An implantable access port including a port housing that defines a fill port cavity and includes a catheter fitting, a filter positioned within the port housing along a delivery flow pathway configured so that fluid injected into the fill port cavity passes through the filter prior to exiting through the catheter fitting, a one-way valve positioned within the port housing along an aspiration flow pathway configured to permit aspirated fluid to flow unfiltered from the catheter fitting to the fill port cavity and prevent injected fluid from flowing unfiltered from the fill port cavity to the catheter fitting, a port cover coupled to the port housing, and a pierceable septum positioned between the fill port cavity and the port cover configured to allow a needle to pierce through the pierceable septum to access the fill port cavity.