Radiology Basics for Oncologists

Radiology for Radiation Oncologists
PART 1- BASIC RADIOLOGICAL INVESTIGATIONS IN ONCOLOGY
FOR BEGINNERS
DR KANHU CHARAN PATRO
1

Disclaimer
• As you know, I am not a radiologist.
• But I know what should a radiation oncologist should know about
radiology
• So limit your unlimited questions
• Just understand the basics
2

My flow
• X-RAY
• CT SCAN
• BARIUM STUDIES
• MAMMOGRAM
• USG
• IMAGE STORAGE & TRANSFER
• MRI
• PET
• BONE SCAN
3

Radiation exposure in investigation
Radiation
• X-ray
• Mammography
• CT
• Fluoroscopy
• Nuclear imaging
• PET
• BONE SCAN
• Other
No radiation
• USG
• Doppler
• MRI
4

Wavelength and energy of radiological procedures
5

Radiation doses in various radiographic procedures
6

Describing the tissues/organs
7
Procedure Like brain Less than brain More than brain
USG Isoechoic Hypoechoic Hyperechoic
CT SCAN Isodense Hypodense Hyperdense
MRI Isointense Hypointense Hyperintense

Discovery of X-ray
• X-rays were discovered in 1895
by Wilhelm Conrad Roentgen
(1845-1923)
• Wuerzburg University in
Germany.
• Working with a cathode-ray tube
in his laboratory, Roentgen
observed a fluorescent glow of
crystals on a table near his tube
9

The first X-ray
• This discovery — that X Rays could
offer a glimpse inside the human
body gave Röntgen an idea
• He asked his wife to place her hand
in front of a photographic plate,
and activated the Crookes tube.
• The dark shadows of her palm’s
bones, including the distinct
shadow of her wedding ring, were
imprinted on the plate.
10

X-ray production
• X-rays are produced due to sudden deceleration of fast-
moving electrons when they collide and interact with the target
anode.
• In this process of deceleration, more than 99% of the electron
energy is converted into heat and less than 1% of energy is
converted into x-rays.
11

Common practice in oncology
• CHEST X RAY
• SPINE[AP/LAT]
• ERECT ABDOMEN
• SKELETAL SURVEY
• SKULL
• SPINE
• PELVIS
• EXTERIMITIES
• PNS AND MANDIBLE
16

Fluoroscopy
• Fluoroscopy is an imaging technique that uses X-rays to obtain real-
time moving images of the interior of an object.
• Fluoroscopy is used in a wide variety of examinations and
procedures to diagnose or treat patients.
• Some examples are: Barium X-rays and enemas (to view the
gastrointestinal tract) Catheter insertion and manipulation (to direct
the movement of a catheter through blood vessels, bile ducts or the
urinary system)
17

A-Airway
• Trachea
• Bronchus
• Lung
• Pleura
31

B-bony structure
•Bony thorax
•Scapula
•Humerus
•Rib
•Spine
35

C-circulation
•Large vessels
•Heart
37

E- EXTRA
• Broncho vascular markings
• Nipple shadow
41

What is barium X-ray
• A barium X-ray is
a radiographic (X-ray)
examination of the GI tract with
barium contrast.
• Upper and lower GI series.
• Used to diagnose abnormalities
of the GI tract.
47

Types
• Barium swallow
• X-ray examinations are used to study the pharynx and esophagus.
• Barium meal
• Examinations are used to study the lower esophagus, stomach and duodenum.
• Barium follow through
• Serial Examinations are used to study the small intestine.
• Small bowel enema, also called Enteroclysis
• Is a barium X-ray examination used to display individual loops of the small intestine
by intubating the jejunum and administering barium sulfate followed
by methylcellulose or air.
• Barium enema
• Examinations are used to study the large intestine and rectum and are classified
as lower gastrointestinal series
48

Use of barium studies
Structural
• Mucosa
• Malignancy
• Ulcer
Functional
• Achalasia
• Swallowing
• Hiatus hernia
49

Use of barium studies
Malignancy
• Carcinoma
• Ulcer/growth
• Stricture
Benign
• Stricture
• Achalasia
• Hernia
50

Imaging
• X ray
• AP
• PA
• LAT
• Oblique
• Supine
• Prone
• Serial
• FLOUROSCOPY
51

