Advanced Clinical Practice - Society of Urologic Nurses and

Systematic Review of the Literature
The Risk of Radiation Exposure
To Assisting Staff in Urological
Procedures: A Literature Review
Tarun Jindal
S
ince the advent and advancement of endourology, fluoroscopy has become an integral part of
urologic practice. Percutaneous
nephrolithotomy (PCNL) and
extracorporeal shock wave lithotripsy (ESWL) now form the first
line of treatment for urinary calculi. Retrograde pyelography
(RGP) is an essentail part of urology, predominantly as a diagnostic procedure and an adjunctive
to other urologic interventions,
such as PCNL, ureteric stenting,
and ureterorenoscopy (URS).
This increased use of fluoroscopy has led to the risk of occupational exposure of the urologist and assisting staff to radiation and its hazards (Hellawell,
Mutch, Thevendran, Wells, &
Morgan, 2005; Kumar, 2008;
Tonnessen & Pounds, 2011).
Fluoroscopy utilizes X-rays,
which are high energy ionizing
radiations. These ionizing radiations enter the human body, and
by the virtue of their energy,
cause cellular damage and even
cell death. The amount of damage depends upon the total dose,
duration of exposure, and the site
of exposure. This damage can
lead to biological effects, which
may be stochastic (independent
of the dosage received) or deter-
Tarun Jindal, MS, is a Post-Doctoral
Trainee in Urology, Department of Urology,
Calcutta National Medical College, Kolkata,
India.
© 2013 Society of Urologic Nurses and Associates
Jindal, T. (2013). The risk of radiation exposure to assisting staff in urological procedures: A literature review. Urologic Nursing, 33(3).
Fluoroscopy is an integral part of urology and is used for various procedures,
such as extra-corporeal shock wave lithotripsy, percutaneous nephrolithotomy,
uretero-renoscopy, and ureteral stenting. This technique exposes the urologist
and assistants to radiation, which is known to have deleterious effects. Although
there have been studies that determine the amount of exposure and the risks to
the operating urologist, the risk to the assisting staff remains largely undetermined. A literature review was conducted to determine the risk of radiation exposure during urological procedures, with emphasis on data concerning assisting
staff. Data from nine major studies is presented in this article.
Key Words:
Radiation, urology, fluoroscopy, extra-corporeal shock wave
lithotripsy, percutaneous nephrolithotomy, uretero-renoscopy,
ureteral stenting, nurse, risk, X-ray, recommendations.
ministic (dose-dependent effects)
(Rehani et al., 2010).
Considering the risks associated with radiation exposure,
numerous guidelines have been
proposed that set the annual permissible limit for the amount of
exposure. Some amount of radiation is present in the environment; thus, human beings are
constantly exposed to radiation.
Medical personnel, especially
urologists, form a special group
of individuals who, apart from
this environmental exposure, are
also exposed to radiation due to
their profession. The major
source of radiation is the C-arm,
which is used to produce images
for surgical guidance. The radiation exposure can be direct or
indirect. Direct exposure is when
the person is in the line of the
radiation rays produced by the
UROLOGIC NURSING / May-June / Volume 33 Number 3 / Epub Ahead of Print
fluoroscopy machine. Indirect
exposure occurs from scattered
rays resulting from the interaction of the primary beam with the
patient that disseminate in all
directions (Kumari et al., 2006).
Review of the available literature describes numerous studies
that assess the risk of radiation to
the operating surgeon. However,
the risk to assistants and nursing
staff has not been given the necessary attention. This article presents results of a literature review
conducted to determine the risk of
radiation exposure during urologic procedures, with emphasis on
data concerning assisting staff.
Quantification of Radiation Exposure
Many different units are used
to quantify radiation. The most
commonly used units are Système
1
international d’unités (SI units)
and conventional units. SI units
are the standard units of measurement recommended by the
International System of Units, and
conventional units are often used
by various authors for quantification of radiation. See Table 1 for
details of the commonly used
units.
Table 1.
