Management of the Lack of Blood Return on a Central Venous Catheter (CVC) Before Chemotherapy

Inclusion Criteria: * Female or male, Age ≥ 18 years at time of study entry. * Undergoing systemic chemotherapy on a CVC. Immunotherapy and targeted therapies are among the systemic therapies that are authorised * Having already received at least one administration of treatment without difficulty. * Coming for a new administration of treatment authorised by the usual biological assessment. * First episode of lack of CVC blood return despite the usual positioning and injection- aspiration manoeuvres * No abnormality on inspection or palpation (turning) of the CVC. * Patient has valid health insurance. * Patient information and signature of informed consent. Exclusion Criteria: * Previous episode of lack of CVC blood return whether explored or not. * Patient currently treated in an interventional therapeutic trial. * Patient with a Picc-line implantable device. * Suspected CVC infection or thrombosis. * Planned chemotherapy with vesicant agent (anthracyclines). * Possible CVC disjunction. * Allergy to X-ray contrast agent or creatinine clearance below 30ml/min prohibiting an iodine injection. * Pregnant, likely to be pregnant or breastfeeding woman. * Persons deprived of their liberty, under a measure of safeguard of justice, under guardianship or placed under the authority of a guardian. * Impossibility of undergoing medical monitoring of the trial for geographical, social or psychological reasons, social or psychological reasons.