Therapy Medical Events in 2014

2014 Event 1
Summary A patient was undergoing external beam radiation therapy using two different isocenters. Since two isocenters were planned, a table shift was required in between the two treatments. The therapists completed the first treatment and then proceeded to the second treatment but did not apply the appropriate table shift to position the patient at the second isocenter. The second treatment field missed the intended region and exposed the first region to > 50% additional prescription dose for that fraction. The discrepancy was noticed during the treatment before the second field was completed.
Root Cause The therapist did not notice that this patient was to be treated with two isocenters. If the two treatment sites are close together, they are often treated with a single isocenter using the accelerator's asymmetric jaws to accommodate the two irradiation regions. The therapist assumed this was the way this patient was being treated.
Corrective Action Multi-isocentric treatments will be clearly marked in the Pre-Treatment Checklist and Field Set Up Notes. All field isocenters will be verified with orthogonal imaging prior to initial treatment. The planned field set up will be reviewed on the day of initial treatment, and documented in the Pre-Treatment checklist. Pre-Treatment "Time Out" before every treatment, will include: patient name, birthdate, treatment site, technique, isocenter location.
Effect on Patient While the single fraction event resulted in a geometric miss and > 50% additional dose over the daily prescription for the one treatment site, the cumulative event dose, after a remedial fractionation schedule, is not expected to cause any significant clinical effects on the patient.
2014 Event 2
Summary A patient received external beam radiation treatments to a site approximately 8.5 cm superior to the intended treatment site. On the first day of treatment the patient was setup on the treatment unit to her computed tomography (CT) reference marks. Shifts from this reference mark to the treatment position were made based on couch/patient movements provided by the planning dosimetrist. Unbeknownst to the therapists, the longitudinal shift was incorrectly transcribed to the setup instructions. As such, the patient was misaligned by approximately 8.5 cm.

Once the patient was setup in the treatment room, portal images were acquired to verify the alignment of the patient. The acquired images were reviewed by the therapists but the longitudinal shift was not noticed when observing bony anatomy. The patient was then treated to an area mostly superior to the intended region.

Following treatment, the therapists marked the incorrect position of the isocenter on patient's skin surface. The anterior/posterior (AP) and lateral megavoltage (MV) portal images of the site were also subsequently reviewed and approved later that evening by the Prescribing Physician.

The patient returned for her second treatment fraction. She was aligned to the isocenter marked on Day 1. An AP portal image was acquired and briefly reviewed by the therapists, again without noticing a discrepancy, and the patient was treated.

The patient returned for her third treatment fraction. She was scheduled on a different linear accelerator that is equipped with both kilo- and megavoltage imaging. Additionally, two new therapists were involved in her treatment. The therapists aligned the patient to the marked isocenter and noticed that the treatment field was superior to where they would have anticipated for the prescribed treatment site (T11-L1 spine). They returned to the original CT reference marks and applied the shifts based on the values provided by the planning dosimetrist, and noted that these shifts were consistent with the location of the marked isocenter. However, to investigate further, the therapists also acquired kV portal images of the patient. Upon reviewing these images, the therapists noticed the patient was misaligned by approximately 8.5 cm.

Root Cause
  • Dosimetrists are manually transcribing digital data (patient's shifts).
  • The questionnaire documenting the Joint Commission-recommended 'Time Out' was not completed.
  • The setup misalignment was not noted by the therapists (Days I and 2) or the attending physician (Day I) during review of the MV or prior to the second treatment.
  • The region from T10-L2 is difficult to setup and image due to the limited landmarks in this region. This is further complicated by the quality of MV images in this region.
  • The patient was receiving treatment to multiple (three) treatment sites.
Corrective Action
  • Process changed to include a double-check of the manually-entered shifts from isocenter prior to treatment.
  • The patient setup document modified so that shifts are listed in the exact order they are specified by the treatment planning system. Additionally, the label for each shift is now consistent between the setup document and the treatment planning system.
  • Automatic method to digitally generate and document shifts to avoid transcription errors is being investigated.
  • Policies (such as the Time Out) reviewed and reinforced. Process established to assess compliance with these policies at regular intervals.
  • Prior to treatment, the need for kV imaging will be determined for cases where it may be difficult to view relevant anatomy with MV imaging.
Effect on Patient Based on the review of the images of the incorrectly placed treatment field, only a 0.8-cm overlap between the intended and actual treatment site was noted. Thus, the majority of the intended site was not treated during the patient's first two treatment fractions, and an unintended area superior to that region was unintentionally treated to a dose of 6 Gy. No acute or long-term adverse effects are expected from the delivery of 6 Gy to the unintended site. A new plan was then created in which the upper field border was decreased to minimize the area of overlap from the previous treatment, and an additional 3.5 Gy per fraction was delivered for three treatment fractions. A total dose of 16.5 Gy was delivered to the intended site. The full 30 Gy was not delivered as the patient opted for hospice.
2014 Event 3
Summary A patient was undergoing breast radiation therapy with bilateral posterior axillary boost (PAB) supraclavicular treatments. After filming the "Left" PAB field correctly the therapists called up and treated with the incorrect "Right" PAB field.
Root Cause
  • This was an unusual situation where two PAB fields were used.
  • Because two PAB fields exist, the therapists did not notice the wrong one was selected.
  • Although there is a time-out policy, it does not require that laterality be addressed.
  • The R/V warning about an incorrect table position was ignored.
Corrective Action The time-out policy has been modified to include that laterality be verified for each field.

