In response to the evolution of the information-seeking behaviour of patients and concerns from health professionals regarding cancer patient information, the French National Federation of Comprehensive Cancer Centres (FNCLCC) introduced, in 1998, an information and education program dedicated to patients and relatives, the SOR SAVOIR PATIENT program (SSP). The methodology of this program adheres to established quality criteria regarding the elaboration of patient information. Cancer patient information, developed in this program, is based on clinical practice guidelines produced by the FNCLCC and the twenty French regional cancer centres, the National League against Cancer, the French Hospital Federation, the National Oncology Federation of Regional and University Hospitals, the French Oncology Federation of General Hospitals, many learned societies, as well as an active participation of patients, former patients and caregivers. The guidelines, "Standards, Options: Recommendations" (SOR) are used as primary information sources. The handbook SOR SAVOIR PATIENT Understanding positron emission tomography (PET) with [18F]-FDG in clinical oncology, integrally published in this issue of the Bulletin du Cancer, is an adapted version of the clinical practice guidelines (CPG) Standards, Options and Recommendations for positron emission tomography (PET) with [18F]-FDG in clinical oncology. The main objectives of this article are to allow persons affected by cancer and their close relatives to better understand this medical imaging technique and its implementation. This document also offers health professionals a synthetic evidence-based patient information source that should help them communicate that information during the physician-patient encounter. Positron emission tomography (PET) is a scintigraphy technique using a radiotracer, [18F]-fluorodeoxyglucose (abbreviated [18F]-FDG), administered intravenously into the patient's arm. This tracer, similar to glucose (sugar), binds to cancer cells and temporarily emits radiations that can be recorded by a special camera in the PET scanner. PET scanning can be used to obtain complementary information at different stages of the disease, whether for assessing diagnosis, treatment evolution or follow-up. By 2007, in the framework of the government plan against cancer, about seventy-five PET scanners are expected to be installed in France. Twenty-four are currently in use; a similar number is under installation. At the end of this process, all French regions should have at least one PET imaging equipment. The SOR SAVOIR PATIENT guide: Understanding positron emission tomography (PET) with [18F]-FDG in clinical oncology and the integral report of CPG SOR 2003: Standards, Options and Recommendations for positron emission tomography (PET) with [18F]-FDG in clinical oncology can be downloaded from the FNCLCC website: http:\\www.fnclcc.fr.