BRAIN METASTASES(CANCER) & RADIOGRAPHY

In case of various type of brain metastases there is no other option than radiography, specially MRI & CT scan. These can be easily diagnosed various type of tumors in brain & then one can look for any other primary lesion in body. It is very essential to take a right decision to go for CT scan of brain or for MRI because in some cases MRI is more effective than CT scan & in some cases CT scan is more acceptable.

Using a contrast injection that is non ionic radiopaque (76%Iodine) contrast media we can easily diagnosed the type or name of tumors in brain.

MRI-basic principles

Clinical Magnetic Resonance Imaging (MRI) uses the magnetic properties
of hydrogen and its interaction with both a large external magnetic field
and radio waves to produce highly detailed images of the human body. In
this first module, we will discuss some basic principles of magnetism, the
magnetic properties of the hydrogen nucleus, and its interaction with the
externally applied magnetic field (B0).
In its early days, MRI was known as NMR. This stands for Nuclear Magnetic
Resonance. Although the name has changed (primarily due to the
negative connotation of the word “nuclear”), the basic principles are the
same. We derive our images from the magnetic resonance properties of
nuclear particles (specifically hydrogen).
In order to perform MRI, we first need a strong magnetic field. The field
strength of the magnets used for MR is measured in units of Tesla. One
(1) Tesla is equal to 10,000 Gauss. The magnetic field of the earth is
approximately 0.5 Gauss. Given that relationship, a 1.0 T magnet has a
magnetic field approximately 20,000 times stronger than that of the
earth. The type of magnets used for MR imaging usually belongs to one of
three types; permanent, resistive, and superconductive.
A permanent magnet is sometimes referred to as a vertical field magnet.
These magnets are constructed of two magnets (one at each pole).

The patient lies on a scanning table between these two plates.
Advantages of these systems are: 1) Relatively low cost, 2) No electricity
or cryogenic liquids are needed to maintain the magnetic field, 3) Their
more open design may help alleviate some patient anxiety, 4) Nearly nonexistant
fringe field. It should be noted that not all vertical field magnets
are permanent magnets.
Resistive magnets are constructed from a coil of wire. The more turns to
the coil, and the more current in the coil, the higher the magnetic field.
These types of magnets are most often designed to produce a horizontal
field due to their solenoid design (figure 2).
As previously mentioned, some vertical field systems are based on
resistive magnets. The main advantages of these types of magnets are:
1) No liquid cryogen, 2) The ability to “turn off” the magnetic field, 3)
Relatively small fringe field.
resistive system:

DIAGNOSTIC RADIOGRAPHY-playing main role in medical sector

Diagnostic radiography is a very common word for us now. More or less all of us have experienced it any of time in our life. X-RAY, CT SCAN, MRI are now not very unknown words for us. Yes, these all are nothing but radiography or radiology. Now these are obvious part of our life, saving our life. If X-RAY is the mother of radiography, then CT scan & MRI come for next generation. Though CT scan based on x-ray, but MRI is not based on it. CT scan represents Computed Tomography while MRI stands for Magnetic Resonance Imaging & no relation with x-ray. Every aspect of these three aids have their own unique applications. While x-ray is very effective for some cases, then CT scan has also some specialties & has great advantages in diagnosis for many disease. Then MRI comes & proves itself as a great fusion of technology & medical science. Radiology is an art & the picture has to be technically & photographically good to be diagnostic.