Understanding Chest X-ray Projections: Implications for Diagnosis

Chest X-rays are vital tools for diagnosing various conditions affecting the lungs, heart, and chest cavity. Different projections like Posterior-Anterior (PA) and Anterior-Posterior (AP) provide unique insights into these organs' structure and function. The PA projection is typically preferred due to reduced magnification artifacts and better accuracy in depicting heart size. Conversely, AP projections are necessary when patients cannot stand for a PA view, although they may introduce some distortion due to increased divergence of the X-ray beam. Understanding these nuances is crucial for radiographers and medical practitioners as they interpret chest X-rays to diagnose diseases like pneumonia, emphysema, or lung cancer.

Running head: PROFESSIONAL FUNDAMENTALS
Professional Fundamentals
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Table of Contents
1. RT - What factors influence patient positioning in radiation therapy?.......................................2
2. NM - Name the 3 most commonly performed phases of a bone scan. Describe what each phase
demonstrates....................................................................................................................................4
3. MI -What are some possible clinical indications for performing a chest x-ray? What are the
basic chest x-ray projections, and what is each intended to demonstrate?......................................6

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1. RT - What factors influence patient positioning in radiation therapy?
Laboratory test depends on various factors that may have both the positive and the
negative impact on the test's outcome. This is indeed very important for the expert that he or she
knows the essentials of conducting a test. Additionally, pre-test requirement should also be
known both to the laboratory expert and the patient as any failure in meeting the requisite points
will lead to error in results. Apart from the pre-requisite elements, the laboratory expert should
also have an idea on how to use the device dedicated for a particular test. This also includes
positioning of patients, which is very important as tests are focused on certain parts and also
certain position will require to be highlighted in front of the testing equipment.
Radiotherapy is not a kind of test but it is actually a therapy treatment, which is used to
treat patients suffering from cancer. It is also used in conjunction with the chemotherapy, which
is used to treat the cancer disease. The main goal of radiation therapy is to kill the cancer cells
and to cause tumors to shrink.
As stated earlier, radiation therapy is used for a very sensitive issue “Cancer”, which is
increasingly becoming a problem to masses. Numbers of people getting infected with the cancer
cells is rapidly increasing. Such a challenge needs to be taken care with effective measures,
which is only possible if both the patients and the therapy experts are well versed in their
respective zones.
It has been identified that a rigid control of patients and a correct positioning of their
target zones are important to get effective outcomes from the radiation therapy. An inappropriate
positioning of the target zone will result in an increase in doses by an approximate of 3% to 5%.
On the other side, positioning the target zone appropriately will effectively reduce the dosage.

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Such a critical therapy needs to be conducted with full accuracy and accurate positioning
of the patient. There are definitely some factors that affect the positioning of the patient while
conducting a radiation therapy. These are those factors that may have an influence on the
treatment and are identified during observing the video of one of such kinds of treatment. One of
those factors is operator-related. It includes an appropriate head position of the patient. As
stated if it is not adjusted properly, this will provide errors to result. Whether the head position is
correct or incorrect will only be identified based on the Frankfurt and mid-sagittal planes. It
means that the laboratory expert will need to take care of the mid-sagittal and Frankfurt planes in
regards to making an identification of the appropriateness of head positioning.
Chin position of the patient is another important point of consideration while preparing
the patient for radiation therapy. This will be identified whether the chin position is correct or
incorrect. Any sort of error can be mitigated by putting the patient’s chin in the chin-cup. It
should also be identified whether there are any needs of cotton rolls that are used to stabilize the
position of patient’s jaws. Examination-related factors are also very important as it includes
ensuring such as checking whether FOV (large or small) or is it only for re-exposures,
temporomandibular joint [TMJ] and others. Patient-related factors are another critical point of
consideration, which should be done accurately to avoid any failure in treatment. This include
like checking the age of the patient, checking the gendered state and ensuring whether there is a
need to keep the eyes closed during the examination.
From the above-stated facts, this can be said that there are in particular the three factors
that are needed to be taken care with utmost precaution to get the treatment done accurately. One
factor is related to the equipment that is used for radiation therapy. Another factor is related to

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the examination, which is very vital and needed to be done with utmost care. The last factor is
related to the classification of patients based on their ages and gender.
2. NM - Name the 3 most commonly performed phases of a bone scan. Describe what each
phase demonstrates.
Bone scans are a study on nuclear medicine (scintigraphic) that uses the Technetium 99m
in the form of an active agent. Bone scintigraphy is one of the most frequently done radionuclide
procedures, which is quick, widely available, relatively inexpensive and exquisitely sensitive.
This can also be used in the numerous diagnostic evaluations of pathologic conditions. The entire
procedure is performed with the help of technetium-99m–labeled diphosphonates. These
compounds get easily accumulated in bones that after 2-6 hours of injection penetrate into the
skeletal system. In such cases, 50% of the injected dose gets penetrated into the system. The
bone scan requires a very little consideration from the patients prior to the bone scan process.
There is no such special requirement prior to the test. Patients will be allowed to have
medications if such are prescribed by the physicians. However, drinking plenty of water in
between the injecting of dose and the bone scanning process will produce better results.
The study is conducted in three phases, which is followed by an intravenous injection of
the tracer. In some cases, the fourth phase which is known as (delayed/delayed) phase is also
performed. The three phases are performed only after cross-checking whether there is a need to
do a bone scan. Following are the pre-processes before commencing the commonly done phases:
Clinical indications:
This will include checking the malignancy that will include detection of skeletal
metastases and a follow-up study of the same. This will also include a detection of

