT images corresponds to the bed information of one of the multiple beds of the PET scan;

obtaining initial PET data, an attenuation correction factor, and a scattering correction factor for each of the multiple beds of the PET scan based on the corresponding single-bed CT image of the bed, wherein obtaining the scattering correction factor for each of the multiple beds of the PET scan based on the corresponding single-bed CT image of the bed comprises:

obtaining an initial PET image by performing a binarization process on the corresponding single-bed CT image;

obtaining an analogue attenuation PET image by performing an attenuation process on the initial PET image with the attenuation correction factor; and

obtaining the scattering correction factor by performing a uniform sampled single scattering simulation on the analogue attenuation PET image;

determining a residual true coincidence count ratio for each of the multiple beds of the PET scan according to the initial PET data, the attenuation correction factor, and the scattering correction factor for the bed;

determining a scanning time proportion for each of the multiple beds of the PET scan based on the residual true coincidence count ratio for each of the multiple beds of the PET scan;

setting up respective scanning times for the multiple beds of the PET scan based on the scanning time proportion; and

performing the PET scan with a PET device in accordance with the respective scanning times for the multiple beds of the PET scan.

2. The method according to claim 1 , wherein said obtaining the initial PET data for each of the multiple beds of the PET scan based on the corresponding single-bed CT image of the bed comprises:

obtaining the initial PET image by performing the binarization process on the corresponding single-bed CT image; and

taking image data of the initial PET image as the initial PET data.

3. The method according to claim 1 , wherein said obtaining the attenuation correction factor for each of the multiple beds of the PET scan based on the corresponding single-bed CT image of the bed comprises:

obtaining a linear attenuation coefficient image by converting each CT value of the corresponding single-bed CT image into a linear attenuation coefficient at a particular energy; and

obtaining the attenuation correction factor by means of orthographic projection of the linear attenuation coefficient image.

4. The method according to claim 1 , wherein said obtaining the initial PET image by performing the binarization process on the corresponding single-bed CT image comprises:

dividing the corresponding single-bed CT image into an air part and a non-air part, and

performing the binarization process on the corresponding single-bed CT image in a condition that all kinds of tissue corresponding to the non-air part have a same activity concentration distribution.

5. The method according to claim 1 , wherein said determining the residual true coincidence count ratio for each of the multiple beds of the PET scan according to the initial PET data, the attenuation correction factor, and the scattering correction factor for the bed comprises:

determining the residual true coincidence count ratio for each of the multiple beds of the PET scan by performing a calculation with the following formula:

λ=( E−S )/( A*E ),

wherein E denotes the initial PET data of one of the multiple beds of the PET scan,

S denotes the scattering correction factor of the bed,

A denotes the attenuation correction factor of the bed, and

λ denotes the residual true coincidence count ratio of the bed.

6. The method according to claim 1 , wherein said determining the scanning time proportion for each of the multiple beds of the PET scan based on the residual true coincidence count ratio for each of the multiple beds of the PET scan comprises:

calculating a reciprocal for the residual true coincidence count ratio; and

setting the scanning time proportion for each of the multiple beds of the PET scan to be equal to the reciprocal of the corresponding residual true coincidence count ratio of the bed.

7. The method according to claim 1 , further comprising:

determining a scattering impact factor for each of the multiple beds of the PET scan according to the initial PET data and the scattering correction factor of the bed; and

adjusting the scanning time proportion for each of the multiple beds of the PET scan with the scattering impact factor of each of the multiple beds of the PET scan.

8. The method according to claim 7 , wherein said adjusting the scanning time proportion for each of the multiple beds of the PET scan with the scattering impact factor of each of the multiple beds comprises:

calculating the scanning time proportion for each of the multiple beds of the PET scan with the following formula:

τ=1 /λ+α*S /( E−S ),

wherein E denotes the initial PET data of one of the multiple beds of the PET scan,

S denotes the scattering correction factor of the bed,

α denotes an empirical constant,

λ denotes the residual true coincidence count ratio of the bed, and

the τ denotes the scanning time proportion of the bed.

