Methods and compounds for the measurement in vivo of oxygen in living tissue. The compounds preferably comprise a substituted porphyrin which is soluble in aqueous solution which is capable of absorbing an amount of energy and subsequently releasing the energy as phosphorescent light. In preferred embodiments,...http://www.google.com.au/patents/US6362175?utm_source=gb-gplus-sharePatent US6362175 - Porphyrin compounds for imaging tissue oxygen
