Some frequently asked questions about radiation therapy safety measures
What measures are in place to catch and prevent errors?
The linear accelerator (LINAC), the machine that delivers radiation therapy to patients, has redundancy systems to control and monitor radiation doses and direction. These systems shut off the LINAC if it is not performing to specifications.
All LINACs undergo an extensive set of quality assurance measurements to ensure that radiation therapy is delivered correctly and that the system for planning radiotherapy treatments is fully in sync with each LINAC. This is followed by a schedule of
daily, monthly, and annual tests to monitor LINAC performance.
A system of independent checks is in place to verify that the calculations used to program the LINAC and position each patient are correct.
All new treatment plans are examined by clinical faculty at meetings known as chart rounds. During these meetings, physicians, treatment planners, physicists, and radiation therapists perform peer reviews of treatment plans and patient charts.
All patients on treatment are monitored by physicians at regular intervals over the course of their therapy.
Patient positioning is regularly verified with X-ray films, which are reviewed by attending physicians.
A non-punitive safety reporting system encourages any member of the department to report errors or near misses. All such reports are reviewed by the multidisciplinary Quality Improvement Committee. This committee suggests improvements in department processes
and communicates with hospital safety committees as well as the Massachusetts Department of Public Health's Radiation Control Program.
What safety checks do staff perform?
Safety checks are conducted by at every phase of machinery operation and treatment planning and delivery. They include:
Linear accelerator safety: Before a LINAC is placed in service, an extensive set of acceptance and commissioning measurements ensures that the machine is working properly and complies fully with the treatment modeling system.
These measurements are verified by an independent assessment by the Radiological Physics Center, which provides auditing services to radiation oncology departments
across the country.
Every morning, staff conduct safety checks of the machinery's dose calibrations and body-positioning features. More detailed checks of mechanical and imaging equipment are conducted monthly, and comprehensive testing is performed annually.
Treatment planning: Radiation therapy physicists and senior therapists conduct independent reviews of all patients' treatment plans. Intensity modulated radiation therapy (IMRT) plans are first delivered on a test basis to a plastic model
to ensure the LINAC will deliver the planned treatment accurately.
Treatment delivery: Settings for the dose and shape of the radiation beam are automatically transferred from the treatment planning system to the LINAC to avoid transcription errors or miscommunications.
A Record and Verify system ensures the LINAC is programmed as planned and logs the delivery of treatment. The Record and Verify system will not allow the LINAC to treat a patient if it is programmed differently than the treatment plan.
Video monitors enable staff to view radiotherapy treatments in progress. Automated bar-coding system ensures proper patient identification, both as the patient enters the department and as treatment information is displayed on the LINAC. A mandatory safety
pause occurs prior to first treatment.
High-level review of proposed new treatments: Approval from the New Technology Committee, which includes senior representatives from each section of the department, is required for all proposed new treatments. The committee reviews policies,
procedures, and the safety record for proposed new treatments and recommends needed resources.
Chart checks: Patient medical charts receive an initial review by a Quality Chart Therapist. During chart or new patient rounds, all patient charts and treatment plans are peer-reviewed by all Radiation Therapy faculty and staff as well
as representatives from every section of the department.
Separate chart reviews are conducted on all brachytherapy cases, in which radioactive "seeds" are placed in cancerous tissue. Radiotherapy physicists check patient charts weekly and after the conclusion of treatment. Physicians assess patients throughout
their treatment and review verification films that confirm patient set-up at least weekly.
How do we know these checks are sufficient?
Dana-Farber and Brigham and Women's maintain a quality assurance system for reporting adverse events and near misses. All such events are reviewed by the Department's Quality Improvement Committee and are reported to the hospital safety committees and
state regulators when appropriate.
Such incidents may trigger a Root Cause Analysis, in which specialists investigate the causes of the problem and formulate plans for preventing it in the future. Our safety record is well documented and very good, but we constantly strive to improve it.
What is the inspection and certification program for radiation therapy machines?
Every morning, staff conduct safety checks of the machinery's radiation output, beam shaping devices, imaging, and body-positioning features. More extensive tests are carried out according to a schedule of weekly, monthly, and annual measurements.
Engineers trained in LINAC systems perform preventive maintenance on a quarterly basis following the guidelines of the LINAC manufacturer. Manufacturer engineers may be consulted and brought in as needed.
How many therapists are involved in complex treatment plans?
No treatment is performed with fewer than two therapists. Each machine is staffed by a group of therapists with oversight from a senior therapist. Busy machines often have more than two therapists present.
What level of reporting does the Commonwealth of Massachusetts require?
The Department of Public Health's Radiation Control Program requires reporting of mistreatments that meet a variety of criteria. These include treating the incorrect patient, the incorrect site,
using the incorrect modality, or treatments that deviate from the specifications of the planned treatment. The criteria for these "misadministrations" are detailed in the program's regulation CMR 120.435.