Glasgow radiotherapy accident, 2006


Treatment Date: January 5-31, 2006

Location: Glasgow, Scotland, United Kingdom

Type of event: Radiation Therapy Overexposure

Description:
A 15-year-old female patient had undergone radiation therapy to treat her brain tumor at Beatson Oncology Centre in Glasgow.  She was given 19 treatments over a period of time, which started in January 5, 2006. As a consequence of human error, all treatments were far in excess of the prescribed dose by about 60 percent. The error was not identified until after her 2nd to last treatments were administered, shortly before the patient was informed in February 1. Symptoms as of early February 2006 included large sores on the scalp and ears and permanently higher than normal body temperature. The total dose was reported as potentially fatal; the localized dose to the brain and neck posed a risk of brain damage, paralysis, or death through damage to blood vessels in nerve tissue. The patient's condition, including damage to the eyes, had improved by late February in response to hyperbaric treatment. In October 19 of that same year, the patient died from as yet unspecified causes; she had been recovering from surgery in September to remove fluid from her brain. An investigation into the cause of the accident is reportedly in its final stages as of October. Reports indicate that 39 other patients at Beatson had received overdoses during radiotherapy between 1985 and 2006, most with no adverse results.

Consequence: 1 death.

Person involved: Lisa Norris, 15-year old patient

Prescribed dose: 1st course:  1.75 Gy x 25 fractions to the whole CNS ≈ 35 Gy
                             2nd course: 1.80 Gy x 11 fractions to the taget tumor ≈ 19.8 Gy

Dose calculation made by the radiographer, for the 20 fractions prescribed:

Daily MU = 1.75 x 91 = 159 MU (used the erroneous entry of 91 MU per 100 centiGrays)

Correct Calculation:

1.75 x 54 = 94.5 MU (54MU/cGy is the correct output for the machine)

Actual dose received by the Central Nervous System:

159 MU is equivalent to 2.92 Gy/fraction x 19 fractions = 55.48 Gy

Excess radiation dose:

 [(55.48 Gy - 35 Gy) / 35 Gy ] * 100 ≈ 60% radiation overexposure

Decision: The treatment was stopped as instructed by the radiation oncologist and abandoned the 2nd course.

Lesson’s learned:
1. Management and quality system responsibilities must be clearly and unambiguously assigned and understood by all and must be subject to a proper system of accountability through regular audit of performance.

2. There must be an appropriate degree of managerial commitment at all levels to the maintenance of an effective quality system.

3. Staffing of treatment planning and delivery units must be reviewed regularly to ensure that levels are suitable and sufficient in terms of (a) the numbers of staff and (b) the required levels of training, experience and seniority. Such review should take account of routine demands for treatment of patients, research and development and maintenance of quality systems and of any unusual pressures such as the commissioning of new equipment or new systems of working. It is not sufficient to define staffing complements on the guidelines of professional bodies alone.

4. The introduction of new equipment or new systems of working must be accompanied by a thorough review of the implications for patient and staff safety, both positive and negative. Such reviews should be conducted in accordance with a well defined plan and the outcomes documented formally.

5. Where systems of working allow for on-the-job training by completion of tasks under supervision, there must be a clear definition of the nature of supervision that is required. In particular, where the task in question has implication for the safety of patients or staff, supervision must be ‘direct’ in the sense that the supervisor must have direct involvement in overseeing all aspects of the work of the trainee.

6. Management should ensure that all staff involved in the planning and delivery of procedures involving ionising radiation are appropriately trained and that this training includes a proper understanding of the requirements for quality system working and awareness of the lessons learned from incidents reported previously.

7. The scheduling of demand for treatment planning must be such as to ensure that sufficient time is allowed for the work to be allocated to appropriately trained staff.

Methods/Procedures performed to mitigate the effect:

Dr. Philip James, the Medical Director of Ninewells Hospital, offered treatment in a hyperbaric
chamber for 14 days to reduce the effects of the overdose. He stated in his interview with BBC
News that damage to skin and blood cells was a reasonably common side effect of radiation
treatment and through this treatment there will be an increase of oxygen available in the teenager body and therefore will recover at a faster rate.

Own procedure/steps/actions/recommendations to prevent the accident/incident to recur in our department:

a. Working with awareness and alertness: Accidental exposures have occurred owing to inattention to details, and lack of alertness and awareness. This could also be made worse if the personnel have to work in conditions prone to distractions.
b. Procedures: Accidental exposures have occurred when there is a lack of procedures and checks, or when they are not comprehensive, documented or fully implemented.
c. Training and understanding: Accidental exposures have occurred when there is a lack of qualified and well-trained staff, with necessary educational background and specialized training.
d. Responsibilities: Accidental exposures have occurred when there are gaps and ambiguities in the functions of personnel along the lines of authority and responsibility. In these cases, safety critical tasks have been insufficiently covered.

Preventive Measures:

1. Independent calculation check. This is vital to be able to find parameters that are not the same as intended because many mistakes in the calculation process are due to mistakes in the act of transferring information.

2. Clinical peer review of treatment preparation (e.g., dose and volume to be irradiated).

3. Clinical monitoring of adverse effects in patients.

4. Documentation systems for procedures.

5. Mandatory comprehensive training of all staff. It is important that staff have a full understanding of the equipment being used as well as the data used.

6. The department should make sure that all responsibilities are allocated and understood, and that the members of staff they have been allocated to are educated according and kept up-to-date in training.

Videos:

Health: Lisa Norris died after overdose of cancer treatment
Health: Teenage cancer patients dies following radiation overdose

References:

1. Holmberg O. Accident Prevention in Radiotherapy. Biomedical Imaging and Intervention Journal 2007; 3(2):e27.




2. Williams M. Radiotherapy Near Misses, Incidents and Errors: Radiotherapy Incident at Glasgow. Clinical Oncology 2007; 19(1):1-3.




3. Unintended overexposure of patient Lisa Norris during radiotherapy treatment at the Beatson Oncology Centre, Glasgow in January 2006 investigated by the inspector appointed by the Scottish Ministers for The Ionising Radiation (Medical Exposures) Regulations 2000.