Radiation protection project

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Shua Almut
awa

200023791

6MI


1



Radiation protection project


Submitted by: Shua Almutawa

200023791

Submitted to : Alistair Simpson


Steve Terney

Submitted date: 2
2

May 2004



Shua Almut
awa

200023791

6MI


2


Terms of reference:


This report is written as a part of Radiation Science III
(IMAG300) and Health Commu
nications III (ENGL 306) course. This
report is about radiation protection. In order to write this report many
resources are used such as Internet sites, books and class notes.


Abstract


This report is about radiation protection, it is in three parts.

Par
t A about the use of p
ractical examples to explain how
altering the following factors will reduce patient does



X
-
ray field size



Lead shielding



Patient position



KVp



Viewing conditions



Compression

Part B is about
how to reduce the

radiation risks to

a

patie
nt
with a long term illness who require
plain films, CT and interventional
examinations.

In part C I am a Chief Radiographer and Fatma is
a pregnant
radiographer who wishes

to work in reception desk for the rest of her
pregnancy, I had to make some changes

to her working practice so
she can continue her work as radiographer.






Shua Almut
awa

200023791

6MI


3

Part A




Among the world it is expected from the professional
radiographers to keep the radiation
dose

to patients and staffs to the
minimum level. In order to maintain this, the

radiographers need to
know what affect the dose to that patients and how to reduce it.

The
re
are some factors that could affect
the radiation dose to the patients
and staff
such as
:


Patient position



The position of the patient can affect the patient d
ose
because
the b
ody’s organs have differen
t sensitivity to the radiation.
For
example
in lateral lumber spine it is recommended to do left lateral
because
liver is less sensitive to th
e radiation than the intestine, and
by doing that the dose to the intes
tine will be less.


X
-
ray field size



X
-
ray

field size is one of the factors that co
ntrol the doses to the
patients. Collimation will directed the beam
to the part of the body and
it reduce scatter radiation and it improve the image contrast.
Reducing
sca
tter means less dose to the patient.


KVp



It is important to keep the exposure in to ALARA (As Low As
Reasonably Achievable)
principle
.

It means that
the
exposure must
be
Shua Almut
awa

200023791

6MI


4

kept

as low as reasonably achievable and the individual dose levels
should remain b
elow the maximum allowed levels.




10 KVp rule can be useful, increase the exposure 10 KVP and
reduce the MAs to the half.

This will reduce the patient dose because
the mAs
(the

radiation quantity) will be reduced.


Compression



Compression is the act o
f flattening soft tissue to improve optical
density. It is an important in many aspects of conventional radiology
and mammography.


Compression brings all the tissue closer to the image receptor
and it reduces the focal spot blur, absorption blurs and sca
tters
radiation. It
results

in thinner tissue and therefore less scatter
radiation
. Add to that it improve contrast resolution and the ability to
detect small, low contrast lesions and high contrast micro calcification.
All this
is
result
ing

in lower dose
to the patient.

(
Bushong
, 1993)


Lead shielding




Shielding is one way of
protection
;

it is implied with lead or
concrete which will attenuate radiations when they are placed between
the source of radiation and the exposed object. There are different
asp
ects of shielding in diagnostic radiology:

1.

X
-
ray Tube shielding

2.

Room shielding

3.

personnel shielding

4.

patient shielding


Shua Almut
awa

200023791

6MI


5



X
-
ray tube shielding



The x
-
ray tube housing is lined with
lead because when the
x
-
ray
is

produced they are scattered in all directio
ns.
This shielding will
allow only the useful
beam to pass through a window and that will
reduce the amount of the weak and scatter radiation
.


Room shielding



The

x
-
ray

rooms in
radiology
department

are designed to
protect the people outside the room fro
m the scatter radiation. The x
-
ray rooms are protective by two types of protective barriers:

a.

Primary Barrier: the barrier that directly attained by the
primary beam.

b.

Secondary Barrier: this is the barrier that is exposed to
the secondary radiation wither
from the leakage from x
-
ray tube or by scattered radiation from the patient.



Control room shielding



It is important to protect the control area where the
radiographers work. The control room is protected in two ways:

a.

The walls and the viewing window
s of the controlling
room should be shielded by lead.

b.

The location of the controlling room. The control room
should
not be

located in the direction of the primary
beam.


Personnel shielding



This type of shielding is to protect the staff in radiology
depa
rtment. This shielding can be achieved by different methods: staff
should not be in the radiation environment if not necessary.
Radiographers should keep distance between them and the sores of
Shua Almut
awa

200023791

6MI


6

radiation
(inverse

square law).

