OF THE DEVICE
computed tomography scanner, known as CT scanner, is a medical device used in
diagnosing parts of the human body and detect lesions through X-ray imaging
procedures. The scanning is fast, painless, non-invasive and accurate. The
main components of a CT scanner are a scanner gantry with X-ray generation
system, a computer and a patient couch.
CT gantry external view:
Sagittal laser alignment
Patient guide lights
X-ray exposure indicator
Emergency stop buttons
Gantry control panels
External laser alignment
ECG gating monitor
gantry internal view:
filters, collimator, and
x-ray tube heat exchanger
high voltage generator
direct drive gantry motor
rotation control unit
data acquisition system
high voltage generator
power unit (AC to DC)
CT scanner uses many X-rays to scan the specific parts of body from different
angles, producing the signals to the computer, and a computer constructs
cross-sectional images along a single axis and generate three-dimensional image
if needed. It allows the users to see inside of the body structures based on
their different absorptions of X-rays.
the scanning procedure, the patient lies the patient couch and moves slowly into
the gantry automatically. The X-ray tube then started to rotate and shot narrow
beams of X-rays around the body, while the detectors which positioned opposite
to the X-ray tube, pick up the X-rays passing through the body and transmit
them to the computer. The continuing rotation is done with the help of slip
computer will construct a cross-sectional image along a single axis or 2
Dimensionally with the completion of every rotation of the X-ray. The
three-dimensional image can be generated by stacking exact number of two
dimensional images together.
functions of collimators and
filters are to limit unnecessary radiation exposure and to improve the image
system lesions: CT scanner can
generate clear images about brain trauma, cerebral infarction, brain tumors,
inflammation, degenerative diseases, congenital malformations etc. CT diagnosis
of acute cerebrovascular diseases such as hypertensive intracerebral
hemorrhage, subarachnoid hemorrhage, cerebral aneurysm and arteriovenous
malformation rupture bleeding, cerebral infarction and acute bleeding may be
considered as the preferred examination.
lesions: CT scanner displays high
quality of images for the lung trauma, infectious lesions, tumors, etc. Even the
connections between the lung mass and the mediastinum can be shown.
system: CT scanner can be used
to diagnose pericardial tumors, pericardial effusion etc. The CT scanning
result for acute aortic dissection aneurysm can be used for qualitative
organs: CT scanner can
accurately show the invasion of the tumor to the adjacent tissue. It has played
a very important role in diagnosing ovarian, cervical and uterine, bladder,
seminal vesicle, prostate and rectal cancer, and the surgical design for
organs: CT scanner can display
most of the parenchymatous organs such as liver, gallbladder, spleen, pancreas
and kidney. For tumor, infection and trauma, it can clearly show the exact
location of the lesion and it helps on the diagnosis and differential diagnosis
of intra-abdominal masses.
lesions: CT examination can
display the intrahepatic point of the lesion, primary liver cancer or
metastatic liver cancer morphology, contour, necrosis, bleeding and growth
patterns. It also helps understand the conditions of organs such as gall
bladder, pancreas, kidney, So, chronic hepatitis, cirrhosis. It is necessary for
patients with suspicious lesions or liver cancer to do CT examination
structure of the bones, joints, such as the spine, sternal lock joints: CT scanner can display the structure of bones and joints. It
has more advantages than the conventional X-ray film in observing the dead bone
destruction zone, calcification, ossification and bone destruction zones.
scanner is a low-moderate risk medical device with non-invasive and
non-hazardous active diagnostic function. The main side effect of doing CT
scanning check is the ionizing radiation produced by X-rays, which may cause
some biological effects to living tissues. Over-exposed to X-rays will increase
the risk of developing tumors or cancers. Other side effects of CT scanner due
to the radiation are pruritus, rashes or other allergies.
RELATED TO THE PROBLEM
Commission on Radiological Protection (ICRP) study confirmed that doing a CT
whole body scan examination, will cause the risk of radiation-induced cancer
increased by about 8%. Exposure to X-rays can cause different tumors, and
cancers including thyroid, breast, lung and skin etc. The risk of developing
cancer depends, to some extent, on the age at the time of exposure. Overdosing
in childhood is associated with an increase in leukemia and thyroid cancer. Although,
the risk of getting these problems is very low, it will accumulate with the number
of CT scan examination the patient took.
is very dangerous for pregnant women and children to take CT scanning check.
There are certain effects of overexposed radiation to the conceptus that are
prenatal death, intrauterine growth restriction, small head size, severe mental
retardation and organ malformation. To children, they may develop childhood
SOLUTIONS AND RECOMMENDATIONS
the application level, it is important to first establish the concept of
radiation protection and correct understanding of the relationship between the
image quality and radiation dose balance. The radiologist should be trained and
proficient in the optimal CT examination to avoid ignoring the radiation dose.
Second, understand the performance of CT scanner used and the relationship
between the various technical parameters to ensure the quality of diagnostic
imaging while reducing the radiation dose. Pay attention to check the
instructions and limit the unnecessary scanning layer, using scan parameters
appropriate for the patient’s cross-sectional area.
and radiologists should discuss to determine whether each CT examination is a
clinical need. Radiologists have the responsibility to work with technicians
and clinicians to control the dose. Strictly control the radiation dose while making
the image quality meet the minimum requirements for clinical examination. For
different diagnostic purposes, images of different noise levels should be
pregnant women and children, they should avoid taking CT scanning check.