Fluoroscopy
• Fluoroscopy is an imaging technique that uses X-rays to obtain real-
time moving images of the interior of an object.
• Fluoroscopy is used in a wide variety of examinations and procedures
to diagnose or treat patients.
52

Double contrast
• An gas producing agent is introduced with barium
• The 'double contrast' refers to the use of positive and negative
contrast agents to increase the sensitivity of the examination.
• Positive contrast: barium or barium-like agent, e.g. Gastrografin ®
• Negative contrast: air or CO2
• The double contrast study is sensitive to visualise mucosal
irregularities.
• Better dissention and separation of loops
54

Barium Sulfate
1. Barium sulfate is the inorganic compound
with the chemical formula BaSO₄.
2. It is a white crystalline solid that is odorless
and insoluble in water.
55

Side effects
• Aspiration
• Constipation
• Anaphylaxis
• Impaction
56

Contraindication
• Hypersensitivity
• Obstruction suspected
• Perforation suspected
• Fistula suspected
57

Barium swallow
Procedure
• You swallow the barium, the
radiologist will take single pictures,
a series of X-rays, or fluoroscopy to
watch the barium moving through
your mouth and throat.
• You may be asked to hold your
breath at certain times during the
test.
• You will be given a
thinner barium drink to swallow
Indication
• Oropharynx and upper GI tract
abnormalities
58

Barium meal
• An upper gastrointestinal series, also called a barium meal,
• Is a series of radiographs used to examine the gastrointestinal tract
for abnormalities.
• A barium meal is a diagnostic test used to detect abnormalities of the
esophagus, stomach and duodenum
62

Barium meal procedure
• Before a barium meal test is performed, the duodenum needs to be
empty to allow clear visualization of structures.
• A patient may be given a laxative the night before the procedure to
ensure the small bowel is empty at the time of the test, which is
usually performed on an empty stomach.
63

Small bowel follow through (SBFT)
• Small bowel follow through (SBFT) is a fluoroscopic technique
designed to obtain high-resolution images of the small bowel.
• The motility of the small bowel can also be grossly evaluated
• A small bowel follow through is a single contrast study (oral contrast,
either barium or water-soluble contrast).
• It is often performed after an upper GI fluoroscopic study, as the
contrast column moves from the stomach and duodenum into the
small bowel
66

Small bowel follow through (SBFT)
67

Small bowel barium enema
• Enteroclysis, also called small bowel enema, is a barium X-ray
examination used to display individual loops of the small intestine by
intubating the jejunum and administering barium sulfate followed
by methylcellulose or air.
• In this procedure continuous infusion of contrast into the bowel as
well as IV contrast injection take place.
• Therefore, there will be more significant small bowel distension
compared to CT enterography which could cause discomfort for the
patient
69

Barium enema
• A lower gastrointestinal series is a medical procedure used to
examine and diagnose colorectal problems
• Radiographs are taken while barium sulfate, a radiocontrast agent,
fills the colon via an enema through the rectum.
71

Barium enema procedure
• The radiologist will then insert a small tube into your rectum and
introduce the barium and water mixture.
• The radiologist may gently push air into your colon after the barium
has been delivered in order to allow for even more detailed X-ray
images.
• This is called an air-contrast barium enema.
72

Imaging correlation
• CT CLONOGRAPHY
• ENDOSCOPY
75

After procedure
• Some patients may feel abdominal bloating after a barium meal test
and the test may also lead to constipation.
• Patients are therefore advised to drink plenty of fluid and eat plenty
of fruit and vegetables. Mild laxatives may also help.
• Stools may be pale or whitish for a few days after the test
76

DEXA scan
• A DEXA scan usually assesses or measures bone density.
• It may also have uses in determining body composition, such as the
percentage of lean muscle and fat.
• The dual-energy X-ray absorptiometry (DEXA) scan uses two low-
energy X-ray beams, which doctors direct toward the bones
• Also called a bone density scan, is a common technique used
to measure bone density.
• This completely painless procedure is easily performed and exposes
the patient to minimal radiation.
78

BASICS OF CT SCAN
Dr Kanhu Charan Patro
84

What is a CT scan?
• CT scan means computed tomography scan
• It use X ray for image
85

