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Figure 4.15 X-ray radiography FONG et al 2011
In Figure 4.16, the constant mass of electron is represented by
݉
, θ for the scatter angles of photons and λ for the diffused
wavelength. When electrons are knocked out from atoms, some energy is released. The theory of Compton scattering is crucial
to understanding the unwanted noises in X-ray radiography and damages done to tissue cells. In Equation 4.7, low incident en-
ergy results in the independence of scattered energy from
θ. Therefore,
݉
with sufficient energy continues in a similar an- gle as X-rays. Even though the use of X-ray is potentially harm-
ful, it produces a clear image. The damage is prevented or lessened through the adjustments of doses exposed, which is
calculated in energy absorbance per single units of tissue cells. Detailed information regarding the doses of X-ray can be ac-
quired from the 2009 report by the Radiological Society of North America.
Disruptions can be caused by cosmic and nuclear radiation as well as radio-activities from the surrounding environment. Sec-
tion 8.5.3 discussed the potential harm associated with the over- dosage of radiations. X-rays is used to scan cancerous cells and
other irregularities of bodily functions through different tones of greys. Images converted and kept in digital formats are general-
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ly more reliable than silver-based photos. Therefore, abnormali- ties such as cancerous cells can be detected through the mainte-
nance of these vital procedures that involves digital image technologies, as X-ray radiography can be ruined such as with
the addition of noise. More comprehensive information of these mechanisms is shown in section 4.2.2.
Figure 4.16 Photon scattering FONG et al 2011 4.2.1.3 Ultrasound
The estimation of ultrasound is dependent on various parame- ters such as sound propagations that comprised dispersing ve-
locity, wave attenuation, the change in phases and acoustic impedance mismatch. Sound propagates across tissues and
hence the bodily structural can be identified Tempkin, 2009, gillespie et al 2010. The propagation has frequencies higher
than that of audible ranges and can propagate across liquid and cells which is then echoed back as images. Lighter images are
produced when sound propagates through cells with higher den- sities, creating images with different shades. To produce an im-
age, a probe is placed on the surface of the body. Ultrasounds are emitted from the probe and echoes are received. For the
generation of echocardiogram if human’s heart, ultrasound is propagated through blood, and echoed back as it stroke the
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valves. Figure 4.17 shows an image produced from the reflec- tion of sound waves. A monochrome is used to diagnose the
health and irregularities associated with the heart. The same procedures are used in different diagnosis, such as detecting the
growth of cancerous cells and renal calculi in the kidneys to prescribe treatment as early as possible. Another common use
of ultrasound is the monitoring of foetus. Figure 4.18 shows an ultrasound image of a 21 weeks normal foetus. The use of the
device is important in this area to identify the gender of the foe- tus and whether there are abnormalities with the unborn baby.
Figure 4.17 Ultrasound image of a beating heart
FONG et al 2011
4.2.2 Analysis and Transmission Medical Image
So far 3 main devices in diagnosis imaging have been evaluat- ed. Next, the procedures in developing these images will be dis-
cussed such as Positron Emission Tomography PET and Optical Coherent Tomography OCT. Certain similarities con-
cerning process algorithms are exhibited by these models with the categories of images that have been discussed previously.
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Figure 4.18 Ultrasound image of a healthy fetus
FONG et al 2011 Technology revolving around the transmittance of diagnosis
imaging between different locations is almost identical to that of transferring an image taken via 3G mobile devices and transfer-
ring it to the Internet. Even though the mechanisms are almost identical, what mainly distinguishes one procedure from another
is the purpose why an image was taken in the first place. For example in medical imaging, an image is taken with the im-
portant purpose of identifying the cancer cells, and this can be done so through the different tones of grayness produced. A
case study is evaluated in order to comprehend the process of transmitting the diagnosis images. In this case, X-ray radio-
graph is transferred to a remote specialist Maintz, 1998, zito- va et al 2003. Take note that the image is a 2-D representation
of 3-D properties of X-ray attenuation formed by exposing tis- sue cells to a certain dosage of X-ray. During the beaming of
the X-ray to the target object, the cross-section of the ray and tissue atoms is represented by A and S while cell’s atomic densi-
ty is represented by N. Therefore, the whole cross-section is N x S and the total atoms stroke by the ray is A x N x S as shown in
Figure 4.19. Rate of changes in ray strength during penetration is shown in the equation below:
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Figure 4.19 X-ray beam strikes the tissue
FONG et al 2011
Figure 4.20 Radiograph showing tumour in the lung
FONG et al 2011 This characteristic is crucial to deduct the attenuation of coeffi-
cient
μ. This coefficient is an entity of the strength of photons in every location of cell which is named as Ix:
4.7
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The formation of images from radiography is essentially a map- ping of photons through the object which comprised of different
densities, such as organs and bones. As an example, cancerous cells can be identified as these cells show distinctively different
shades of grey compared to other structures. Figure 4.20 shows an image captured using radiography where darker masses can
be observed on the left of patient’s lung cavity which indicates the degradation of internal lung cells. This is a condition called
spontaneous pneumothorax induced by pneumonia. Without this image, it would be impossible to identify the condition and
to prescribe the correct diagnosis. The degradation of the left lung cells is compared to the right lung which looks lighter and
normal. However, it must be ensured that all data must remain intact during image transfer as the loss of any information will
halt the effort of diagnosis. Analogue images can be observed everywhere in the surrounding environment. This is particularly
true as our observation and interpretation of the surroundings is comprised of a collection of various spectrums with uncounta-
ble distinctive features, and it is not possible to transmit images with infinite features. Hence, to enable an image to be transmit-
ted, it has to be converted to a finite or exact size, such as the bitmap arrays of colored or grey dots known as pixels. Next,
to transmit an image, a network bandwidth with sufficient data rate is required. For instant, a considerable sized image with
3000 × 2000 pixels at 6 megapixels of resolution and 256 dif- ferent grey tones will contain the size as shown below:
4.8
4.9
