Tissue Distribution of BacteriochlorinaLabelled with^99mTc-pertechnetate in Hamster Greene Melanoma

Abstract

Bacteriochlorin a (BCA), a new photosensitizer for photodynamic therapy, was labelled with 99mTc-pertechnetate following a method for the irreversible coupling of 99mTc-pertechnetate to proteins. Biodistribution studies were conducted in male Syrian Golden hamsters with hamster Greene melanoma implanted s.c. on both sides of the abdomen. After i.v. administration of 99mTc-pertechnetate-labelled BCA 17 tissue and fluid samples were analysed at time intervals ranging from 1 to 24 h. Technetium-labelled BCA showed a pronounced affinity for tissues belonging to the reticuloendothelial system. Peak activities, 1 h post-injection, were distributed as follows: lung, liver, spleen, urine > small intestine, kidney, blood, heart, stomach, large intestine > thyroid, tumour, bone, skin, muscle, eye >> brain. It is concluded that the technetium-labelled photosensitizer BCA does not accumulate selectively in neoplastic tissue.

The Effects of Photodynamic Therapy on Human Neutrophil Migration Using Bacteriochlorin a

“…Typically, illumination of tumors occurs immediately after BCA administration or within 1-2 h, viz. when plasma levels are high (14). Rovers et al, extracting BCA from liver metastases 1 h after administration of the dye, found a value of 17.55 ?…”

Metal Complexes as Photo- and Radiosensitizers

“…Tumors in different animal models were clearly visualized by scintigraphy using this preparation. Similar reaction conditions with bacteriochlorin-a, a potent long-wavelength photosensitizer, and 99m Tc either as TcO 4 - or TcO 2 failed to yield labeled products, probably due to the constraint space of the macrocycle cavity 7 …”

Increase of the photosensitizing efficiency of the Bacteriochlorin a by liposome-incorporation

“…In vivo experiments have Photodynamic therapy (PDT) is an attractive method for shown that BCA has good tumor localizing properties and, the treatment of certain malignant tumors. The treatment is upon irradiation, is able to induce the destruction of tumors based on the retention of photosensitizers by cancerous [3][4][5][6]. tissues in combination with oxygen and light irradiation.…”