CT Scan
Computed tomography (CT) a method of body imaging in which a thin x-ray beam rotates around the patient. Small detectors measure the amount of x-rays that make it through the patient or particular area of interest. A computer analyzes the data to construct a cross-sectional image. These images can be stored, viewed on a monitor, or printed on film. In addition, three-dimensional models of organs can be created by stacking the individual images, or "slices."

Person will be asked to lie on a narrow table that slides into the center of the scanner. Depending on the study being performed, one may need to lie on your stomach, back, or side. If contrast dye is to be administered, an IV will be placed in a small vein of a hand or arm. Much like standard photographic cameras, any motion causes blurred images in CT. Therefore, the operator will give instructions through an intercom on when to hold breath and not move. As the exam takes place, the table will advance small intervals through the scanner. Modern "spiral" scanners can perform the exam in one continuous motion. Generally, complete scans will only take a few minutes. However, additional contrast-enhanced or higher-resolution scans will add to the scan time. The newest multidetector scanners can image your entire body, head to toe, in less than 30 seconds.

CT provides rapid, detailed cross-sectional imaging of the patient which can then be reconstructed into three-dimensional models, as needed. Intravenous contrast enhanced scans allow for evaluation of vascular structures and further evaluation of masses and tumors. CT is often utilized in the trauma setting to evaluate the brain, chest, and abdomen. As well, CT can be used to guide interventional procedures, such as biopsies and placement of drainage tubes.

Isotope study
Nuclear radiology is a sub-specialty of radiology in which radioisotopes (compounds containing radioactive forms of atoms) are introduced into the body for the purpose of imaging, evaluating organ function, or localizing disease or tumors. Unlike conventional or computed radiography (such as plain x-rays and CT scans) in which x-ray beams are generated within a machine and projected through the patient, in isotope studies the radiation (gamma rays) originates from within a radiopharmaceutical (material tagged with a radioisotope) in the body. Special detector cameras are placed close against the area of interest for a period of time, and once enough gamma rays are "seen," a computer creates an image showing where the isotope localized within the organ or body. Generally, nuclear medicine scans do not provide the level of anatomic detail seen on x-ray, ultrasound, CT, or MR images. However, correlation with other imaging, clinical information, and laboratory results helps identify and confirm disease.

A radioactive isotope needs to be introduced into the body. After a certain period of time has passed (ranging from a few hours to a day or more for different exams), a counter is placed over the organ, and the amount of radioactivity or intensity of radioactivity is recorded.

MRI
MRI is a non-invasive procedure that uses powerful magnets and radio waves to construct pictures of the body. Unlike conventional radiography and computed tomographic (CT) imaging, which make use of potentially harmful radiation (x-rays), MRI imaging is based on the magnetic properties of atoms. A powerful magnet generates a magnetic field roughly 10,000 times stronger than the natural background magnetism from the earth. A very small percentage of hydrogen atoms within a human body will align with this field. When focused radio wave pulses are broadcast towards the aligned hydrogen atoms in tissues of interest, they will return a signal. The subtle differences in that signal from various body tissues enables MRI to differentiate organs, and potentially contrast benign and malignant tissue. Any imaging plane (or slice) can be projected, stored in a computer, or printed on film. If contrast is to be administered, an IV will be placed, usually in a small vein of the hand or forearm.

Several sets of images are usually required, each taking from 2 to 15 minutes. A complete scan, depending on the organs studied, sequences performed, and need for contrast enhancement may take up to one hour or more. Newer scanners with more powerful magnets utilizing updated software and advanced sequences may complete the process in less time. Because the strong magnetic fields can displace or disrupt the action of implanted metallic objects, people with cardiac pacemakers cannot be scanned and should not enter the MRI area. There is no pain. The magnetic field and radio waves are not felt.
An MRI can provide additional imaging information for the clinician based upon its superior tissue contrast resolution. Combined with other imaging methods, a more definitive diagnosis can be given in the work up of a patient's disease. Sequences performed with intravenous contrast may provide additional data about the blood vessels within masses. An MRA, or magnetic resonance angiogram, is a special type of MR that creates three-dimensional reconstructions of vessels containing flowing blood and is often utilized when conventional angiography cannot be performed due to renal failure or other contraindications.

Preventive health care
The most important part of preventive health care is maintaining good health habits. This includes: Daily exercise; Weight control; Proper nutrition; Avoidance of smoking and drug abuse; Abstinence from or moderation of alcohol use; Proper control of any diseases or disorders (such as high blood pressure, diabetes, or high levels of cholesterol in the blood). In addition to these habits, there are some other professional services that may prove worthwhile in either preventing or at least minimizing disease.

1. Periodic screening of adults for specific problems is recommended by the National Institute of Health, USA. These include: Pap smear for cervical cancer screening; Breast self-examination (BSE) for early detection of breast cancer; Mammography for early detection of breast cancer; Testicular self-examination (TSE) during adolescence; Prostate cancer screening; Cholesterol screening; Colon cancer screening; Blood pressure measurement; periodic Weight measurement; periodic Dental examinations and cleaning.

2. Many diseases can be effectively treated when detected early. See your primary health care provider right away if: A lump or persistent lesion appears; unexplained weight loss; prolonged fever; chronic cough develops (or coughing up blood); or continued body aches and pains.

3. Keep immunizations up-to-date. Adults should receive periodic boosters for diseases such as tetanus. Those older than 65 or with significant heart or lung problems, influenza vaccine and pneumonia vaccine should be considered.

Ultrasound
Ultrasound involves the use of high-frequency sound waves to create images of organs and systems within the body. An ultrasound machine creates images that allow various organs in the body to be examined. The machine sends out high-frequency sound waves, which reflect off body structures. A computer receives these reflected waves and uses them to create a picture. Unlike with an x-ray, there is no ionizing radiation exposure with this test. The test is done in the ultrasound or radiology department. A clear, water-based conducting gel is applied to the skin over the area being examined to help with the transmission of the sound waves. A handheld probe called a transducer is then moved over the area being examined. Preparation for the procedure will depend on the body region being examined. The reason for the examination will depend on symptoms.

(Information given here has been abridged from authentic sources like NIH, USA)