PDF 8.3 Medicine

8/22/2019 PDF 8.3 Medicine

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A Look at NuclearScience and Technology

Larry Foulke

Atomic and Nuclear Physics Radioisotopes

8.3 Medical Use of Radioisotopes


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This material includes excerpts from apresentation by Alan Waltar at the World

Nuclear University in 2012-2103.

Used by permission from World Nuclear

Association and Alan Waltar.

NOTE: Dr. Waltar is the author of the book, RADIATION AND MODERN LIFE:Fulfilling Marie Curie's Dream, Prometheus Books, 2005


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Numbers of Patients

Benefiting from NuclearMedical Techniques

Over 18 million/year in the U.S. Over 30 million/year globally 1 in 3 patients entering U.S. hospitals

or medical clinics benefit from

nuclear medical techniques


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MEDICINE

Sterilization of Medical Products Surgical dressings, sutures, catheters, syringes

New Drug Testing Over 80% of all new drugs tested withradioactive tagging before approval Between 200 and 300 radiopharmaceuticals

in routine use

Medical Imaging (~90%)Diagnose the ailment

Therapy (~10%) Cure the ailment or ease the pain

Image Source: See Note 1


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Types of Medical Imaging

X-ray(teeth, broken bones, mammograms)(Diagnostics ~ 90% of nuclear procedures)


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Radiography involves the use of an X-

ray tube and a photographic plate.

The patient is placed between the twoand an image is produced on the filmof the area exposed.

A common chest X-ray is an

example of a radiographic X-ray.



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Types of Medical Imaging

X-ray(teeth, broken bones, mammograms) CT (Computerized Tomography, 3D X-ray) Radiotracers

SPECT (single photon emission computerizedtomography)

PET (positron emission tomography)MRI (Magnetic Resonance Imaging)

(Diagnostics ~ 90% of nuclear procedures)


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CT Scan




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Radionuclides are used to determine theextent of a medical problem in a patient.

The radionuclide is attached to a

pharmaceutical, which has the properties todeposit the radioisotope in the organ ofconcern for a patient.

External radiation detectors are used to

determine abnormalities in the organ.



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Different parts of the human body absorb different

elements but do not discriminate between differentisotopes.

In tracer techniques a radioactive isotope of an element,such as iodine or technecium-99m, is injected into the body.

The signals coming from the ensuing radiation then give

a picture of the size and location of the area where the

isotope was absorbed. Usually isotopes of a relatively short half-life, of the

order of minutes or days, are used to minimize long-termradiation damage.


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PET (positron emission tomography)

scans involve the injection into the

body of an isotope which decays by

positron emission.

When this positron encounters an

electron they annihilate each other,

emitting two photons.

The energy and path of these photons

leaving the body can then be used to

give an accurate picture of the area

where the isotope was absorbed.


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PET (positron emission tomography)

The multitude of allthese lines of

response is used

to calculate a slice

image in a certain

plane.

When a pair of detectors detects simultaneously one 511keV

photon each, a positron must have annihilated on a straightline connecting those two detectors the so called line of

response.



13/23HSR MILANO

PET IMAGE OF THE BRAIN


oSlice of the brain of a56 year old man taken

with positron emission

tomography (PET).

o Image was generatedfrom a 20 minute

measurement with a

PET Scanner.

o Red areas show moreaccumulated tracer

substance and blue

areas are regions wherelow to no tracer have

been accumulated


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Uses gamma cameras, or multi-heads slowly rotated around the

patient.

Able to provide true 3D

information.

Information presented as cross-

sectional slices.

85% of all nuclear medicine

examinations use Mo/Tc Generators

for diagnostics of liver, lungs,

bones.



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Mo-99 is the most in demand medical isotope

Mo-99 is shipped to point of use (66 hrs half life)

itsdecay product

Technetium-99m is used as

tracer (6-hour half life)

Comes easily from a handful of existing,

publicly funded nuclear research reactors Reactors are getting old and are being shut down


16/23Image Source: See Note 10

Magnetic resonance imaging

generates pictures of the

arteries to evaluate them for

abnormal narrowing or

vessel wall dilatations, at risk

of rupture. MRI technology is

often used to evaluate the

arteries of the neck and

brain, the thoracic and

abdominal aorta, the renal

arteries, and the legs


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Medical Therapy

First applied to Thyroid Cancer(20,000 patients/year)Blood IrradiationOther Cancer(prostate, breast, brain, liver, etc.)

External External Beam Radiation

Protons X-rays

Internal BNCT (boron neutron capture) Cell Directed

Placed inside the body Smart bullets

Decrease pain of bone cancer

~ 10 % of nuclear procedures


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The CyberKnife or

Gamma Knife system is

a method of delivering

radiotherapy, with theintention of targeting

treatment more

accurately than standard

radiotherapy.



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Production and distribution of125I seeds and 192Ir wires

BRACHYTHERAPY




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Take Away Points Nuclear medicine uses radiation to provide

diagnostic information about human health.

Radiotherapy can be used to treat medicalconditions, especially cancer, using radiation to

weaken or destroy particular targeted cells.

Millions of nuclear medicine procedures areperformed each year, and demand for radioisotopes

is increasing rapidly.

Medical Therapy Using Radiation Technology NowGrowing Rapidly

Materials based on RADIATION AND MODERN LIFE:Fulfilling Marie Curies Dream by Alan Waltar,

Prometheus Books, Nov. 2004Image Source: See Note 14


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1. Public domain:http://www.nrc.gov/reading-rm/doc-collections/nuregs/brochures/br0217/r1/br0217r1.pdf

2.

Creative CommonsAttribution Share-Alike 3.0 Unported. ThomasBjorkan.http://en.wikipedia.org/wiki/File:Xraymachine.JPG

3. Creative CommonsAttribution Share-Alike 3.0 Unported.rosiescancerfund.com.http://en.wikipedia.org/wiki/File:Rosies_ct_scan.jpg

4. Public domain:http://en.wikipedia.org/wiki/File:CT_ScoutView.jpg

5. Public domain:http://commons.wikimedia.org/wiki/File:PET-

Image Source Notes


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6. Public domain:http://en.wikipedia.org/wiki/File:ECAT-Exact-HR--PET-Scanner.jpg

7.

Public domain:http://en.wikipedia.org/wiki/File:PET-schema.png

8. Public domain:http://en.wikipedia.org/wiki/File:PET-image.jpg

9. Creative CommonsAttribution Share-Alike 3.0 Unported. Ytrottier.http://en.wikipedia.org/wiki/File:SPECT_CT.JPG

10.Creative CommonsAttribution Share-Alike 3.0 Unported. Ofirglazer.http://en.wikipedia.org/wiki/File:Mra1.jpg

Image Source Notes


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11. Public domain:http://en.wikipedia.org/wiki/File:Gamma_Knife_Graphic.jpg

12.Creative CommonsAttribution Share-Alike 3.0 Unported. Rock mc1.http://en.wikipedia.org/wiki/File:Clinical_applications_of_brachytherapy.jpg

13.Public domain:http://en.wikipedia.org/wiki/File:Brachytherapy.jpeg

14.Public domain:http://en.wikipedia.org/wiki/File:Marie_Curie_c1920.png

Image Source Notes

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