Fundamentals of Radiology
(Nuclear Medicine). Radiological
anatomy of Thorax and Upper
Limb
TSMU
DEPARTEMENT OF RADIOLOGY
What is nuclear medicine?
 Detection and Subsequent Processing of
Radioactive Radiation of Investigated Probe
(Human Body or Its Any Tissue Sample)
What is Radioactivity?

Radioactivity (i.e., radioactive decay) is the process by
which unstable atoms that do not have sufficient binding
energy to hold their nuclei together emit ionizing
radiation.

Henri Becquerel discovered spontaneous radioactivity
from uranium in 1896, and Pierre and Marie Curie
discovered radium and polonium in 1898. As a result, all
three received the Nobel Prize in Physics in 1903.
Radioactivity (cont)



An unstable nucleus will decompose spontaneously, or decay, into
a more stable configuration by emitting certain particles (alfa and
beta) or certain forms of electromagnetic energy (gamma rays).
Radioactive decay is a property of several naturally occurring
elements as well as of artificially produced isotopes of the
elements. The process continues until a stable nucleus has been
formed.
Alpha decay
 Beta decay
 Gamma decay
Alpha decay

Alpha particle (identical to a helium nucleus) is emitted.

Travel a few centimeters in air.

Unable to penetrate the outer layer of dead skin cells.

High charge and mass, can cause serious cell injury, if in the body.
How?

Food or air.

Alexander Litvinenko – Poisoned by Polonium-210
Beta decay

Beta particle (electron or positron) is emitted.

Smaller mass.

Travel further in air for few meters.

It can penetrate skin a few millimeters.

Carl Anderson discovered the positron (the “positive
electron”) in 1932 and subsequently received the Nobel
Prize in Physics in 1936.
Gamma decay

Gamma ray does not consist of any particles, unlike its
predecessors. Instead consisting of a photon of energy
(electromagnetic radiation) being emitted from an
unstable nucleus.

No mass or charge.

Can travel 150 meters.

Can be stopped by high atomic value material
such as lead.
A radioactive compound or Radioisotope.



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A Radioisotope is an unstable form of an element that emits
radiation from its nucleus as it decays.
Radioisotopes - artificial and natural.
Natural - Uranium and Thorium.
Artificial – Induced radioactivity, Radiopharmaceuticals.
Irene and Frederic Joliuo-Currie, 1934.
Awarded the Nobel Prize for Chemistry for the
synthesis of new radioactive isotopes 1935.
Radiopharmaceuticals
How it works?
Any substance might be “marked” by radionuclide (radioisotope), called
radiotracer, radiopharmaceutical, or radiopharmacopreparation (RPP),
that enables to locate and monitor this substance in the organs and tissues
using external detection of emitted β or γ emission.
Bones Phospate
Radiopharmace
uticals
Thyroid –
Iodine
Brain Glucose
RPP Has to meet the following
requirements:
 Nontoxic
 Strong β or γ Emission
 Relationship to Definite Organ or Tissue
(Property of Specific Uptake)
 Optimum Effective Semiexcretion Period
(ESP)
Quantitative parameters of radioactive
isotops:

Half-life period – the period of time, in which
radioactivity decreases to the half of initial;

Semi-excretion period – the period of time, in which the
half of administered RPP is excreted

Effective semi-excretion period - the period of time, in
which the initial radioactivity of administered RPP is
halved due to physical break-up and biological excretion
processes
Commonly Used Radioisotopes in Diagnostic
Nuclear Medicine
How are nuclear medicine imaging
tests generally performed?
 We Administer the RPP to the patient
 RPP is Accumulated by Investigated Organ
 We can monitor the RPP accumulation
and
lead out processes
 We can get the information about RPP
distribution in the studied organ and construct it’s
image, as well as, receive numerical data (digits)
and curves.
cont.

For Planar scintigraphy and SPECT, gamma rays are emitted by the
radioactive isotopes in the radiotracers.
 For PET, positrons that are emitted by the radioactive isotopes in the
radiotracer molecules travel several millimeters within tissue before
annihilating with electrons that are encountered, leading to emission of
two gamma rays in opposite directions.
 The gamma rays leave the body, pass through a collimator (in planar
scintigraphy and SPECT), and are detected by one or more scintillation
crystals in detectors surrounding the patient. The light signals created
by the scintillation crystals are then detected by photomultiplier tubes
(PMT), which lead to creation of voltage signals that are digitized for
computers to process.
Gamma rays
Collimator
Scintillation
crystals
Photomultiplier
tubes
Computer
Scheme for apparatus of
gamma camera system
Gamma camera system used
in planar scintigraphy
What is Planar Scintigraphy?

Creates non-tomographic 2D planar images of accumulation of a
radiotracer in the body.
 Performed using a gamma camera system.
Mostly used to scan
 Bone
 Thyroid
 Biliary system
 Lung
 Full body.
MRI, CT and Bone Scintigraphy
Increased uptake in the right proximal humerus (red arrows) as well as the apex of the skull
(orange arrows). There is also an increased uptake in thyroid gland (Yellow arrows).
Computed tomography scan of the right arm showing a mass lesion (red arrow). Magnetic
resonance imaging of the head showing an enhancing calvarial mass (marked X) invading
into the subcutaneous tissue (red arrow).
What is SPECT?

