Applications of Nuclear Technology

Nuclear Technologies 1

Sciences and Applications (S&A)

Sciences bring ideas, concepts and discoveries together and their applications lead to technologies. The research and development (R&D) of nuclear technologies were red hot, and they have matured.

S&A of stone, metal and steel lead to tools for ancient people.S&A of gun powder powered ancient heroes and empires.S&A of steam engine revolutionised industry in Europe.S&A of X-rays changed medical diagnoses and sciences.S&A of radioactivity opened new frontiers. S&A of fission and fusion promised power for war and peace.S&A of nuclear phenomena led to many nuclear technologies.

Yet R&Ds brought new challenges.


Nuclear Technologies

X-rays give penetrating vision to inner structures under cover.X-rays and computers give 4-D images of wholes. X-ray diffraction enables us to determine crystal and molecular structures, including those of DNA.Ionizing radiation effects and sterilization empower industries.Radioactive decay kinetics enables dating.Radioactivity causes and cures illness.Nuclear reactions led to nuclide and element synthesis.Pair productions give positrons and electrons for accelerators.Positron-electron annihilations tell stories of organ functions. Nuclear reactions activate atoms and nuclides in microscopic samples.Fission and fusion energy for war and peace.


Radiology

Radiology is a scientific discipline dealing with medical imaging using ionizing radiation, radionuclides, nuclear magnetic resonance, and ultrasound. The following procedures are currently widely available:

Central Nervous System: Brain,SpineCardiovascular System: heart, blood vesselsMusculoskeletal System: bone, muscles, and jointsDigestive, Urinary, and Respiratory System: intestines, kidneys, liver, stomach, lungsReproductive System and Mammography: male and female reproductive organs and breasts


X-ray Tubes

Top: X-ray tubes for industry and sciences.Right: Non-destructive testing X-ray tubes for X-ray Inspection and X-ray Baggage Inspectionand Thickness Gauging.There are hundreds of X-ray tubes for medical applications.

Image from prd004-5 of Varian.


X-ray Imaging

Other imaging techniques:

Ultrasound - images due to speed of amounts of sound energyMagnetic resonance - magnetic properties of H used for imagingElastography - shows localized strain levels in tissue produced in response to small axial external applied compressions

Absorption of X-ray and gamma-ray by different material for image: today, 2-dimensional solid state detectors are used in place of films for X-ray and gamma-ray imaging as shown in this image by Varian

Image of female from www.varian.com/xry/prd004.html


Mammography and CT Scan

X-rays provide the sharpest images of the breast's inner structure. Mammogram detects small tumors and changes in the breast tissues.

Computed tomography (CT), scanner takes images by rotating an x-ray tube around the body while measuring the constantly changing absorption of the x-ray beam by different tissues in your body.

The sensitive scanner provides small differences in absorption of the beam by various tissues. The information is fed into a computer which reconstruct images of thin cross sections of the body.


A transaxial image of a Stradivarius violin


DEXA – duel energy X-ray absorptiometry

Dual energy X-ray absorptometry (DEXA) is also called dual x-ray absorptometry (DXA).

A high and a low energy x-ray beams pass through the bone and the difference in absorption is used to estimate the bone mineral density.

Bone mineral density (BMD) is an indication of of bone mass. BMD generally correlates with bone strength and its ability to bear weight. Low BMS is osteoporosis with risk of easy bone fracture.


Impact of X-ray Diffraction

This is one of the diffraction X-ray tubes with beryllium windows by Varian, operating at 60 keV, 1500 - 2000 wats, target W, Mo, Cu, and Cr, ($3000 each).

Using X-ray diffraction, nearly all structure of compounds artificially made or isolated from nature have been determined, including structures of semiconductors, DNA molecules, and proteins. Structure data banks serve science, technologies, and medicine.


