In vivo quantification of photosensitizer concentration using fluorescence differential path-length spectroscopy: influence of photosensitizer formulation and tissue location.
In vivo measurement of photosensitizer concentrations may optimize clinical photodynamic therapy (PDT). Fluorescence differential path-length spectroscopy (FDPS) is a non-invasive optical technique that has been shown to accurately quantify the concentration of Foscan® in rat liver. As a next step towards clinical translation, the effect of two liposomal formulations of mTHPC, Fospeg® and Foslip®, on FDPS response was investigated. Furthermore, FDPS was evaluated in target organs for head-and-neck PDT. Fifty-four healthy rats were intravenously injected with one of the three formulations of mTHPC at 0.15 mg kg(-1). FDPS was performed on liver, tongue, and lip. The mTHPC concentrations estimated using FDPS were correlated with the results of the subsequent harvested and chemically extracted organs. An excellent goodness of fit (R(2)) between FDPS and extraction was found for all formulations in the liver (R(2)=0.79). A much lower R(2) between FDPS and extraction was found in lip (R(2)=0.46) and tongue (R(2)=0.10). The lower performance in lip and in particular tongue was mainly attributed to the more layered anatomical structure, which influences scattering properties and photosensitizer distribution.
University Medical Center Groningen, Department of Oral and Maxillofacial Surgery, Division of Oncology, The Netherlands. s.a.h.j.de.visscher@umcg.nl
Sebastiaan A H J
SA
de Visscher
Max J H
MJ
Witjes
Slávka
S
Kascáková
Henricus J C M
HJ
Sterenborg
Dominic J
DJ
Robinson
Jan L N
JL
Roodenburg
Arjen
A
Amelink
D000268:Adhesiveness; D000818:Animals; D008027:Light; D008046:Lip / Q000473:pathology; D008081:Liposomes / Q000737:chemistry; D008099:Liver / Q000473:pathology; D008297:Male; D008652:Mesoporphyrins / Q000737:chemistry*; D018613:Microscopy, Confocal / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012044:Regression Analysis; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014059:Tongue / Q000473:pathology
D008081:Liposomes; D008652:Mesoporphyrins; D017319:Photosensitizing Agents; C072269:temoporfin