A detachment system for delivering embolic coils to a treatment site in a vasculature of a patient, comprising: an elongated, flexible polymer tube having a distal portion and a proximal portion, said polymer tube having a tubular wall with an inner surface, an outer surface and a first thickness, said distal portion of said tubular wall of said flexible polymer tube having a score line formed in at least one of said inner surface and said outer surface 26) of said tubular wall, said score line having a second thickness that is less than said first thickness, said inner surface of said tubular wall defining an interior lumen extending through said flexible polymer tube between said distal and proximal portions of the flexible polymer tube; a resistive heating element located adjacent to said score line and extending longitudinally along at least one of said inner surface and said outer surface of said tubular wall of said distal portion of said flexible polymer tube, said resistive heating element being configured to provide direct heating of the distal portion of the flexible polymer tube adjacent to said score line when the resistive heating element is energized; and a therapeutic embolic coil releasably mounted to the distal portion of said flexible polymer tube, said embolic coil having a distal end and a proximal end, said therapeutic embolic coil including a headpiece having a distal portion and a proximal portion, the distal portion of the headpiece being attached to the proximal end of the embolic coil, and the proximal portion of the headpiece being releasably attached within said distal portion of said flexible polymer tube, said proximal portion of the headpiece being releasable from said distal portion of said tubular wall by heating of said distal portion of the tubular wall to cause said distal portion of the tubular wall to split along said score line to release said headpiece of said therapeutic embolic coil from said flexible polymer tube, characterized in that said resistive heating element is in immediate contact with at least one of said inner surface and said outer surface of said tubular wall of said distal portion of said flexible polymer tube and said resistive heating element is disposed longitudinally along and beside said score line. an elongated, flexible polymer tube having a distal portion and a proximal portion, said polymer tube having a tubular wall with an inner surface, an outer surface and a first thickness, said distal portion of said tubular wall of said flexible polymer tube having a score line formed in at least one of said inner surface and said outer surface 26) of said tubular wall, said score line having a second thickness that is less than said first thickness, said inner surface of said tubular wall defining an interior lumen extending through said flexible polymer tube between said distal and proximal portions of the flexible polymer tube; a resistive heating element located adjacent to said score line and extending longitudinally along at least one of said inner surface and said outer surface of said tubular wall of said distal portion of said flexible polymer tube, said resistive heating element being configured to provide direct heating of the distal portion of the flexible polymer tube adjacent to said score line when the resistive heating element is energized; and a therapeutic embolic coil releasably mounted to the distal portion of said flexible polymer tube, said embolic coil having a distal end and a proximal end, said therapeutic embolic coil including a headpiece having a distal portion and a proximal portion, the distal portion of the headpiece being attached to the proximal end of the embolic coil, and the proximal portion of the headpiece being releasably attached within said distal portion of said flexible polymer tube, said proximal portion of the headpiece being releasable from said distal portion of said tubular wall by heating of said distal portion of the tubular wall to cause said distal portion of the tubular wall to split along said score line to release said headpiece of said therapeutic embolic coil from said flexible polymer tube, characterized in that said resistive heating element is in immediate contact with at least one of said inner surface and said outer surface of said tubular wall of said distal portion of said flexible polymer tube and said resistive heating element is disposed longitudinally along and beside said score line.