radiotherapy accident in costa rica - cause and prevention of radiation accidents in hospitals...
TRANSCRIPT
RADIOTHERAPY ACCIDENT IN COSTA RADIOTHERAPY ACCIDENT IN COSTA RICA - CAUSE AND PREVENTION OF RICA - CAUSE AND PREVENTION OF
RADIATION ACCIDENTS IN HOSPITALS RADIATION ACCIDENTS IN HOSPITALS
Module XIX
2
Cause and prevention of Cause and prevention of radiation accidents in hospitalsradiation accidents in hospitals
Radiation accidents with severe and even fatal consequences do occur in medical facilities
Human error is most common cause of radiation accidents
3
Main initiating eventMain initiating event
22 Aug 1996, at San Juan de Dios Hospital in San Jose, Costa Rica, a calibration error was made for new 60-Co source
Consequently, the delivered dose to cancer patients was overestimated by about 60 %
By 27 Sept 96 115 patients treated
4
Severity of effects in Severity of effects in surviving 73 patientssurviving 73 patients
4 patients had catastrophic effects 16 marked effects and high risk for
future 26 not severe at that time 22 no effect of significance at that time 2 underexposed patients (radiotherapy
was discontinued) 3 could not be seen
5
Findings of IAEA team in Findings of IAEA team in July 1997July 1997
42 patients died by July 1997 42 patients died by July 1997 (10 months after exposure) (10 months after exposure)
7 deaths primarily due to overexposure 22 deaths not related to the overexposure 13 insufficient data
6
Findings of IAEA mission Findings of IAEA mission in Oct 1998in Oct 1998
61 patients died by Oct 199861 patients died by Oct 1998
(25 months after exposure) (25 months after exposure) 13 deaths primarily due to overexposure 4 possibly related to overexposure 35 death not related to overexposure 9 insufficient data
7
Permanent epilation Permanent epilation (high risk for brain necrosis)(high risk for brain necrosis)
8
Effects on the skinEffects on the skin
severe erythema in the sacral region
9
Brain necrosis and paralysis Brain necrosis and paralysis
• lethargy, ataxy
• dementia
• leuko-enceophalopathy
• cerebral necrosis
• deafness
• paralysis (myelopathy)
• spinal cord changes
10
Cause and prevention of Cause and prevention of radiation accidents in hospitalsradiation accidents in hospitals
Significant overdoses or underdoses (errors exceeding 10% of prescribed dose) result in unacceptable severe consequences
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, %
Category of complications Distribution forstandardradiotherapy
July 1997(10 months)
October 1998(25 months
*** Catastrophic complications 0 6 4
** Marked complications 1 23 24
* Increased complications 5 37 44
0 No complications 90 31 26
- Underexposed 4 3 2
12
Prevention of radiation Prevention of radiation accidents in hospitalsaccidents in hospitals
Regulations should cover training and competence required to deal with potentially hazardous radiotherapy sources
Specific trainingSpecific training of staff should be provided before they work in a radiotherapy unit
13
Prevention of radiation Prevention of radiation accidents in hospitalsaccidents in hospitals
Calibration of radiotherapy devices should be done by appropriately trained persons and independently checked
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 Prevention of radiation accidents in hospitalsaccidents in hospitals
In radiotherapy accidents, the tumour dose may not be the parameter of primary interest
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 Prevention of radiation accidents in hospitalsaccidents in hospitals
Early and reliable informationEarly and reliable information and clear communication crucial to good management of radiation accidents
Radiotherapy recordsRadiotherapy records should be uniform, clear, consistent and complete
Use defence-in-depth methodology to test and ensure that quality assurance programmequality assurance programme has sufficient safety layers to make accidents very unlikely
16
Lessons learned Recommendations
Define responsibilities, develop procedures and supervise compliance
Implement, monitor and enforce existing regulations as soon as possible
17
Lessons learned Recommendations
Establish and foster safety culturesafety culture and provide education and training
Implement additional educational programmes for radiotherapy staff
18
Lessons learned Recommendations
Implement quality assurance and record keeping programme
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