Biomedical Engineering Reference
In-Depth Information
Table 5.2
Radioactivity Nomenclature
orifices (each nostril, ears, mouth, and rectum)
should be swabbed and a 24-hour stool and urine
collection should be done if internal contamination
is considered. The swabs and 24-hour collections
should be assayed for radioactivity. This informa-
tion will help determine the extent of the exposure,
need for internal decontamination, and prognosis
(Table 5.1).
In the case of injury and radiological expo-
sure, aggressive therapy will be required to allow
survival. Surgical priorities for acute or life-
threatening injury must precede any treatment
priority for associated radiation injury. Because
radiologic contamination poses little risk to health
care providers, these patients are prioritized by
standard trauma protocols. In the presence of trau-
matic injury, hypotension must be considered to
be due to hypovolemia and not radiological injury.
While the skin is impermeable to most radionu-
clides, particles can be absorbed through wounds.
Therefore, contaminated wounds should be decon-
taminated with copious irrigation. It should be
noted that any residual fluid in the wound might
hide weak beta and alpha emissions from detec-
tors. Because wound healing is markedly compro-
mised by radiation injury, open wounds that are
allowed to heal by secondary intention will serve
as a potentially fatal nidus of infection in the radio-
logically injured patient. If possible, all wounds
should be extensively debrided and closed as soon
as possible.
Patients with combined trauma and radiolog-
ical contamination pose a significant challenge to
the medical system. Given the immunosuppres-
sive effects of radiation exposure and associated
delayed wound healing, there is a narrow time
window for accomplishing definitive and recon-
structive surgical care (Figure 5.4). The surgical
correction of injuries must be done within 36-48
hours post injury or delayed 6-8 weeks. The
surgical system maybe faced with a large number
of patients who need surgical correction of wounds
within a narrow window of time. This differs from
the normal time course of routine trauma and could
put a large burden on the medical system caring
for these patients while they recover from their
radiation illness with untreated wounds.
Radio-
activity
Absorbed
dose
Dose
equivalent
Exposure
Common
units
Curie
(Ci)
Rad
Rem
Roentgen
(R)
SI units
Becquerel
(Bq)
Gray
(Gy)
Sievert
(Sv)
Coulomb/
kilogram
(C/kg)
Figure 5.3
Systematic survey for radiologic contamination
AFRR1.
Passing a radiation detector over the entire body
can readily assess the presence of radiological
contamination. The goal should be less than
1mrem per hour of beta and 1000 disintegra-
tions per min alpha radiation. If present, decon-
tamination of the skin and hair is accomplished
by washing. However, open wounds should be
covered before decontamination to prevent further
contamination. Care should be taken to avoid
scrubbing or abrading the skin as this can break
the protective barrier of the skin and introduce
contaminates. If practical, the decontamination
effluent should be sequestered and disposed of
appropriately. For all patients with confirmed
or suspected exposure, a complete blood count
should be obtained on presentation and after
24 hours to determine the absolute lymphocyte
count. At 24 hours, an absolute lymphocyte count
<1000/mm
3
suggests moderate exposure and
<500/mm
3
suggests severe exposure. All body