Principle of CT
• Circular X ray
• Absorbed X ray different tissue to tissue
• That detected on detector
• Converted to image
90

Preparation
• 4 hour fasting
• No renal problem
• Consent
• Anaphylaxis kit on console
97

FOV
• (FOV) The field of view is the
maximum diameter of the
area of the scanned object
that is represented in the
reconstructed image.
99

Density
• Brain – Reference
• Hypodense-darker
• Isodense- same
• Hyperdense -brighter
100

Hounsfield unit
• CT number
• Different for different tissue
• Related to composition of tissue
101

A. Brightness refers to the overall lightness or
darkness of the image.
B. Contrast is the difference in brightness between
objects in the image.
107

Brightness- window levelContrast- window width
108

Sagittal[s-s] Coronal[A-P] Axial[S-I]
114

Artifacts
• Artifacts are commonly encountered in clinical computed
tomography (CT), and may obscure or simulate pathology. There are
many different types of CT artifacts, including noise, beam hardening,
scatter, pseudoenhancement, motion, cone beam, helical, ring, and
metal artifacts
118

Ring Artifacts- defective detector element
119

Mammogram
• A mammogram is an x-ray picture of the breast
• Mammography is a specific type of breast imaging that uses low-dose
x-rays
• A mammography exam, called a mammogram, aids in the early
detection and diagnosis of breast diseases in women.
122

Procedure
• Places breasts between 2 plates
• Press the plates together to flatten your breast
• Take an x-ray, which lasts a few seconds
• Images from mammography are typically from two to four angles
(or views). So, 'Cranial-Caudal' (CC) is a view from above.
• While an oblique or angled view 'mediolateral-oblique', or (MLO)
123

Digital mammography
• Digital mammography, also called full-field digital mammography
(FFDM), is a mammography system in which the x-ray film is replaced
by electronics that convert x-rays into mammographic pictures of the
breast.
• These systems are similar to those found in digital cameras and their
efficiency enables better pictures with a lower radiation dose.
• These images of the breast are transferred to a computer for review
by the radiologist and for long term storage.
• The patient's experience during a digital mammogram is similar to
having a conventional film mammogram
126

Digital mammograms
• Digital mammograms record the images on a computer, rather than
on film.
• Digital records are easier to store and share with other health care
professionals.
• The image contrast is also sharper, which can make it easier to find
small changes
127

3-D breast imaging- tomosynthesis.
• Another advance is 3-dimensional (3-D) breast imaging. It is also called
breast tomosynthesis
• For this exam, the breast is positioned and flattened the same way it is for
a digital mammogram.
• But a tomosynthesis takes a few seconds longer than a digital
mammogram.
• This is because an x-ray tube moves in an arc and takes pictures of the
breast from many angles.
• The information is processed by a computer, which creates images that
show multiple thin sections of the breast. A radiologist analyzes the results.
130

Breast tomosynthesis
• Also called three-dimensional (3-D) mammography and digital breast
tomosynthesis (DBT), is an advanced form of breast imaging where
multiple images of the breast from different angles are captured and
reconstructed ("synthesized") into a three-dimensional image set.
• In this way, 3-D breast imaging is similar to computed tomography (CT)
imaging in which a series of thin "slices" are assembled together to create a
3-D reconstruction of the body.
• Although the radiation dose for some breast tomosynthesis systems is
slightly higher than the dosage used in standard mammography;
• Large population studies have shown that screening with breast
tomosynthesis results in improved breast cancer detection rates and fewer
"call-backs," instances where women are called back from screening for
additional testing because of a potentially abnormal finding.
131

Breast tomosynthesis
• Earlier detection of small breast cancers that may be hidden on a
conventional mammogram
• Fewer unnecessary biopsies or additional tests
• Greater likelihood of detecting multiple breast tumors
• Clearer images of abnormalities within dense breast tissue
• Greater accuracy in pinpointing the size, shape and location of breast
abnormalities
132

Computer-aided detection (CAD)
• Computer-aided detection (CAD) systems search digitized
mammographic images for abnormal areas of density, mass,
or calcification that may indicate the presence of cancer.
• The CAD system highlights these areas on the images, alerting
the radiologist to carefully assess this area.
137

