The insertion of peripherally inserted central catheters (PICCs) represents a minimally invasive and safe method for establishing long-term central venous access in patients requiring prolonged intravenous therapy, including chemotherapy, parenteral nutrition, and long-term antibiotic treatment. Ultrasound-guided cannulation of peripheral arm veins improves procedural success, reduces complications, and increases patient comfort compared with centrally inserted central catheters.Accurate positioning of the catheter tip at the cavo-atrial junction is essential for optimal catheter function and safety. The Sherlock 3CG Tip Confirmation System combines electromagnetic tracking with intracavitary electrocardiography (ECG) to enable real-time catheter tip navigation and positioning.The aim of this prospective clinical study is to evaluate the accuracy and safety of ultrasound-guided PICC insertion using the Sherlock 3CG system, as well as to assess the impact of PICC placement on venous wall integrity. Ultrasound examination of the target vein will be performed before catheter insertion and after catheter removal to evaluate potential vascular wall changes associated with catheter use. A chest X-ray examination will be performed after each catheter insertion to confirm final catheter tip position and to assess the accuracy of the navigation system.Fluoroscopic guidance will be used only in selected cases, such as patients with anatomical anomalies, previously known difficult vascular access, or unsuccessful standard catheter advancement.A total of 80 adult patients with a clinical indication for PICC placement will be enrolled over a three-year study period.