<qa>  What is the model 10642 Catheter tube?The Model 10642 Implantable Intravascular Catheter being used in this study is investigational, meaning it has not been approved by the FDA to be safe. The Model 10642 Catheter is different from other commercially available drug delivery catheters because the Model 10642 Catheter tube has a one-way valve designed to allow the medication to flow out but keep blood from flowing back into the catheter tube. The Model 10642 Catheter is reinforced to prevent kinking and crushing, which could interrupt the flow of medication. 