Guidelines for comprehensive quality assurance in brachytherapy.

Brachytherapy treatment techniques can provide significant improvement in local control and overall survival, but only when quality assurance can be guaranteed. In the absence of well-trained personnel and inadequate equipment undesirable results usually follow. To establish brachytherapy quality assurance, basic requirements for three predetermined subdivisions of clinical institutions will be forwarded. These are: (1) centers having minimum requirements to provide brachytherapy, (2) intermediate centers such as regional or community hospitals, and (3) optimal centers such as university hospitals and cancer centers. A minimum center would have no board certified radiation personnel, would make use of services of a gynecologist or surgeon, be limited to afterloading or remote afterloading techniques for uterus cancer, and quality control would be guaranteed by using simple treatment protocols with fixed intrauterine applicators. Additional quality assurance such as leak testing, etc. would be provided by a parent organization (W.H.O. or Optimal Center). An intermediate center would have at least one certified radiation personnel with expansion of brachytherapy techniques to interstitial implants with several isotopes. Like the minimum center, no teaching would be provided but some quality assurance policies would be performed at the center (e.g., autoradiographs). The optimal center would have a full complement of personnel, have total brachytherapy capabilities, have teaching programs for its staff and possibly the minimum and intermediate centers and be able to provide its own quality assurance. This presentation will highlight personnel needs, equipment requirements, academic activities, clinical experience with these systems and proposed quality assurance guidelines.

High dose rate 60Co remote afterloading irradiation in cancer of the cervix in Haiti, 1977-1984.

From 1977 through 1984, 293 previously untreated patients with biopsy proven carcinoma of the uterine cervix were treated by whole pelvis irradiation and high intensity 60Co remote afterloading (RAL) intrauterine tandem techniques in Haiti. The treatment results were analyzed retrospectively to evaluate the therapeutic results and prognostic factors of a strict protocol involving 40 Gy to the whole pelvis (2 Gy/day, 5 days/week). In addition, on the 5th day of the 3rd week, the first outpatient 60Co remote afterloading intracavitary insertion, delivering 7.5 Gy to point "A" with each insertion, repeated 3 times by a week separation for a total of 4 times. The total TDF for external beam plus RAL was 158 and 175 for early and late effects respectively. One hundred-four patients were evaluable after 1 year or more follow-up, with a median of 26.5 months. No evidence of disease (NED) by Stage at 1 year was: Stage I of 100% (3/3), Stage II of 82% (9/11), Stage III of 80% (47/59), and Stage IV of 58% (18/31). The post-therapeutic complication rate was 7.7%, with no fistulas or requirement of surgical intervention. Those with documented follow-up of at least 2 years (74 patients) had comparable survival to other high dose rate and low dose rate studies. This study shows that outpatient brachytherapy can be carried out without sophisticated and expensive equipment with minimal staff trained in radiation therapy. A detailed description of this outpatient RAL technique and results are described so that this method can be adapted to other developing and industrialized nations where cost containment is becoming a key issue.

Radiation from the uranium collimators of the Varian 4-MeV accelerator.

The uranium collimator of the Varian 4-MeV accelerator produces a dose rate of 100 mR/h near the collimator opening. It can be decreased to 4% by a 6-mm Lucite shield at the level of the collimator opening. A better solution is a lead glass-mylar (EM) shield which decreases the uranium radiation to less than 3% and also provides better skin sparing during treatment than the open collimator.

Remote afterloading endocurie therapy for carcinoma of the cervix.

Since October 1975, 41 cancer patients were treated with a remote afterloading device using fractionated high dose-rate intracavitary radiation. Nineteen of these 41 patients were treated for carcinoma of the cervix. Remote afterloading high dose-rate fractionated intracavitary radiation was given in combination with external irradiation. The dose fractionation and rad equivalent therapeutic (RET) values and various points of interest are discussed.

Problems and solutions in achieving uniform dose distribution in superficial total body electron therapy.

In treating mycosis fungoides (MF) and Sezary syndrome patients with electron beam, the entire thickness and the area of the skin from crown to sole should be irradiated uniformly. To achieve irradiation of the entire thickness of the skin, electron beams of 3 - 4 MeV energy with 80 percent depth dose at 6 mm is sufficient. This unique property of limited penetration of electron beam does not cause any systemic toxicity during or after total body electron therapy. However, this property of limited penetration of electrons poses the problem of self-shielding in the curvaceous human body. The optic lens, which is within the range of penetrability of electron beam energy used for total body electron therapy, is to be shielded artificially.The purpose of this paper is to discuss the problems of self and artificial shielding in the superficial total body electron therapy for MF and Sezary syndrome.

Early experience in using and 18 Me V linear accelerator for mycosis fungoides at Howard University Hospital.

