Transcript Costa Rican accid

RADIOTHERAPY ACCIDENT IN COSTA
RICA - CAUSE AND PREVENTION OF
RADIATION ACCIDENTS IN HOSPITALS
Module XIX
Cause and prevention of
radiation 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
2
Main 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

3
Severity of effects in
surviving 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

4
Findings of IAEA team in
July 1997

42 patients died by July 1997
(10 months after exposure)
7 deaths primarily due to overexposure
 22 deaths not related to the overexposure
 13 insufficient data

5
Findings of IAEA mission
in Oct 1998

61 patients died by Oct 1998
(25 months after exposure)
13 deaths primarily due to overexposure
 4 possibly related to overexposure
 35 death not related to overexposure
 9 insufficient data

6
Permanent epilation
(high risk for brain necrosis)
7
Effects on the skin

severe erythema in the sacral region
8
Brain necrosis and paralysis
• lethargy, ataxy
• dementia
• leuko-enceophalopathy
• cerebral necrosis
• deafness
• paralysis (myelopathy)
• spinal cord changes
9
Cause and prevention of
radiation 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

10
Distribution of expected radiation effects from
standard radiotherapy protocols and clinical
examinations of the surviving patients, %
Category of complications
Distribution for July 1997
standard
(10 months)
radiotherapy
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
11
Prevention of radiation
accidents in hospitals

Regulations should cover training and
competence required to deal with potentially
hazardous radiotherapy sources

Specific training of staff should be provided
before they work in a radiotherapy unit
12
Prevention of radiation
accidents 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
13
Prevention of radiation
accidents 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

14
Prevention of radiation
accidents in hospitals
Early and reliable information and clear
communication crucial to good management of
radiation accidents
 Radiotherapy records should be uniform, clear,
consistent and complete
 Use defence-in-depth methodology to test and
ensure that quality assurance programme has
sufficient safety layers to make accidents very
unlikely

15
Lessons learned
Recommendations
Define responsibilities, develop
procedures and supervise compliance
 Implement, monitor and enforce existing
regulations as soon as possible

16
Lessons learned
Recommendations
 Establish
and foster safety culture
and provide education and training
 Implement additional educational
programmes for radiotherapy staff
17
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
18
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
19