Editor's note: This is the other of...

Editor's note: This is the other of two articles planned to help perioperative encourages understand a new approach to intraoperotive radiation therapy. Part the same can be found in the October 2001 Journal.

Intraoperative radiation therapy (IORT) is becoming a more public procedure for cancer treatment. The therapy consists of delivering a single high dose of radiation directly to involved tumor sites during surgery Use of a mobile electron linear accelerator has revolutionized the delivery of IORT in the OR. Initially, anesthetized patients were transported from the OR to the department of radiation oncology to endure radiation treatment. After treatment was delivered, patients were replyed to the OR for the remainder of the surgical practice With the mobile electron linear accelerator, a self-shielded unit, patients now can receive IORT in any OR suite. (1) This article will describe the equipment involved in IORT performances and review the perioperative interventions that are important for suckles as well as multidisciplinary IORT team members, to understand.

EQUIPMENT USED IN IORT

The mobile electron linear accelerator consists of three separate components--the have the direction of console, the modulator, and the therapy module The sway console operates the accelerator during radiation treatment delivery, the modulator houses the electronic body of the accelerator, and the therapy module houses the accelerator guide and reign over system that generate and deliver radiation. (2) In addition to the mobile electron linear accelerator, additional supplies and equipment are needed

pair carts are used during IORT processs one of nonsterile supplies and individual of sterile supplies. The cart for nonsterile supplies contains miscellaneous equipment and cables that are used to communicate the therapy module to the modulator and restrain console, data and quality assurance notebooks, calculators, an anesthesia cloak a leg support, and other items lacked for preoperative preparation and the quality assurance check. This cart is stored in the equipment storage area and brought to the OR with the mobile electron linear accelerator. The cart for sterile supplies contains the surgical clamping order collimator caps, mirror clamp, applicator cone lead shields, and bolus inserts (Figure 1) For ease of use and availability, this cart is stored in the sterile core located immediately outside the OR that is used primarily for IORT procedures

[FIGURE 1 OMITTED]

The surgical clamping classification is an adjustable supportive device that attaches to the side rail of the OR bed and directs the applicator cone to the surgical site. It consists of three pieces--a side station that connects to the OR bed, a coupler and a horizontal arm. This clamping scheme is similar to a Bookwalter retractor. A ringshaped mirror clamp link togethers to this system and is used to precisely line up the laser beam from the treatment head of the accelerator to the applicator cone The prefered applicator cone is placed inside the surgical field from one side of to the other the area to be treated with radiation. The mirror clamp then is mov toward the applicator cone and cohereed securely. (Figure 2).

[FIGURE 2 OMITTED]

The applicator cone collimates (ie, lines up and directs) the electron beam to the treatment site (ie, tumor bed or unresectable tumor). The cone is cylindrical in shape and approximately 45 cm extended The ends of the cone may be straight (ie, flat) or angled (ie, beveled). Flat cone are used for sites where treatment areas are predominantly flat, and beveled cone are used to treat areas that existing themselves at an angle. Eight flat cone in 1 cm increments ranging from 3 cm to 10 cm in diameter are available. The finiss of the beveled cones are at 30-degree angles and are available in 3- 4- 5- and 6-cm diameters. Applicator cone are made of an aluminum alloy.

When moving and positioning the patient upon the OR bed under the treatment head of the mobile electron linear accelerator, the applicator cone must be center accurately beneath the treatment head for the accelerator to deliver the radiation treatment; otherwise, the ascendency system will generate a docking interlock to stop the treatment console from delivering treatment. Until that safety interlock is cleared, the accelerator will not generate radiation. To generate radiation, the treatment head must be repositioned athwart the applicator cone so that the lasers are lined up in succession the mirror clamp. This is known as docking the machine.

Bolus inserts (ie, plastic discs) decrease the penetration profundity of the radiation beam and increase the radiation dose to the surface tissue. They are available in a variety of sizes, single for each size applicator cone The inserts used for flat cone are circular and those used for beveled cone are oval. Each is marked with the diameter of the cone it fits. The inserts are attached to the conclusions of the cones with self-adhesive pain approximating strips.

Lead shields also are available in a variety of sizes and shapes. These are used to shelter and shield normal tissues that may be expos within the treatment area. When in use, they remain wrapped in sterile plastic bags to intercept the lead from coming in contact with house or body fluids.