Lead aprons, hand gloves and th
yroid
shields should be used when necessary.



Patient shielding




Even that the patient is the one who receives the highest
does some radiographers does not really be attention to them
. It is
recommended that the thyroid, breast and gonads shielding is g
iven to
the patient.


(Protection, 2004)


Viewing conditions



Viewing conditions has an affect on radiation protection
especially in CT scan, where you can view the images in different
windows. For example you can scan the brain and view it in bone
window

and then view it again in soft tissue window without reexamine
the patient.
This will allow you to see if there is any abnormality in the
brain or the skull and you want need to x
-
ray the skull in general x
-
ray.


Using digital radiology will reduce
dose t
o the patient by
reducing
the chance of repeating examinations due to the brightness
of the image, because radiographer will be able to adjust the
brightness of the image on the screen before
saving

or printing the
film.



Other factors


There are also som
e other factors that could reduce the

radiation
dose to the public.

Shua Almut
awa

200023791

6MI


7


Red light in front of the x
-
ray room and closing the
door during
exposing will stop any one to get in to the room and that will save
them from accidentally exposed to the radiation.


Doub
le check the patient name and ID will prevent the
radiographer form exposing the wrong patient.


Reading the x
-
ray request carefully before the examination and
checking the old x
-
ray will give the radiographer an idea of what
exposure he/she would use for

this patient and it will reduce the
chance of repeating the films.


To sum up part A, there are some factors that could protect the
patient and the radiology staff from radiation dose. Some of these
factors are in the x
-
ray machine itself and some are co
ntrolled by the
radiographer.
It is important to ably radiation protection even if in
small amount.
















Shua Almut
awa

200023791

6MI


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Part B



Radiation can affect the body and it can cause some diseases
such as cancer if the patient receives high amount of radiation.
Pati
ents with a long term illness will surly required many medical
imaging examinations such as general x
-
ray
, interventional and

computed tomography.


Radiation risk



It is important that the radiology staff and doctors understand
the radiation risk to the p
atient. What is radiation risk?


According

to Simpson 2004,
it is referred to the likelihood of
exposure to radiation leading to harmful stochastic effects such as
cancer.


Reduce exposure of the patient



To avoid radiation risk it is important to reduce
the exposure of
the patients, and that can be achieved by the following methods:


In general radiography u
sing the
correct exposure

will avoided
repeating images, and knowing that the patients required following up
examinations it is
recommended that the r
adiographers write what
exposure they used on the film
s
.

Using the right FFD will also affect
the dose.

Using lead apron when possible is an important factor in
reducing the dose to the patient.




Shua Almut
awa

200023791

6MI


9


Radiation does to the patient in fluoroscopy:



There ar
e some factors can affect th
e radiation dose to the
patients who required follow up examinations, the factors are
:



The size of the patient.



The size of the viewing field



The distance from the x
-
ray tube to the patient



The distance of the detector from the
patient
and the use of the grid.


The size of the patient is an uncontrollable factor that affects the
radiation dose. For example, large patient will require more x
-
ray to
get the good quality image
. Using
c
ompression

in this case can be
useful.

As low mA

as possible and as high kVp as possible to obtain
image quality is needed to reduce the patient dose.


To determine the size of the x
-
ray field collimators are used.
Large field size mean large amount of scatter which reduce the image
quality. By tightly
collimating the x
-
ray beam to the interest area the
amount of scatter will be reduced, the volume of tissue exposed will
also reduced and the quality of the image will be improved. To reduce
the patient dose use the tightest collimation possible.


X
-
ray em
anated from the focal spot of the x
-
ray tube. The
intensity of the x
-
ray beam decreases as the square of the distance
form this focal spot (inverse square law). That means the further away
the x
-
ray tube from the patient the less radiation dose to the pati
ent
and less chance to get skin burn.

For patient safety the x
-
ray tube
should be as far as possible from the patient.

Shua Almut
awa

200023791

6MI


10

The image intensifier (detector) need to be closer to the patient,
because the closer the detector to the patient the more x
-
rays will
be
recorded. The magnification and the accompanying distortion of the
anatomy and image blur will be reduced.

To reduce the patient dose
keep the image intensifier as close a
s possible to the patient.
(
Bushong
, 1993)

Cross secti
o
nal

examinations


Some CT
examinations require contrast injection to the patient.
In this case it is important that a little dose of the contrast is injected
to the patient b
efore starting the examination to ensure that the
contrast get into the vein.


