Beiträge zur ROC-Analyse-Semantik beim „medical fused imaging“ und Methoden der Thermo-Biometrie

Röntgen/NIR Additions-Bildgebung bei semantischer Bewertung durch ROC- Analyse X-Ray/NIR add-up-imaging by semantical evaluations with ROC-Analysis In the last 15 years the diaphanoscopic transillumination in the NIR (Near Infrared Radiations) spectral range (700 – 1300 nm) has been used by medical diagnostics – particularly in laser-assisted optical diagnostics of rheumatoid arthritis (RA) in small joints. The transillumination depends on tissue-optical scattering- and absorption spectra – the so-called tissue optical coefficients (µa, µs and g) – from pathological states of the finger-joints. By the conventional X-Ray image we can see the structural parts (i. e. bones) in the region of interest. By the NIR-diagnostics we can see the functional problems of the tissue (changes of absorption- and scattering in the tissue). Our investigations have shown the recently developed add-up-imaging - a special form of the fused imaging-procedure of NIR and conventional X-Ray-diagnostics. This combination delivers improved and considerable more diagnostic information. The procedure of Receiver Operating Characteristic (ROC) - analysis is a first step of a semantical evaluation. Especially the „Youden-Index“ is a good instrument for an optimal tuning of the add-up-procedure and the „Classificator-Identification“. Methodical investigations of a new thermo-biometrical technique for LITT-dosimetry During laser-induced tumor therapy (LITT) for prostate cancer or hyperplasia light (about 1000 nm wavelength) is delivered through optical fiber to a light scattering applicator (diffuser fiber tip). This tip is placed inside the tumor where it distributes light in a way that leads to a hyperthermical volume in which an increase in temperature can be observed. About 40-55 degree Celsius are the therapeutic temperature range for the cancer, the hyperplasia and the normal tissue surrounding. Dosimetry studies are necessary to optimize the application of LITT. In the work presented here we employ for the first time a laser-induced fluorescence cell viability assay that yields information about the vital ATPase and its thermal dependency. We found, that this specific fluorescence signal shows a typical “flip-point” - that indicates a disturbed mitochondrial membrane activity when the membrane gel-phase transitions to a liquid - phase of the membrane structure. Knowledge about this flip-point forms the foundation for additional dosimetric observations in this situation – for finding the optimal therapeutic temperature. The “flip-points” are new land - marks for thermal dosimetry.