Quantification of Radiation Exposure: Details of the Commonly
Used Units
Unit (Abbreviation)
SI/Conventional
SI
Measures the amount of
radiation exposure. It is the
radiation required to create 1
coulomb of charge in 1 kilogram
of matter.
Roentgen (R)
Conventional
Measures the amount of
radiation exposure.
Recommendations for Radiation
Exposure
The International Commission on Radiation Protection
(ICRP) recommends guidelines
for radiation exposure. For medical personnel, it has been recommended that the exposure should
not exceed 20 mSv per year. The
maximum duration for which
this level of exposure is allowed
is 5 years, hence a maximal total
body exposure over 5 years
should not exceed 100 mSv. ICRP
has also given organ-specific permissible limits for radiation
exposure. The maximum permissible exposure recommended is
150 mSv for the eye and 500 mSv
for the skin as well as the extremities. These values can be used
for the subset of population
whose specific organs are exposed to radiation rather than the
whole body. ICRP also advocates
the principle of “as low as reasonably achievable” (ALARA).
The ALARA principle accepts
that some amount of radiation
exposure may be inevitable. ICRP
recommends the radiation exposure should be based upon the
principles of justification, optimization, and dose limitation.
Measures should be taken to
reduce the radiation exposure in
the form of provision of shielding
from radiation, limiting the time
of exposure, and increasing the
distance between the radiation
source and the personnel. Therefore, a “reasonably” low level of
radiation exposure should be
attained. Medical personnel involved in radiation should be
screened monthly or quarterly to
quantify the radiation exposure,
and the total exposure should not
be allowed to exceed the annual
permissible limits (Wrixon, 2008).
2
Definition
Coulomb per kilogram
(C/kg)
1 Roentgen = 2.58×10-4 C/kg
Gray (Gy)
SI
It is the unit of radiation absorption. It is the amount of radiation
required to deposit 1 Joule of
energy in 1 kilogram of matter.
Radiation absorbed
dose (rad)
Conventional
Measures the amount of
radiation absorbed by a target.
A dose of 1 rad means the 100
ergs of radiation energy has
been absorbed per gram of
absorbing material/tissue.
100 rad = 1 Gy
Sievert (Sv)
SI
It is the unit for equivalent
absorbed radiation dose. It
quantifies the biological risk of
radiation exposure.
1 Sv = 1000 mSv = 106 mSv
Roentgen equivalent
man (rem)
Conventional
It is the unit for equivalent
absorbed radiation dose.
100 rem = 1 Sv
Note: SI = Système international d’unités.
Materials and Methods
The databases of major search
engines, such as PubMed,
Highwire Press, Scopus, and
Google scholar, were searched
with the key words radiation,
urology, risk, recommendations,
X-ray, and fluoroscopy. All major
articles found were analyzed.
Emphasis was given to the articles where assistants and nurses
constituted a significant part of
the study population. Details
regarding the site of exposure,
total duration of exposure, and
the amount of exposure received,
if available, were recorded.
The method of measurement
of radiation exposure varied in
the literature. The majority of the
studies employed the thermoluminescence dosimetry for quantification of exposure. Thermo-
luminescence dosimetry uses
chips impregnated with crystals
that can be worn by medical personnel. These crystals absorb
radiation, which can subsequently be measured to quantify the
amount of personal radiation
exposure. The studies reviewed
in this article used variable units
for the description of radiation
exposure. To provide homogenous data to facilitate comparison
between the studies, the amount
of exposure received has been
converted to µSv for all studies.
Results
A total of nine major studies
were found in the English literature that addressed the issue of
radiation exposure to the assistants and nurses. The studies,
with their findings, are outlined
UROLOGIC NURSING / May-June / Volume 33 Number 3 / Epub Ahead of Print
in Table 2. PCNL was the most
common urological procedure
studied for the assessment of the
radiation exposure. Only two
studies assessed the risk of exposure during other procedures,
such as ureterorenoscopy (URS),
RGP, and stenting. One study
addressed the issue of radiation
exposure during ESWL. Some
authors (Hellawell et al., 2005;
Majidpour, 2010) mentioned
organ-specific exposure, while
others (Giblin, Rubenstein,
Taylor, & Pahira, 1996; Kumari et
al., 2006) calculated the whole
body exposure.