Although a warning appeared that the table was in the incorrect position, the warning was ignored. The therapists see these warnings on a regular basis, and the vast majority are "nuisance" warning appearing due to tolerance tables being poorly designed. Over time the therapist have become de-sensitized to these warnings. The tolerance tables are being re-designed to reduce the occurrence of nuisance warnings.

Effect on Patient Although the treatment to the left PAB represents a partial geographic miss, the other 27 fractions delivered are expected to result in an overall acceptable treatment.
2014 Event 4
Summary A patient received part of one fraction of radiation treatment to an area superior to the intended area. Patient was to receive treatment to his larynx. During preparation, and after images and isocenter location were verified by staff and dosimetry, and before treatment began, a staff member moved the patient superior to the isocenter. The reference setup marks were remarked but the staff member failed to move the patient back to the isocenter for the treatment. This resulted in the patient receiving treatment to his face instead of his neck. Staff discovered the error and stopped treatment after 3/5 of planned fields were treated.
Root Cause Imaging was not repeated after moving the patient off isocenter. There was no specific department policy about reimaging after moves are made prior to treatment.
Corrective Action A new department policy will specifically state that once images are verified, all involved staff will confer prior to allowing treatment to begin. Thereafter, the patient will have immediate treatment delivery. Any shifts off isocenter after preliminary imaging will require reimaging prior to treatment delivery.
Effect on Patient The doses that the unintended structures received were evaluated and will not cause clinical harm.
2014 Event 5
Summary Due to an error in patient positioning, the prostate of a patient was only partially treated during the first four treatment fractions with a linear accelerator. Also, an unintended dose of approximately 8 Gy was delivered to the patient's rectum.

The facility was using a real time tracking system that employs radiofrequency beacons implanted in the prostate for accurate initial positioning and continuous monitoring of prostate motion during treatments. Prior to treatment, the beacon coordinates are located on the patient's treatment planning computed tomography scan. The beacon positions are manually entered into the system for each accelerator that will be used during the course of treatment.

While preparing for initial patient treatment, the therapists noted difficulties with the system tracking the location of the prostate. This prompted notification of the on-call physicist. Similar discrepancies were also found on Days 2 and 3. On Day 4, there were problems again and the patient was moved to a different treatment unit. Prior to the fifth treatment a broader team was notified of the problem and the Attending Physician was alerted that there had been set-up issues on the previous treatment days.

A physician informed the patient that further treatments would be postponed until an investigation was completed. The patient was re-simulated with CT and a new treatment plan was developed taking into account the previously incorrect treatment fractions. Treatment was recommenced.

Root Cause
  • Standard operating procedure (SOP) was not followed for this patient with respect to timing of documenting the location of the beacon coordinates from the planning system.
  • The SOP was also inadequate by using a screen shot rather than the original treatment plan which led to the input of the wrong coordinates into the tracking system.
  • There was a lack of a second check of positioning, such as with radiographic imaging.
  • There was a failure to have a clear process to notify individuals when problems were encountered to ensure adequate follow up before treatment continues.
Corrective Action
  • The treatment plan evaluation checklist for Physics was updated to include a review of the beacon coordinates compared to the final approved treatment plan.
  • Treatment set up policy was revised to require radiographic verification of beacon locations on the first day of treatment for each new treatment plan.
  • Staff re-educated to report any patient set up problems in the departmental web-based incident learning system.
Effect on Patient No acute or long term adverse effects are expected from the unintended dose. The Attending Physician has discussed the incident and expected effects with the patient.
2014 Event 6
Summary A patient undergoing external beam radiation therapy had the initial radiation treatment applied to the incorrect skin lesion on the patient's back.

The patient was initially seen by an Attending Physician and a Medical Resident in which they identified and noted that the treatment location was a lesion on the patient's right back and that the patient confirmed the location. The patient returned on another day for a simulation and treatment. The Attending Physician was not in the clinic that day. Another Attending Physician met with the Resident and the patient to plan the patient's treatment. They defined the region with a marker on the patient's skin. The patient confirmed the location. Treatment was designed and delivered according to the plan. The next day the patient spoke with the Resident by phone and reported that his wife noticed that the incorrect region was marked on his skin. The patient's Attending Physician was notified. After a review of the patient's medical record the Attending Physician confirmed that the incorrect site was treated. The correct location was simulated and treatment was resumed.

