Working storage management in medical imaging systems

Claim 1

In a medical imaging system including a medical image acquisition device, a working storage memory for short term storage of medical images, a display for displaying a medical image, a printer for printing a copy of a medical image, a long term memory for long term storage of medical images, and a data base for storing information about medical images stored in said working storage memory; the method of managing the capacity of said working storage memory to maintain the usage level of said working storage memory within selected limits, said method comprising the steps of: assigning to said working storage memory a high water mark storage capacity and a low water mark storage capacity less than said high water mark storage capacity; for each medical image stored in said working storage memory, storing in said data base, usage count data representing the usage count of each said stored medical image, and last access data representing the most recent time that said image has been accessed for display, printing, acquisition, or long term storage; wherein said usage count data is incremented, a) when a request is made to print a medical image stored in said working storage memory, or b) when a request is made to store a medical image from said medical image acquisition device in said working storage memory, or c) when a request is made to retrieve a medical image from said long term memory for storage in said working storage memory; and the usage count data is decremented, a) when a medical image is printed by said printer, or b) when a medical image is stored in said long term memory; and continuously monitoring the current storage capacity of said working storage memory by comparing said current storage capacity to said high water mark storage capacity, and if the current storage capacity exceeds said high water mark storage capacity, repeatedly deleting medical images from said working storage memory until said current storage equals or is less than said low water mark working storage; wherein said medical images are deleted according to the rule "delete the least recently accessed study with usage count equal to zero".