A homemade inexpensive manual rapid cassette changer for angiocardiography and cerebral angiography.

Abstract

The purpose of this article is to describe a manual rapid cassette changer which anyone can make inexpensively (at a cost of less than $60.00) and to mention two advantages which it offers over previous devices. Briefly, the cassette changer consists of a “cookie sheet” to hold the cassettes as they are pushed manually through an elongated wooden channel which has lead covers on either side of the part of the body to be exposed. Wooden spacer blocks hold the cassettes in place in the “cookie sheet”: a long narrow spacer at the top of the cassettes when they are placed in the tray with their longest dimension crosswise of the x-ray table (lengthwise of the channel), and a short block the width of the tray when their longest measurement is parallel to the table (crosswise of the channel). A Lysholm grid is placed between the lead covers to complete the upper surface of the channel. Figure 1 shows the parts of the cassette changer with the technician holding the control rod in his right hand and the exposure switch in his left. Figure 2 shows the patient in place for a cerebral angiogram, with the needle in the internal carotid artery and the operator protected by the lower half of an old lead-rubber apron draped around the tube. Specifications The inside measurements of the wooden frame are 60 ½ × 13 ⅝ × ⅝ inches. The bottom of the channel is made of plywood and is nailed or screwed solidly to the sides. The inside surfaces of the sides are grooved near the top to accommodate the plywood and lead covers, each of which measure 24 × 14⅜ inches. One plywood and lead cover is fixed at one end of the channel, while the other has stops in its grooves so that it may slide 1 ½ inches from the near end of the channel. A ¼-inch hole (to accommodate a ¼-inch metal thumb key resembling a violin peg) is drilled through the end of one side of the channel at the proper place to bridge the groove for the movable lead cover so as to hold it 1 ½ inches from the grooved end. One-inch squares are cut from ⅜-inch plywood and nailed to the sides of the channel at points where they will guide the Lysholm grid and hold it in position over the opening in the middle of the channel. Four 4-inch wood clamps (C-clamps) suffice to hold the channel to the x-ray table. The cassette tray, resembling a “cookie sheet,” is made of galvanized tin. Its inside measurements are 39½ × 13¼ inches, with ½-inch sides. A 1-inch square flattened metal cabinet handle is soldered to one end of this tray, fitting into the key-seat near the end of the solid metal control rod. The key-seat is a round hole through the control rod with a slightly smaller slot, opening the hole to one side of the rod so that the metal cabinet handle will be barely admitted when the rod is in a vertical position and will not slip out of the key-seat when the rod is in a horizontal position, as shown in Figures 1 and 2.