• Conventional radiography: plain X-ray
• Fluoroscopy
• Mammography
• IVU: intravenous urogram
• Angiography
• Computed radiography

All involve radiation

• X-ray lie between visible light an gamma rays

• Wilhem Conrad Roentgen (X-rays aka Roentgen rays; Radiology aka Roentgenology)
• Professor of physics at the University of Wurzburg, Germany
• 8^th Nov. 1895

• Behaviour of cathode rays (electrons) in high-energy cathode ray tubes.
• High-voltage discharge - ionisation of remaining gas - faint light from fluorescence of paper coated with Barium platinocyanide.

• If a photon has 15eV or more of energy, it is capable of ionising atoms and molecules - ionising radiation.
• An atom is ionised when it loses an electron.
• Gamma rays, x-rays - ionising radiation.

• The three main parts of any X-ray tube are the anode, cathode and the tube.
• When a filament is heated, electrons are ejected from the surface of the filament.
• A large electrical potential, voltage, between the cathode and the anode force electrons emitted from the filament to accelerate towards the anode.
• X-rays are produced by energy conversion when a fast-moving stream of electrons is suddenly decelerated at the tungsten target of the anode.

• Reduction in the intensity of x-ray beam as it traverses matter by either absorption or deflection of photons from the beam.
• Some tissues attenuate more x-rays than other tissues.
• The amount of attenuation depends on the energy of radiation and 3 characteristics of tissue (density, atomic no., electrons/gm)
• The size of this differential determines the amount of contrast in an X-ray image.

• No known safe radiation dose.
• Spontaneous genetic mutations and malignant diseases.
• Man-made radiation = 15%.
• Diagnostic medical exposures account for 97% of it.
• Somatic: Carcinogenesis - leukaemia (long latent period)
• Genetic: Mutations - pregnancy

• No practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the exposed individuals or to society to offset the radiation detriment it causes (justification of practice)
• As low as reasonably achievable (ALARA), optimisation of protection
• Exposure of individuals subject to dose limits

• Shielding of organs with lead (esp. testis, ovaries, thyroid)
• Filtration of x-ray beam (x-ray beams only go to area of interested, not everywhere
• Control of irradiation and recording of irradiation time
• Radiographic film processing
• Quality assurance
• Avoid unnecessary requests.
• Decrease repeat exams
• Decrease number of films taken
• Limit size of x-ray beam

• Radiograph = Still images shown on film or computer screen
• Fluoroscopy = Movie (dynamic) viewed on TV monitor or computer screen

Gastrointestinal tract:

• Barium swallow - hypopharynx and oesophagus
• Barium meal - stomach and duodenum
• Barium follow-through - small bowel
• Barium enema - large bowel

Genitourinary tract:

• Micturating cystourethrogram - bladder, urethra (Usually children: VUR) (adults: trauma, stricture)
• Hysterosalpingogram - uterus, fallopian tubes.
• UGS Ix do not use barium

• Barium: inert, smells and tastes bad
• Water-soluble contrast medium: eg. Gastrographin (cheap, hypertonic: causes fluid shift into GIT if Pt dehydrated, can cause shock), Isotonic (new-borns)
• Air

Perforation

• Peritoneal adhesions and granulomata
• For assessment of suspected gastrointestinal perforation, water-soluble contrast should be used instead

Aspiration

• Relatively harmless
• Physiotherapy

• Pulmonary oedema if aspirated - hypertonic contrast medium
• Hypovolaemia (shift of fluid into GIT) - hypertonic contrast mediums in GIT
• Allergic reactions (usually after intravascular procedures)

Need to explain these risks to Pt before procedure

Esp. for atopic patients

Reduction of anxiety

• Risk from Radiation.
• Risk from Contrast Medium.
• Risk due to technique

• ? Admission: bleeding disorders?
• ? Pregnancy: last menstrual period to make sure Pt not pregnant
• Informed consent: more invasive procedures require written consent
• Bowel preparation
• Fasting: IV contrast infection (some may have nausea), barium meal (requires stomach to be empty)
• Previous films and notes
• Premedication

Indications:

• Difficulty/pain in swallowing (dysphagia)
• Preoperative assessment of oesophageal cancer.
• Postoperative: check anastomosis (surgery) is working

Picture - Normal

• Barium shows mucosa to see if there are any irregularies (should be smooth, mucosal pattern)
• Can see peristalsis of oesophagus and bolus of contrast going down

Picture - Oesophageal cancer

• Views: frontal, side, oblique
• Concentric narrowing of oesophagus
• Any complications of tumour: eg. Fistula formation

Indications:

• Dyspepsia/epigastric pain.
• Weight loss (ca stomach is a silent cancer)
• Assessment for suspected stomach cancer.