This paper describes the problems and solutions in using 18 MeV linear accelerator, with minimum 6 MeV electron capability, for total skin irradiation for mycosis fungoides. The 6 MeV electron energy can be degraded to acceptable electron energy of 3.2 MeV by interposing a plexiglass sheet of 9.6 mm in the beam. To minimize the bremsstrahlung, the degrading plexiglass should be kept away from the machine head. A wide area with uniform dose distribution over single plane can be achieved by using dual fields but homogenous dose distribution over irregular body surface cannot be achieved mainly because of self-shielding. The nails and the ocular lens can be easily shielded from the low energy electrons with 1.5 mm lead shield.

Radiation dose monitoring in a breast cancer patient with a pacemaker: a case report.

A pacemaker-bearing patient with left-sided breast cancer was treated with adjuvant external beam radiation therapy to the intact breast. She was treated via tangential fields and a single anterior supraclavicular field using 6-MV x-rays. The pacemaker, originally in the treatment field, was removed and a new one placed 4 cm outside the radiation field prior to treatment. Silicon diode chamber Keithley-Farmer type 0.6 cc ionization chamber, and lithium fluoride (LiF) (TLD) chips were used to measure, in vivo, the dose to the pacemaker. From all the fields treated, total dose to the pacemaker was 164 cGy by diode measurements, 182 cGy by ionization chamber measurements, and 171 cGy by TLD measurements. The pacemaker functioned normally throughout the course of treatment.

Intraluminal radiation for esophageal cancer: a Howard University technique.

The objective of radiotherapeutic management in esophageal cancer is to accomplish maximum tumor sterilization with minimal normal tissue damage. This sincere effort is most often countered by the differential in tumor dose response vs normal tissue tolerance. Intraluminal isotope radiation, with its inherent advantage of rapid dose falloff, spares the lungs, the spinal cord, and other vital structures, yet yields adequately high doses to esophageal tumor. Though in existence since the turn of the century, the method of intracavitary radium bougie application dropped out of favor due to technical difficulties imposed by the size of the radium source and radiation exposure to the personnel involved. The authors describe a simple "iridium 192 afterloading intraluminal technique" that eliminates technical problems and reduces radiation exposure considerably.

Treatment of a Down's syndrome patient for hyperthyroidism with radioactive iodine.

A Down's syndrome patient was hospitalized for evaluation of vomiting, abdominal pain, and a history of weight loss. A subsequent workup revealed that she had hyperthyroidism. The treatment of choice was radioactive iodine therapy. The patient had a history of consistent nausea and incontinence for urine and feces. Special problems posed by the patient and radiation safety are discussed.

The first simultaneous intraoperative hyperthermia and radiotherapy procedure: dog experiment and technique.

The Department of Radiation Therapy of Howard University Hospital was the first to revive (1976) the use of intraoperative radiotherapy, or direct view irradiation, using electron beam (IORTe(-)) in the United States. Since that time, this pioneering effort has gained both national and international acceptance. Now, many leading centers employ this investigational treatment modality. Recently, a new mode of cancer therapy has been gaining acceptance, namely hyperthermia (the treatment of cancer by heat). Hyperthermia has been shown, both experimentally and clinically, to improve the rate of local control (thermal enchancement ratio [TER]) when combined with radiation therapy in the treatment of cancer. Maximal TER has been observed with simultaneous or immediate application of radiation and hyperthermia for both tumor and normal tissues. Therefore, to achieve maximum therapeutic gain, selective, intraoperative, simultaneous heating and irradiation of the tumor with mechanical retraction of the normal and sensitive structures from the treatment field seems a promising alternative.There have been no published reports, to the authors' knowledge, on the combination of simultaneous IORTe(-) with intraoperative hyperthermia (IOHT). To employ this combination in human subjects, several questions must be answered first using animal models, including the technical and practical feasibility, the toxicity and morbidity, as well as the pathologic changes that may arise. The technical aspects of the first animal case, using a mongrel dog, applying simultaneous IORTe(-) and IOHT are presented.

Internal mammary implantation: the need for revival of a simple technique.

Available statistics on breast cancer indicate a high frequency of positive internal mammary nodes, which is associated with decreased five-year survival rates. The close proximity of the majority of internal mammary nodes (87 percent within 1 cm) to the internal mammary vessels makes them easily accessible to high-dose intravascular continuous irradiation by afterloading radioactive ribbons (iridium 192) in the internal mammary vessels that are surgically exposed. This is a simple technique that can be carried out at the time of mastectomy or as a separate procedure, either as a primary radiation modality, for post-XRT recurrence, or as a boost in combination with conventional parasternal radiation therapy. The step-by-step technique, indications, need for revival, and future implications are presented.

Iodine-131 treatment of hyperthyroidism in a patient on dialysis for chronic renal failure.

A 7- to 8-cm diffuse toxic goiter with associated symptoms of hyperthyroidism developed in a 38-year-old black female undergoing regular hemodialysis for renal failure. Our treatment of choice was an ablative dose of radioactive iodine in the form of sodium iodide (Na-131I). To our knowledge, this is only the 4th documented case of hyperthyroidism in a patient with renal failure. Detailed monitoring of 131I radioactivity in the blood, thyroid gland and the dialysate demonstrated that there was no radiation hazard to personnel involved in the patient management.