The doped silica core region of a core rod for an optical fiber preform is protected against unwanted fluorine doping during fluorine doping of the outer silica layer by selectively consolidating the core region prior to fluorine doping. High speed programming of data is achieved by interleaving pages of the data to be programmed amongst the memory devices in the system, such that different pages of data are stored in different memory devices. Each actuator is deployed in an own corner of the camera module. The system further includes a spring coupled to the compression plate and only one spring interface. Furthermore, an external indicator gives feedback to the surgeon as to how far firing has progressed, as well as providing a manual retraction capability. Any emboli released into the vessel as a result of the interventional treatment are blocked by the filter member while fluid is allowed to pass there through.