Indications:

• Change in bowel habit.
• Pain.
• Mass.
• Blood in stools.
• Bowel obstruction.

Contrast medium per rectal

Double contrast: air pumped into colon

Bowel preparation: low residue diet, fluid diet, cleansing enema, Dulcolax (2-3d beforehand)

Micturating cystourethrogram (MCU)

Indications:

• Vesicoureteric reflux.
• Study of the urethra during micturition.

Contraindications:

• Acute urinary tract infection.

Water-soluble contrast is introduced into the bladder using a Foley's catheter

When voiding occurs, can see if there is any reflux

Not frequently done

Contrast injected via cervix, very uncomfortable

Indications:

• Infertility: Fallopian tubes patent?
• Recurrent abortions.
• Following tubal surgery.

Contraindications:

• Pregnancy.
• Pelvic Inflammatory disease.

Demonstrate the urinary tract for suspected urinary tract pathology

Less used now compared with other modalities

Inject contrast into Pt's veins; contrast excreted by kidney into urinary system

Patient preparation: laxative: faecal material causes shadows on x-ray

Fast for 4 hours: nausea during examination

Hydration.

Micturate before IVU.

Take preliminary KUB (Kidney Ureter Bladder): any opacities along urinary tract (eg. ureteric stone)

IVU can show whether or not opacity is in ureter

Compression device: prevents contrast travelling too quickly through ureters

See: filling defect, stone, tumour, hydronephrosis

Release compression: Release KUB

Bolus of contrast travels down ureter and you take image of ureters

Finally image UB

Contraindications

• Pregnancy
• Serious reactions to previous injections of contrast media
• Diabetes with renal insufficiency
• risk of acute renal failure (esp. DM)

Can use other modalities instead (more expensive)

• MRU: Magnetic Resonance Urogram
• US

X-ray imaging used to create detailed images of the breast.

X-ray system designed specifically for imaging the breasts.

Uses low-dose x-ray; high contrast, high-resolution film

Views

• Oblique view
• Craniocaudal view

Avoiding performing just before menstrual period (increased sensitivity)

Screening of choice for ca br

• Asymptomatic women - early detection of small breast cancers
• Diagnostic mammography - breast complaint

Arteriogram done much frequently than venograms

Other modalities: MRA, CTA

Indications

• Assessment of arterial/venous disease.
• Localisation of site of haemorrhage.
• Investigation of malignant tumours

Done for embolisation for chemotherapy (interventional as well as diagnostic)

Eg. Investigate BV to tumour (arteriogram), then inject chemo into BV (eg. TOCE)

Puncture sites

• Femoral artery - most frequent (even when investigating cerebral BV, still inject catheter through femoral artery and then position catheter to position of interest)
• Axillary artery.
• Brachial artery.

Complications

• Tear artery
• Dissect artery
• Embolise AS plaques

• Admission to hospital.
• Discontinue anticoagulants.
• Puncture site is shaved
• LA at site of puncture
• Premedication.

• Due to contrast medium.
• Due to drugs.
• Due to technique:
• Local (bleeding due to puncture, dissection of vessel if Pt's BV are friable, dislodge emboli)
• Distant (stroke)

Esp. careful with cerebral vasculature

Conventional projection radiography, in which the image is acquired in the digital format using an imaging plate rather than film.

Monitors and equipment are expensive

• Complex image processing can be performed by computers
• Electronic storage possible (optical disk)
• Electronic image transmission possible
• Image management through connectivity to Picture Archiving and Communication system (PACS)

• Represented in continuous fashion
• Computer cannot manipulate analogue data

• Represented in discrete units
• Computers can only manipulate and process images in a digital format

• Reduction of storage space
• Saving of manpower
• Minimal time loss through portering system

• Serviceable from main remote hospital
• One-man department possible

• Save on chemicals / films
• Phosphor imaging plate is reusable