There was a case of 54 year o
ld lady with history of Breast
cancer

she was taking chemotherapy. She

was for chest, abdomen and
pelvic CT. she was injected by the contrast during the
scanning;

the
images appear on the monitor with no contrast at all. The doctor

was
asking what was

wron
g! After the scan the nurse went to check the
patient and she found that the patient’s arm was blue and then she
discovered that the contrast did not get in
to

the vein! It just leak
under the patient’s arm skin.

The doctor asked the radiographer to
repeat
the examination aging and the patient were injected aging on
other vein on the same arm!
*



To sum up part B, there are some methods to reduce the patient
dose in general x
-
ray or in the interventional and cross sectional
examinations.

It is important to f
ollow these methods in order to
protect the patient form radiation risks.



* Case I observed during the work placement 2004.

Shua Almut
awa

200023791

6MI


11

Part C


Once the female radiographer gets pregnant she starts to get
worried about her foetus. Some of them may ask the
Chief
Radi
ographer

to change
their duty or to let them

work in the reception
desk

during their pregnancy.


It is
well known that
the
radiation can cause

some
series affect
s

to

the developing

foetus. These affects can appear as abnormalities or
as cancer
s
.

That made
pregnant radiographer
s

worried about their
foetus.

So it is
important that the pregnant radiographer understand
that
she can continue her work as radiographer

without c
ausing any
affect to her foetus, however she should be encouraged to monitor her
film
-
ba
dge readings and report any un
u
sual
reading to the radiation
safet
y officer.

The dose limit to the foetus of
a pregnant radiographer
is 1 mSv

over the pregnancy.

(Simpson,2004)


There are no necessary changes in duties but pregnant
radiographer
should avoi
d

duties that could include high radiation
dose
, which can be danger to the

developing

foetus
.

Pregnant radiographer

can work

normally in general
radiography. She has to follow
radiation protections principle
-

which
was explanted in part A

-

to protect t
he patient
, herself

and her
developing

foetus.




In mobile radiography pregnant radiographer should keep the
safety distance

from the radiations
source which is almost six feet
, she
has to ask for nurses’ help in lifting the patient. She can use high KVp
and low mAs to reduce the dose to her and to the patient. Wearing the
lead apron is also

an
important

factor in reducing the radiation dose
.
Pregnant radiographer
could avoid mobile radiography not because of
the radiation but because of the heavy work

whi
ch may affect the
Shua Almut
awa

200023791

6MI


12

foetus,
such as carrying the cassettes

which are normally heavy
,

and
driving the mobile machine.


Pregnant radiographer

should

also stop doing
operation
theater

examination and

interventional screening because
it re
quired heavy
work

which

can affect the foetus
, and it is a
high radiation dose

examination
. Instead of that
pregnant radiographer

can do ultrasound
causes

because of the
absent

of the radiations which made it safer
environment for the

developing

foetus.



It is recommended that
pregnant radiographer does not do
mammography examination during her pregnancy because of the high
mAs,

which result in high dose,
but

if she had to do it she can wear
the lead apron to protect the foetus from the scatter radiation.


Pregn
ant radiographer

should not
deal with

nuclear medi
an at all
during her pregnancy, because

of the high dose situations such as
d
ealing with radioactive spills, which can result in serious prob
lems for
the developing foetus such as affecting the foetus thyroid.


Working on C
omputed Tomography and Magnetic Resonance
Imaging

will not be a problem for the pregnant radiographer because it
dose not affect the

developing

foetus.


In general to protect

her foetus
,

pregnant radiographer

should

wear lead apron

when necessary
. She
has
to keep

a safety
distant
from

the radiation sours and s
he should not be in
the
radiation field
unnecessarily
.


To sum up pregnant radiographer should understand how to
protect herself and her foetus from the radia
tion without a big change
on

her

duties
.




Shua Almut
awa

200023791

6MI


13


Bibliography


*
Bushong, Stewart C.
Radiologic Science for Technologists
. US:
Mosby, 1993.



*
Protection Against Radiation Hazard.



http://www.ijri.org/articles/archives/
2002
-
12
-
2/Radiation_157.htm

accessed on May 2004


*
Simp
son, Alistair.
Mobile X
-
ray Equipment.

Course notes. DWC,
Health Science Department. Mar 2003



*
Simpson, Alistair.
Radiation Science IV.
Course notes. DWC,
Health Science Department. 2004