Root Cause
  • Inadequate review of relevant documentation, including a Dermatology photo, in the patient's medical record during the consultation and treatment planning process. There was a reliance on the patient's word with respect to the treatment location.
  • There was a lack of consultation between the Attending Physician and the Prescribing Physician during the treatment planning process.
  • There was confusion due to the terminology used in the written documentation to describe the treatment location.
Corrective Action
  • Staff and Residents will be reminded that they must review the Dermatology photo prior to consult.
  • The possibility of patients only being simulated when the patient's Attending Physician is on-duty will be evaluated at an upcoming meeting of the Variance Committee.
  • If a patient sees a physician other than his or her Attending Physician, that physician must review relevant records prior to treatment. Patient verification may be a double check, but his or her verification must be verified by a pathology report or other source of reference.
  • A software tool is under development that will aid physicians in tracking the status of their own patients at key parts of the simulation and planning process.
Effect on Patient An unintended dose of 2 Gy was delivered to the wrong treatment site. No acute or long term effects are expected from the unintended dose. The Prescribing Physician has discussed the incident and the expected effects with the patient.
2014 Event 7
Summary Patient was to have keloids removed from both ears surgically followed by radiation treatments. A radiation treatment plan was created for both the left and right ear ahead of the surgical procedure. During surgery it was decided to remove only the keloid from the left ear. When therapy began, both ears were treated for 3 fractions before a therapist recognized that the right ear had no surgery performed.
Root Cause The fact that the right ear did not have surgery was not communicated to the radiation therapists. The primary physician was on vacation at this time and a locum physician reviewed the patient prior to treatment and approved the clinical setup for both ears.
Corrective Action
  • Keloid patients will have a check list requiring the therapists to verify that surgery had been performed on the treatment site before radiation is delivered.
  • An attempt will be made to prevent the scheduling of keloid surgeries while the primary physician is away to maintain continuity of care.
Effect on Patient It is believed that the unintended radiation on the right ear will have little to no adverse effect on the patient but will have no significant benefit to the intact keloid of the right ear.
2014 Event 8
Summary Patient receiving prescribed external beam radiotherapy to the left breast was treated using the left breast parameters of a different patient. The therapy delivered was a single fraction only. The dose at the reference point in the center of the breast was 2.9 % high. This resulted in a slight difference in intended treatment area compared to the actual treatment area. The dose provided to the anterior portion of the breast was slightly higher than intended.
Root Cause The event was precipitated by inappropriate interrogatories. The patient was not asked to provide her name and birthdate, but was asked to confirm that the provided name and birthdate was hers. The patient response was positive affirmation.
Corrective Action Existing procedures include requesting the patient provide their name and birthdate which was not done. Staff will be provided with education on the possibility that a patient could respond affirmatively to the wrong name and birthdate provided. Staff must ask for the patient to provide their name and birthdate.
Effect on Patient The facility staff anticipates no sequelae or compromise in treatment outcome. It is believed there was no harm done to the patient. The patient was not notified of the misadministration. The treating physician believes it is not in the best interest of the patient to inform her of the incident.
2014 Event 9
Summary A patient was prescribed a treatment to two regions of the skull, the Right Frontal Calvarium (RFC) and the Left Parieto-occipital Calvarium (LPC). The first region (RFC) was irradiated as planned after acquiring and evaluating localization images. The second region (LPC) was not irradiated as planned due to positioning error caused by using localization images obtained during treatment instead of the planned localization images before treatment. After completing treatment of both the RFC and LPC fields, an inconsistency between the field images and the localization images was noticed by the therapists.
Root Cause A number of factors contributed to the event but the root cause was a failure to follow imaging policy and the imaging directive. The imaging policy required that that on the first treatment for all patients localization imaging will be performed prior to treatment. There was confusion over having two plans, one of which was imaged prior to treatment.
Corrective Action The imaging policy will be reviewed by all staff and will be clarified. The policy will be included in the therapist treatment competency. In addition, the Time Out policy, which requires those involved in the treatment to take a moment before treatment starts to verbally cite any concerns or lack thereof before continuing with treatment, will be reviewed. Also measures will be taken to increase the culture of safety, including more frequent reviews of treatment related policies, discussion of upcoming new patient plans, and more discussion on near misses.
Effect on Patient The prescribed region of the RFC received some overlap of treatment from the fields designated to deliver dose to the LPC. The physician determined that this overlap, and the related prescription dose delivered to normal tissues, would not have a harmful effect on the patient.

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