Fluorescence imaging improves prostate cancer diagnosis

(Editor's note: This paper explains how optical and electronic technologies are used in a sophisticated medical instrument which combines two optical techniques to compensate for the shortcomings of each other.)

The protocol for prostate cancer diagnosis is currently based on PSA determination followed by ultrasound-guided biopsies. These biopsies are normally conducted by covering the prostate volume to increase chances of identifying the tumor. Often, for technical reasons, a series of such biopsies must be done, which adds to the difficulties and increases potential complications.

Development of a method designed to localize the tumor, or a suspect zone, within the prostatic tissue during the biopsy would have numerous benefits. It would considerably improve detection sensitivity, reduce the number of samples required, avoid the second or third series of biopsies as well as other currently proposed tests that are more costly without proven performance, and, last but not least, avoid recourse to multiple MRI scans and/or complex fusion methods.

As part of an ANR TECSAN project and on the initiative of the Bordeaux University Hospital Center (CHU), a consortium developed a bimodal probe allowing an optical measurement to be added to the traditional ultrasound diagnosis.

This probe was designed to perform two types of optical measurement:

•Fluorescence measurement, after injection of a fluorescent tracer specific to tumor cells. This modality ensures localization of these cells with a very high specificity. Its drawback is that it depends on the authorization to market the markers.

•Light absorption measurement, where the optical probe measures the optical properties of the prostate that tumor presence can cause to vary (detection of hyper-vascularization zones and measurement of the oxygen saturation). Its main drawback is its lack of specificity, as factors other than cancer are able to modify vascularization and oxygen saturation.

To read the full paper about the design of the probe and its overall operation, click here.

The authors and their affiliations:

BOUTET, Jérôme¹; DEBOURDEAU, Mathieu¹; HERVE, Lionel¹; VRAY, Didier²; MESSINEO, Odile³; NGUYEN, DINH An³; GRENIER, Nicolas⁴; DINTEN, Jean-Marc¹ are with:

1. CEA-LETI Minatec Campus, 17 av.des Martyrs, 38054 Grenoble, France
2. INSA-Lyon CREATIS, 7 avenue Jean Capelle, 69621 Villeurbanne, France
3. VERMON SA, 180 rue général Renault, 37038 Tours, France
4. Hôpital PELLEGRIN, Service d'Imagerie Diagnostique et Interventionnelle de l'Adulte, Pl. A. Raba-Léon, 33076 Bordeaux