Ultrasound
• Ultrasound scans, or sonography, are safe because they use sound waves or
echoes to make an image, instead of radiation
• The image produced is called a sonogram
• Ultrasound scans are safe and widely used.
• They are often used to check the progress of a pregnancy.
• They are used for diagnosis or treatment.
• No special preparation is normally necessary before an ultrasound scan
• The term “ultrasound” refers to sound with a frequency that humans cannot
hear.
• The 'normal' hearing frequency range of a healthy young person is about 20 to
20,000Hz
• For diagnostic uses, the ultrasound is usually between 2 and 18 megahertz (MHz).
138

Echogenic
• Hyperechoic
• Hypoechoic
• Isoechoic
139

Image capture in ultrasound
• Ultrasound will travel through blood in the heart chamber, for example, but if it
hits a heart valve, it will echo, or bounce back
• The denser the object the ultrasound hits, the more of the ultrasound bounces
back.
• This bouncing back, or echo, gives the ultrasound image its features. Varying
shades of gray reflect different densities.
• The person who performs an ultrasound scan is called a sonographer, but the
images are interpreted by radiologists, cardiologists, or other specialists.
• The sonographer usually holds a transducer, a hand-held device, like a wand,
which is placed on the patient’s skin.
• Ultrasound is sound that travels through soft tissue and fluids, but it bounces
back, or echoes, off denser surfaces. This is how it creates an image
140

Ultrasound transducers
• The transducer, or wand, is normally placed on the surface of the
patient’s body, but some kinds are placed internally.
• These can provide clearer, more informative images.
• Examples are:
• An endovaginal transducer, for use in the vagina
• An endorectal transducer, for use in the rectum
• A transesophageal transducer, passed down the patient’s throat for use in
the esophagus
• Some very small transducers can be placed onto the end of a catheter and
inserted into blood vessels to examine the walls of blood vessels.
141

Transesophageal ultrasound
144

Doppler ultrasound
• Doppler ultrasound can assess the flow of blood in a vessel or blood pressure. It
can determine the speed of the blood flow and any obstructions.
• An echocardiogram (ECG) is an example of Doppler ultrasound. It can be used to
create images of the cardiovascular system and to measure blood flow and
cardiac tissue movement at specific points.
• It can also be used to:
• examine the walls of blood vessels
• check for DVT or an aneurysm
• check fetal heart and heartbeat
• evaluate for plaque buildup and clots
• assess for blockages or narrowing of arteries
• A carotid duplex is a form of carotid ultrasonography that may include a Doppler
ultrasound.
• This would reveal how blood cells move through the carotid arteries.
145

PACS
• A picture archiving and communication system (PACS) is a medical
imaging technology which provides economical storage and
convenient access to images from multiple modalities (source
machine types).
• Electronic images and reports are transmitted digitally via PACS; this
eliminates the need to manually file, retrieve, or transport film
jackets, the folders used to store and protect X-ray film
147

DICOM
1. Digital Imaging and Communications in Medicine is the standard for
the communication and management of medical imaging
information and related data
2. DICOM is used worldwide to store, exchange, and transmit medical
images. DICOM has been central to the development of modern
radiological imaging
3. DICOM incorporates standards for imaging modalities such as
radiography, ultrasonography, computed tomography (CT),
magnetic resonance imaging (MRI), and radiation therapy.
148

PARTS OF MRI
• MAGNETIC FIELD
• GRADIENT COIL
• RADIOFREQUENCY COIL
• COMPUTER SYSTEM
152

MRI invention
• Damadian, along with Larry
Minkoff and Michael Goldsmith,
obtained an image of a tumor in
the thorax of a mouse in 1976.
• They also performed the first
MRI body scan of a human being
on July 3, 1977, studies they
published in 1977

Discovery of NMR
•Felix Bloch
•Edward Purcell
•1952 Nobel
Prize

Isidor Isaac Rabi
• 1944 Nobel prize

MAGNETIC FIELD
GRADIENT COIL
MAGNETIC FIELD
GRADIENT COIL GRADIENT COIL
GRADIENT COIL GRADIENT COIL GRADIENT COIL
RF COIL
RF TRANSMITTER GRADIENT POWER SUPPLY RF RECIEVER
156

