Describe the patient journey through the Radiology department
- Referring physician generates a radiology referral
- patient arrival to radiology
- radiographer acquires imaging
- Images sent to PACS
- Radiologist reviews and creates radiology report
Radiology department data management systems
- Review Workstation
- PACS
- Modality
- RIS
- HIS
Patient preparation for imaging
- Hello, my name is……
- Check patient identity (4W’s) and details using 3C’s protocol
- Verification and Justification of Procedure
- Check for Pregnancy
- Remove radio-opaque objects
- Change if necessary
- Continue to reassure and communicate throughout procedure
4ws
- What is your full name?
- What is your date of birth?
- What is your address?
- What examination/procedure are you here for today?
3cs
- Correct Patient
- Correct Procedure
- Correct Site
Duty of radiographer to check clinical history to verify
o Standard procedures
o Normal/abnormal variations
o Pathological conditions
o Selection of exposure factors
What is palpation
o Physical examination in medical diagnosis by pressure of the hand or finders to the surface of the body
Colours of different objects in imaging
- Black = air/gas
- Dark Grey = Fat
- Light Grey = Soft Tissues/water
- Off White = Bone
- White (Bright) = Contrast Material/Metal
- Different grey scales represent different absorption by tissue types
Methods of introduction of contrast media
- Oral o Barium Compounds / Gastrografin - Injected o Iodinated Compounds - Administered Directly o Rectally / Bladder / Fistulas o Barium Compounds
Side effects and contraindication of barium sulphate compounds
stomach cramps
constipation
Contraindications: perforation/obstruction
Side effects and contraindications of Iodinated contrast IV or IA
Expected : feeling of warmth, metallic taste, sensation of passing urine
• Mild reactions: nausea, itching, hives
• Moderate reactions: wheezing; severe skin rash; shortness of breath
• Severe reactions: swelling of throat; convulsions; difficulty breathing;
cardiac arrest
Contraindications:
• known allergies to iodine
• history of asthma and hay fever
• history of kidney, heart diseas
Precautions that need to be taken during use of contrast media
- Screening of patients through questionnaire
- Informed Consent
- Leave the cannula in place throughout the examination
- Observed the start of the injection
- Maintain a visual of your patient throughout the CT scan
- React promptly if there is a reaction
- Ensure emergency trolley is readily accessible
MRI Contrast agent - Gadolinium based compounds
Gd-DTPA (Gadopentetate dimeglumine) is a clear
injectable contrast agent
◦ Lower toxicity and fewer side effects than iodinated
contrast
◦ Gd-DTPA results in greater MR signal and higher contrast
in areas damaged by pathologic processes
◦ Improves visualisation of small tumours particularly in
evaluation of the central nervous system
Side effects and contraindications of gadolinium
- Side Effects
o FDA warnings about the risk of nephrogenic systemic fibrosis for all gadolinium-based contrast agents - Contraindicated
o In patient with acute or chronic severe renal insufficiency
o Should not use GCBA in these patients unless the diagnostic information is essential and not available with non-contrast enhances magnetic resonance imaging
Medical Imaging modalities
- MRI
- CT
- Nuclear Medicine
- Mammography
- Ultrasound
- Fluoroscopy
Explain Computed Tomography (CT)
- Patient lies on the positioning couch which moves through the acquisition plane in the gantry
- The x-ray beam rotates round the patient
- Detector arrays measure the radiation passing through the patient and record it digitally
- The information is fed into a computer which produces images from different x-ray absorption readings as the beam travels through the patient
CT Application
- Diagnostic Imaging o Demonstration of tumours, masses, enlarged organ or lymph nodes o Used for imaging all body parts o More information than plain x-rays Trauma (internal injuries) Diagnose disease Plan medical, surgical and radiation treatment o For Oncology Patients Initial Diagnosis of disease Extent of disease for staging Assess response to treatment Check for recurrence of disease - Radiation Therapists o CT SIM For simulation and treatment planning
CT simulators in RT
- Pivotal in the development of treatment planning
- Flat tabletop to reproduce linear accelerator table
- Larger bore than diagnostic scanners to accommodate treatment positions (80-90cm)
- External lasers
- High tube heat capacity
- Modality used for dose calculation and distribution
- Shorter scan times
- Organ motion management
Limitations of CT
o Suboptimal tissue contrast
o Lack of functional information (only anatomical information)
o Inability to visualise small groups of cancer cells that are separated from the gross tumour
MRI
- Uses magnetic field and pulses of radio waves energy to create detailed images of organs and tissues
- Large cylindrical magnet device in which the patient lies with the RF coils surround the patient
- Good contrast resolution makes it an excellent soft tissue imaging technique, particularly for the brain and spinal cord
- Non-ionising radiation
- No hazardous bioeffects at current field strengths
- Tissue heating can occur at 3 Tesla and above and potential source of RF burns
o Patient positioned no skin folds touching and pads
o Tattoos, eye shadow containing iron oxides
MRI Imaging safety zones
- MRI Zone 1 – Outside the MRI
- MRI Zone 2 – Taking patient to MRI
- MRI Zone 3 – Control Room (restricted from general public)
- MRI Zone 4 – Magnet Room (no individual is allowed in the scan room without being supervised)
Contraindications for MRI
o Artificial joints
o Surgical clips
o Pacemakers, defibrillators
o Sheet metal workers
What is Magnetic Resonance Spectroscopy
- Glioma
- MRS can help increase our ability to predict grade
- As the grade increase NAA and creatine decreases and choline, lipids and lactate increase
What is Nuclear Medicine
- Use radioisotopes to diagnose and treat disease
- Small amounts of radioactive tracers target a specific area in the body
- Radioactive tracers used emit gamma rays which are detected by a Gamma camera
o Functional study
o Anatomical detail is poor compared to other imagine modalities
o Provides complementary information
o Sensitive for detection of some pathologies - Can identify diseases within its earliest stages
