A BRIEF INTRODUCTION TO RADIOLOGY & ITS MODALITIES

3. Introduction To General Radiology And
Its Specialities & How Nuclear
Medicine And Its Modalities Differs
From General Radiology
Presented by
Qurat-ul-ain
MS .(Medical Imaging Technology)
BS(hons).(Diagnostic Radiology & Imaging Technology)

4. WHAT IS RADIOLOGY ?
 Radiology represents a branch of medicine that deals with radiant energy in the
diagnosis and treatment of diseases by using imaging technologies( modalities).
This field can be divided into two broad areas.
 Diagnostic radiology
 Interventional radiology

5. Diagnostic Radiology
 Diagnostic radiology uses different radiological modalities such as x-rays
,ultrasound , CT scans, MRI scans to obtain images for the diagnosis of multiple
diseases anywhere in the body.
 Radiology is the backbone of medical science for diagnosis and final treatment of
any disease.

6. Diagnostic Radiology
 Neuroradiology
 Paediatric radiology
 Breast imaging
 Cardiovascular imaging
 Chest radiology
 Gastro intestinal radiology
 Genitourinary radiology
 Musculoskeletal radiology
 Emergency radiology
 Nuclear radiology

7. Interventional Radiology
 A subspecialty of radiology that focuses on the diagnosis and treatment of patients
utilizing minimally invasive interventional techniques (non- surgical procedure)
 These include
 Imaging and treatment of blood vessels disease(angiography)
 Biopsy procedures
 Cardiac- catheterization
 Angioplasty (balloon dilatation of blood vessels)
 Stents
 Laser treatment of varicose veins
 Fluid abscess drainage

8. What Is Medical Imaging?
 Medical imaging is the visualization of body parts, tissues , or organs for clinical
diagnosis , treatment and disease monitoring.
 Imaging techniques encompass the fields of radiology , nuclear medicine and
image –guided intervention.

9. Introduction
 General radiography , commonly referred to as x-rays.
 X-ray is an important diagnostic tool and first established modality of diagnostic
imaging-rays are used to create images of the body’s internal structures.
 These images are used to detect abnormalities in bones, lungs and other internal
organs.
 X-ray works on the basic principle of ionizing radiation.

10. Radiation
 Emission and transfer of energy generated by source & transferred through space
is called radiation.
 Any type of energy that is capable of ionizing matter is known as ionizing radiation.
 Ionizing radiation is a special interaction between radiation and matter that may
cause ionization i.e X-rays .
(ionizing radiation is any type of radiation that is capable of removing any
orbital electron from the atom with which it interacts ).

11. Continued…
 Matter that intercepts radiation and absorbs part or all of it said to be exposed or
irradiated.
 Spending a day at the beach exposes you to ultraviolet light causes sunburn.( sun
=> source , person => irradiated)
 During a radiographic examination the patient is exposed to x –rays .The patient is
said to be irradiated.

12. Sources of Ionizing Radiation
 Divided into two main categories
 Natural environmental radiation
 Man-made radiation
 Natural environmental radiation results in an annual dose of Approximately 3
millisieverts (mSv).
 Man made radiation results in 3.2 Msv ANNUALLY
 An mSv is unit of effective dose.

13. What are the Specialities of Radiology?
General specialities
 X-rays
 Ct scan
 Mammography
 Fluoroscopy
 Ultrasound
 MRI
 Interventional radiology & angiography

14. Radiography (X-RAYS)
 X-ray machine provide a static image on radiograph.
 X-ray or radiography uses a very small dose of ionizing radiation to produce
images of the body’s internal structures.
 X-rays are the oldest and most frequently used form of medical imaging.

16. Uses of X-rays
 The most familiar use of x-rays is checking for fractures (broken bones)
 Chest x-rays can spot pneumonia, bronchiectasis, tuberculosis, lung cancer,
emphysema.
 In dental radiology x-rays help in many procedures.
 Ist test in case of emergency ,trauma is x-rays.

