Apparatus and method for dual signal integration per channel

In a gamma camera system having a photomultiplier tube array wherein each photomultiplier tube within said array outputs a separate channel signal, a channel circuit comprising:

• a current to voltage converter circuit coupled to receive a channel signal from a particular photomultiplier tube and for generating a first output voltage signal in response thereto;
• a baseline voltage offset circuit coupled to receive said first output voltage signal from said current to voltage converter circuit, said baseline offset voltage circuit for increasing said voltage signal by a programmable baseline voltage offset amount to generate a second output voltage signal;
• an amplification circuit coupled to receive said second output voltage signal from said baseline voltage offset circuit, said amplification circuit for amplifying said voltage signal by a programmable gain amount;
• an analog to digital converter coupled to receive said third output voltage signal from said amplification circuit, said analog to digital converter for converting said third output voltage signal digitally to generate a digital signal;
• an integration circuit coupled to receive said digital signal from said analog to digital converter, said integration circuit further comprising:
• (i) a first integrator circuit coupled to said separate channel signal for integrating said separate channel signal over a first integration period;
• and
• (ii) a second integrator circuit coupled to said separate channel signal for independently integrating said separate channel signal over a second integration period.

A gamma camera system comprising:

• a detector comprising:
• a crystal layer for receiving gamma rays and for generating scintillation events in response thereto;
• and a photomultiplier array wherein each photomultiplier within said photomultiplier array outputs a separate channel signal;
• a plurality of integration circuits coupled to receive signals from said photomultiplier array wherein a particular integration circuit is coupled to receive a separate channel signal from a particular photomultiplier of said photomultiplier array in response to a gamma event, said particular integration circuit comprising:
• (i) a first integrator circuit coupled to said separate channel signal for integrating said separate channel signal over a first integration period;
• and
• (ii) a second integrator circuit coupled to said separate channel signal for integrating said separate channel signal over
• a second integration period;
• and
• a data processor for processing integration data output from said plurality of integration circuits, said data processor for generating a total energy value and spatial coordinate of said gamma event.

In a gamma camera system, a method of processing a signal from a photomultiplier tube array, said method comprising the steps of:

• receiving a particular channel signal associated with a particular photomultiplier tube of a photomultiplier tube array within a gamma detector;
• initiating a first integrator to integrate said particular channel signal over a first integration period by providing a first trigger signal in response to a first gamma event;
• initiating a second integrator to independently integrate said particular channel signal over a second integration period by providing a second trigger signal in response to a second gamma event, wherein said second trigger occurs within said first integration period;
• storing an integration result of said first integration period;
• and
• storing an integration result of said second integration period.

In a gamma camera system, a method of processing signals from a photomultiplier tube, said method comprising the steps of:

• receiving plurality of channel signals associated with a photomultiplier tube array within a gamma detector, wherein each photomultiplier tube of said photomultiplier tube array generates an individual channel signal;
• providing an individual first integrator and an individual second integrator for each channel signal;
• initiating each individual first integrator to integrate each channel signal over a first integration period by providing a first trigger signal in response to a first gamma event;
• initiating each individual second integrator to integrate each channel signal over a second integration period by providing a second trigger signal in response to a second gamma event, wherein said second trigger signal occurs within said first integration period;
• storing an integration result of said first integration period for each channel signal;
• and
• storing an integration result of said second integration period for each channel signal.