Rad/Bio: radioisotopes and radiation protection

What are isotopes

Atoms of the same element (same number of protons) with different numbers of neutrons

What are radioisotopes

Isotopes of a particular element that are unstable because of their neutron-proton configuration undergoing changes to rectify the unstable arrangement

Cancerous growths or tumors can either be eliminated or controlled by ?

Irradiation of the area containing the growth

Radiation therapy may be delivered ? (2)

Externally or internally

How is external radiation delivered?

Accelerator

How is internal radiation delivered?

Infusion/implantation

Radiation therapy is in the form of ______ _____ or fast electrons (beta radiation)

Gamma rays

________ cells are more sensitive, so ____ is used in Ca treatment

Oxygenated/02

Iodine-125 (125153) has been used extensively in the form of?

Titanium-encapsulated cylindrical seeds for prostate cancer

What is the half life for iodine-125?

59.4 days

What is the goal of iodine-125?

To deliver 145 Gy to at least 90% of the prostates volume while limiting dose to adjacent structures like the urethra, bladder and anterior rectal wall

How long should loved ones distance themselves from patients who have iodine-125 seeds?

6 months at least

What is the most important therapeutic radioisotope?

Iodine-125

What is the half-life for iodine-131 (131153)

8 days; but dose produce highly penetrating gamma rays

Iodine-131 can be joined chemically with sodium to form a radioactive compound called?

Sodium iodide 131 I which can be delivered orally

What is sodium iodide 131 i typically used for?

To obliterate and any left over thyroid tissue after ca surgery

T/F: its difficult to shield against sodium iodide 131 i

True; needs at least 1 mm thick mobile shield

What is the radioactive decay process for sodium iodide 131 i?

Beta decay

What should happen in terms of radioactive disposal

All items, drugs, bodily fluids or otherwise radioactive materials are stored in a shielded area for 10 half lives then disposed of in the regular trash

Nuclear medicine employs radioisotopes to? (3)

Study organ function in a pt
Detect the spread of ca into the bone
Treat certain types of disease

Nuclear medicine typically makes use of short lived radioisotopes as tracers because?

NM is not therapy, its apart of the diagnosis process

NM: uses iodine-123 (123153) concentrates in the _______ ______ & achieves levels of concentration that can be directly correlated with the ______ ______ performance status

Thyroid gland(s)

NM also uses Technetium-99m (99mTc); it is an extremely versatile radioisotope because it can be incorporated into a wide variety of different compounds or biologically active substances, each with?

A specificity for different tissues of organs of the body

What is Positron emission tomography?

PET scan/imaging method that uses a radioactive substance to show activity in an organ.

What is annihilation radiation initiated by?

Initiated by the radioactive decay of the nucleus of an unstable isotope having too many protons within the nucleus (matter is being turned into energy)(paraproduction)

When a positron is passing close to an electron will interact _________

Destructively, annihilating one another

When the two photons emerge from the annhiliation site in opposite directions, each with a kinetic energy of?

511 keV

PET and CT use Flourine-18 (18F9), what is it?

Positron emitter

What is the most important isotope in PET

Fluorine-18

Fluorine can be attached to a glucose molecule, yielding the compound, fluorodeoxyglucose (FDG) a radioactive tracer that?

Will be taken up or metabolized by cancerous cells

What is patient prep time?

A time span of 45-60 minutes after dosing radioactive medications for a PET/NM where radiation needs to circulate

High energy annihilation photons scatter from?

The patient

What is radioimmunotherapy? (RIT)

Ca treatment through radioactive isotopes combining immunotherapy and radiation

What does RIT affect?

Immune system
Monoclonal antibodies

What are some radiation safety considerations for RIT

1m distance from those patients for a week after treatment

Terrorists can utilize radiation as a weapon. What types of contamination weapons are created?

Dirty bomb
Dispersal device

What is the decontamination process following a terrorist attack?

Use of GM detectors
removing all clothes and showering the patients before working on them to remove dust and debris
Full PPE

What is the dose limit for individuals engaged in nonlife-saving activities in the case of terrorism attacks?

50 mSv

What is the dose limit for individuals engaged in life saving activities in the case of terrorism attacks?

250 mSv

Cleanup of a contaminated urban area following a terrorist attack is?

Removal of topsoil
Digging up roadways

What is the protocol for medical management of persons experiencing radiation bio effects following a terrorist attack?

PPE
Handing patients with ARS by administering bone marrow transplants
Testing blood and urine of the patients to monitor the dose

Following terrorism, how are patients with ARS treated?

Dilution by giving fluids, laxatives and emetics to block absorption

What does the NIH believe in reference to radiation terrorism?

"The outcome will most likely be minimal"