X-ray Diffraction Results

Two X-ray diffraction patterns are shown:Top: diffraction pattern from Al-wire recorded on a film revealing preferred orientation and size of micro-crystals in the wire.Bottom: X-ray diffraction pattern of a single crystal showing positive image of X-ray beams. Intensities of these beams allows us to determine molecular and crystal structures.

Various data banks of structures are now available for research and development.


X-ray Diffraction Results

Tetrahedral Bonding in Diamond, Silicon,Zinc sulfide, Gallium Arsenide etc.


Positron Emission Tomography

Positron emitting nuclides 11C, 13N, 15O, and 18F are attached to compounds as probes. They are injected into a patient, the probe or its metabolites will be accumulated in certain area facilitated by the specific function of certain organs.

The annihilation of positron emits two 511keV gamma rays at opposite directions. The detectors in these machines can detect the location of the probes or metabolites of the probes, and thus understand the functionality of various organs.

The function of the organs provides better diagnosis than CT.


Nuclides and Probes for PET

The nuclides mentioned previously are synthesized by these nuclear reaction with particles from accelerators such as cyclotrons.

Production Half life Sample Dosage Function

14N(p, ) 11C 20 min acetate 20 mCi Metabolism and blood

16O(p, ) 13N 10 min ammonia 25 mCi Myocardial Perfusion

14N(d, n) 15O 2 min water 50 mCi Brain blood flow

18O(p, n) 18F 110 min F- ion 5 mCi Bone function

18O(p, n) 18F 110 min FDG* 10 mCi Myocardial viability *FluoroDeoxyGlucose


Radionuclide in Medicine

Radionuclides are used in imaging for diagnosis and treatment.In addition to PET, there are other nuclides specifically accumulated in organs for image and diagnoses.

Radionuclide therapy selectively deliver radiation doses intarget tissues. Radiopharmaceuticals - DNA, sugar, protein, and drug molecules, eg. 131I or I-MIBGRadionuclide therapy still finds itself in a last position among other treatments.


Radionuclide 131I131I is for thyroid cancer treatment.

Production: 130Te (n, ) 131I or from isolate from fission products

Decay: , 364 (81%) 337 (7.3%) and 284 KeV (6%), and 610 KeV to stable 131Xe. Half-life 8.04 days

Preparation: NaI in gelatine capsule or solution for oral administration, and solution for IV injection

After oral administration, 90% is absorbed in the upper gastrointestinal tract, mostly accumulated in the thyroid compartment. Accumulation is high for cancerous cells. Effective half-life is 0.43 days for 40% and 7 days for 60%.


123I, 99mTc and 131I Scan123I electron capture decay energy 1.24 MeV, t½ 13.27 hr99mTc, 0.143 MeV (IT), t½ 6.01 hr

The shorter t½ of 123I allows a lower radiation dose than using 131I.

99mTc as pertechnetate, TcO4?-, is rapped by the thyroid iodide

concentrating mechanism but is not incorporated into organic form. 123I is trapped and organified by thyroid tissues.

Usual dose is 200 to 400 Ci by mouth or intravenous route. The 13-hour half life makes it suitable for imaging upto 24 hrs using the gamma camera.

This image shows a cold nodule on the left


Indications of Endocrine Nuclear Medicine1. Determination of thyroid size, function, and position.

2. Evaluation of functional status of thyroid nodules.

3. Evaluation of thyroid and neck masses.

4. Evaluation of patients with history of head and neck irradiation.

5. Quantitative thyroid uptake (I-131 uptake).

6. Detection of ectopic thyroid tissues such as substernal or sublingual locations of thyroid tissue (I-123).

7. Treatment for hyperthyroidism, neoplasm (I-131).

8. Detection of thyroid metastases and assessment of response to therapy (I-131) uic.edu/com/uhrd/nucmed/tyroid.htm


Radionuclide 131I-MIBG

131I-iodine-meta-iodobenzylguanidine 131I-MIBG is the approved name.

