Clinical experience with the integral photodynamic theraphy of bladder carcinoma.

Photodynamic therapy PDT was given to 20 patients who had recurring superficial tumours after unsuccessful application of other treatments. The phototherapeutic results were evaluated by check-ups at 3 month intervals (endoscopy, cytology, bladder mapping, renal ultrasonography) and computed tomography (CT) examination at 8-13 month intervals. In six patients treated with PDT no tumour recurrence was found over the whole observation period up to nearly 5 years. Four patients remained free of tumour (12 and 14 months) after repeated transurethral resection (TUR) and Nd:YAG laser therapy following PDT. Due to an initial application of insufficient irradiation, four patients required a second photodynamic treatment. In one of these cases a circumscribed dysplasia which appeared at the left ostium 26 months following PDT was treated successfully using the Nd:YAG laser following TUR. In six patients slight mucosal atypia persisted for a period of at least 2.5 years. One cystectomy had to be performed because of bladder shrinkage. The dissected bladder was free of tumour. According to these preliminary results, PDT with strict patient selection (worst case situation with recommended cystectomy) is justified in the case of recurrent superficial TIS bladder carcinoma

Fluorescene detection and photodynamic treatment of photosensitized tumours in special consideration of urology.

Most methods of modern laser tumour therapy are physically based on the conversion of light to heat. Recently tumours have also been treated using ionizing processes for tissue ablation. Photodynamic laser therapy (PDT), however, involves light-induced non-thermal biochemical processes and the use of a photosensitizer. Several drugs are known to be stored selectively in tumours after systemic application. This transient marking can be used for diagnostik and therapeutic procedures. The marker most commonly used is dihaematoporphyrin ether/ester (DHE) intravenously injected at doses of 0.2-3.0 mg/kg bodyweight for diagnosis and therapy, respectively. The corresponding clearance intervals after injection of DHE range from 3-48 h to 25-75 h. Detection of photosensitized tumours might offer great advantages. The highly sensitive two-wavelenght laser excitation method with computerized fluorescene imaging recently has been transferred to the hospital for clinical tests. Photoinduced production of singlet oxygen is claimed to be the initial process which leads to later tumour destruction and therapy. PDT has been applied to 20 patients suffering from superficial tumours (TIS GII-III) recurred after application of other treatments. The results after PDT were evaluated by three-monthly check-ups (endoscopy, cytology, bladder mapping, renal ultrasonography) as well as by computed tomography (CT) examination at 8-13 month intervals. In six patients treated by PDT no tumour recurrence has been found over the whole observation period of up to 5 years. Four patients have remained free of tumour (12 and 14 months) after repeated transurethral reserction (TUR) and Nd-YAG laser therapy following PDT. Due to an initial application of insufficient irradiation four patients required a second PDT. In one patient a cirumscribed dysplasia appeared at the left ostium 26 months following PDT and was treated successfully by means of thermal Nd-YAG laser irradiation following TUR. In six patients slight mucosal atypia persisted for a period of at least 2.5 years. One cystectomy had to be performed because of bladder shrinkage. The dissected bladder, however, was free of tumour. These preliminary results suggest that PDT is justified in patients who are in a worst-case situation with cystectomy recommended in case of recurrent superficial TIS bladder carcinoma and indicate the future potential of photodynamic therapy of tumours. Homogenous irradiation of the area to be treated and a reliable light dosimetry are perequisites for an effective tumour therapy. Standard instruments for a routine application do not exist, but are under development

Laser-assisted fluorescence detection of plaque.

Selective fluorescence-marking of plaque offers new possibilities in cardiovascular diagnosis and therapy. Angioscopic investigations and spectrometry-assisted laser angioplasty will be simplified and more effective as compared with methods of today. It might help to make laser angioplasty a further promising interventional method to overcome, at least partially, the problems caused by atheromatous or atherosclerotic changes in the cardiovascular system. Fluorescence detection and imaging of markers is usually limited by the intrinsic fluorescence of tissue. Optical differential methods in combination with two-wavelength laser excitation and computer-assisted image processing, however, allow for discrimination of background-related signals and enable plaque detection and imaging at a high contrast. Plaque consists of either fibrotic, lipoid, or calcified depositions and is rather bradytrophic. For that reason in vitro experiments on human specimens post mortem seem to be justified and of clinical evidence. Due to intrinsically different fluorometric properties of plaque and normal vascular tissue imaging of marker-free plaque areas is possible. Additionally the specimens have been incubated with a haematoporphyrin-containing fluorescence marker at concentrations of 10-40 μg ml -1 and incubation times of 60 min in order to obtain a corresponding increase in contrast. Lipoid depositions show the highest contrast because of lipophilic properties of the marker, while fibrotic and calcified plaque is slightly less effectively marked. The results, however, so far obtained indicate that fluorescence detection of plaque promises further progress in diagnosis and therapy of cardiovascular diseases