Brachytherapy is the use of radionuclides to treat malignancies or benign conditions by means of a radiation source placed close to or into the tumor or treatment site. This guideline refers only to the use of radionuclide brachytherapy. Brachytherapy alone or combined with external beam therapy plays an important role in the management and treatment of patients with cancer.
Low-dose-rate (LDR) brachytherapy has traditionally been used for treating prostate, head and neck, breast, cervical, and endometrial cancers as well as obstructive esophageal or bronchial lesions. It has been practiced for over a century with a variety of sources including radium-226, cesium-137, and, more recently, iridium-192, iodine-125, and palladium-103. LDR brachytherapy can be given as interstitial, intracavitary, or intraluminal therapy to a wide variety of treatment sites.
LDR brachytherapy is accomplished by 1) temporary implants, i.e., afterloading radioactive sources into applicators that are placed into the patient, or 2) permanent implants, placing the radioactive sources permanently into the cancerous tissue. Source handling and loading into the applicator or tissue can be performed manually or remotely, with source loading performed by a computerized unit. LDR brachytherapy is delivered at dose rates of 4 to 200 cGy per hour at a designated point. Brachytherapy can also be administered using remote afterloading, high-dose-rate (HDR) techniques. The use of HDR brachytherapy is covered in the "ACR–ASTRO Practice Guideline for the Performance of High-Dose-Rate Brachytherapy" (see the National Guideline Clearinghouse [NGC] summary).
The use of brachytherapy requires detailed attention to personnel, equipment, patient and personnel safety, and continuing staff education. Since the practice of radiation oncology occurs in a variety of environments, the judgment of the radiation oncologist and medical physicist should be used to apply these guidelines to individual practices.
This guideline addresses sealed sources as they are used for LDR brachytherapy. Guidelines for unsealed sources can be found in the "ACR–ASTRO Practice Guideline for the Performance of Therapy with Unsealed Radiopharmaceutical Sources" (see the NGC summary).
The use of LDR permanent brachytherapy for prostate cancer is covered in a separate "ACR–ASTRO Practice Guideline for Transperineal Permanent Brachytherapy of Prostate Cancer" (see the NGC summary).
There is a separate practice guideline referring to the practice of vascular brachytherapy. See the "ACR Practice Guideline for the Performance of Coronary Vascular Brachytherapy (CVBT)" (see the American College of Radiology [ACR] Web site for this practice guideline and additional ones mentioned below).
The licensing of radioactive sources (radionuclides) and the safety of the general public and health care workers are regulated by the Nuclear Regulatory Commission (NRC) or by agreement states*. Medical use of radionuclides for therapeutic procedures must adhere to the constraints set forth by these regulatory agencies. Detailed descriptions of NRC licensing and safety issues can be found in the Code of Federal Regulations, Part 20 and Part 35. State requirements for the agreement states are found in the respective state statutes.
*An agreement state is any state with which the U.S. Nuclear Regulatory Commission or the U.S. Atomic Energy Commission has entered into an effective agreement under Subsection 274.b of the Atomic Energy Act of 1954, as amended (73 Stat. 689).
Process of Brachytherapy
The use of LDR brachytherapy is a complex multistep process involving trained personnel who must work in concert to carry out a variety of interrelated activities. Communication among brachytherapy team members and well-defined procedures are essential for accurate and safe treatment.
- Clinical Evaluation
The initial evaluation of the patient includes history, physical examination, review of pertinent diagnostic studies and reports, and communication with the referring physician and other physicians involved in the patient's care. The extent of the tumor must be determined and recorded for staging. Staging facilitates treatment decisions, determines the prognosis of the patient, and enables a comparison of treatment results. Clinical evaluation and staging are discussed in the "ACR Practice Guideline for Radiation Oncology."
- Establishing Treatment Goals
LDR brachytherapy is indicated for treatment when the target volume can be well defined and is accessible to source placement. Brachytherapy is commonly used as adjunctive treatment to accompany external beam therapy, increasing the total dose to a specified target volume.
The goal of treatment (curative, palliative, or to establish local tumor control) should be documented as clearly as possible. Treatment options and their relative merits and risks should be discussed with the patient. Integration of brachytherapy with external beam or other therapies is necessary to define the intended course of treatment. A summary of the consultation should be communicated to the referring physician. See the "ACR Practice Guideline for Communication: Radiation Oncology."
- Informed Consent
Informed consent must be obtained and documented as logistically feasible. See the "ACR Practice Guideline on Informed Consent – Radiation Oncology."
- Applicator/Source Insertion
Oncologic practice, including brachytherapy, commonly requires the interaction of multiple specialists. The choice and placement of afterloading applicators and the loading and unloading of radioactive sources are the responsibility of the radiation oncologist.
Each type of brachytherapy procedure has its own set of unique characteristics. The brachytherapy team should operate according to an established system of procedural steps that have been developed by the radiation oncologist and brachytherapy team members. This systematic approach to applicator or source insertion should include a description of preimplantation procedures, sedation or anesthesia needs, applicator options, and insertion techniques. Standard orders or care guidelines may enhance the systematic approach to the insertion process.