131I-MIBG is selectively taken up by normal adrenergic tissues, such as the adrenal medulla and the sympathetic autonomic nervous system, and by tumours of these neuroectodermally derived tissues.A dose of 100-300 mCi of 131I-MIBG with a high specific activity (up to 1.48 GBq/mg) is administered intravenously over a 0.5 to 4 hour period.

Ionizing radiation kills cancer cells.


Radionuclide 32P

Sodium phosphate Na332PO4

32P is a pure beta emitter, with maximum and average beta energy of 1.71 and 0.695 MeV respectively, range in tissues 3 mm to 8 mm, half-life 14.3 days.

Once IV injected, the phosphate is incorporated into proliferating and protein synthesizing cells as well as into cortical bone. The biological half-life in bone marrow is 7-9 days.

Phosphate is actively incorporated into the nucleic acids of rapidly proliferating cells. It suppresses hyperproliferative cell lines rather than to eradicate them.


Implant of Radionuclide

Radionuclides are encapsulated in plastics and surgically implanted close to cancerous cells to deliver 2 Sv of dosage to these cells for a few days.

Intra-cavity implant and interstitial implant are used.

Brachytherapy combined with CT and PET results in precise and effective implantations.

Typical radionuclides are:125I, low energy radiation confined to small region.226Ra, half life 1600 y, alpha, 4.78 MeV, gamma from Rn 0.184 MeV137Cs half life 34.4 h, and 137mCs Half-life 9 h, positron, EC, and gamma


History of Nuclear Midicine

1985 – discovery of X-rays

1934 – discovery of artificial radioactivity

1937 – artificial radioactivity was used to treat leukemia at UC Berkeley

1946 – use of radioactive iodine cured thyroid cancer

1948 – Abbott Laboratories began distribution of radioistopes

1950s – radioactive iodine was widely used to diagnose and treat thyroid

1953 – Gordon Brownell and H.H. Sweet built a positron detector

1971 - The American Medical Association officially recognized nuclear medicine as a medical speciality


About Nuclear Medicine

There are nearly 100 different nuclear medicine imaging procedures available today.

Nuclear medicine uniquely provides information about both the function and structure of virtually every major organ system within the body.

There are approximately 2,700 full-time equivalent nuclear medicine physicians and 14,000 certified nuclear medicine technologists in the U.S.

In Kitchener-Waterloo, the nuclear medicine unit is in the St. Mary Hospital.


Nuclear Medicine Applications

Neurologic: Diagnose stroke, alzheimer’s disease, localize seizure foci, evaluate post concussion

Oncologic: Tumor localization, staging, and response to treatments

Orthopedic: Evaluate bone, arthritic changes, and extent of tumors

Renal: Detect urinary tract obstruction and measure renal functions

Cardiac: Diagnose coronary artery, measure effectiveness of bypass surgery, identify patients of high risk heart attack, and diagnose heart attacks

Pulmonary: Measure lung functions

Other: Diagnose and Treat Hyperthyroidism (Grave's Disease)


Irradiation Sterilization

Irradiation by ionizing radiation kills bacteria and cells. This effect has been applied for the following areas:

sterilize medical equipment

sterilize consumer products such as baby bottle, pacifiers, hygiene products, hair brush, sewage

sterilize common home and industry products

food preservation


Irradiation for Food Processing

Soon after discovery, X-rays were used to kill insects and their eggs.

After WWII, spent fuel rod were used to sterilize food, but soon, 60Co was found easier to use in th 1950s.

The US army played a key role in R & D of food processing, and soon other countries followed.

In 1958, USSR granted irradiation of potatoes for sprout inhibition. Canada granted irradiation of potatoes, onions, wheat, dry spices.

At 1980 meeting, a committee considered a dose of 10 kGy safe.

However, food processing has many other problems such as regulation, labelling, marketing and public acceptance to deal with.


Neutron Activation Analysis (NAA)

Neutron activation analysis is a multi-, major-, minor-, and trace-element analytical method for the accurate and precise determination of elemental concentrations in materials.

