Tomorrow I report for one of my six-month radiation follow-ups. My radiation oncologist will review how I've fared for the past two years since my left breast was zapped, day after day, week after week, in an aggressive attempt to keep cancer from returning to the same local area where it first reared its ugly head. How horrified I would be if I learned the machines used to treat my cancer were faulty, that they did not in fact do anything aggressive, that they were essentially ineffective.Hundreds of brain cancer patients may be hearing this horrific news, now that malfunctioning machines have been ordered shut down following a manufacturer's warning.
Brainlab of Munich, Germany claims a small targeting error occurred with their machines but that it is unlikely to cause problems for patients. If I were one of these patients, I would still be worried. Targeting the tumor bed area is crucial in any cancer treatment. I don't like the sound of "targeting error," regardless of how minor it may be.
There are 550 Brainlab radiotherapy machines in use worldwide, the largest concentration of them in the United States. The malfunction is believed to have occurred in just seven models, located at two hospitals in France, one in Spain, and two in the United States. The Cleveland Clinic is one and has discontinued use of the machine. So has Valley Medical Center in the Seattle suburb of Renton, Washington.
1. Specific Mechanical Component/Software Incompatibility Resulted in 1.25 mm Shift in Target Area Alignment in Radiosurgery Treatment
A mechanical component/software incompatibility caused by a specific combination of the BrainLAB Target Positioner version 40700-3A for Leksell headrings and BrainLAB planning software resulted in a 1.25 mm shift in target area alignment during radiosurgery treatment. Two hospitals in the US were performing radiosurgery using this specific configuration. Seven hospitals have purchased this configuration worldwide, six of which were in clinical use—two are located in the US, four in France.
The shift in target area alignment for this specific configuration of mechanical components and software used in radiosurgery was discovered by a BrainLAB support engineer and a customer during an installation procedure. A custom-made test, performed in addition to the normal tests for commissioning a system, detected a shift in alignment from the intended target treatment area of 1.25 mm. This alignment shift falls within accepted safety margins and known deviations published in the field of radiosurgery and for this reason was not discovered earlier during routine product test and customer commissioning procedures.
Investigation has shown the cause to be a mechanical component/software incompatibility for one specific BrainLAB configuration. The shift in target area alignment only occurs through the combination of the BrainLAB Target Positioner version 40700-3A for Leksell headrings and BrainLAB software. All other BrainLAB configurations of mechanical components and software were also tested during the investigation and it was confirmed that the problem is limited to this specific configuration.
BrainLAB follows a strict quality process to investigate all reports of complaints or potential incidents. This process includes a prompt investigation and notification of the customer and relevant regulatory authorities as soon as possible once a preliminary investigation of the issue is completed. A Product Notification Letter is sent to alert customers of potential problems and ensure safe and effective use of BrainLAB products. To ensure that the Product Notification Letter is given priority, standard BrainLAB quality procedure requires strongly worded warnings, except in cases where all risk of injury can be excluded.
Upon confirmation of the cause, BrainLAB immediately notified all customers with this specific configuration, as well as the FDA (Mfr. Report 8043933-2007-00007). These written notifications were sent on June 5, 2007. Notification was received by the FDA and the two affected US customers on June 5, 2007. Because of time zone differences, all seven customers had received notification as of June 6, 2007. The Product Notification Letter informed the customers that a shift in target alignment of 1.25 mm was found in the specific configuration at the seven facilities.
Unintentional radiation of critical structures in the brain can have potentially serious side effects. However, due to the nature and direction of this specific shift in target area alignment, the potential risk of side effects is low.
BrainLAB has consulted with physicists, radiation oncologists and neurosurgeons performing radiosurgery to understand the potential effects of this shift in target area alignment. The conclusion from these discussions is that there appears to be minimal risk of adverse effects because the shift in target area alignment falls within the calculated safety margin used in treatments.
In radiosurgery, a high-energy beam of radiation is focused on a target area from various angles. During treatment, the radiation delivery device moves around the patient so that the beam penetrates the target area from different angles, avoiding vital structures. Where the beams intersect, a higher-concentration of the radiation dose is created that is strong enough to effectively treat tumors. While the target area receives the full dose of radiation, the surrounding area receives a lesser dose, reducing the effect on normal tissue. The shape of the tumor determines the target area, which in turn decides the diameter of the radiation beam. For effective treatment, the target area must be large enough to encompass the entire tumor. A safety margin around the tumor is included in calculations to ensure that no portion of the tumor falls outside of the target area.
In cranial radiosurgery, a headring is first securely fastened to the head of the patient and then a series of CT scans is acquired. A treatment plan is created using the CT scans, determining the optimal delivery of radiation for the patient. The patient is then placed into position for treatment. It is during patient positioning that the shift in target area alignment occurred. The alignment of the radiation beam shifted from the intended target area, but remained within the safety margin. For this reason, this shift in alignment was not detected until a supplemental, custom-made test was conducted.
While the potential for risk may be minimal, BrainLAB regrets any emotional distress caused to patients due to this incident and any confusion caused to our customers. BrainLAB is working closely with clinicians and authorities to provide information about this incident, as well as taking corrective and preventive actions. In addition, BrainLAB has replaced the affected configuration at each customer site with another that is not affected by this incompatibility issue, as well as supporting all sites in their individual investigations.
BrainLAB complies with globally recognized standards for the development and testing of radiosurgery products. All BrainLAB products are certified for medical use and comply with regulatory requirements in the markets where our products are sold and used. BrainLAB currently has 63 FDA cleared medical devices for distribution in the US (the first cleared in 1992, the latest in April 2007).
Worldwide, there are more than 550 hospitals using BrainLAB for radiosurgery today. For more than 12 years, BrainLAB has been providing innovative and highly effective cancer care to thousands of patients. BrainLAB is committed to improving the quality and precision of its products for the safety and well being of patients. This specific configuration of BrainLAB Target Positioner version 40700-3A for Leksell headrings and BrainLAB planning software should not be confused with complete radiosurgery systems. Centers offering radiosurgery treatments without this specific configuration do not experience this shift in target area alignment.
Posted at 1:13PM on Aug 1st 2007 by Kate Franco