An apparatus comprising: a therapeutic or diagnostic device having a distal end; and a releasable mount device mounted on the distal end of the therapeutic or diagnostic device and coupling an operative element with the distal end of the therapeutic or diagnostic device, the releasable mount device comprising: a tubular base coupled with the distal end of the therapeutic or diagnostic device, the tubular base having a proximal end, a distal end, and a central longitudinal axis, and further comprising a slot extending in a longitudinal direction between the distal end and the proximal end of the tubular base, wherein at least one longitudinal edge of the tubular base defining the slot has a rounded surface; and a support member coupled with the tubular base; the apparatus further comprising an operative element coupled with the support member, characterized in that: the releasable mount device further comprises at least one gripping member positioned in an interior surface of the tube base, the at least one gripping member extending radially inwardly from the interior surface of the tubular base, extending longitudinally from the distal to the proximal end of the tubular base and each gripping member comprising a friction surface; and wherein the interior diameter of the tubular base is larger than the diameter of the distal end of the therapeutic or diagnostic device; and the said at least one longitudinal edge comprises a contact member located along the entire length of the at least one longitudinal edge, wherein the contact member extends away from the interior surface of the tubular base to form a radiused contact surface that contacts an outer surface of the therapeutic or diagnostic device. a therapeutic or diagnostic device having a distal end; and a releasable mount device mounted on the distal end of the therapeutic or diagnostic device and coupling an operative element with the distal end of the therapeutic or diagnostic device, the releasable mount device comprising: a tubular base coupled with the distal end of the therapeutic or diagnostic device, the tubular base having a proximal end, a distal end, and a central longitudinal axis, and further comprising a slot extending in a longitudinal direction between the distal end and the proximal end of the tubular base, wherein at least one longitudinal edge of the tubular base defining the slot has a rounded surface; and a support member coupled with the tubular base; a tubular base coupled with the distal end of the therapeutic or diagnostic device, the tubular base having a proximal end, a distal end, and a central longitudinal axis, and further comprising a slot extending in a longitudinal direction between the distal end and the proximal end of the tubular base, wherein at least one longitudinal edge of the tubular base defining the slot has a rounded surface; and a support member coupled with the tubular base; the apparatus further comprising an operative element coupled with the support member, the releasable mount device further comprises at least one gripping member positioned in an interior surface of the tube base, the at least one gripping member extending radially inwardly from the interior surface of the tubular base, extending longitudinally from the distal to the proximal end of the tubular base and each gripping member comprising a friction surface; and wherein the interior diameter of the tubular base is larger than the diameter of the distal end of the therapeutic or diagnostic device; and the said at least one longitudinal edge comprises a contact member located along the entire length of the at least one longitudinal edge, wherein the contact member extends away from the interior surface of the tubular base to form a radiused contact surface that contacts an outer surface of the therapeutic or diagnostic device.