Single photon emission computed tomography (SPECT).
 Several tomographic (cross-sectional) two-dimensional images with multiple
two-dimensional angels.
 Creates three-dimensional images.
 SPECT/CT (fuses two imaging modalities – CT & Nuclear medicine ) are
most often employed for SPECT imaging to provide coregistered molecular
and structural images.
 It also requires the use of a collimator, which generally
results in lower sensitivity and poorer image quality
compared to PET .
Mostly used to scan
 Brain, Heart, Bone.
SPECT (bottom) slices at level of basal ganglia (A) and cerebellum (B) in patient presenting with
right middle cerebral artery infarction. (A) SPECT image shows greater extension of ischemia
than MRI (yellow arrows). (B) Anatomic representation of cerebellar hemispheres is normal,
whereas decreased tracer uptake (hypoperfusion) is seen in left cerebellar hemisphere (white
arrowhead).
What is PET (Positron emission tomography)?

PET creates tomographic (cross-sectional) images of accumulation of a
positron emitting radiotracer in the body.
 Creates three-dimensional images.
 Nowadays, used with CT and MRI- called PET/CT and PET/MRI
(PT/MRI an emerging imaging technology) which provides better
molecular and structural images, improving image quality, anatomic
localization of sites of radiotracer uptake, and diagnostic performance. .
 PET/CT and PET/MRI fuses two imaging modalities – CT & Nuclear
medicine or MRI & Nuclear medicine
PET/CT-MRI Mostly used to
 Detect cancer, hidden metastasis, staging, follow ups, recurrence.
 Heart, Bone, Brain.
Typical PET/CT scanner with gantry (which contains x-ray
tube for CT and scintillation crystals for PET) and patient
table.
Axial PET, CT, PET-CT, and Planar Scintigraphy
images in a patient of lung cancer.
a–e. A 59-year-old female patient had therapy for carcinoma of the right breast. She presented
with back pain. Bone scintigraphy was performed to rule out bone metastasis. Planar bone
scintigraphy images (a, b) Planar scintigraphy shows focal uptake in the L5 vertebra (arrow). (c)
Axial SPECT image shows uptake in the region of right facet joint of the L5-S1 vertebrae
(arrow). Axial CT (d) and SPECT-CT (e) images show L5-S1 vertebrae right facet joint arthritis
with increased tracer uptake (arrow; score 5). On these images, SPECT, CT and SPECT-CT
characterized the planar scintigraphy indeterminate lesion as benign
Nuclear medicine techniques are used not only for diagnostic purposes,
but also less commonly to treat cancer, in which case the radiotracers
used accumulate in tumor sites and also emit charged particles that
promote cancer cell death.
Patient can briefly be the source of radiation exposure to others.

Limit exposure

Increase distance

Shielding

Isolation
Lastly, how does molecular imaging(NM) differ
from structural imaging(X-Ray, CT, MRT, US)?
Molecular imaging (Nuclear Medicine)

Molecular characterization of normal tissues and disease,
even when morphologic changes in tissues have not yet
occurred.
Radiography, [CT], [MRI], and [US]

Assessment of normal tissues and disease based on
morphologic and gross functional alterations.
ANY QUESTIONES?
Thorax Bones and Upper Limb
How Can we image it?

Conventional X-Ray filming

Computed Tomography (CT)

Magnetic Resonance Imaging (MRI)
Thorax Bones

Sternum, Ribs, and Vertebrae

1-7 ribs – True ribs

8–12 ribs - False ribs

11-12 ribs – Floating ribs
Joints between ribs and vertebrae
3D Reconstraction of Thorax bones
Sternum
Sternum on CT and MRI
sagittal view
Chest X-Ray
anteroposterior and lateral.
Chest CT coronal slices
Upper Limb Bones
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Scapula
Clavicle
Humerus
Radius and Ulna
Carpal bones
Metacarpals and
Phalanges
Shoulders

Clavicle.

Scapula.

Humerus.
Shoulder (cont.)
Anterior-Posterior View of the Scapula
Lateral View of the Scapula
Oblique and Anteroposterior View
of the Clavicle
Axial radiograph of the proximal
Humerus
Shoulder development X-Ray
Shoulder CT
Shoulder CT (cont.)
Shoulder MRT
Shoulder MRT (cont.)
Humerus
Lateral and Anterior-Posterior View of the Upper Arm
Elbow
Anterior-Posterior and Lateral View of the Elbow
Elbow radiographs, (a) 7-month-old child, (b) 3-year-old child, (c) 6-year-old child, (d)
9-year-old child
Forearm
Hand and Wrist
Hand and Wrist
Bones of the hand (dorsopalmar radiographs), (a) of a 10-month-old child, (b) of a 2year-old child, (c) of a 6-year-old child, (d) of a 9-year-old
child,toillustratecentresofossification,(e) of an 11-year-old child.
Elbow MRT
Forearm MRT and CT
Wrist CT and MRT
ANY QUESTIONES?