Highly specific tissue imaging

A method of imaging comprising:

• (a) disposing a population of first targeting ultrasound-switchable fluorophores and a population of second non-targeting ultrasound-switchable fluorophores in an environment;
• (b) exposing the environment to an ultrasound beam to create an activation region within the environment;
• (c) disposing the populations of first targeting fluorophores and the second non-targeting fluorophores within the activation region to switch the first targeting fluorophores and the second non-targeting fluorophores from an off state to an on state;
• (d) exposing the activation region with one or more beams of electromagnetic radiation, thereby exciting the population of first targeting fluorophores and second non-targeting fluorophores;
• (e) detecting a first photoluminescence signal emitted by the population of first targeting fluorophores, and a second photoluminescence signal emitted by the population of second non-targeting fluorophores;
• (f) determining a photoluminescence property of the population of second non-targeting fluorophores from the second photoluminescence signal;
• and
• (g) using the determined photoluminescence property of the population of second non-targeting fluorophores to deconvolute the first photoluminescence signal into the population of first targeting fluorophores bound and unbound to a first target binding element in the environment.