PRELIM 1: NUC MED

Nuclear Medicine

A medical specialty that focuses on the use of radioactive materials called radiopharmaceuticals for diagnosis, therapy, and medical research.

Radiology

• A field that determines the presence of disease based on structural appearance (anatomy).

• uses sealed source of radiation, in the form of x-rays

NUCLEAR MEDICINE

• Determine the cause of medical problem based on organ or tissue function (physiology)

• uses unsealed source of radiation, in the form of gamma rays

1. Injection

2. Swallowing

3. Inhalation

Mode of administration:

1. specific

2. non-invasive

• TRACER Thus it is considered as:

As Low As Reasonably Achievable

ALARA

GAMMA CAMERA

• Is a special equipment used to transform these emissions into images that provide information about the function, primarily, and anatomy of an organ or system being studied.

Radioactive Tracers

produce gamma ray emissions from within the organ being studied

1. Nuclear Medicine Physician

2. Nuclear Medicine Technologist

3. Physicist

4. Pharmacist or specially prepared technologist

NUCLEAR MEDICINE TEAM:

Nuclear Medicine Physician

a specialist with extensive education in the basic and clinical science of medicine who is licensed to use radioactive materials.

Nuclear Medicine Technologist

who performs the tests and is educated in the theory and practice of nuclear medicine procedures.

Physicist

who is experience in the technology of nuclear medicine and the are of the equipment, including computers.

Pharmacist or specially prepared technologist

who is qualified to prepare the necessary radioactive pharmaceuticals

John Dalton(1803)

• is considered as the father of modern theory of atoms and molecules.

• measured atomic weights in reference to hydrogen in which he assigned the value of 1 (the atomic number of this element).

John Dalton(1803)

He stated that all atoms of a given element are:

- chemically identical

- unchanged by chemical reaction

- combine in a ratio of simple numbers

Henri Becquerel

discovered naturally occurring radioactive substances.

Marie Curie (1898)

discovered two new elements in the uranium ore pitchblende

1. polonium (after her homeland, Poland)

2. radium

Marie Curie trace elements:

radioactivity

Curie also coined the term: _______

• a process by which atoms spontaneously emit high energy particles or rays from their nucleus.

Georg de Hevesy (1923)

often called the “father of nuclear medicine”, developed the tracer principle.

Georg de Hevesy (1923)

He coined the term radioindicator and extended his studies from inorganic to organic chemistry.

radium and radon

The first radioindicators were naturally occurring substances such as ___________

Ernest Lawrence (1931)

invented cyclotron, made it possible for de Hevesy to expand his studies to a broader spectrum of biologic processes by using phosphorus-32, sodium-22 and other cyclotron-produced (man-made) radioactive tracers.

Enrico Fermi et.al. (1946),

• Radioactive elements began to be produced in nuclear reactors which was developed by;

• he greatly extended the ability of the cyclotron to produce radioactive tracers

Hal Anger (1958)

• A key development was the introduction of gamma camera by;

• As well as the invention of digital computer made feasible the continued growth of nuclear medicine.

Thyroid

Was one of the first organs to be examined by nuclear medicine studies using external radiation detectors

radii

The term radiation is taken from Latin word ____:

- which refers to the spoke of wheels leading out from a central point.

radioactivity

is used to describe the radiation of energy in the form of high-speed alpha or beta particles or waves (gamma rays) from the nucleus of an atom

nuclide

is used to describe atomic species with a particular arrangement of protons and neutrons in the nucleus.

Isotopes

Elements with the same number of protons but a different number of neutrons.

neutron-to-proton ratio

________ in the nucleus determines the stability of an atom.

decay

At certain ratios, atoms may be unstable, and a process known as spontaneous ______ can occur as the atom attempts to regain stability.

ground state

Energy is released in various ways during this decay, or return to ______

radionuclides

used in nuclear medicine are produced in reactors, or particle accelerators.

Technetium-99m (99mTc)

The most commonly used radionuclide in nuclear medicine, which is produced in a generator system.

Parent and Daughter Nuclide-Principle Parent

is the original nuclide which undergoes radioactive

Daughter

the more stable nuclide which results from radioactive decay

Technetium-99m

• Discovered in 1937 by Perrier and Segre

• Named after the Greek word technetos, meaning artificial

21 isotope

_________ of Technetium have been discovered (all radioactive)

Mo99/Tc99m generator

first produced generator in 1957

TECHNETIUM -99m

6 hour half-life

High photon yield of 140 keV

Pure gamma emitter

Generator availability

Chemically reactive

In-vivo function agents

trace or mimic certain bodily processes without altering the process in any way so that a true measure of function can be obtained.

DMSA

1.Morphologic studies of renal cortex

2.Individual kidney function

3.Location of ectopic kidney

DTPA

1. Renal perfusion studies

2. Glomerular filtration rate estimation

3. Diuretic washout

4. Lung aerosol study

MAA

1. Lung perfusion study

2. Leg venography

SESTAMIBI

1. Myocardial perfusion study

2. Parathyroid study

3. Breast imaging

PHYROPHOSPHATE

Bone imaging

Myocardial infarct study

Gastrointestinal bleeding study

SULFUR COLLOID

Liver/spleen imaging

Gastroesopageal reflux study

Gastric emptying study

DIPHOSPHONATE DERIVATIVES

Bone mineral study

Bone scintigraphy

IMMINIDIACETATES

Hipatobiliary imaging

Diagnosis of acute/chronic cholecystitis

Gallbladder perforation

Common duct obstruction

PERTECHNETATE

Meckels diverticulum study

Testicular study

Thyroid imaging

Thallium-201

Myocardial perfusion study

Tumor viability study

Gallium-67

Inflammatory diseases

Diagnosis and staging lymphomas, especially Hodgkin’s disease

Iodine-131

Thyroid uptake study

Thyroid imaging

Therapy for thyroid cancer

Therapy for thyrotoxicosis

Thyroid metastases study

Strontium-89

Therapy for bone metastases

Static

Whole-body

Dynamic

SPECT

diagnostic imaging examinations are performed in nuclear medicine:

STATIC IMAGING

• Is the acquisition of a single image of a particular structure.

• This image can be thought of a “snapshot” of the radiopharmaceutical distribution within a part of the body.

• EXAMPLES

  Lung scans

  Spot bone scan images

  Thyroid images

WHOLE-BODY IMAGING

• Uses a specially designed moving detector system to produce an image of the entire body or a large body section.

• The gamma camera collects data as it passes over the body.

• EXAMPLES

  Whole body bone scan

  Whole body tumor or abscess imaging

  Other clinical and research application

DYNAMIC IMAGING

• Display the distribution of a particular radiopharmaceutical over a specific period.

• A dynamic or “flow” study of a particular structure is generally used to evaluate blood perfusion to the tissue.

• EXAMPLES

  Renal perfusion study

  Hepatobiliary study

Single Photon Emission Computed Tomography (SPECT)

• Produces images similar to those scanned be CT or MRI.

• The computer creates a thin slices through a particular organ.

• This technique has proved very beneficial for delineating small lesions within tissues.

• Can be used on virtually any structure or organ. i.e. cardiac and 3-phase bone studies.

Positron Emission Tomography (PET)

An imaging technique that uses positron emissions from specific radionuclides to produce detailed functional images in the body.

Radioactive Tracers

Radioactive substances used in nuclear medicine to study organ or tissue function.

Half-life

The time required for half of the radioactive atoms in a sample to decay.

Diagnostic Radiopharmaceuticals

Agents used to obtain images of physiological processes.

Tracer Principle

The concept of using radioactive tracers to study the functions of various organs in the body.