Diagnostic Techniques

• Ultrasound scan uses a transducer - producing high frequency sound waves.
• Sound waves penetrate through soft tissue.
• Gel is applied to the skin.
• Gel used to help transducer make better contact between transducer & skin.
• Transducer places on skin.
• Transducer requires receiver to detech sound waves.
• Connected to computer - processed the data from transducer.
• Computer creates image.
• Shows abnormalities.

Advantages:

• Non-invasive.
• Low risk to foetus.
• Can be used when X-Rays cannot.
• Provides real time moving image.
• Inexpensive compared to MRI.

Disadvantages:

• Poor quality & shows less detail.
• cannot penetrate bones - no good for scans on brain. 

• Gel cushion is placed over area required treatment.
• Lithotripter produced high intensity sound waves.
• High intensity sound waves bombard object.
• Energy waves observed by object.
• Object shatters.
• Lithotripsy breaksing gallstones - able to pass through bile duct into intestine - be excreted.
• Lithotripsy breaking stones - urinary tract - pass through urine.
• Used for - treating kidney stone, breaking gallstones, treating stones in urinary tract.

Advangatges:

• Less invasive than surgery to remove stones.
• Avoids needs of surgery.

Disadvantages:

• Stones can reoccur.
• Doesn't prevent stones forming.
• Stones could shatter & cause further problems. 

• Electromagnetic radiation of short wavelenghts.
• Enables penetration of soft tissue - not bones.
• Machine directs rays at affect area - underneath a photographic plate.
• X-Rays pass through soft tissues - causing a change in film.
• Patient having X-Ray - wear lead apron - covered in lead.
• Medical practitioner - wear lead apron - stands being lead wall.

Advantages:

• Quick & Easy.
• Results obtained quickly.
• Cheap.

Disadvantages:

• Radiation - can cause damage to cells - leading to cancer. 

• Contrast medium - used to dye hollow or fluid organs.
• Medium shows up on X-Rays.
• E.g. Barium meals - digestive tract & Iodine - angiograms (heart).

Advantages:

• Quick & easy.
• Results obtained quickly.
• Cheap.

Disadvantages:

• radiation - can cuase damage to cells - leading to cancer. 

• Computerised tomography.
• Uses X-Rays - build up an image - slice through body.
• Patient put through tube contain scanner - rotating around body - emitting x-rays pulses.
• Data received - processed using computer software. 
• Need to lie still & breath normally.

Advantages:

• Digital image.
• 3D.
• Clear images.
• Can scan areas encased in bone.

Disadvantages:

• Radiation risk - can cause cancer.
• Expensive.
• Large size of equipment.

• Patient moves through cylinder - with electromagnets.
• Causes magnet field in body - aligns all H atons in the body.
• Radio waves pulses knock H atoms back out - causing detectable radio signals.
• Strength of returned signal - determines what type of tissue it came from.
• Tissue containing H atoms - bright white - tissue containing few H atoms - dark.

Advantages:

• 3D image.
• Greater contrast of abnormal cells.
• No harmful radiation.

Disadvantages:

• Expensive equipment.
• Some patient worry about the process.

• Isotopes of elements that decay quickly.
• Level of radioactivity declines qucikly - not at particular risk.
• Combined with other element - from radioactive versiokn of substance within the body - used to.
• Substances introduced into patient's body - via drip - build up in target organs.
• Number of scanning methods used to pick up radiation emitted from target organs. 

• Positron emission tomography.
• Radionuclide introduced - patient placed on a gamma ray camera.
• Receiver picks up emitted readiation from target organs.
• Computer process image - colour image.
• Red & yellow - most radioactivities - normally functioning areas.
• Dark areas - not working normally - restriction of blood flow.

Advantages:

• More effective on the brain.
• Painless.

Disadvantages:

• Equipment large.
• Expensive chemicals.
• Isotopes emit radiation - leading to cancer. 

• Diagnosis of disorders - circulatory system.
• Electrodes places on patient's skin - by skick pads.
• Electrodes attached to chest, wrist & ankles.
• Electrodes linked to machine - recording electrical activity of the heart.
• Electrodes show each contraction.
• Producing an electrocardiogram - PQRST wave pattern.
• Healthy heart - produces normal wave pattern - on moving graph monitor screen.
• Anbromal wave pattern - indicates dsyfunction.
• Trained cardiologist - interprets wave pattern.
• Patient may be aksed to exercise while readings are taken place. 

Advantages:

• Non-invasive.
• Cheap.
• Smaller equipment.

Disadvantages:

• Further investigation needed.

• Sample of living tissue - taken from patient.
• Insertion of hollow needle - capture clyinder of tissue.
• Usually from area of abnormality - lumps.
• Different types - punch biopsy (skin discs) - smear test - CVS.

Advantages:

• reduced uncertainty.

Disadvantages:

• Invasive & painful.

• Used to view inaccessible areas of the body.
• Camera equpped with a light - fibre optic cable.
• Images shown on TV screen.
• Used in conjunction with biopsy.
• Name depends on target area - e.g. bronchoscopy used for lungs - gastroscopy used for stomach.

Advantages:

• Tissues examination with little damage.
• No incision needed.

Disadvantages:

• Invasive.
• Cause distress.

• Urine - caught in pot - tested chemically - dipstick - culturing for infection.
• Blood - sample taken - sent away for analysis - unless sugar test for diabetes.
• Mucuc - sample taken - cultured.
• Amniocentesis.
• CFS - central spinal fluid.

Advantages:

• Quick, easy, littel discomfort.
• Wide range of information gathered.

Disadvantages:

• Invasive with some risk - Amniocentesis & CFS.