In-vivo optical detection of cancer using chlorin e6--polyvinylpyrrolidone induced fluorescence imaging and spectroscopy.
BACKGROUND
Photosensitizer based fluorescence imaging and spectroscopy is fast becoming a promising approach for cancer detection. The purpose of this study was to examine the use of the photosensitizer chlorin e6 (Ce6) formulated in polyvinylpyrrolidone (PVP) as a potential exogenous fluorophore for fluorescence imaging and spectroscopic detection of human cancer tissue xenografted in preclinical models as well as in a patient.


METHODS
Fluorescence imaging was performed on MGH human bladder tumor xenografted on both the chick chorioallantoic membrane (CAM) and the murine model using a fluorescence endoscopy imaging system. In addition, fiber optic based fluorescence spectroscopy was performed on tumors and various normal organs in the same mice to validate the macroscopic images. In one patient, fluorescence imaging was performed on angiosarcoma lesions and normal skin in conjunction with fluorescence spectroscopy to validate Ce6-PVP induced fluorescence visual assessment of the lesions.


RESULTS
Margins of tumor xenografts in the CAM model were clearly outlined under fluorescence imaging. Ce6-PVP-induced fluorescence imaging yielded a specificity of 83% on the CAM model. In mice, fluorescence intensity of Ce6-PVP was higher in bladder tumor compared to adjacent muscle and normal bladder. Clinical results confirmed that fluorescence imaging clearly captured the fluorescence of Ce6-PVP in angiosarcoma lesions and good correlation was found between fluorescence imaging and spectral measurement in the patient.


CONCLUSIONS
Combination of Ce6-PVP induced fluorescence imaging and spectroscopy could allow for optical detection and discrimination between cancer and the surrounding normal tissues. Ce6-PVP seems to be a promising fluorophore for fluorescence diagnosis of cancer.
Chin
William W L
WW
Division of Medical Sciences, National Cancer Centre Singapore, Singapore. chin.will@gmail.com
Thong
Patricia S P
PS
Bhuvaneswari
Ramaswamy
R
Soo
Khee Chee
KC
Heng
Paul W S
PW
Olivo
Malini
M
D000818:Animals; D045744:Cell Line, Tumor; D002642:Chick Embryo; D002735:Chlorophyllides; D049033:Chorioallantoic Membrane / Q000473:pathology*; D004195:Disease Models, Animal; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008856:Microscopy, Fluorescence / Q000379:methods*; D011166:Porphyrins; D011205:Povidone / Q000032:analysis; D011524:Protoporphyrins / Q000032:analysis; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D001749:Urinary Bladder Neoplasms / Q000473:pathology*
D002735:Chlorophyllides; D011166:Porphyrins; D011524:Protoporphyrins; C062985:phytochlorin; D011205:Povidone