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Effect of photodynamic therapy on RIF‐1 tumor metabolism and blood flow examined by 31 P and 2 H NMR spectroscopy
Author(s) -
Mattiello James,
Evelhoch Jeffrey L.,
Brown Eileen,
Schaap A. Paul,
Hetzel Fred W.
Publication year - 1990
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940030204
Subject(s) - nuclear magnetic resonance spectroscopy , spectroscopy , chemistry , nuclear magnetic resonance , photodynamic therapy , blood flow , radiochemistry , physics , medicine , organic chemistry , quantum mechanics
Photodynamic therapy utilizes the tumor localizing drug dihematoporphyrin ether and red laser light to produce both direct tumor cell destruction via damage to mitochondrial membranes, and also indirect cell kill via destruction of the tumor vasculature. As a first step towards examining the mechanistic relationship between metabolic and vascular effects of photodynamic therapy, murine RIF‐1 tumors were treated with a subcurative treatment (500J/cm 2 ). Tumor metabolic status was monitored using in vivo 31 P NMR before, during and after the treatment. The tumor blood flow immediately before and after treatment was measured by direct intratumor injection of D 2 O saline and observation of the tracer signal clearance from the tumor via 2 H NMR. During the photodynamic therapy treatment, significant decreases were observed for the nucleoside triphosphate concentrations, tumor pH and tumor blood flow, while inorganic phosphate concentrations increased. Animals treated with laser light alone and those not given any treatment, demonstrated no significant changes in tumor metabolic status, tumor pH or tumor blood flow. Further studies are required to determine whether tumor blood flow or metabolic status is affected first.