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Home       > Electronic Reading       Room       > Document       Collections       > General       Communications       > Information       Notices       > 2000       > IN 2000-22

UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDSWASHINGTON, D.C. 20555-0001

December 18, 2000
NRC INFORMATION NOTICE 2000-22:  MEDICAL MISADMINISTRATIONS CAUSED BY HUMAN ERRORS INVOLVING       GAMMA STEREOTACTIC RADIOSURGERY (GAMMA KNIFE)- Addressees: 
- Purpose: 
- Description   of Circumstances: 
- Discussion: 
Addressees:
All medical licensees authorized to conduct gamma stereotactic radiosurgery treatments.
Purpose:
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to remind addressees of the importance of following written directives and treatment planning procedures, and the need to pay attention to detail during preparation and administration of gamma stereotactic radiosurgery. It is expected that recipients will review the information for applicability to their facilities and consider actions, as appropriate, to avoid similar problems. However, suggestions contained in this IN are not new NRC requirements; therefore, no specific action nor written response is required.
Description of Circumstances:
NRC has become aware of 16 medical misadministrations, involving gamma stereotactic radiosurgery, that have occurred during the past few years. Fifteen of these 16 misadministrations were attributed to human error, especially while entering data into a computer treatment program and during the verification of patient coordinate settings. The descriptions of the 15 misadministrations are summarized in Attachment 1.
Discussion:
The most common reported human error is the transposition of coordinate settings, mainly the Y and Z coordinates. Other human errors are the selection of incorrect parameters such as treatment sites, doses, and exposure times, and failure to follow established procedures.

Licensees have adopted the following corrective actions to prevent recurrence of misadministrations:
1)   A licensee requires two independent checks of the X, Y and Z       coordinate settings before each exposure, instead of one independent       check, to reduce the transposition of coordinates. In a "single check,"       the coordinates are called out and person A sets the coordinates, then       Person B checks them against the written treatment plan. In a "double       check," person A sets the coordinates, then Persons B and C independently       check them against the written treatment plan.2)Another licensee requires a minimum of three staff members to set the       X, Y, and Z coordinates on the stereotactic frame to reduce the       probability of transposition errors. Treatment is administered only after       the three staff members concur on the coordinate settings.3)A licensee limits the conversations in the treatment room to only       those required for the treatment of the patient, and restricts telephone       calls in the treatment control area. These actions reduce distractions to       members of the treatment team.4)A licensee requires the neurosurgeon, the radiation oncologist, and       the medical physicist to verify the treatment plan before each procedure.       The neurosurgeon and either the radiation physicist or the radiation       oncologist has to be physically present during the treatment. This       oversight improves procedure adherence and attention to   detail.5)A licensee requires marking each page of the patient treatment plan       with a unique name and time stamp that the radiation oncologist or medical       physicist has to initial before delivery of the radiosurgery treatment.       This prevents the transposition of a patient treatment sheet from one       medical file to another among patients receiving the same type of       treatment on the same day.
The medical physicist participation in the entire treatment-planning process is important, especially during the pretreatment review of the treatment plan. Neurosurgeon and radiation oncologist collaboration at critical points in the process, such as dose selection, approval of the written plan, and initiation of the treatment, is also essential. Licensees are reminded that 10 CFR 35.32(a)(1) requires that written directives be prepared before administration of gamma sterotactic radiosurgery. Subsections 35.32(a)(3) and (4) require that final treatment plans and related calculations, and each administration, are in accord with the respective written directives. It is important that written directives and procedures are kept up to date and provide adequate information. It is also important that management place a high value on staff following all procedures and directives; that all staff are adequately trained; and that training programs are effective in relaying necessary information. In all the cases listed in Attachment 1, written directives and procedures were in place. However, a lack of attention to detail, failure to adhere to the procedures and directives, or a failure to perform adequate, independent verification of treatment plans, patient identities, and treatment doses, contributed to misadministrations.

This information notice requires no specific action nor written response. If you have any questions about the information in this notice, please contact the technical contact listed below or the appropriate NRC regional office.
/RA/       
Donald A. Cool, DirectorDivision of Industrial and Medical Nuclear       SafetyOffice of Nuclear Material Safety and   Safeguards
Technical Contact:Roberto J. Torres, NMSS (301) 415-8112 E-mail:       rjt@nrc.govAttachments:1. Description       of event circumstances2. List of Recently Issued NMSS Information       Notices 3. List of Recently Issued NRC Information   Notices(ADAMS Accession Number ML003761619)
ATTACHMENT 1