9. An apparatus for determining PET scanning time, comprising a processor configured to read and execute machine-executable instructions which correspond to a control logic for determining the PET scanning time and are stored in a machine-readable storage medium, wherein the machine-executable instructions cause the processor to:

perform a CT scan with a CT device to obtain a CT image of a subject;

divide the CT image into multiple single-bed CT images according to bed information corresponding to different positional segments of multiple beds of a PET scan, wherein each of the multiple single-bed CT images corresponds to bed information of one of the multiple beds of the PET scan;

obtain initial PET data, an attenuation correction factor, and a scattering correction factor for each of the multiple beds of the PET scan based on the corresponding single-bed CT image of the bed, wherein when obtaining the scattering correction factor for each of the multiple beds of the PET scan based on the corresponding single-bed CT image of the bed, the machine-executable instructions cause the processor to:

obtain an initial PET image by performing a binarization process on the corresponding single-bed CT image;

obtain an analogue attenuation PET image by performing an attenuation process on the initial PET image with the attenuation correction factor; and

obtain the scattering correction factor by performing a uniform sampled single scattering simulation on the analogue attenuation PET image;

determine a residual true coincidence count ratio for each of the multiple beds of the PET scan according to the initial PET data, the attenuation correction factor, and the scattering correction factor for the bed;

determine a scanning time proportion for each of the multiple beds of the PET scan based on the residual true coincidence count ratio for each of the multiple beds of the PET scan;

set up respective scanning times for the multiple beds of the PET scan based on the scanning time proportion; and

perform the PET scan with a PET device in accordance with the respective scanning times for the multiple beds of the PET scan.

10. The apparatus according to claim 9 , wherein, when obtaining the initial PET data for each of the multiple beds of the PET scan based on the corresponding single-bed CT image of the bed, the machine-executable instructions cause the processor to:

obtain the initial PET image by performing the binarization process on the corresponding single-bed CT image; and

take image data of the initial PET image as the initial PET data.

11. The apparatus according to claim 9 , wherein when obtaining the attenuation correction factor for each of the multiple beds of the PET scan based on the corresponding single-bed CT image of the bed, the machine-executable instructions cause the processor to:

obtain a linear attenuation coefficient image by converting each CT value of the corresponding single-bed CT image into a linear attenuation coefficient at a particular energy; and

obtain the attenuation correction factor by means of orthographic projection of the linear attenuation coefficient image.

12. The apparatus according to claim 9 , wherein, when obtaining the initial PET image by performing the binarization process on the corresponding single-bed CT image, the machine-executable instructions cause the processor to:

divide the corresponding single-bed CT image into an air part and a non-air part, and

perform the binarization process on the corresponding single-bed CT image in a condition that all kinds of tissue corresponding to the non-air part have a same activity concentration distribution.

13. The apparatus according to claim 9 , wherein, when determining the residual true coincidence count ratio for each of the multiple beds of the PET scan according to the initial PET data, the attenuation correction factor, and the scattering correction factor for the bed, the machine-executable instructions cause the processor to:

determine the residual true coincidence count ratio for each of the multiple beds of the PET scan by performing a calculation with the following formula:

λ=( E−S )/( A*E ),

wherein E denotes the initial PET data of one of the multiple beds of the PET scan,

S denotes the scattering correction factor of the bed,

A denotes the attenuation correction factor of the bed, and

λ denotes the residual true coincidence count ratio of the bed.

14. The apparatus according to claim 9 , wherein, when determining the scanning time proportion for each of the multiple beds of the PET scan based on the residual true coincidence count ratio for each of the multiple beds of the PET scan, the machine-executable instructions cause the processor to:

calculate a reciprocal for each of the residual true coincidence count ratios; and

set the scanning time proportion for each of the multiple beds of the PET scan to be equal to the reciprocal of the corresponding residual true coincidence count ratio of the bed.

15. The apparatus according to claim 9 , wherein the machine-executable instructions further cause the processor to:

determine a scattering impact factor for each of the multiple beds of the PET scan according to the initial PET data and the scattering correction factor of the bed; and

adjust the scanning time proportion for each of the multiple beds of the PET scan with the scattering impact factor of each of the multiple beds of the PET scan.

16. The apparatus according to claim 15 , wherein, when adjusting the scanning time proportion for each of the beds with the scattering impact factor of each of the multiple beds of the PET scan, the machine-executable instructions cause the processor to:

calculate the scanning time proportion for each of the multiple beds of the PET scan with the following formula:

τ=1/λ+α* S/ ( E−S ),

wherein E denotes the initial PET data of one of the multiple beds,

S denotes the scattering correction factor of the bed,

α denotes an empirical constant,

λ denotes the residual true coincidence count ratio of the bed, and

τ denotes the scanning time proportion of the bed.