Discussion
The biological effects of radiation pose a serious threat to
medical personnel. These can be
dependent on the total dose
(deterministic effects) or independent of dose (stochastic
effects). It is evident that smaller
doses of radiation, which are
generally encountered in many
diagnostic procedures, may not
exceed the threshold dose for
deterministic effects. However, a
probability still exists for stochastic effects. Radiation exposure has been linked to self-limiting diseases, such as skin erythema and cataracts, as well as to
life-threatening illnesses, such as
cancer and leukemia (Rehani et
al., 2010).
Data from this review of nine
studies revealed the amount of
exposure to assisting staff and
nurses during urologic procedures was low. The average
amount of exposure was less
than 2 µSv per case. Assistants
were exposed to higher levels of
radiation as compared to nurses.
One causative factor for this may
be that assistants are placed more
closely to the operating surgeon
and the radiation source. They
are therefore exposed to higher
amounts of radiation. This effect
has also been shown by
Hellawell et al. (2005), who
demonstrated the average distance of the surgeon, assistant,
and the nurse was approximately
75, 90, and 150 cm, respectively,
from the source of radiation. This
resulted in a lower exposure to
the nurse as compared to the surgeon and the assistant. Further,
the thyroid and lower extremities
of assistants were subjected to a
higher amount of radiation as
compared to other parts of the
body. The exposure to the head
was 0.05 µSv/case, while it was
0.01 µSv, 0.025 µSv, and 0.1 µSv
to the eyes, the fingers, and the
legs, respectively, per case
(Majidpour, 2010). The exposure
to thyroid was 2 µSv per case in
another study (Tse et al., 1999).
Considering ICRP recommendations, this exposure was well
below the maximum annual permissible limits. Even if the assistant was exposed to a workload
of 10 to 15 cases per week, the
total amount of exposure remains
well below the recommended
level.
The review also indicated
that radiation exposure was very
high in older studies. The mean
dose to which an assistant was
exposed ranged from 21 to 40
µSv/case in the 1980s (Bush,
Jones, & Brannen, 1985). In more
recent studies, this exposure was
shown to be less than 2 µSv/case
(Hellawell et al., 2005). Probable
reasons may include advancement in technology, increase in
urologists’ expertise to perform
endourological procedures, lesser requirement of fluoroscopy
during surgery, and better operating instruments. Decrease in fluoroscopy time, which was significantly higher in older studies as
compared to recent studies,
could also be an influencing factor. A single case of PCNL that
earlier required the fluoroscopic
guidance for approximately 20
minutes now requires only 4 to 6
minutes (see Table 2).
Recommendations
Even if results of this limited
review appear to be reassuring,
assisting staff should be aware of
the potential risk of the stochastic effects of radiation. Necessary
precautions are mandatory for
personnel exposed to any amount
of radiation. These include the
use of lead aprons to shield the
body, thyroid shields to protect
UROLOGIC NURSING / May-June / Volume 33 Number 3 / Epub Ahead of Print
the thyroid, and eye glasses to
protect the ocular lens. Assistants should distance themselves
as much as technically feasible
from the site of radiation. If not
actively involved in the procedure, assistants should withdraw
behind the lead screens. This can
help in reducing radiation exposure (Wrixon, 2008, Rehani et al.,
2010). It is also recommended
that all assisting staff wear
dosimeters so individual radiation exposure can be recorded. It
is important that techinical staff
perform periodic checks on the
fluoroscopy machines so excessive radiation dosing is not delivered (Kumar, 2008).
