Therapy Misadministrations in 2008

Event
Summary A patient undergoing palliative spine radiosurgery of the thoracic spine received an unintended dose of 9.8 Gy to the T3 vertebra due to errors in treatment planning and geometry. The intended treatment dose of 16 Gy was to be administered in a single treatment to the T4 vertebral region of the spine but was administered to the T3 vertebral region instead. In a typical treatment of 16 Gy to the T4 vertebra (primary site) the adjacent T3 vertebra would receive about 6.3 Gy. Therefore, the T3 vertebra received about 56% more than usual. Due to the misalignment, the T4 vertebra received about 7.4 Gy or 54% less than the intended 16 Gy treatment dose. The facility discovered the treatment planning and misalignment errors when the patient was undergoing treatment planning for additional tumor sites.
Root Cause Several factors contributed to the misadministration. Most notable were the facts that no individual counted the vertebra to ensure that the proper site was being targeted and there was no independent check of the treatment plan prior to administering the single therapeutic dose.
Corrective Action
  • Requiring the physician be present at the time of virtual simulation in order to place the treatment isocenter at the correct position
  • Requiring independent verification by the physician, dosimetrist, planning physicist and chart checking physicist that the treatment area corresponds to the prescribed area
  • Requiring that all spine stereotactic radiosurgery undergo a quality assurance chart review.
Effect on Patient No adverse effects were noted by the patient or are expected. An additional treatment to the primary site will be performed at a later date.
Event
Summary A patient undergoing radiation therapy received three treatment fractions in excess of the intended prescription for the treatment course. The patient received 37.8 Gy instead of 32.4 Gy, a difference of 17%.
Root Cause The patient was treated at another hospital with an initial dose of 18 Gy. The physician prescribed another 18 Gy in 10 fractions for total dose of 36 Gy. Near end of treatment, the patient was reevaluated and the physician increased the total prescribed dose to 50.4 Gy. At the time the new prescription was ordered, the facility failed to account for the initial 18 Gy delivered at the first hospital. The patient received the higher dose for three too many treatment fractions before the error was caught at the next physics QA.
Corrective Action Staff training was conducted with respect to prescriptions in the paper chart. When physicians include previous treatment information in the prescription, this information will be entered in the facility's Record-and-Verify system.
Effect on Patient Unknown.
Event
Summary A patient undergoing radiation treatment for lung cancer received 6.83 Gy of unintended dose.
Root Cause The patient was set-up for treatment according to written instructions. Port films were taken and checked by the radiation oncologist. The films were found to be incorrect and this was traced to the set-up instructions being in error. However, the discovery of this error and the corrected set-up instructions were not recorded in the patient's treatment record. As a result the patient received three treatments with the isocenter placed 5.2 cm too far to the left.
Corrective Action This was discovered after the third treatment and reported to the attending physician and the physicist. A discussion then occurred with the therapist who did not record the correction to the setup instructions. The importance of following procedures and recording needed changes in patient setup was emphasized. The quality assurance failure was discussed in the weekly chart rounds of the radiation oncology department.
Effect on Patient The facility determined that medically this will have no adverse impact on this patient.

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