Patient
Application of magnetic
field
Application
radiofrequency
Withdrawn of
radiofrequency
Release of energy
Fourier transmission
Conversion of analogue
signal to digital signal
Converted to image
Playing with TR and TE and RF
By varying the sequence of RF pulses applied & collected,
different types of images are created
Quickness of release of energy varies as
per tissue. Give differential image
Sequence of events in MRI

PHYSICS OF MRI
• MRI is based on the magnetization properties of atomic nuclei.
• The protons that are normally randomly oriented within the water nuclei of the tissue
• A powerful, uniform, external magnetic field is employed to align the protons that are normally randomly oriented
within the water nuclei of the tissue being examined.
• This alignment (or magnetization) is next disrupted by introduction of an external Radio Frequency (RF) energy.
• The nuclei return to their resting alignment through various relaxation processes and in so doing emit RF energy.
• After a certain period following the initial RF, the emitted signals are measured.
• Fourier transformation is used to convert the frequency information contained in the signal from each location in
the imaged plane to corresponding intensity levels, which are then displayed as shades of gray in a matrix
arrangement of pixels.
• By varying the sequence of RF pulses applied & collected, different types of images are created.
• Repetition Time (TR) is the amount of time between successive pulse sequences applied to the same slice.
• Time to Echo (TE) is the time between the delivery of the RF pulse and the receipt of the echo signal.
• Tissue can be characterized by two different relaxation times - T1 and T2.
158

Human body composition
• 70 PERCENT WATER
• WATER AND FAT CONTAIN
HYDROGEN ATOMS
159

Hydrogen atom the tiny magnet
+
e-
o2
+
e-
+
e-

Hydrogen atoms Randomly oriented
• Proton spin is called precession
• The rate of precession is called
LARMOR frequency
161

Application of magnetic field
[parallel and anti parallel]
163

Application of RF- 90 degree alignment
RF 164

Application of RF- 180 degree alignment
RF 165

RF turned off- energy released atom
COMPUTER
CONVERT
ANALOGUE SIGNAL
TO DIGITAL SIGNAL
STORED IN K SPACE
AND CONVERTED
TO IMAGE BY
CALCULATION
167

RF Turned Off- Energy
COMPUTER
CONVERT
ANALOGUE SIGNAL
TO DIGITAL SIGNAL
STORED IN K SPACE
AND CONVERTED
TO IMAGE BY
CALCULATION
168

Quickness of release
• Quickness of release of energy
varies as per tissue
• Give differential image
169

Function of gradient magnet
• Secondary magnet
• Arranged in different axis
• Spatial encoding and Image
localization
• Responsible for loud noise
• Z runs in long axis-axial
• Y runs in longitudinal axis- coronal
• X runs in transverse axis- sagittal
170

BRAIN SEQUENCES IN ONCOLOGY PRACTICE
171

Types of image
• Structural image
• Functional image
172

What is a Sequence?
• Sequence of events in MRI
machine
• By varying the sequence of RF
pulses applied & collected,
different types of images are
created
• PHILIPS
• GE
• TOSHIBA
• SIEMENS
• HITACHI
173

• TR
• Repetition time
• The time between two
excitations
• TE
• Echo time
• The time interval in which
signals are measured after RF
excitation
174

175

Intensity
•Shades of grey of tissues/water in MRI called
intensity
•Hypointense- Black
•Hyperintense- Bright
•Isointense- Grey
177

T1 sequence
•T1
•Fat bright[white]
•Water black
•Normal anatomy
•Vascular changes
178

T1 contrast
• T1 contrast • T1 contrast
• Vessels -hyperintense
179

T2 sequence- Flip side of T1
•T2
• CSF, AQ/VT HUMOR WHITE
•Fat black
•Water white
•Blood vessel dark
•CSF study
•Lesions in brain
180

Flair sequence
• Fluid attenuation inversion
recovery
• Flair-ventricular ooze
• CSF black
• Pathological fluid white
181

T2 vs FLAIR- Flip side of T2
182

Identify-T1 VS T2 VS FLAIR
183

MR Diffusion
• Ghost sequence
• Diffusion weighted image
• DWI
• Fluid restriction
• Whiter –cytotoxic edema
184

ADC MAP
• Apparent diffusion coefficient
• Statistical measure of restriction
• ADC measuring the diffusion
• ADC without T2 effect –black
185