Sensitivity for certain elements are below nanogram level.

The method is based on the detection and measurement of characteristic gamma rays emitted from radioactive isotopes produced in the sample upon irradiation with neutrons.

High resolution germanium semiconductor detector gives specific information about elements.


The NAA Method

Block diagrams of the NAA method

Neutron Source

Material for NAA

radioactive nuclides

Prompt rays

rays

Gamma-ray spectrometer

Data analysis and results reporting

Material original

rays


Application of NAA

Aluminum Gadolinium Neodymium Sodium Antimony Gallium Nickel Strontium Arsenic Germanium Niobium Tantalum Barium Gold Osmium Tellurium Bromine Hafnium Palladium Terbium Cadmium Indium Platinum Thorium Cerium Iodine Potassium Thulium Cesium Iridium Praseodymium Tin Chlorine Iron Rhenium Titanium Chromium Lanthanum Rubidium Tungsten Cobalt Lutetium Ruthenium Uranium Copper Magnesium Samarium Vanadium Dysprosium Manganese Scandium Ytterbium Erbium Mercury Selenium Zinc Europium Molybdenum Silver Zirconium

Elements (60) listed here are routinely analyzed by the NAA center in Cornell University. It analyzed samples from agriculture, archaeology, engineering, geology, medicine, to oceanography, serving various disciplines and industries.osp.cornell.edu/vpr/ward/NAA.html


Canadian NAA Facilities

The (Safe LOW POwer Kritical Experiment)SLOWPOKE reactor in the University of Toronto offers instrumental neutron activation analysis services. It has an on site gamma-ray spectrometer for the analysis.

The experimental nuclear reactor in McMaster University Nuclear Reactor (MNR) began operating in 1959 as the first university based research reactor in the British Commonwealth. It offers nuclear dating, NAA, and neutron radiography.


Raiocarbon Dating

Carbon consists of 0.989 12C, 0.011 13C, and 1e-12 14C in equilibrium due to its production in the atmosphere. The 14C half-life is 5730 years. Thus, number of 14C atom in 1 g of C is

N = 6.022e23*1.3e-12 / 12 = 6.5e10 14C/g CActivity = 6.5e10 * ln(2) / (5730*365.25*24*60) = 15 dpm/g of C

Thus, by measuring specific decay rate of carbon enable us to estimate the period in which the sample was not actively exchange carbon with the atmosphere.

Tree-ring chronology indicated some variation of 14C level, and correction factors give reasonable estimates.For example, the scrolls from the Dead Sea was 14C dated to be 2000 years old.


Raiocarbon Formation and Exchange

Cosmic rays

n proton

14C

14N

CO2

14CO2


Physical Data of 14C

Beta energy 156keV (maximum), 49 keV (ave)

Half life 5730 y

Biological half life 12 dEffective half life 12 d (unbound)

40 d (bound)

Max. beta range in air 24 cmMax. beta range in water 0.28 mm

Fraction of 14C beta transmitted through dead layer of skin at 0.07 cm depth is 1%


Radiopotassium 40K Dating

Radiopotassium 40K decays to stable 40Ar. Thus, by measuring relative ratio of 40K and 40Ar in rocks enable us to determine the age of rocks since its formation.The half life of 40K is 1.25e9 y.


Nuclear Technologies

X-rays give penetrating vision to inner structures under cover.X-rays and computers give 4-D images of wholes. X-ray diffraction enables us to determine crystal and molecular structures, including those of DNA.Ionizing radiation effects and sterilization empower industries.Radioactive decay kinetics enables dating.Radioactivity causes and cures illness.Nuclear reactions led to nuclide and element synthesis.Pair productions give positrons and electrons for accelerators.Positron-electron annihilations tell stories of organ functions. Nuclear reactions activate atoms and nuclides in microscopic samples.Fission and fusion energy for war and peace.

Business

Applications of Nuclear Technology