Simultaneous reconstruction of emission activity and attenuation coefficient distribution from TOF data, acquired with external shell source

A system for generating images from time of flight (TOF) data associated with a scan of at least one object using a positron emission tomography system, comprising:

• a processor;
• and
• a computer-readable medium having stored thereon instructions for causing the processor to perform the steps of:
• providing initial values for an activity image to yield a current activity image;
• estimating initial values for an attenuation map (μ-map) image based on the TOF data to yield a current μ-map image;
• repeating, until at least one termination condition is met, the steps of:
• updating the current activity image based on at least the current μ-map and a first update algorithm, and
• updating the current μ-map image based on at least on the updated activity image and a second update algorithm,
• outputting an image of the at least one object based on the current μ-map and the current activity image.

A non-transitory computer-readable medium having stored thereon a computer program with a plurality of instructions for causing a computing device to perform the method comprising:

• providing initial values for an activity image to yield a current activity image;
• estimating initial values for an attenuation map (μ-map) image based on the TOF data to yield a current μ-map image;
• repeating, until at least one termination condition is met, the steps of:
• updating the current activity image based on at least the current μ-map and a first update algorithm, and
• updating the current μ-map image based on at least on the updated activity image and a second update algorithm,
• outputting an image of the at least one object based on the current μ-map and the current activity image.