Re: Radiology deals with x-rays, etc but what other area's does it involve?

Radiology is essentially about using radiation to produce images of the 
insides of the human body. There are types of imaging techniques that 
don’t really use radiation, such as Ultrasound. The following describes 
some of the radiological imaging techniques that are currently used:

RADIOGRAPHS: This is where x-ray radiation is passed through the patient. 
A sensitive film is placed behind the patient that collects those x-rays 
that passed through the patient, and is developed (much like a regular 
photograph) to produce an image of the patient’s insides. Dense tissues in 
the body absorb x-rays (such as bones) and are said to be radiopaque, 
whilst other tissues allow x-rays to pass through and are said to be 
radiolucent.

FLUOROSCOPY: Here, the patient is positioned between the x-ray source and 
a sensitive fluorescent plate. The plate is connected to a TV monitor, and 
this allows live x-ray images to be taken and recorded (much like you use 
a VCR to record TV programmes). This is useful if a doctor wants to see 
what happens inside a patient as they move – for example when they swallow 
(this is called a barium swallow because a thick radiopaque liquid (a 
barium “milkshake”) is given to the patient to swallow).

ANGIOGRAPHY: This is where a radiopaque contrast medium is injected into a 
specific artery or vein so that an x-ray can be taken of that artery or 
vein. The contrast medium is used to highlight the artery or vein the 
doctor is interested in.

COMPUTED TOMOGRAPHY (CT): X-rays are passed through the patient to 
detectors on the other side. These detectors are linked to a computer that 
records the information as the x-ray source and detectors are rotated 
around the patient. The data collected by the computer can be presented to 
the doctor as image “slices” through the patient. Contrast media may also 
be used.

MAGNETIC RESONANCE IMAGING (MRI): X-rays are not used. Instead, powerful 
magnetic fields and coils (radio frequency antennas) are used. The 
magnetic field causes the protons in the atoms of water within the patient 
to all "line-up". Then, a high-frequency electro-magnetic pulse knocks 
many of the protons out of alignment. Next, a very sensitive radio 
antenna "listens" for the "resonance" signal that each proton gives off, 
as it goes back into alignment. These minute resonance signals occur in a 
pattern that a computer uses to create 3D information. The pictures look 
like “sections" or "cuts" - just like in CT.  Except in MRI, the resulting 
image primarily reflects the water protons in the patient, as well as 
their chemical association with proteins, etc.

NUCLEAR MEDICINE: Nuclear medicine involves making the patient radioactive 
for a short time using a very small amount of isotope. Images are obtained 
by looking for the small amount of radiation given off by the patient. 
Choosing the right isotopes and attaching them to physiologic molecules 
allows certain organs or tissues to be isolated - e.g. thyroid imaging 
with radioactive Iodine.

ULTRASOUND (US): High frequency sound waves are emitted and the 
echoes "listened to" in order to produce real-time images of living 
tissue - a common use of US is that of imaging babies as they grow in the 
womb; US is used as no potentially harmful radiation is needed. US 
produces real-time moving images that represent slices through the patient.

Interventional Radiology is a speciality that focuses on using 
radiological images to guide tiny instruments through the body in order to 
carry out operations. You can read more about Interventional Radiology at:
 
http://ww
w.amerasekera.freeserve.co.uk/interventional.html

One area of medicine that overlaps with radiology is Radiation Therapy. In 
Radiation Therapy, large doses of radiation are directed at cancer cells 
in order to kill them. You can read more about Radiation Therapy at: 
 
http://oncolink.upenn.edu/specialty/rad_onc/general/xrt_intro.html