ultrasonography

ULTRASONOGRAPHY
It uses a very high frequency (3.5-10 MHz) pulsed ultrasound send off which is directed in to the body from a transducer placed at a time in contact with the skin. It produces echoes, which are converted in to signals and thence in to black,white and grey visual echo insure icon ,which is displayed on the television.screen. It represents a topograohical map of the depth of the tissue interfaces.
illusion DOPPLER
This is a recent advance which utilizes a change in the frequency of sound reflected from a moving source to invent arterial and venous blood flow.The computer then adds the distinguish colour ,to the vascular structures in the visual echo picture image, making differentiation among structures easy.
ADVANTAGES
Uses nonionising actinotherapy,so there is decreased radiation dose.
Non invasive ,easily available and inexpensive
Images show good differentiation between soft tissues and are very sensitive for evaluation of salivary gland disease.
DISADVANTAGES
It has limited use in the head and sleep together region as the sound waves are not draped by the bone.Its use is restricted to yhe superficiakl structures.
Technique is opereator dependent
Images can be difficult to interpret for inexperienced operators as the image closedown is poor.






APPLICATIONS
Evaluation of the swelling of the head and neck-lymph nodes,thyroid and salivary gland.
It is used as a diagnostic modality for salivary gland sonography in children to avoid the radiation effects of CT and in adults with allergy to contrast agents.
It is the investigation of choice to diffrenciate between loyal and cystic lesions.
Determination of the relationship of vascular structures to masses with the attachment of COLOR DOPPLER imaging.
Detection of salivary gland and duct calculi.

RADIONUCLEIDE IMAGING
It requires the wasting disease /injection of specific radioactive materials such as isotopes with unfit nuclei which undergo radioactive...If you want to get a full essay, position it on our website: Ordercustompaper.com



If you want to get a full essay, wisit our page: write my paper