FSPGR Sequence
• [3D FSPGR (fast spoiled gradient
echo)
• More differentiation of normal
structure
• Contrast as well as non contrast
• Improves anatomical display
186

Fiesta sequence
• FIRST IMAGING EMPLOYING
STEADY STATE ACQUSITION
• Clear visualization of ventricles
• Cranial nerves AT SKULL BASE
• Cisterns
188

STIR sequence. Fat saturated/FATSAT sequence
• Short tau inversion recovery
• These chemically selective
pulses cause the signal
from fat to be nulled (saturated)
• Packing materials
• Gel foam
• Fat
189

MRS
• Magnetic resonance
spectroscopy
• Chemical measurement
• Grading of tumours
190

MR Angio
• Magnetic resonance angiography is
used to generate images of arteries in
order to evaluate them for stenosis,
occlusions, aneurysms or other
abnormalities
192

MR perfusion
1. Sequence to see perfusion of
tissues
2. The acquired data are then post-
processed to obtain perfusion maps
with different parameters, such as
BV (blood volume), BF (blood flow)
3. The main role of perfusion imaging
is in evaluation of ischemic
conditions neoplasms (e.g. identify
highest grade component of diffuse
astrocytoma help to
distinguish glioblastomas from
cerebral metastases) and
neurodegenerative diseases.
193

Gradient echo sequence
• Gradient recalled echo (GRE) (T2
WI) is a relatively new (MRI)
technique.
• GRE T2 WI can detect the
smallest changes in uniformity
in the magnetic field and can
improve the rate of small lesion
detection
• Detection and Evaluation of
Microbleeds
194

1. PITUITARY ADENOMA-STIR
2. TRIGEMINAL NEURALGIA- FIESTA
3. CP ANGLE TUMOR-GRE
4. GLIOMA-DIFFUSION,PERFUSION
5. AVM-ANGIO
6. GRADING OF TUMORS- MRS
195

What is a bone scan?
• Also known as bone scintigraphy is a nuclear medicine imaging
technique of the axial skeleton.
• It can help diagnose a number of bone conditions, including cancer
related bone lesion or metastasis, location of bone inflammation and
fractures, and bone infection.
197

Radiopharmaceutical Agent.
• Radiopharmaceuticals are the compounds that contain radioisotopes
emitting ionizing radiation and are used in treatment or diagnosis.
• The procedure involves giving the patient
a radiopharmaceutical molecule marked with a gamma-emitting
radioisotope.
• Once the molecule fixed on the target organ or tissue, the emitted
gamma rays easily escape from the body can be detected by
detector panels
198

Radionuclide scan
200
DISEASE TRACERS
• Thyroid post op • 131I NaI
• Cardiac • 99m Tc MUGA
• Brain • 99m Tc MIBI
• Neuroendocrine • 68Ga DOTANOC
• Renal • 99mTc DMSA/DTPA
• Parathyroid • 99m Tc MIBI
• Adrenal • 131I MIBG
• Bone • 99m Tc MDP
• Prostate • 68Ga PSMA
• Meningioma vs cavernous sinus • 99mTc RBC

Radionuclide therapy
201
Organ /diseases Radioisotopes
• Thyroid • 131I NaI
• Bone • 153 Sm EDTMP
• 177Lu EDTMP
• Prostate • 177Lu PSMA
• Neuroendocrine • 177Lu DOTATAC
• Medullary thyroid • 131I MIBG

Terminology
• Scintigraphy also known as a gamma scan,
• Bone scans are planar 2D images in a similar process to the capture
of x-ray images.
• In contrast, SPECT is a form 3D and it also use gamma cameras to
detect internal radiation
203

George de Hevesy
• Hungarian radiochemist
• Nobel Prize in Chemistry
• Recognized in 1943 for his key role in the
development of radioactive tracers to study
chemical processes such as in
the metabolism of animals
204

Hall Anger and gamma camera
205

Radiopharmaceutical agent
• The most common radiopharmaceutical for bone scintigraphy is 99mTc
with methylene diphosphonate (MDP)
207

Indication
Benign
• Osteomyelitis
• Arthritis
• Trauma /stress injuries
• Metabolic bone
disorders
Malignant
• Unexplained bone pain
in cancer patients
• Suspicion of bone mets
• Some primary tumors
209