IN 2000-22Page 1 of 3
DESCRIPTION OF EVENT CIRCUMSTANCES- A patient being treated for brain lesions was undergoing the fourth of   five planned treatments, when a treatment site received an unintended repeat   dose because of inattention to detail. The treatment site was supposed to   receive 1200 centiGray (cGy) (rad), but instead received 2400 cGy   (rad).  
- A patient being treated for pituitary adenoma received a dose of 1260 cGy   (rad) to an unintended site of his frontal lobe. The unintended site was   approximately 4.2 centimeters (cm) (1.65 inches) away from the intended site.   The treatment planning for the patient was uneventful. A nurse and the medical   physicist checked the adjustments on the device stereotactic frame for   accuracy. Nonetheless, when staff members started to set up the patient for a   second administration, they realized the Y and Z coordinates on the   stereotactic frame were transposed on the previous treatment.  
- A gamma knife unit was set up incorrectly and delivered a dose to the   wrong site on a patient's brain. A radiosurgery treatment was to be delivered   to Patient A's left trigeminal nerve. On that same date, Patient B was also   scheduled to receive the same treatment as Patient A. During the signature   phase of treatment plan approval, Patient B's dose delivery treatment sheet   was inadvertently transposed with that of Patient A. Therefore, Patient A was   treated with the radiosurgery parameters that were intended for Patient B.   This resulted in a dose of 8000 cGy (rad) delivered to the wrong treatment   site. The actual dose received by the intended treatment site was 20 cGy   (rad).  
- A patient being treated for an arteriovenous malformation, in the left   part of his brain, received treatment to the right side of his brain. During   the treatment planning process, the computer software refused several times to   accept the "correct" orientation (as viewed by the planning team) of the   patient's image. Eventually, the neurosurgeon and the medical physicist   instructed the computer system to accept the image they believed to be   correct. After initiating the treatment, the physicist noticed that the X   coordinates indicated a definite right-side target and stopped the treatment.   The physicist and the neurosurgeon were unaware that a different angiography   room had been used to acquire the patient's X-ray images during the quality   assurance (QA) runs. QA tests had been performed in what the physicist   believed to be the only angiographic suite. This room was equipped in such a   way that the lateral X-ray tube could only be on the patient's right side,   with the patient in a supine position. The actual angiographs were performed   in another room where the tube focus was on the patient's left side.  
- A patient received a dose of 3000 cGy (rad) to the intended site of his   brain, instead of the prescribed dose of 2300 cGy (rad). This event was caused   because the licensee did not follow the treatment plan and used an incorrect   collimator helmet.  
- A patient received a dose 54.5 percent below the intended dose. The   prescribed dose was 2200 cGy (rad) and the patient received a dose of 1000 cGy   (rad). The treatment physician failed to enter the prescribed dose into the   treatment planning system. This resulted in the system's default value (1000   cGy) (rad) being used for the treatment. The error was missed by all three   team members involved in the treatment planning.  
- A patient received a total treatment dose that differed from the   prescribed dose by more than 10 percent. As the third treatment site was being   prepared for treatment administration, the licensee discovered that the   patient's position would have to be changed from supine to prone, to   physically achieve the appropriate coordinates. When replanning the third area   of treatment, the neurosurgeon and the medical physicist realized the Y and Z   coordinates were transposed during the previous treatment.  
- A patient was prescribed a treatment of 9000 cGy (rad) to the left   trigeminal nerve of his brain. However, the treatment was actually   administered to the right trigeminal nerve. The medical physicist had   inadvertedly prepared a treatment plan for the wrong side of the patient's   head and the radiation oncologist (authorized user) signed the treatment plan   without properly verifying the neurosurgeon's request identifying the correct   site.  
- A patient received treatment to an unintended area of his brain. The   treatment plan called for three doses of radiation. The first treatment was   set up and delivered to the patient. When the coordinates for the second   treatment were set, it was discovered that the Y and Z coordinates had been   transposed on the first treatment. The prescribed dose for the first treatment   was 1100 cGy (rad), but 50 cGy (rad) were administered. The licensee indicated   that possible contributing factors to this event were: a) the reduction to two   staff members, instead of the usual three, for setting up the patient; and b)   the Z coordinate was set before attaching the Z bar to the stereotactic   frame.  
- A patient received a dose of 2600 cGy (rad) to the first of three lesions,   instead of the prescribed dose of 1600 cGy (rad). During preparation of the   treatment plan for the second lesion, the settings for the first treatment   site were unintentionally used. This resulted in two treatments to the first   lesion. The error was not identified, even though the neurosurgeon and the   radiation oncologist reviewed and signed the treatment plan.  
- A patient being treated for brain cancer received a therapeutic underdose   of 12.3 percent. The licensee selected the wrong-year date in the treatment   planning system, which resulted in the administration of 1052 cGy (rad)   instead of the prescribed dose of 1200 cGy (rad). The licensee failed to   recognize a computer warning that the entered treatment date differed from the   system date.  
- A patient received treatment to an unintended area of his brain, resulting   in a dose of 500 cGy (rad) being delivered 1 to 5 cm (0.4 to 2 inches) from   the intended location. An error in treatment geometry occurred because   licensee staff members transposed the Y and Z coordinates.  
- A patient received treatment to an unintended area of his brain in excess   of 1000 cGy (rad). The treatment plan that was developed indicated a single   exposure of 1600 cGy (rad) to a brain lesion. One of the seven parameter   settings of the gamma knife, the "left Y" coordinate, was erroneously set,   resulting in a 5-millimeter (0.2 inch) translocation of the treatment volume.   This event was caused by one member of the treatment team setting an initial   erroneous coordinate setting, and by another member of the treatment team   failing to independently verify the coordinate setting.  
- A patient received a therapeutic overdose to the intended part of his   brain. The dose was 11 percent greater than the prescribed dose. The   authorized user failed to enter the correct exposure time in the   treatment-planning software system, and the exposure time from the previous   treatment fraction was used.  
- A patient received treatment to an unintended area of his brain, resulting   in a dose of 460 cGy (rad) being delivered 11-millimeter (0.43 inches) from   the intended location. The radiosurgery treatment prescribed three   administrations of 1200 cGy (rad) each to a tumor volume. When the licensee   started setting up the coordinates for the second administration, it was   discovered that the Y and Z coordinates had been transposed on the first   administration. The event was caused because the licensee had not checked the   coordinates of the patient's head frame against those required by the written   treatment plan prior to the first treatment administration.