Brachytherapy is the use of radioactive isotopes to treat malignancies or benign conditions by means of a radioactive source placed close to or into the tumor or treatment site. 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 as treatment for prostate, head and neck, breast, cervical, and endometrial cancers as well as obstructive esophageal or bronchial lesions. LDR brachytherapy has been used since the late 1800s with a variety of sources including radium-226, cesium-137, and, more recently, iridium-192, iodine-125, and palladium-103. Such treatment can be given as interstitial, intracavitary, or intraluminal therapy to a wide variety of treatment sites. This guideline does not apply to intravascular brachytherapy.
LDR brachytherapy is accomplished by 1) temporary implants, after-loading radioactive sources into applicators that are placed into the patient, or 2) permanent implants, placing the isotope permanently into the cancerous tissue. Source handling can be manual, with source loading into the applicator or tissue by hand, or remote, 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.
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 National Guideline Clearinghouse (NGC) summary of the American College of Radiology (ACR) Practice Guideline for the Performance of Therapy with Unsealed Radiopharmaceutical Sources.
Process of Brachytherapy
The use of LDR brachytherapy is a complex 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. This will facilitate treatment decisions, determine the prognosis of the patient, and enable a comparison of treatment results.
- Establishing Treatment Goals
LDR brachytherapy is indicated for treatment where 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 therapy should be defined. A summary of the consultation should be communicated to the referring physician.
- Informed Consent
Informed consent must be obtained and documented.
- Applicator/Source Insertion
Oncologic practice, including brachytherapy, commonly requires the interaction of multiple specialists. The choice and placement of after-loading applicators and 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 steps, sedation or anesthesia procedures, the specific applicators used, and the 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 loading, the prescription must designate the treatment site, the isotope, the number of sources, the planned dose, and the dose rate to designated points. Applicator geometry and isotope positions are defined with simulation radiographs. The specific isotope positions 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 Patient and Personnel Safety section, below).
- 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 (see 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 of 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, 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.
Qualifications of Personnel
The brachytherapy team includes the physician, physicist, dosimetrist, radiation therapist, nurse, and radiation safety officer. Qualifications of the brachytherapy team include credentials listed below:
- Radiation Oncologist
Satisfactory completion of an Accreditation Council for Graduate Medical Education (ACGME) approved residency program in radiation oncology.
OR
Certification in Radiology by the American Board of Radiology of a physician who confines his/her professional practice to radiation oncology. Alternatively, certification in Radiation Oncology or Therapeutic Radiology by the American Board of Radiology, the American Osteopathic Board of Radiology, the Royal College of Physicians and Surgeons of Canada, or Le College des Medecins du Quebec may be considered proof of adequate physician qualifications.
- Qualified Medical Physicist
A Qualified Medical Physicist is an individual who is competent to practice independently in one or more of the subfields in medical physics. The American College of Radiology considers that certification and continuing education in the appropriate subfield(s) demonstrate that an individual is competent to practice one or more of the subfields in medical physics, and to be a Qualified Medical Physicist. The ACR recommends that the individual be certified in the appropriate subfield(s) by the American Board of Radiology (ABR).
The appropriate subfields of medical physics for this guideline are Therapeutic Radiological Physics and Radiological Physics.
The continuing education of a Qualified Medical Physicist should be in accordance with the ACR Practice Guideline for Continuing Medical Education (CME).
- Radiation Therapist
Must fulfill state licensing requirements and should have American Registry of Radiologic Technologists (ARRT) certification in radiation therapy.
- Medical Dosimetrist
Certification by the Medical Dosimetrist Certification Board is recommended.
- Nurse
State licensure as a registered nurse or practical nurse is recommended
Equipment
LDR brachytherapy requires a variety of applicators to be used with manual or remote LDR applicators. After-loading LDR units, applicators, treatment-planning computers and software, and procedure and treatment aids should be appropriately selected for the clinical applications. Regular inspection, maintenance, and repair of this equipment are mandatory. The physicist supervising the quality improvement program is responsible for documenting the maintenance and repair of manual equipment, remote after-loading units, and applicators. (See the ACR Technical Standard for the Performance of Brachytherapy Physics: Remotely Loaded HDR Sources.)
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 Nuclear Regulatory Commission (NRC) or appropriate state agencies.
- Annual training of staff in emergency procedures in case of equipment malfunction.
- Charting systems and forms for prescription, definition and delivery of treatment parameters, and recording and summation of brachytherapy and external beam therapy treatment.
- A physics program for ensuring accurate dose delivery to the patient.
- A system for the radiation oncologist and physicist to verify independently (by another person or another method) all brachytherapy parameters to be used in each procedure (source, isotope and activity, dose rate, total dose, treatment duration, etc.) prior to institution of LDR brachytherapy.
- Personnel safety measures should include:
- A radiation exposure-monitoring program, as required by the Nuclear Regulatory Commission or appropriate state agencies.
- Routine leak testing of all sealed sources, as required by regulatory agencies.
- Appropriate safety equipment for use of sealed sources.
Educational Program
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 initially and for retraining must cover the following:
- The safe operation of LDR applicators, sources, and manual or remote after-loading 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).
Documentation
Reporting should be in accordance with the ACR Practice Guideline for Communication: Radiation Oncology.
Quality Control and Improvement, Safety, Infection Control, and Patient Education Concerns
See the "Description of Implementation Strategy" field, below.