17. Chest x-ray Hand x-ray

18. Computerized Tomography (CT)scan
 Basic principle of CT scan is derived from x-ray.
 A computerized tomography (CT)scan combines a series of x-ray images taken
from different angles and uses computer processing to create cross sectional
images or slices of the bones blood vessels and soft tissues inside the body.
 Ct scan imaging provide more detailed information than plain x-rays do.
 Ct scan can be used to visualize nearly all parts of the body and is used to
diagnose disease or injury as well as to plan medical, surgical or radiation
treatment.

20. CT SCAN -USES
 Diagnose muscle and bone disorders –such as bone tumour's and fracture
 Pinpoint the location of a tumour, infection or blood clot.
 Guide procedures such as surgery ,biopsy and radiation therapy.
 Detect and monitor diseases and conditions such as cancer ,heart disease ,lung
nodule's and liver masses.
 Monitor the effectiveness of certain treatments such as cancer treatments.
 Detect internal injuries and internal bleeding.

21. CT scan brain

22. Fluoroscopy
 Fluoroscopy is based on x rays (X ray tube is installed).
 Radiation dose is higher than radiography.
 Provide both static and dynamic images.
 Fluoroscopy is similar to radiography and X-ray computed tomography (X-
ray CT) in that as it generates images using X-rays.
 X-ray & CT scan provide only still images on film whereas fluoroscopy provides
live moving pictures that were not stored. It provides spot pictures and video
recording.

24. Fluoroscopy Uses
 Urology
 Interventional radiology
 Cardiac catheterization
 Endoscopy
 GIT studies

25. Barium enema showing normal colon
mucosa

26. Ultrasound
 Ultrasound is a type of imaging which uses high-frequency sound waves to look at
organs and structures inside the body.
 Health care professionals use it to view the heart , blood vessels , kidneys ,liver
and other organs.
 Ultrasound is considered always safe for both patients and health care
professionals.( no ionizing radiations are generated)

28. Ultrasound uses
 Breast Usg for diagnosis of cancers and fibro adenomas.
 Thyroid ultrasound for thyroid gland disorders.
 Abdominal ultrasound for evaluation of liver , spleen , pancrease , gall bladder.
 Pelvis ultrasound for evaluation of reproductive organ diseases.
 Brain ultrasound of new born to evaluate hydrocephalus.
 Obstetric ultrasound is only the safe and accurate method for foetus observation. It
is safe modality for both mother and foetus.
 Color Doppler ultrasound for varicose veins and carotid Doppler usg in case of
stroke are very common.

29. Kidney& left lobe of liver Obstetric USG
on an ultrasound image

30. Mammography
 A mammogram is specialized medical imaging test that uses a low dose of x-ray to
examine the breast, early detection of cancer and other breast diseases .It is used
as diagnostic and screening tool.
 It may even detect small tumours at initial stages, the women has more treatment
options .
 X-rays usually have no side effects in the typical diagnostic range for this exam.

31. A Normal Mammography Image, CC
Projection

32. Magnetic Resonance Imaging(MRI)
 Magnetic Resonance Imaging is a type of scan that uses strong magnetic fields
and radio waves to produce detailed images of inside body.
 An MRI scanner is a large tube that contains powerful magnets and coils .You lie
inside the tube during the scan.
 An MRI scan differs from CT scans and x-rays because it does not use ionizing
radiation that can be potentially harmful to a patient.

34. WHAT ARE MRI SCANS USED FOR?
 Abnormalities of brain and spinal cord
 Tumours ,cysts and other abnormalities in various parts of the body
 Injuries or abnormalities of the joints such as back pain
 Certain types of heart problems
 Diseases of the liver and other abdominal organs
 Causes of pelvic pain in women ( fibroids , endometriosis)
 Suspected uterine abnormalities in women undergoing evaluation for infertility .
 MRI contrast studies are also done to improve the appearance of a certain body
tissues.

35. Normal brain MRI

36. What is Nuclear Medicine?
Nuclear medicine is a medical specialty that
uses radioactive materials for both diagnosis
and treatment of disease.
Nuclear medicine imaging documents organ
functioning and structure.

