An effective amount of {HEAD ~ a photosensitive agent} for {TAIL ~ PDT} is administered to a patient 
An effective amount of { HEAD ~ a photosensitive agent } for { TAIL ~ PDT } is administered to a patient
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH