RADIOTHERAPY ACCIDENT IN COSTA RICA - CAUSE AND PREVENTION OF RADIATION ACCIDENTS IN HOSPITALS Module XIX

2 Cause and prevention of radiation accidents in hospitals l Radiation accidents with severe and even fatal consequences do occur in medical facilities l Human error is most common cause of radiation accidents

3 Main initiating event l 22 Aug 1996, at San Juan de Dios Hospital in San Jose, Costa Rica, a calibration error was made for new 60-Co source l Consequently, the delivered dose to cancer patients was overestimated by about 60 % l By 27 Sept patients treated

4 Severity of effects in surviving 73 patients l 4patients had catastrophic effects l 16marked effects and high risk for future l 26not severe at that time l 22no effect of significance at that time l 2 underexposed patients (radiotherapy was discontinued) l 3 could not be seen

5 Findings of IAEA team in July 1997 l 42 patients died by July 1997 (10 months after exposure) l 7deaths primarily due to overexposure l 22deaths not related to the overexposure l 13 insufficient data

6 Findings of IAEA mission in Oct 1998 l 61 patients died by Oct 1998 (25 months after exposure) (25 months after exposure) l 13deaths primarily due to overexposure l 4possibly related to overexposure l 35 death not related to overexposure l 9 insufficient data

7 Permanent epilation (high risk for brain necrosis)

8 Effects on the skin l severe erythema in the sacral region

9 Brain necrosis and paralysis lethargy, ataxy dementia leuko-enceophalopathy cerebral necrosis deafness paralysis (myelopathy) spinal cord changes

10 Cause and prevention of radiation accidents in hospitals l Significant overdoses or underdoses (errors exceeding 10% of prescribed dose) result in unacceptable severe consequences l Doses administered in fewer than normal sessions but with higher doses per treatment result in excessive number of early and late complications

11 Distribution of expected radiation effects from standard radiotherapy protocols and clinical examinations of the surviving patients, %

12 Prevention of radiation accidents in hospitals l Regulations should cover training and competence required to deal with potentially hazardous radiotherapy sources l Specific training l Specific training of staff should be provided before they work in a radiotherapy unit

13 Prevention of radiation accidents in hospitals l Calibration of radiotherapy devices should be done by appropriately trained persons and independently checked l When there is a high incidence and severity of acute side effects during radiotherapy treatment, further treatment should be stopped and the source calibration immediately checked

14 Prevention of radiation accidents in hospitals l In radiotherapy accidents, the tumour dose may not be the parameter of primary interest l Often the biologically equivalent 2 Gy per fraction dose to radiosensitive organs, e.g. intestine, spinal cord and heart, more important

15 Prevention of radiation accidents in hospitals l Early and reliable information l Early and reliable information and clear communication crucial to good management of radiation accidents l Radiotherapy records l Radiotherapy records should be uniform, clear, consistent and complete quality assurance programme l Use defence-in-depth methodology to test and ensure that quality assurance programme has sufficient safety layers to make accidents very unlikely

16 Lessons learned Recommendations l Define responsibilities, develop procedures and supervise compliance l Implement, monitor and enforce existing regulations as soon as possible

17 Lessons learned Recommendations safety culture l Establish and foster safety culture and provide education and training l Implement additional educational programmes for radiotherapy staff

18 Lessons learned Recommendations l Implement quality assurance and record keeping programme l Include verification of physical arrangements and clinical aids (patients’ charts) used in treatment verification of appropriate calibration and conditions of operation of dosimetry equipment

19 Lessons learned Recommendations regular and independent quality audit reviews of programme participation in intercomparison exercises such as IAEA-WHO postal dose check service procedures to take action if deviation found