Procedure
• In a typical bone scan technique, the patient is injected (usually into a vein in
the arm or hand, technetium-99m-MDP and then scanned with gamma
camera, which captures planar anterior and posterior planar images or single
photon emission computed tomography (SPECT) images.
• In order to view small lesions SPECT imaging technique may be preferred over
planar scintigraphy
210

Steps
• Explaining to the patient
• Injection of 20mCi of Tn-99m MDP
• Frequent voiding and hydration
• Scan after 3-4 hour with gamma camera
211

Preparation and precaution
• No preparation required
• Hydration and voiding
• After procedure stay away from children and pregnant lady
• At least twice flush after toilet
• Tc half life is six hours so one day precaution required
212

Frequent voiding and hydration
214

Type of lesions
• Osteoblastic
• Osteolytic
216

Super scan
• Superscan is intense symmetric activity in the bones
with diminished renal and soft tissue activity on a
Tc99m diphosphonate
218

Normal uptake
• JOINTS
• TRAUMA AREA
• GROWTH ENDS
220

Diagnostic Correlation
• When there is any doubt about diagnosis
• SPECT
• PET
• MRI
• CT
221

Positron emission tomography-PET
222

Radiopharmaceutical
• Radiopharmaceutical consists of two components-
• Pharmaceutical which enables the distribution of
radiopharmaceutical
• Radionuclide enables study of distribution of radiopharmaceutical to
be measured
• Example-F18 FDG.
223

Radionuclide imaging principle
• Radiotracer
• Radiopharmaceutical agent
• Ingestion/injection
• Attach to specific organ
• Emits gamma
• Detector
• Conversion to image
224

225
Principle- Coincidence Detection
Detector
Detector
Positron is a subatomic particle with the same mass as an
electron and a numerically equal but positive charge.

PET tracers in use - Diagnosis
227
TRACERS DISEASE
• Fludeoxyglucose (18 FDG) • Carcinoma
• Lymphoma
• Gallium-68 PSMA PET/CT • Prostate ca
• Brain glioma
• 68Ga-DOTA-PET • Neuroendocrine Tumours
• Meningioma
• C11 L- Methionine • Brain
• 18 NaF • Bone metastasis
• 18 F FLT • Lymphoma
• 18 F MISO • TUMOR HYPOXIA
• TK 1 ACTIVITY • Lung

229
CT
• Anatomical detail
• Better resolution than PET
• Cannot differentiate between
active and inactive disease

230
PET/CT
• Combines the functional information
with the anatomical detail
• Accurate anatomical registration
• Higher diagnostic accuracy than PET or
CT alone

232
Scan Process
1) CT scout view performed first
2) Full CT performed second
3) Patient moved into scanner and PET scan acquired third
4) Normally acquired from base of skull to mid thigh.

234
Production of Radionuclides-Cyclotrons in Hospitals

235
FDG
CH2HO
HO
HO
O
OH
18F
CH2HO
HO
HO
O
OH
OH
glucose
2-deoxy-2-(F-18) fluro-D-glucose
• Most widely used PET tracer
• Glucose utilization
• Taken up avidly by most tumours
• Measures Glucose metabolism of
tissue
• Rationale for the use of FDG for PET
imaging majority of malignant cancer
phenotypes exhibit an increased
glucose metabolism due to Warburg
effect

Normal Distribution of FDG
TISSUE Mechanism of uptake Importance
Myocardium Variable to intense Lesions near heart missed due to partial
volume effect
Brain Obligate use of glucose therefore Intense
uptake
Less contrast between tumor and normal
tissue
Brown adipose tissue
(predominantly children)
Direct heat generation through anaerobic
glycolysis
False positive scan in nape of
neck,supraclavicular regions,paravertebral
regions
Alimentary tract Uptake variable Interpretation slightly difficult
Genitourinary tract FDG not transported by Sodium glucose
cotransport
High activity in bladder
High activity in renal pelvis
May obscure small lesions near them
Bone marrow Mild to intense d/t high turnover Intense when on G-CSF
Lymphoid tissue Waldeyers ring Increased uptake False negative if malignancy present.
236

