New technique for treating occlusive and stenosing tumours of the trachea and main bronchi: endobronchial irradiation by high dose iridium-192 combined with laser canalisation

A new technique is described for treating patients with inoperable malignant tumours causing occlusion or stenosis of the trachea or main bronchi. High dose iridium-192 (20 Ci) was introduced by an afterloading device under computer control via a 4 mm delivery tube into the tumour mass. In 29 of the 56 patients the tumour mass was canalised by a neodymium-YAG laser immediately before the afterloading delivery tube was introduced. In 44 (79%) of the patients, there was impressive relief of dyspnoea, accompanied by tumour regression observed at endoscopy and also by highly significant improvement in ventilatory function values, lung perfusion scans, and levels of arterial oxygen tension. In the other 12 patients (21%) there was no detectable improvement. The findings suggest that this recently developed combination treatment is of value in patients with advanced tumours of the trachea and main bronchi in whom there is no possibility of further treatment by external irradiation or repeated laser coagulation.

[New methods in the radiotherapy of bronchial carcinoma. Endobronchial small-field irradiation using the iridium-129 high-dose afterloading technic in combination with the neodymium-YAG laser]

106 patients with inoperable malignant tumours constricting the central bronchial tree underwent endobronchial small-field radiotherapy with iridium-192 at high dose between June 1983 and September 1985. Treatment was performed using the computer-guided after-loading technique and a flexible bronchoscope under local anaesthesia. In complete occlusion of a bronchus by the tumour, a neodymium YAG-laser was applied (57 patients) to allow insertion of the after-loading probe. Endoscopy showed tumour regression in 75% of the patients, accompanied by clinical improvement. Pulmonary function tests, arterial blood gas analyses and pulmonary perfusion scans yielded a highly significant improvement of data after treatment. The procedure also proved effective upon exhaustion of external radiation. Apart from its positive palliation, endobronchial small-field radiotherapy using high doses of iridium-192 also has a curative effect, thus opening up a new approach to the therapy of advanced bronchial carcinoma.

Direction and frequency specific processing in the perception of long-range apparent movement

The presentation of repetitive apparent movement (AM) produces the illusion of smooth sinusoidal movement. During prolonged observation this impression vanishes periodically. On the basis of these observations, it was postulated that such long-range AM are processed via direction and frequency specific subsystems. This hypothesis was examined by means of selective adaptation. A bi-stable movement display was used to measure the adaptation effect. Generally a frequency specific reaction for horizontal and vertical movement was verifiable. In addition to this, the existence of the presumed narrow-band processing channels was confirmed by the tuning curves determined. The significance of the results for AM perception and their applicability to the processing of real movement Gestalt will be discussed.

[Localization of perceptual processes: figural aftereffects during conditions of binocular rivalry]

Figural aftereffects were measured under binocular-rivalry conditions, the suppressed part of the binocular-rivalry situation being used as an inspection figure. The results show that figural aftereffects are reduced in a partly suppressed configuration and disappear completely when the inspection figure is fully suppressed. This indicates that the figural aftereffect process is localized at a higher level in the visual system than area 17.