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Services & Therapies
Image-Based 3-Dimensional HDR Brachytherapy Program

What is Brachytherapy
Brachytherapy is a procedure of placing radioactive materials near or in diseased tissues as a means to administer high doses of radiation. This treatment has been used for over 100 years as a method of treating cancer. The primary advantage of internal radiation placed within the tumor is its ability to deliver a high radiation dose to the tumor while limiting the radiation that the normal tissues receive. About 5% of cancer patients are candidates for brachytherapy.

Our department performs more than 150 brachytherapy procedures annually, excluding prostate seed implants (described elsewhere). In the majority of these treatments, radiation applicators are placed within a cavity of the body, for example, the bronchus in the lung or the vagina.

The Department of Radiation Oncology performs brachytherapy to treat cancer of the vagina, cervix and uterus, as well as, tumors in the lung, breast, esophagus, head, neck and extremities.

Brachytherapy has been used to treat cervical cancer since the beginning of the last century. Low Dose Rate (LDR) brachytherapy, that is, radiation delivered slowly or at a low dose, was implemented as the first internal radiation system. Prescribing a radiation dose that would eliminate the cancer with this method necessitates the placement of radiation delivery instruments for an extended period of time. For example, patients with cervical tumors must stay in the hospital with applicators in the gynecologic tract for 2 to 3 days remaining as motionless as possible to minimize movement of the applicator containing the radioactive sources. Disadvantages of LDR brachytherapy include radiation exposure to hospital staff, high probability of movement of the placed instruments during the 2-3 days of treatment, costs incurred from hospitalization along with patient discomfort and inconvenience. Recently, radioactive sources with very high radioactivity, such as iridium, have become available which deliver a high dose of radiation in a very short period of time. This is generally referred to as High Dose Rate (HDR) brachytherapy. Our decision to completely transition to HDR brachytherapy at Loyola resulted from our desire to overcome the challenges of LDR.

The HDR system uses a single, tiny, (1mm x 3 mm) highly radioactive source of Iridium-192 that is laser welded to the end of a thin, flexible stainless steel cable. The source is housed in a device called an afterloader. The computer-guided afterloader directs the source into the treatment catheters or applicator that has been placed in the patient by the radiation oncologist. The source travels through each catheter in 5mm steps, called "dwell" positions. At Loyola we now have a CT scan Image –Based 3-Dimensional Planning system which allows us to administer Brachytherapy more accurately while sparing normal tissues.

In contrast to Low Dose Rate (LDR) brachytherapy where treatments require 2 to 3 days, HDR brachytherapy is delivered over minutes. Because the afterloader controls the radiation source, radiation exposure to the physicians, hospital staff and family members is eliminated. After the HDR treatment, the source retracts into the afterloader. The patient is no longer radioactive.

HDR brachytherapy treatment courses can be from 3 to 10 treatments, depending on the type of cancer being treated. There are many factors that the physician considers in determining the radiation dose and how many treatments a patient should receive.

At Loyola, we have a dedicated HDR brachytherapy suite with ultrasound and fluoroscopic imaging capabilities for complex planning. The proximity to the ambulatory surgery unit allows us to administer a short general anesthetic if required to place the implant applicator and then administer the brachytherapy treatment under one roof.

What are the benefits of brachytherapy
The benefits of brachytherapy vary depending on the patient, their priorities, and preferences, though as a minimally invasive treatment method, the benefits of avoiding surgery are universal. These include faster recovery time, less time spent in the hospital, and a reduced risk of post operative infections. The benefits of using brachytherapy in the treatment of early stage prostate cancer are quite pronounced. There is a much lower incidence of impotence and incontinence than occurs with a radical prostatectomy, and most men resume walking within a few hours of the procedure and other normal activity within a few days. In the case of breast cancer, the course of traditional radiation treatment following a lumpectomy lasts six weeks, with daily installments given at a hospital or clinic, whereas brachytherapy treatment lasts for five days.

Typical HDR Procedures

Step 1. Inserting the implant
The radiation oncologist decides which type of implant the patient requires, based on location, tumor extent and other factors. The three types are:
Intracavitary, where an applicator is inserted into a body cavity to reach the tumor. Intracavitary implants are performed in the HDR suite on an out-patient basis. Local anesthesia and/or conscious sedation is all that is required. Sometimes short general anesthetic may be required. (USED FOR GYNECOLOGICAL TUMORS) Intraluminal, where the catheters are inserted into a "tube" such as the bronchus, esophagus, or bile duct. These are treated the same as intracavitary implants on an outpatient basis. (USED FOR LUNG AND ESOPHAGEAL TUMORS)

Interstitial implants are more complex. The implants are done in the operating room with the patient under general or spinal anesthesia. Interstitial catheters are inserted through the body tissue to encompass the tumor.
(USED FOR BREAST AND HEAD AND NECK TUMORS)

Step 2. Simulation
After the implant has been placed, either CT or special x-ray films are taken by the radiation therapists to determine the exact location of the implant in the body and the relationship to adjacent organs. The therapists' expertise in taking these films assures that the implant and nearby organs are visualized clearly. The physician reviews these films and makes final adjustments to the implant if necessary.

Step 3. Dosimetry (3-Dimensional Planning)
The CT images or films are then given to the dosimetrist to enter into the treatment planning computer. The position of the catheters or applicator is entered along with the location of the nearby structures. The computer calculates the radiation doses within and around the implant. The dosimetrist then "fine tunes" the implant by increasing or decreasing the time the source spends in each dwell position to achieve the shape and doses that the physician prescribes to the tumor and the nearby structures. After the isodose plan has been approved by the physician, the computer transfers the treatment plan instructions to the HDR remote afterloader. (we use 3-D planning –see above)

Step 4. Treatment
The patient is moved into the brachytherapy treatment room. The ends of the applicator or treatment catheters that protrude outside the body are connected to "transfer" tubes which are then connected to the afterloader. The programmed instructions tell the afterloader which tube/catheter to send the source into and where and how long the source will stay in each dwell position. The patient is alone in the treatment room while the treatment is being given, but the therapists and nurses are continually monitoring them and in contact through an intercom and closed circuit TV monitors. The time the source spends in the implant is about 10 to 15 minutes. The entire treatment process takes about 60-120 minutes. These time estimates will vary depending on the size and complexity of the tumor and on the activity of the source.

Step 5. Implant removal
After the treatment(s) have been given, the implant is removed. Intracavitary and intraluminal applicators are simple to remove and the patient goes home. With interstitial implants, sutures holding the template and/or catheters in place are clipped and the implant is gently removed. Some minor bleeding usually occurs, which is quickly stopped by applying direct pressure to the implant site with gauze pads. Post- implant care instructions are given by the nurses before the patient leaves the HDR suite. A date for a follow-up appointment will also be given.