A system for non-invasive measurement of tissue oxygen concentration based on phosphorescence lifetime measurements, comprising: a light source ; a detector ; and a controller in electrical communication with the light source and the detector , the controller configured to execute a program stored in the controller to: (i) trigger the light source to emit a first pulse of light for illumination of a target , the first pulse of light having a first pulse duration; (ii) actuate the detector after a first delay time following emission of the first pulse of light to begin detecting a first signal from the target for a first detection time; (iii) calculate a current value relating to the quality or quantity of data; and (iv) repeat (i), (ii) and (iii) until the calculated current value is greater than or equal to a threshold signal, varying for each repetition at least one of the first pulse duration, the first delay time, and the first detection time, wherein the current value is calculated by averaging or otherwise aggregating the detected signal acquired from each of the previous repetitions, the controller further configured to output the detected signal, pulse duration, delay time, and detection time from each repetition to a computational device, and the computational device configured to utilize the detected signal, pulse duration, delay time, and detection time from each repetition to calculate a background intensity component and a phosphorescence decay component by exponential or linear fitting. a light source ; a detector ; and a controller in electrical communication with the light source and the detector , the controller configured to execute a program stored in the controller to: (i) trigger the light source to emit a first pulse of light for illumination of a target , the first pulse of light having a first pulse duration; (ii) actuate the detector after a first delay time following emission of the first pulse of light to begin detecting a first signal from the target for a first detection time; (iii) calculate a current value relating to the quality or quantity of data; and (iv) repeat (i), (ii) and (iii) until the calculated current value is greater than or equal to a threshold signal, varying for each repetition at least one of the first pulse duration, the first delay time, and the first detection time, wherein the current value is calculated by averaging or otherwise aggregating the detected signal acquired from each of the previous repetitions, (i) trigger the light source to emit a first pulse of light for illumination of a target , the first pulse of light having a first pulse duration; (ii) actuate the detector after a first delay time following emission of the first pulse of light to begin detecting a first signal from the target for a first detection time; (iii) calculate a current value relating to the quality or quantity of data; and (iv) repeat (i), (ii) and (iii) until the calculated current value is greater than or equal to a threshold signal, varying for each repetition at least one of the first pulse duration, the first delay time, and the first detection time, wherein the current value is calculated by averaging or otherwise aggregating the detected signal acquired from each of the previous repetitions, the controller further configured to output the detected signal, pulse duration, delay time, and detection time from each repetition to a computational device, and the computational device configured to utilize the detected signal, pulse duration, delay time, and detection time from each repetition to calculate a background intensity component and a phosphorescence decay component by exponential or linear fitting. <EOS>