37. Why We Need Nuclear Medicine?
 Branch of medical imaging that uses small amounts of radioactive material
(radioisotopes) to diagnose and determine the severity of or treat variety of
diseases.
 Including many types of cancers, heart diseases, gastrointestinal ,endocrine,
neurological disorders & other abnormalities within the body.

38. Nuclear medicine a Marvellous Innovation
Nuclear medicine scans emphasis is not only imaging anatomy , but on function. For
such reason , it may also called a physiological imaging modality.
The development of Spect in 1980’s led to three dimensional reconstruction of the
heart and establishment of the field of nuclear cardiology.
Pet is a functional imaging technique that uses radiotracers to measure changes in
metabolic processes and in other physiological activities including blood flow , regional
chemical composition, and absorption.

39. Modalities of Nuclear Medicine?
 Most common nuclear medicine modalities used in clinical practice
 Gamma camera
 Single photon emission computed tomography (SPECT)
 Positron emission tomography(PET)

40. Gamma Camera 2D - Imaging
 A gamma camera is an imaging device used in nuclear scanning. It was invented
by H. Anger in the 1960s and is often referred to as the Anger camera.
 The radiotracer injected into a vein, emits gamma radiation as it decays. A gamma
camera scans the radiation area and creates an image.
 Gamma camera works on the principle of radiopharmaceutical.
 Most commonly used radiopharmaceuticals used are tc99, I131, MIBI etc,
 Energy of tc99 is 128 Kev.

43. Planar bone scan

44. Uses of Gamma camera
 Thyroid scan
 Bone scan
 HIDA scan
 Dynamic renal scintigraphy
 Meckel’s scan
 Brain scan

45. SPECT
 Single Photon Emission Computed Tomography
 Multiple views of three dimensional distribution of radioactivity from different
directions.
 Detector systems rotated around the object so that many different angular views
(projections) of object are obtained.
 Reconstructed images from multiple projections – emission computed tomography
 Multiple planar views acquired .
 SPECT utilizes the single photons emitted by gamma-emitting radionuclides such
as 99mTc, 67Ga, 111In and 123I

47. Spect CT chest images extensive
consolidation

48. Uses of Spect
 Brain disorders
 Heart problems
 Bone disorders

49. PLANAR IMAGING vs SPECT
Planar imaging or conventional imaging is 2-D projections of a 3-D
source distribution.
Images at one depth are obscured by superimposed images of
overlying & underlying structures.
Spect obtain tomographic imaging
3D images = multiple 2D slices of a 3D object
More accurate quantitation of activity at specific locations within the
body.

50. Continued…
 SPECT camera designs have more than one head or constructed with a ring of
detectors.
 Single and multiple head cameras, the heads are mechanically rotated around the
patient to obtain the multiple projections views.
 Ring detectors have a ring of individual small crystals or a single, donut-shaped
crystal that does not rotate.

51. Spect Camera With Single Donut Shaped
Crystal & Triple Headed SPECT Camera

52. WHAT IS PET?
 Positron emission tomography is an imaging technique that assists in the
diagnosis and management of many diseases particularly cancer.
 Pet images show metabolism and other functions rather than the gross anatomy
and structure revealed by conventional x- rays or CT scans .As a result pet can
examine the fundamental biological nature of disease that occurs early on even
before symptoms occur is some cases ,while CT and MRI examine structural
alterations due to disease that may occur later.
 Clinicians can use this unique information to detect disease better in its early
stages when treatments is simpler and more effective. They can also use it to
provide accurate assessments of therapeutic response.

53. PET
 Often replaces multiple medical testing procedures with a single exam while
producing imaging information of superior quality .
 Images and measures metabolic processes .
 Validates and alter patient management and care .
 Reduces patient risk, improves treatment outcome may reduce or eliminate
ineffective and un-necessary surgical or medical treatments and hospitalization.
 Avoids needless pain to the patient.
 It is safe.