Radiological protection is
essential and should form an
integral part of the instruction of
urologists and allied medical
personnel who use radiation routinely as per ICRP recommendations. Interventional procedures
that depend on fluoroscopy are
technically demanding. Clinicians, therefore, need to be well
versed with these procedures
and also be conscious regarding
the requirements of proper radiological protection. At least 15
hours of training for urologists
and allied staff in radiological
protection have been recommended (Rehani et al., 2010).
Conclusion
Based on this literature review, assisting staff were well
within the maximum permissible
limits of annual radiation exposure during urologic procedures
utilizing fluoroscopy. However,
considering the ALARA principle, all measures should be taken
to reduce radiation exposure.
Assistants and nursing staff must
be mindful of the deleterious
effects of excessive radiation
exposure and take an active role
in reducing their exposure.
References
Baldock, C., Greener, A.G., & Batchelor, S.
(1992). Radiation dose to patients
and staff from Storz Modulith SL20
lithotripter. The Journal of Stone
Disease, 4(3), 216-219.
Bush, W.H., Jones, D., & Brannen, G.E.
(1985). Radiation dose to personnel
during percutaneous renal calculus
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Table 2.
Review of Major Studies Quantifying Radiation Exposure to the Assisting and Nursing Staff
during Urologic Procedures
Number
Author
Medical
Personnel
Number of
Procedures
Types of
Procedures
Duration of
Exposure
Mean Dose
1
Bush, Jones, &
Brannen, 1985
Assisting
nurse
77
PCNL
24 minutes
(mean)
40 mSv/case (measured
at the level of the neck)
Surgical
assistant
7
PCNL
27.8 minutes
(mean)
37 mSv/case to neck and
25 mSv/case to right and
left hand
Scrub nurse
7
PCNL
27.8 minutes
(mean)
12 mSv/case (measured
at the level of the neck)
Circulating
nurse
6
PCNL
Information
not available
19 mSv/case (measured
at the level of the neck)
2
Lowe, Auster, Beck,
Chang, & Marshall,
1986
Information not available
3
Rao et al., 1987
Scrub nurse
18
PCNL
21.9 minutes
(mean)
4
Baldock, Greener, &
Batchelor, 1992
Assisting staff
Information
not available
ESWL
Information
not available
4800 mSv annually
5
Giblin, Rubenstein,
Taylor, & Pahira, 1996
Assistant
5
PCNL
Information
not available
500 mSv/hour
6
Tse et al., 1999
Scrub nurse
20
PCNL, RGP,
stenting, URS
63.1 minutes
(for 20 cases)
40 mSV (for 20 cases)
to the thyroid
Assistant
24
PCNL, RGP,
stenting, URS
0.1 to 22.9
minutes
PCNL, RGP,
stenting, URS
0.1 to 22.9
minutes
7
Hellawell, Mutch,
Thevendran, Wells, &
Morgan, 2005
Nurse
8
9
24
Measurement done for
eyes and hands
2.1 ± 0.5 to 120 ± 30
mSv/case
Higher dose to legs
0.5 ± 0.1 to 24 ± 6
mSv/case
Higher dose to legs
Assisting
surgeon
50
PCNL
6.04 minutes
(range 1.8 to
12.16 minutes)
12 mSv/case
Technical
assistant
50
PCNL
6.04 minutes
(range 1.8 to
12.16 minutes)
2.6 mSv/case
Scrub nurse
50
PCNL
6.04 minutes
(range 1.8 to
12.16 minutes)
0.3 mSv/case
Floor nurse
50
PCNL
6.04 minutes
(range 1.8 to
12.16 minutes)
0.16 mSv/case
0.05, 0.01, 0.025, and
0.1 mSv to the head,
eye glasses, fingers,
and legs, respectively,
per case
Zero (0)
Kumari et al., 2006
Assistant
100
PCNL
4.5 minutes
(range 1 to 8
minutes)
Circulating
nurse
100
PCNL
4.5 minutes
(range 1 to
8 minutes)
Majidpour, 2010
Notes: PCNL = percutaneous nephrolithotomy, ESWL = extra corporeal shock wave lithotripsy, URS = ureterorenoscopy.
4
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