Search

The maximum rate at which the light dose may be delivered during interstitial photodynamic therapy (PDT) has been measured for several types of delivery fibre. Measurements of light irradiance at the skin surface overlying subcutaneous experimental tumours were made during interstitial irradiation by 200Μm core diameter fibres whose output ends were either plane-cut or 5 mm long cylindrical diffusers. For plane-cut fibres, a rapid fall in light transmission, due to blood coagulation at the fibre tip, was observed at output powers greater than 229 mW and 104 mW in tumours with and without photosensitizer, respectively. Such a rapid fall was not observed with cylindrical diffusing fibres at output powers up to 1 W.

Abstract: Three cases of secondary amyloidosis are reported, two in patients who had unequivocal Crohn's disease and one in whom the clinical course was that of Crohn's disease, but with histologic findings that were more suggestive of ulcerative colitis. All had evidence of renal failure. A prospective study of 177 patients with inflammatory bowel disease of greater than five years' duration was carried out in an attempt to establish the incidence of secondary amyloidosis, using rectal biopsy and simple renal function tests. No new cases were found. Neither was there evidence of renal failure due to other conditions. In the absence of renal dysfunction, a search for secondary amyloidosis probably is not justified.

Abstract: Skin photosensitivity remains the major side-effect of current clinical photodynamic therapy using porphyrin based drugs. We have studied the usefulness of oral activated charcoal in 12 patients undergoing photodynamic therapy and a control group of patients treated without charcoal. Detailed pharmacokinetic studies were carried out and measurements of skin erythema responses to known light doses were made using a reflectance spectrophotometer in these patients. There were no significant differences with respect to the area under the curve, clearance, mean residence time or half-life of the drug between the two groups and no significant differences in reflectance values. Prolonged skin photosensitivity as assessed by reflectance spectrophotometry was confirmed up to and beyond 2 months after treatment.

The risk of carcinogenesis from radiation exposure is well known. It has been questioned for some time therefore, whether it is wise to treat benign disease with radiotherapy. We report a case of a patient who developed bilateral breast carcinomas almost 30 years after treatment of chest wall keloids with radiotherapy. There are only anecdotal reports in the literature of malignancies following treatment of keloids with radiotherapy. We review these reports and discuss the safety of this approach to the management of keloid scars.