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radiographically occult fractures. Examples include insufficiency fractures or stress. This also
includes osteomyelitis, Paget’s disease, reflex sympathetic dystrophy and hip joint prosthesis that
are done to evaluate whether there is any infection or loosening.
Patient preparation:
 Checking the hydration level
 Removing the metal objects
 Void is immediately required to be done before the study
Tracer dose and route of administration:
Tc99m diphosphonate is put on administration intravenously, by maintaining a dose of 20
mCi.
Phases:
Flow phase-
After injecting the dosage, approximately around 2-to-5 second images are captured for
every 60 seconds. It demonstrates the perfusion and characterizes where the blood flow. A
particular area is identified where the blood flows.
Blood pool phase-
After five minutes of injecting the dosage, the blood-pool image is obtained. It
demonstrates the blood pool, but not the blood flow. It then produces inflammation that causes
capillary dilatation and an increase blood flow. In case of a study, which is based on conducting

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a triphasic bone scan, a third phase gets added to the entire phases of a bone scan. The third
phase is the Delayed phase.
Delayed phase-
In this phase, the bone image is attained after 2-4 hours. This phase of scan is also done
when urinary excretion has caused a decrease in the amount of the radionuclide in the soft tissue.
This scan is also familiar with cases when uptake mechanism is not indecisively known. This
phase is also required when the uptake degree depends on the rate and blood flow of the new
bone formed.
3. MI -What are some possible clinical indications for performing a chest x-ray? What are
the basic chest x-ray projections, and what is each intended to demonstrate?
Clinical indications for performing a chest x-ray:
An X-ray can be understood as an imaging test that produces radiation in a small amount
to enable taking the pictures of the organs, bones and body tissues. When chest area exposed to
X-ray device, the imaging will help to know various ailments like diseases related to airways,
bones, heart, blood vessels and lungs. This can also determine if there are fluids in the lungs or
fluid surrounding to the lungs.
Chest X-ray can be prescribed by the doctors after they have identified several ailments
like assessing the injuries that may have produced due to an accident. Additionally, the
examination can also be prescribed to monitor what is the level of progression of a particular
disease like cystic fibrosis. The examination can also be prescribed to a person if he or she

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complains of a chest pain. Chest X-ray is advised to those patients also who have met an accident
and have injured the areas surrounding their chest.
Chest X-ray has remained a valuable way of knowing the basic ailments in the chest and
the surrounding areas. Doctors rely significantly on the chest X-ray. This is a primary measure of
basic ailments in the chest that are listed below as follows:
 Fever
 A persistent cough
 Chest pain
 Breath shortness
Such ailments can be the result of several symptoms that a chest X-ray can detect. Following are
such symptoms:
 Heart failure
 Lung cancer
 Pneumonia
 Emphysema (is a long-term persisting condition that produces breathing difficulties)
There are some other uses of chest X-ray such as to see the shape and size of the heart. If there
are some abnormalities in the shape and size, this will indicate that there is an issue with heart
function. Doctors may also consider chest X-ray to monitor the progress of chest area that has
been put into surgery.
Chest X-ray can identify certain regions, which can be classified as ABCDEF and be
summarized as follows:

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 Airways that also include enlargement or adenopathy
 Bines like lytic bone lesions and detecting cardiac
 Cardiac silhouette and detecting the cardiac enlargement
 Diaphragms like perforation indicative of an abdominal viscus and free air evidence
 Edges like pneumothorax, apices for fibrosis and plaques or pleural thickening
 Extrathoracic tissues
 Fields like (lung parenchyma), as an evidence of alveolar flooding
 Failure like diseases in alveolar airspace with or without pleural effusions
Basic chest x-ray projections:
There are various projections for chest X-ray; however, it depends on the case scenario
and also on the geographical preferences. Different countries use different types of chest X-ray
projections in order to get the result. Following are the types of projections:
Posterior-Anterior (PA) projection:
The kind of chest X-ray requires a person standing in front of an X-ray beam passing him
or her from Posterior to Anterior (PA). The image thus generated will appear as if the observer is
looking at the person from the front face. It means the heart is visible on the right side of the
observer.
Anterior-Posterior (AP) projection:
In some situations, conducting a PA chest X-ray is not possible. In all such situations, it
is advisable to go with the AP projection. In this imaging, the X-ray beam passes from Anterior

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to Posterior (AP). The image thus obtained appears as if the observer is viewing at the patient
face-to-face.
AP vs. PA – Heart size:
In the AP projection, heart size appears as exaggerated. This is because the heart is
relatively at a farther distance from the detector. This is also because the beam obtained from the
X-ray imaging is more divergent. The divergence is because the source is placed nearer to the
patient.
On the other hand, the PA projection produces a much closer to the real size. This is
because the heart is placed relatively at a nearer distance to the detector. Heart magnification is
also reduced by using a narrower beam. The narrower beam is produced from an increased
distance between the patient and the source.
AP v PA - Scapular edges:
Doctors will always mention the projection mode when there is a need for an X-ray
imaging to a patient. If in case there is no labeling put to the image, it will be assumed as a
standard PA view. If a new practitioner is put to the examination and he or she is not able to
understand on which projection to use, it is advisable then to consult the experts available at the
center. They will make understand the required projection mode to for a particular case study.