Therapy Medical Events in 2012

Summary A patient undergoing external beam radiation therapy received a fractionated dose of 14 Gy in 2 Gray fractions to an area that was approximately 15.6 cm from the intended treatment site.
Root Cause The treatment error was due to improper marking of the isocenter following laser alignment on the patient's external body contour. A CT scanner table movement was required to align the field set lasers with the anticipated isocenter. The actual direction of the table movement was in the opposite direction than assumed. At that point the isocenter was incorrectly marked. The treatment plan was correctly generated, and the treatment plan was reviewed and received physician and physics approval. Treatment port film verification on the first day of treatment was performed, but there was a failure to recognize the improper location of the isocenter and treatment commenced. A subsequent set of port films were again reviewed and erroneously approved. At the interval of the third porting of the treatment fields it was recognized that the isocenter was far inferior to the anticipated site. At this point treatment was paused.
Corrective Action Corrective action includes re-training personnel on the use of the Tumor-Loc software used with the CT scanner, implementing a policy that all patients are to have the day before their first treatment dedicated to filming instead of trying to perform it on the same day as and immediately prior to their first treatment, and implementation of a double check policy that addresses isocenter placement on the patient, as visualized by the radiation therapist and physicist, dosimetrist or other therapist.
Effect on Patient The facility reviewed the patient dosimetry with regard to the normal tissues unintentionally irradiated and expects no adverse effects in the short or long term related to the seven treatments delivered.
Summary A patient undergoing radiation therapy to the spine received a single fractionated dose of 3 Gy to L3-L5, an area approximately 20 cm from the intended treatment site of T10-L1.
Root Cause The patient was incorrectly setup on the treatment couch by two therapists. After the therapists cleared and exited the treatment vault, the therapist who was operating the treatment unit noted that the treatment couch was out of tolerance as compared to its position during the previous treatment fraction. Per policy, if a significant treatment couch deviation is identified, the patient setup is required to be rechecked visually by the therapists (including a verification of isocenter, light field, lasers) and a setup verification film must be acquired. A setup image was acquired and the setup film was reviewed by a third therapist but the patient's setup was not rechecked in the treatment room. The patient's image was approved and treatment began.

At the time of treatment, it appears that the therapists did not carefully review the patient's setup instructions. Although uncertain, it is believed that the therapists aligned the patient to skin marks that are typically used to level the patient rather than using the skin marks that denote the treatment isocenter. It was also apparent that one of the therapists did not give proper attention to review of the setup images for verification of the treatment fields.
Corrective Action Two therapists received a verbal warning and suggestions on how to avoid a recurrence of this incident. The third therapist who reviewed the patient's setup image but did not review the patient setup in the treatment room received disciplinary notice. All therapists were reminded treatment cannot commence unless each person involved in the treatment participates in a pre-treatment meeting inside the treatment room to review the patient's chart, including the patient's name, the written directive, the equipment necessary for treatment, the set-up marks, and the rationale for imaging the patient. It was also agreed that whoever initiates the patient's treatment must verify the patient's setup image. Additionally, all therapists in the department reviewed relevant departmental patient setup, imaging, and override policies and procedures.
Effect on Patient Based on the prescribing physician and colleagues review of the images of the incorrectly placed treatment field, there is no overlap between the intended and actual treatment sites. No long-term adverse effects are expected from the delivery of a single fraction of 3 Gy to the unintended site. The prescribing physician has discussed the incident and the expected effects with the patient.
Summary A patient undergoing external beam radiation therapy received one treatment fraction to an area that was approximately 6 cm inferior to the intended treatment site.
Root Cause The treatment error was due to improperly matching images acquired the first day of treatment to the initial set up images. Normally, a complete set of orthogonal images are performed on the first treatment day to verify treatment location. In this situation only an AP image was taken. The lack of having orthogonal images led to a mismatch in vertebrae on the two sets of images. The event was discovered the day after it occurred via a review of port images by staff members and the prescribing physician. The patient was notified at the following treatment.
Corrective Action A Quality Assurance Incident Report was filled out and reviewed by all staff involved. To prevent a possible recurrence it was decided that from now on orthogonal set up fields will always be performed on new patients on the first day of treatment.
Effect on Patient There were no reported acute side effects to the patient from the event and the facility believes that it caused no meaningful additional risk of cancer induction to the patient.

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