# 1.1 Medical imaging and diagnostics  (Page 3/9)

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## Phet explorations: simplified mri

Is it a tumor? Magnetic Resonance Imaging (MRI) can tell. Your head is full of tiny radio transmitters (the nuclear spins of the hydrogen nuclei of your water molecules). In an MRI unit, these little radios can be made to broadcast their positions, giving a detailed picture of the inside of your head.

## Section summary

• Radiopharmaceuticals are compounds that are used for medical imaging and therapeutics.
• The process of attaching a radioactive substance is called tagging.
• [link] lists certain diagnostic uses of radiopharmaceuticals including the isotope and activity typically used in diagnostics.
• One common imaging device is the Anger camera, which consists of a lead collimator, radiation detectors, and an analysis computer.
• Tomography performed with $\gamma$ -emitting radiopharmaceuticals is called SPECT and has the advantages of x-ray CT scans coupled with organ- and function-specific drugs.
• PET is a similar technique that uses ${\beta }^{+}$ emitters and detects the two annihilation $\gamma$ rays, which aid to localize the source.

## Conceptual questions

In terms of radiation dose, what is the major difference between medical diagnostic uses of radiation and medical therapeutic uses?

One of the methods used to limit radiation dose to the patient in medical imaging is to employ isotopes with short half-lives. How would this limit the dose?

## Problems&Exercises

A neutron generator uses an $\alpha$ source, such as radium, to bombard beryllium, inducing the reaction ${}^{4}\text{He}+{}^{9}\text{Be}\to {}^{\text{12}}\text{C}+n$ . Such neutron sources are called RaBe sources, or PuBe sources if they use plutonium to get the $\alpha$ s. Calculate the energy output of the reaction in MeV.

5.701 MeV

Neutrons from a source (perhaps the one discussed in the preceding problem) bombard natural molybdenum, which is 24 percent ${}^{\text{98}}\text{Mo}$ . What is the energy output of the reaction ${}^{\text{98}}\text{Mo}+n\to {}^{\text{99}}\text{Mo}+\gamma$ ? The mass of ${}^{\text{98}}\text{Mo}$ is given in Appendix A: Atomic Masses , and that of ${}^{\text{99}}\text{Mo}$ is 98.907711 u.

The purpose of producing ${}^{\text{99}}\text{Mo}$ (usually by neutron activation of natural molybdenum, as in the preceding problem) is to produce ${}^{\text{99m}}\text{Tc.}$ Using the rules, verify that the ${\beta }^{-}$ decay of ${}^{\text{99}}\text{Mo}$ produces ${}^{\text{99m}}\text{Tc}$ . (Most ${}^{\text{99m}}\text{Tc}$ nuclei produced in this decay are left in a metastable excited state denoted ${}^{\text{99m}}\text{Tc}$ .)

${}_{\text{42}}^{\text{99}}{\text{Mo}}_{\text{57}}\to {}_{\text{43}}^{\text{99}}{\text{Tc}}_{\text{56}}+{\beta }^{-}+{\overline{v}}_{e}$

(a) Two annihilation $\gamma$ rays in a PET scan originate at the same point and travel to detectors on either side of the patient. If the point of origin is 9.00 cm closer to one of the detectors, what is the difference in arrival times of the photons? (This could be used to give position information, but the time difference is small enough to make it difficult.)

(b) How accurately would you need to be able to measure arrival time differences to get a position resolution of 1.00 mm?

[link] indicates that 7.50 mCi of ${}^{\text{99m}}\text{Tc}$ is used in a brain scan. What is the mass of technetium?

$1\text{.}\text{43}×{\text{10}}^{-9}\phantom{\rule{0.25em}{0ex}}\text{g}$

The activities of ${}^{\text{131}}\text{I}$ and ${}^{\text{123}}\text{I}$ used in thyroid scans are given in [link] to be 50 and $\text{70 μ}Ci$ , respectively. Find and compare the masses of ${}^{\text{131}}\text{I}$ and ${}^{\text{123}}\text{I}$ in such scans, given their respective half-lives are 8.04 d and 13.2 h. The masses are so small that the radioiodine is usually mixed with stable iodine as a carrier to ensure normal chemistry and distribution in the body.

(a) Neutron activation of sodium, which is 100% ${}^{\text{23}}\text{Na}$ , produces ${}^{\text{24}}\text{Na}$ , which is used in some heart scans, as seen in [link] . The equation for the reaction is ${}^{\text{23}}\text{Na}+n\to {}^{\text{24}}\text{Na}+\gamma$ . Find its energy output, given the mass of ${}^{\text{24}}\text{Na}$ is 23.990962 u.

(b) What mass of ${}^{\text{24}}\text{Na}$ produces the needed 5.0-mCi activity, given its half-life is 15.0 h?

(a) 6.958 MeV

(b) $5\text{.}7×{\text{10}}^{-\text{10}}\phantom{\rule{0.25em}{0ex}}\text{g}$

where we get a research paper on Nano chemistry....?
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
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