Conventional red-light PDT of facial BCC’s has a lower clearance-rate compared to other sites. During photoactivation, we've noted that faces tend to flush more than other sites so we postulated that haemoglobin may be acting as a competing-chromophore.
Removing blood whilst delivering light is achieved when the treatment area is compressed during emission with an IPL-head. A new issue of oxygen shortfall is created though, because high-fluence photoactivation requires abundant oxygen.
We propose that oxygen deficiency can be overcome with a period of red-light photoactivation performed immediately prior to the IPL-emission. During photoactivation some oxygen is consumed but hyperaemia occurs and heat develops. Heat will dissociate oxygen from haemoglobin. A net increase in pO2 may result.
During the IPL emission, filters can be selected to include stronger photoactivating wavelengths in the green-yellow spectra. Increased penetration and increased scattering of light from collagen occurs when tissue is drained of blood. Removing blood should specifically result in increased delivery of light to peripheral-cells of BCC nodules. They are likely important growth cells and are located close to vessels.
Since 2018, we have been treating thin BCCs (<2mm) using a modified photodynamic protocol where photoactivation is performed using Aktilite immediately followed by IPL applied with enough mechanical pressure to blanch the lesion. Optical-coherence-tomography has been used to establish tumour depth, and to verify tumour removal in most cases.
In our initial series of 36 BCCs (most were nodular, most were facial) there have been 2 incomplete clearances at a mean 24-month follow-up.