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Biomedical subjects

A E Profio

Publications and source records attributed to A E Profio.

At least 19 recordsLinked to original sources
PubMed1993

Detection of dysplasia and carcinoma in situ with a lung imaging fluorescence endoscope device.

The performance of a novel bronchoscopic fluorescence imaging system was compared with conventional white light bronchoscopy with a data base of 328 biopsy-confirmed sites from 53 patients and 41 volunteers. The two methods were found to have the same specificity (94%); however, the sensitivity of the fluorescence system (72.5%) was found to be 50% greater than that of the white light bronchoscopy (48.4%) in detecting dysplasia and carcinoma in situ. The fluorescence system uses a nonlinear discriminant function combining the red and green image intensity values to form a pseudoimage that, when displayed on an RGB monitor, allows the detection and delineation of abnormal areas. In 15% of the patients with lung cancer, synchronous carcinoma in situ was found in addition to the large invasive cancer. Of the current smokers in this study, 40% had moderate dysplasia and 12% had severe dysplasia. For the ex-smokers 25% had moderate dysplasia, 6% had severe dysplasia, and 13% had carcinoma in situ. Fluorescence imaging may become an important adjunct to conventional bronchoscopic examination to improve our ability to diagnose and stage lung cancer more accurately.

Aged↗
PubMed1990

Detection of early lung cancer using low dose Photofrin II.

Fluorescence imaging using hematoporphyrin derivative (HpD) or Photofrin II as a tumor marker has been used for localization of early bronchogenic carcinoma. Wider clinical application of HpD or Photofrin II as a cancer imaging agent has been hampered by the potentially serious and prolonged skin photosensitivity. Using a sensitive fluorescence bronchoscope system with a ratio fluorometer probe, carcinoma in situ was detected in four patients with low dose Photofrin II (0.25 mg/kg) with no apparent skin phototoxicity to 30 J/cm2 visible light on skin photosensitivity test.

Aged↗
PubMed1989

Fluorescence spectra in lung with porphyrin injection.

The fluorescence emission spectra from human bronchial mucosa and tumors, before and after injection of dihematoporphyrin ether/ester, have been measured with an optical multichannel analyzer from 500 to 750 nm. Fluorescence was excited with a violet krypton ion laser (average wavelength 410 nm). The autofluorescence spectra decrease monotonically with increasing wavelength except for a small broad peak near 600 nm. The spectra from tumor sites, after injection of the fluorescent porphyrin, exhibit the characteristic fluorescence emission at 630 and 690 nm, added to the autofluorescence spectrum. The spectra from control or nontumor sites are similar but the magnitude of the component due to the injected porphyrin is smaller than at a tumor site. The magnitude ratio of tumor to control site fluorescence depends on concentration of the porphyrin, tumor thickness, and time after injection. Autofluorescence degrades contrast and thus makes very thin tumors difficult to image. Subtraction of the autofluorescence background is desirable.

Humans↗
PubMed1987

Dose measurements in photodynamic therapy of cancer.

A theory and method for prediction and measurement of the effective absorbed dose in photodynamic therapy of cancer is presented. The method depends on measuring the concentration of the photosensitizer (such as dihematorporphyrin ether), the flux density of the light, and the relative photodynamic effectiveness. Previous, less exact methods relied on specifying the drug dosage and delay after injection and or the irradiance at the surface or power from an interstitial fiber. The new formulation should permit closer control of the effective absorbed dose and better clinical results with photodynamic therapy.

Dihematoporphyrin Ether↗
PubMed1985

Laser instrumentation and safety.

A review of the operation principles of lasers and the various types used in chest medicine is given. This includes CO2, Nd:YAG, argon, krypton, and dye lasers. Safety considerations in the use of lasers are also outlined.

Argon↗
PubMed1984

Imaging fluorescence bronchoscopy for localizing early bronchial cancer and carcinoma in situ.

A system of imaging fluorescence bronchoscopy instrumentation and methods has been devised that has succeeded in localizing very small (1 X 2 mm) areas of bronchial mucosal cancer, in individuals with radiologically occult lung cancer (positive sputum cytology for malignant cells and a negative chest X-ray). These areas were located solely by their fluorescence, and were visibly normal on white-light examination. The detection of lung cancer in individuals with radiologically occult lung cancer depends upon adequate methods of sputum collection and processing. Proving that fluorescing areas show "true positive" fluorescence depends upon accurate brush and forceps biopsies, providing adequate cytological and biopsy material. The entire system of the diagnosis and localization of early or pre-invasive lung cancer (while still confined to a bronchus) rests on skilled cytopathology methods and interpretation, not only skilled fluorescence bronchoscopic examination and adequate instrumentation.

Aged↗
PubMed1982

Fluorescence bronchoscopy in the localization of bronchogenic carcinoma.

Fluorescence bronchoscopy using hematoporphyrin derivative as a tumor marker has been developed for localization of early bronchogenic carcinoma. Recent clinical results have been obtained with a krypton laser and a fused quartz fiber illumination system, which is clearly superior to the mercury vapor lamp system used previously. Fifteen patients have been examined, two with the laser. The potential of the technique is demonstrated by a case study of a patient with positive sputum cytology and a negative chest radiograph. The small early invasive tumor could be detected only with difficulty by subtle mucosal changes under white light bronchoscopy. Positive fluorescence was observed in the suspicious area. Malignancy was confirmed by biopsy and histologic examination upon subsequent lobectomy.

Aged↗
PubMed1977

A feasibility study of the use of fluorescence bronchoscopy for localization of small lung tumours.

The possible use of fluorescence bronchoscopy for localization of bronchogenic tumours at the carcinoma in situ stage has been investigated. The target lesion is 80 micrometer thick with a mass of 250 microgram, containing 250 pg of haematoporphyrin derivative. The injected haematoporphyrin-derivative is preferentially taken up or retained by a malignant tumour, and can be detected in small amounts by its red flourescence under illumination by violet light. Previous clincial trials were successful in detecting tumours, but the instrumentation was only marginally adequate, the fluorescent compound was not standardized and no measurements or calculation of sensitivity were made. In this work, a fibreoptic bronchoscope system with a 200 W mercury vapour lamp, special violet-transmitting light conductor, sharp cut-off blue and red filters and three-stage image intensifier tube was designed and assembled. Measurements in vitro indicate the design objectives were met, and test on tumours are in progress.

Animals↗