Imaging techniques such as X-rays, ultrasound, CT scans, MRI, PET scans, and SPECT scans are important diagnostic tools that use different physical principles to produce images of the inside of the body. Each technique has specific applications and advantages - for example, X-rays are used to image bones, ultrasound for cardiac and obstetric imaging, and MRI provides detailed soft tissue images without radiation. Together these techniques allow physicians to diagnose and monitor a wide range of diseases.

1. Imaging techniques

2.  Important diagnostic tool for taking images of
dense parts of the body such as bones
 is a transmission-based technique in which X-
rays from a source pass through the patient
and are detected either by film or an ionization
chamber on the opposite side of the body

3.  Dual-Energy Imaging
◦ produces two separate images corresponding to soft tissue
and bone
◦ imaging the chest region because both soft-tissue
abnormalities and small calcifications can be visualized more
clearly
 X-Ray Angiography
◦ produce images that show selectively the blood vessels in the
body
◦ is used to investigate diseases such as stenoses and clotting
of arteries and veins and irregularities in systemic and
pulmonary blood flow
 X-Ray Fluoroscopy
◦ is used for placement of stents and catheters, patient
positioning for interventional surgery, and many studies of the
GI tract

5. Uses
• determining the presence and severity of
fractures or cracks in the bone structure
• Dual-energy scanning is used for
diagnosing lung disease and detecting other
masses within the chest wall
• Vascular imaging is performed to study
compromised blood flow in the brain and
heart
• Diseases of the GI tract and the urinary tract
• Mammography

6.  It involves sending very high frequency sound
waves through obtaining pictures or images from
inside the human body
 also called ultrasound scanning or sonography
 sound waves are reflected off the internal organs
and are sensed using appropriate equipments
 Ultrasound images are captured in real time and
displayed on a television monitor

8. For the imaging of
 Cardiology
 Obstetrics
 Gynaecology
 Gastroenterology
 Musculoskeletal
 Urology
 Vascular
 Intervention
 Breast
 Small Parts
 Endocrinology

9.  X-ray computed tomography, computed
tomography (CT scan), computed axial
tomography (CAT scan)
 is a medical imaging procedure that utilizes
computer-processed X-rays to
produce tomographic images or 'slices' of specific
areas of the body

11.  Diagnostic uses
◦ Head
◦ Lungs
◦ Pulmonary angiogram
◦ Cardiac
◦ Abdominal and pelvic
◦ Extremities
 Advantages
◦ eliminates the superimposition of images
◦ differences between tissues that differ in physical density
can be distinguished
◦ can be viewed as images in the axial, coronal, or sagittal
planes
 Adverse effects
◦ a small increased risk of cancer with CT scans
◦ Causes nausea, vomiting and itching rashes

12.  Magnetic resonance imaging (MRI), nuclear
magnetic resonance imaging (NMRI), or magnetic
resonance tomography (MRT)
 Developed by Felix Bloch and Edward M. Purcel
 Based on the phenomenon nuclear magnetic
resonance
 is a medical imaging technique used in
radiology to visualize internal structures of the
body in detail
 Specialized MRI scans are available like Diffusion
MRI, Magnetization transfer MRI, real time MRI
etc

13.  Applications and uses
◦ To detect tiny lesions of multiple sclerosis on Brain and
Spinal cord
◦ To examine joint injuries and slipped discs in vertebral
column
◦ To detect minute cancerous tumors such as brain tumors

15.  Is a diagnostic examination that involves the
acquisition of physiologic images based on the
detection of radiation from the emission of
positrons
 system detects pairs of gamma rays emitted
indirectly by a positron-emitting radionuclide
 8F- fluorodeoxyglucose(FDG) has been used as
active molecule

16.  Applications
◦ Oncology
◦ Neuroimaging
◦ Cardiology
◦ Pharmacology
◦ Small animal imaging
◦ Musculo-skeletal imaging
 Limitations
◦ risk from the test radiation
◦ high costs
◦ Need careful planning with respect to patient scheduling
since the half life of the active molecule is less

18.  Single-photon emission computed tomography
(SPECT)
 is a nuclear medicine tomographic imaging technique
using gamma rays
 It is able t
 information is typically presented as cross-sectional
slices through the patien to provide true 3D information
 a radioisotope of gallium(III) is used as active molecule

19.  tumor imaging, infection (leukocyte) imaging,
thyroid imaging or bone scintigraphy
 to provide information about localised function in
internal organs, such as functional cardiac or brain
imaging
 used for the diagnosis of ischemic heart disease
 used in functional brain imaging