54. Brain PET Scan

55. PET Has High Accuracy
Cancer Type Diagnostic Accuracy
 Lung cancer
 Solitary pulmonary nodule
 Head & neck cancer
 Colorectal cancer
 Melanoma
 Lymphoma
 Breast cancer
 Ovarian cancer
 Muscular skeletal tumour's
91%
94%
92%
94%
88%
97%
92%
81%
93%

56. How Pet different from Gamma camera
and Spect
 Detector used in PET imaging is bismuth germinate crystal
 As positron contain 511 Kev energy which is a highest energy range.
 Radioisotopes used in PET scans are different from planar imaging and general
radiology imaging .
 Some common isotopes used are 18f , 15O , 13N , 11C.

59. Difference Between General Radiology And
Nuclear Medicine?
General radiology Nuclear medicine
 In general radiology main principle of
imaging is transmission imaging.
 Imaging process in general radiology
is from x rays.
 X-rays origin is from outer shells of
an atom.
 Image receptor is screen film for
radiography.
 Nuclear medicine is emission
imaging.
 Nuclear medicine imaging results
from gamma rays.
 Origin of gamma rays are direct from
nucleus of an atom.
 Image receptor for gamma rays is
NaI detector desingned for absortion
of gamma rays.

60. Continued…
 Contrast material used in general
radiology are easily available in
market and procedures of general
radiology are available in many
hospitals.
 Contrast agents used in general
radiology are safe.
 Little or none aftercare is needed
after general radiology exam or
procedure.
 Contrast agents used in nuclear
medicine called radioisotopes are
usually of explosive nature. And not
available in many hospitals.
 Because of their explosive nature
they are available in specific hospitals
under care and observation of
specific Govt. team.
 Patient is source of radiation due to
max. half life of radioisotopes
aftercare is needed.

61. Clinical Differences between General Radiology
and Nuclear Medicine
General Radiology Nuclear Medicine
 Radiology is designed to see
anatomy shapes & sizes.
 Radiology is most commonly used
for diagnostic purpose.
 General radiology modalities
generally have very good spatial
resolution.
 General radiology studies have less
noise on images.
 Without contrast we can do
examination and get data about ROI.
 Nuclear medicine is designed to see
physiology ( cells , molecules ,
interactions etc..).
 Nuclear medicine includes both
diagnosis & treatment.
 Nuclear medicine studies have poor
spatial resolution.
 Nuclear medicine studies have more
noise on images.
 We can examine only with contrast
agents or radio tracers.

62. Hybrid imaging
 Hybrid imaging refers to the fusion of two (or more) imaging modalities to form a new
technique. By combining the innate advantages of the fused imaging technologies
synergistically, usually a new and more powerful modality comes into being.
Existing hybrid imaging modalities comprise
 PET-CT
 SPECT-CT
 MRI-PET
 MRI-SPECT
 Ultrasound and MRI
 Ultrasound and CT
 MRI and CT

63. The general benefits of hybrid imaging include
 Increased diagnostic accuracy
 A further step towards individualised medicine
 Precise monitoring of interventional procedures
 Reduced radiation exposure
 Following is an image of PET-CT.
Cross-sectional abdomen image.

64. Mcqs
 A patient with presentation of head trauma , loss of conscious level which test is
gold standard for early diagnosis?
a) SPECT b) MRI
c) X-RAY d) CT Scan
 Which modality is considered to be safe in diagnosis of breast cancer <30 year of
age?
a) Mammography b) MRI
c) PET scan d) Ultrasound

65. Mcqs…
 In the diagnosis of thyroid cancer which is the first test to be done?
a) Thyroid ultrasound b) Thyroid CT scan
b) Thyroid scan d) Thyroid MRI
 If a patient having suspicion of berry aneurysm in brain which scan is
considered to be gold standard?
a)PET b) SPECT CT
c) Planner imaging d) MRI brain

66. Mcqs…
A patient having deranged RFT’S and complaint of oliguria we have to check
glomerular filtration best modality of choice is
a) PET –CT B) MRI
b) ULTRASOUND D) Dynamic renal scintigraphy

67. Thank you