Patent ID: 8483468

Claim:
An apparatus for determining cerebral blood flow, comprising a processor and a memory, wherein the memory storing program instructions causing the apparatus, by being executed by the processor, to: obtain second nuclear-medicine-brain-imaging-data resulting from a second radioisotope-drug-injection; obtain values required for a formula that is used in the following formulas (1) or (2) among t 3 which is the time when the second radioisotope-drug-injection took place, t 5 which is the time when acquisition of the second nuclear-medicine-brain-imaging-data started, and t 6 which is the time when acquisition of the second nuclear-medicine-brain-imaging-data finished, wherein obtaining is conducted by searching within the second nuclear-medicine-brain-imaging-data or by reading out the values from corresponding storages respectively; obtain, respectively from corresponding storages, a standard input function S(t) which is a function representing temporal changes in inflow of a radioisotope medicine into a standard brain, mC f which is a scaling factor, V d which is a cerebral-blood-distribution-coefficient, and k 1 which represents the cerebral blood flow generated in a certain cerebral region corresponding to the first radioisotope-drug-injection performed prior to the second radioisotope-drug-injection; seek, utilizing the following formula (1) or (2), k 1d which represents cerebral blood flow generated in a certain cerebral region corresponding to the second radioisotope-drug-injection; and B d ⁡ ( t ) = k 1 ⁢ ⅇ - k 2 ⁢ t 3 ⁢ mC f ⁢ ∫ t 0 t 3 ⁢ S ⁡ ( τ ) ⁢ ⅇ k 2 ⁢ τ ⁢ ⅆ τ ⁡ ( ⅇ - k 2 ⁢ d ⁡ ( t - t 3 ) ) + k 1 ⁢ d ⁢ mC f ⁢ ∫ t 3 t ⁢ ( S ⁡ ( τ ) + S ⁡ ( τ - t 3 ) ) · ⅇ - k 2 ⁢ d · ( t - τ ) ⁢ ⅆ τ ⁡ ( t ≥ t 3 ) ( 1 ) ∫ t 5 t 6 ⁢ B d ⁡ ( t ) ⁢ ⅆ t = k 1 k 2 ⁢ d ⁢ ⅇ - k 2 ⁢ t 3 ⁢ mC f ⁢ ∫ t 0 t 3 ⁢ S ⁡ ( τ ) ⁢ ⅇ k 2 ⁢ τ ⁢ ⅆ τ · ( ⅇ - k 2 ⁢ d ⁡ ( t 5 - t 3 ) - ⅇ - k 2 ⁢ d ⁡ ( t 6 - t 3 ) ) + ∫ t 5 t 6 ⁢ k 1 ⁢ d ⁢ mC f ⁢ ∫ t 3 t ⁢ ( S ⁡ ( τ ) + S ⁡ ( τ - t 3 ) ) · ⅇ - k 2 ⁢ d · ( t - τ ) ⁢ ⅆ τ ⁢ ⅆ t ⁡ ( t ≥ t 3 ) ( 2 ) output the sought cerebral blood flow k 1d ; wherein B d (t) in formula (1) or (2) is a radiation count obtained from the second nuclear-medicine-brain-imaging-data and is a radiation count of the certain cerebral region at a time of t, t 0 is the time when the first radioisotope-drug-injection took place, k 2 is the blood-outflow-rate-constant of brain tissues in the certain cerebral region corresponding to a first radioisotope-drug-injection, where k 2 =k 1 /V d , and k 2d is the blood-outflow-rate-constant of brain tissues in the certain cerebral region corresponding to the second radioisotope-drug-injection, where k 2d =k 1d /V d .