What has changed to make SPDT a more attractive therapy option today?

What has changed to make SPDT a more attractive therapy option today?

The development of new sensitizers with the following characteristics:

• Increased selectivity; they are taken up almost exclusively by cancer cells. This allows treatment of the whole body, rather than limiting the therapy to small, local areas (with the risk of not treating some metastases at all).
• Less toxicity.
• Oral administration (as opposed to intramuscular or intravenous injection).
• Rapid clearance from normal cells, thus avoiding sensitivity to ambient light.
• Increased potency-greater oxygen radical production.
• Increased penetration depth, because they absorb at longer (red and infra-red) wavelengths.
• Greater understanding of mechanisms of action(3),(10).