- Treatment Planning
LDR brachytherapy is administered according to the written, signed, and dated prescription of the radiation oncologist. Before treatment, the final prescription must designate the treatment site, the radionuclide used, the number of sources, the planned total dose, and the dose rate at designated points. Applicator geometry and source positions are defined with localization images or cross-sectional imaging. The specific radionuclides are designated by the radiation oncologist, as part of the LDR prescription. Computerized dosimetry is performed by the medical physicist or his/her designee and approved by the radiation oncologist. Independent verification of brachytherapy parameters (by another person or another method) is done pretreatment (see the Equipment section in the original guideline).
- Treatment Delivery
LDR sources are manually or remotely loaded into applicators to deliver the prescribed treatment. If treatment modification is required, such modification must be documented. Treatment delivery must be subject to detailed scrutiny as described in the patient and personnel safety section below.
- Radiation Safety Considerations
Patients should be provided with written descriptions of the radiation protection guidelines, including, but not limited to, discussion of potential limitations on patient contact with minors and pregnant women.
Safety considerations should be consistent with state and federal regulations. The radiation oncologist, the medical physicist, and the radiation safety officer should define the radiation safety guidelines.
- Patient Evaluation during Temporary Implants
The radiation oncologist evaluates patients on a regular basis during their brachytherapy treatment. Applicator and source placement, medical condition, and radiation safety issues should be addressed during the course of therapy. The patient's progress through therapy is documented in the hospital chart. At the end of treatment, the patient and room must be surveyed to ensure that all radiation sources have been retrieved.
- Treatment Summary
At the conclusion of the course of treatment, a written summary of the treatment delivery parameters should be generated, including the total dose of brachytherapy and the total dose of external beam therapy if given, treatment technique, treatment volume, any acute side effects, clinical course, and patient disposition.
- Follow-Up Evaluation
Patients treated with brachytherapy should be evaluated after treatment at regular intervals by the radiation oncologist for response and early and late effects on normal tissues. See the "ACR Practice Guideline for Radiation Oncology."
Qualifications of Personnel
The brachytherapy team includes the physician, medical physicist, dosimetrist, radiation therapist, nurse, and radiation safety officer. See the original guideline for specific qualifications and credentials of the brachytherapy team.
Patient Selection Criteria
The use of brachytherapy is integral to the treatment of many malignancies, especially gynecologic, head and neck, sarcomas, bronchus and trachea, central nervous system (CNS), gastrointestinal and genitourinary malignancies. LDR prostate brachytherapy is discussed in the NGC summary of the ACR–ASTRO Practice Guideline for Transperineal Permanent Brachytherapy of Prostate Cancer. Temporary and permanent techniques can be used, depending on the clinical presentation as well as the experience, preference, and expertise of the treating physician.
In recent years, HDR brachytherapy has become more commonly used in many locales, and details of brachytherapy indications are included in the HDR practice guideline reference. LDR brachytherapy remains an appropriate method of dose delivery in clinical situations where brachytherapy is indicated.
See the original guideline document for information about equipment specifications.
Patient and Personnel Safety
Patient protection measures include those related to medical safety and radiation protection.
- Patient Protection Measures Should Include:
- A radiation exposure-monitoring program, as required by the NRC or appropriate state agencies
- Annual (re)training of staff in emergency procedures in case of equipment malfunction, and brachytherapy-specific quality management procedures
- Charting systems and forms for dose specification, definition and delivery of treatment parameters, and recording and summation of brachytherapy and external beam therapy treatment
- A physics quality assurance program for ensuring accurate dose delivery to the patient
- A system for the radiation oncologist and medical physicist to verify independently (by another person or another method) pertinent brachytherapy parameters to be used in each procedure (e.g., source model, radionuclide, source strength, dose rate, total dose, and treatment duration) prior to LDR brachytherapy
- Personnel Safety Measures Should Include:
- A radiation exposure-monitoring program, as required by the NRC or appropriate state agencies
- Routine leak testing of all sealed sources, as required by regulatory agencies
- Appropriate safety equipment for use of sealed sources
Continuing medical education programs should include radiation oncologists, medical physicists, dosimetrists, nurses, and radiation therapy staff. Radiation safety programs should also include hospital-based personnel who will be involved with brachytherapy patients. Educational programs used for both initial training and retraining must cover the following:
- The safe operation of LDR applicators, sources, and manual or remote afterloading equipment, as appropriate to the individual's responsibilities.
- Treatment techniques and new developments in radiation oncology and brachytherapy.
The program should be in accordance with the "ACR Practice Guideline for Continuing Medical Education (CME)."
Reporting should be in accordance with the "ACR Practice Guideline for Communication: Radiation Oncology." There should be documentation of parameters such as the actual number of sources, source strength(s), treatment duration (for temporary implants), and total dose after the implant has been completed.