237
Standard Uptake Value (SUV)
SUV = Activity in ROI (MBq) / vol (ml)
Injected activity (MBq)/patient weight (g)
• Higher the SUV, greater the risk of disease
• More than 2.0 is considered to be suggestive of malignancy,
whereas lesions with SUVs less than this value are considered to
be benign.
before chemotherapy
SUV = 17.2
chemotherapy day 7
SUV = 3.9
chemotherapy day 42
SUV = 1.8
ROI

FDG-PET: Applications in Oncology
• Differentiating benign from malignant lesions
• Staging and restaging for choice of Rx.
• Predicting and monitoring response to treatment (As a
Biomarker)
• Radiation planning
• Metabolic classification of tumors for prognostication
• Differentiation of Necrosis vs Residue/ Recurrence
• Identifying Unknown Primary.
238

Where is the Target?
6/5/2020 239Mahatmagandhi cancer hospital and research institute
SPARE THE ROD AND SPOIL THE CHILD
DO NOT LOOSE SHIGHT OF FOREST [OAR]FOR THE TREE

PET IN EBRT PLANNING
• CT- poor contrast between tumor and normal tissue
• Advantages-
• Precise delineation of primary target volume
• Optimized Target delineation
• Superimposition of tumor metabolic activity on exact anatomic
location.
• Decreased inter and intra observer variation
• Differentiate atelactatic from tumor tissue
240

TRIPLE FUSION
PET
CTMRI
6/5/2020 244
Mahatma Gandhi Cancer Hospital & Research
Institute,Visakhapatnanm

Concept of triple-fusion
6/5/2020 245Mahatmagandhi cancer hospital and research institute

Target volume definition
6/5/2020 246Mahatma Gandhi Cancer Hospital & Research

Imaging
6/5/2020
247

IMAGING
6/5/2020 248

PET vs.MRI
6/5/2020 249

PET vs.MRI
6/5/2020 250

Avoid unnecessary toxicity
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251

Unknown primary
6/5/2020
252

Impact on radiotherapy
6/5/2020
253
1.Elective nodal irradiation
2.Nodal boost

Interobservor variation
6/5/2020
254

C. Messa et al.; Q J Nucl Med Mol Imaging 2006
NSCLC: PET/CT During Radiotherapy
6/5/2020 255

Adaptive –decrease toxicity
6/5/2020
256

Pet CT planning
6/5/2020
258

Image based contouring
6/5/2020 259

SUV based contouring
6/5/2020 260

Tumor Volume
6/5/2020 261

Nodal Volume
6/5/2020 262

VN.C., f, 34y; Cancer of Cervix Uteri; Additional Retroperitoneal Metastases
Example: Increased Target Volume cervix –PA node
6/5/2020 263

W.L., f, 61y; NSCLC; No Contralateral Involvement
Example: Decreased Target Volume
6/5/2020 264

Moureau et al. IJROBP 2005
Increased Target Volume in Oesophageal Carcinoma
6/5/2020 265

PET-CT-WIN-WIN SITUATION
PARAMETER VOLUME CHANNGE
T STAGE INCREASE
UPSTAGING
1. PREVENTS TUMOR TISSUE MISSING
2. CHANGES TT FROM CURATIVE TO PALLLIATIVE
DECREASE
DOWN STAGING
1. PREVENTS EXTRA DOSE TO NORMAL TISSUE
2. CHANGES TT. FROM PALLIATIVE TO CURATIVE
3. DOSE ESCALATION IS POSSIBLE
N STAGE INCREASE
UPSTAGING
1. PREVENTS TUMOR TISSUE MISSING
2. CHANGES TT FROM CURATIVE TO PALLLIATIVE
DECREASE
DOWN STAGING
1. PREVENTS EXTRA DOSE TO NORMAL TISSUE
2. CHANGES TT. FROM PALLIATIVE TO CURATIVE
3. DOSE ESCALATION IS POSSIBLE
M STAGE INCREASE CURATIVE-TO PALLIATIVE
DECREASE PALLIATIVE TO CURATIVE
6/5/2020

Bird’s eye view Eagle’s eye view
6/5/2020 270
Be like Eagle

Acknowledgement
• Google
• Dr Satya Narayan Patro
• Dr Raghava Kasyap
• Dr Randheer M
• Dr P Madhuri
• Dr N Santosh
272

Radiology Basics for Oncologists

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