Photodynamic tumour therapy

Tissue transillumination experiments allow multi-spectral determination of tissue optical constants and light fluxes, with application to optical mammography [51], photodynamic tumour therapy [52,53] and brain oxygenation measurements... 

Porphyrinoids (porphyrin analogues, porphyrin homologues and porphyrin vinylogues [31]), like porphyrins, are of interest as sensitizers in photodynamic tumour therapy [32]. Some of these systems, e.g. 41 - 43 have been synthesized (Franck, Vogel 1990) [33]. Their nomenclature takes into account the cyclic conjugation of the annulene perimeter and the number of methine groups between the four pyrrole units, e.g. porphyrin 1 is described as [18]porphyrin(l.l.l.l) porphycin 43, which is isomeric with porphyrin, is known as [18]porphyrin(2.0.2.0). 

Bistolfi F (2000) Red radioluminescence and radiochemiluminescence premises for a photodynamic tumour therapy with X-rays and haematoporphyrin derivatives. A working hypothesis. Panminerva medica 42(1) 69—75... 

Busetti, A., Soncin, M., Jori, G., and Rodgers, M.A.J., Treatment of malignant melanoma by high-peak-power 1064 nm irradiation followed by photodynamic therapy, Br. J. Cancer, 79, 821,1999. Jori, G. and Spikes, J.D., Photothermal sensitizers possible use in tumour therapy,. Photochem. Photobiol, B Biol, 6, 93, 1990. 

Photodynamic therapy for the treatment of tumours involves the selective uptake and retention of a highly-coloured porphyrin sensitiser (Figure 6.17) in the tumour. Irradiation by a laser with a wavelength corresponding to the absorption maximum of the porphyrin (D) causes excitation of the porphyrin to the excited singlet state. 

Ochsner M (1997) Photophysical and photobiological processes in the photodynamic therapy of tumours. J Photochem Photobiol B 39 1-18. 

Le Doan T, Perrouault L, Rougee M, Bensasson RV, Helene C (1985) In Jori G, Perria C (eds) Photodynamic Therapy of Tumours and other Diseases, Libreria Progetto, Padova, p 56... 

Figure 4.21 Outline of photodynamic therapy (PDT) treatment of tumours.

As shown in Fig. 7.6, texaphyrins have a larger cavity than porphyrins so they can form complexes with lanthanide metals such as gadolinium (XCYTRIN ), that enhances the efficacy of treatment for certain brain tumours, and lutetium (LUTRIN ), used as a sensitizer for photodynamic therapy of recurrent breast cancer [17], Crucial to their success is the increased number of donor atoms available as the more lanthanide binding sites that a ligand can satisfy, the more stable the complex. 

II 000 cm-1). Nevertheless, the photophysics of lanthanide porphyrinates is attractive because it could be of great help in medicine. For instance, hematoporphyrin derivatives are known to accumulate in malignant tumours and are used in medical diagnosis and photodynamic therapy of cancer. It is noteworthy that the Yb(III) complex with meso-tetra(3-pyridyl)porphyrin displays a substantial quantum yield (1.4%) when inserted into micelles formed by the non-ionic surfactant Triton X-100, a medium that can be considered as a model for biological tissues. 

Singlet oxygen is used in the treatment of cancer by photosensitization (photodynamic therapy). This involves treatment with certain porphyrin derivatives which localize preferentially in the tumour, fol-... 

Gadolinium texaphyrin (Gd-tex Figure 4.8) is reported to be an effective radiation sensitizer for tumour cells, whilst the corresponding lutetium compound, which absorbs light in the far-red end of the visible spectrum, is in Phase II trials for photodynamic therapy for brain tumours and breast cancer. 

Ferguson, M.W. (1998) Photophysical and photochemical properties of photosensitizers for photodynamic therapy of tumours, Ph.D. thesis, University of Wales. 

Photodynamic therapy (PDT) is a treatment that is used for the destruction of certain types of tumours, and is based on the administration of a photosensitizer that concentrates in tumour cells and, upon subsequent irradiation with visible light in the presence of oxygen, selectively destroys the cancerous cells. Wei et al. reported the thermal stability, melting temperature, enthalpy of fusion and thermal decomposition kinetics of porphyrins and their nickel complexes [205]. 

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