A. radiation sources Flashcards by carlos cordova

Radiation can be emitted in the form of

particles, electromagnetic radiation, or both

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Emitted radiation includes

alpha, beta, and gamma rays

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Alpha particles are ___ charges

positively

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Beta particles are ___ charges

negatively

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Gamma rays have ____ charge

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____________ occurs as the source emits radiation in attempt to become stable

Radioactive decay

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1 Becquerel (Bq) = ___ dps

1 dps

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1dps = ____ Curie(ci)

2.70X 10^ -11 CI

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______ of a radioactive source describes the average lifetime decay

mean life (Ta)

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Radioactive materials can be used for diagnostic tests like

nuclear medicine

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What is example of nuclear medicine radioactive material

Technetium-99

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What are some examples of therapeutic radioactive materials?

Iodine-125, Palladium- 103, iridium- 192, colbolt-60, Strontium- 90

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what is the formula for mean life (Ta)

Ta = 1.44 x T1/2

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what is half life (T1/2)

radioactive source describes the duration of time it takes for the activity to decay half of the original value

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_____ the radioactive source of decay

Activity

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the formula for activity is____

A=A0 (.5) ^ T1/2

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Brachytherapy is common used for treatments of the

Uterus, cervix, lung, prostate, and breast

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External applicators, brachy, are used to treat

tumor beds, skin surfaces, or mucosal surfaces

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Vaginal cylinders, tandem and ovoid, and fletcher-suit applicator are what type of brachytherapy applicators

Intracavitary

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_____ is a type of brachy where the radioactive source is placed with needles, wire, or seeds directly into malignant tissues

interstitial

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sources that are used for low dose rate brachytherapy (LDR)

40-200 cGy/hr

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sources that are used for high dose rate brachytherapy are

12 Gy/hr - .2 Gy/min

____ was the original radioactive isotope, which helped start brachytherapy

Radium (ra-226)

Half life= 2.67 days
Ex use: liver caner and lymphoma treatment
Exampling which radioactive source:

Yttrium (y-90)

Half life= 2.7 days Ex of use= Permanent implant (seeds) for prostate cancer treatment Exampling which radioactive source:

Gold (Au-198)

Half life= 8 days Ex of use= thyroid cancer treatment Exampling which radioactive source:

Iodine(I-131)

Half life= 17 days Ex of use= permanent implants for prostate cancer treatment Exampling which radioactive source:

Palladium (Pd- 103)

Half life= 50.5 days Ex of use= treats pain caused by bone mets Exampling which radioactive source:

Strontium (sr- 89)

Half life= 59.4 days Ex of use= permanent implants for the treatment of prostate cancer Exampling which radioactive source:

Iodine (I-125)

Half life= 73.8 Days Ex of use= HDR treatments and made of nylon ribbons with seeds Exampling which radioactive source:

Iridium (Ir-192)

Half life= 30 years Ex of use= Brachytherapy for cancers of the cervix or uterus Exampling which radioactive source:

Cesium ( C-137)

produced in kilovoltage (KV) for diagnostic x-ray machines 1 kilovolts = 1,000 volts

1 kilovolts = 1,000 volts

Tungsten has a Z number of ___ and melting point of ___

Z = 74 Melting point= 3370 Celsius

produced in megavoltage (MV) for linear accelerators for radiation therapy 1 megavolt = 1 megavolts =

1 megavolts = 1,000,000 volts 1 megavolts = 1,000 kilovolts

Rotating anodes allow for more ______

heat dissipation

Hooded anodes prevent unwanted

secondary electrons

Target in megavoltage therapy machines are known as

transmission targets

In a linear accelerator, there is a waveguide between the electron gun and target to increase

electron energies

____ efficiency for diagnostic x-ray tubes ____ converted for heat

1% , 99%

30%-95% for

30%-95% efficiency for linear accelerators

therapy x ray photons have energy ranges from

50 kev - 25 MeV

superficial therapy energies ranges from _____

50-150 Kv

orthovoltage energies range from

150 kv - 500 kv

_____ electrons interaction that occurs near the nucleus when electrons hit the target

Bremsstrahlung - electron slows down as it approaches the nucleus and then changes its direction - only occurs in MV ranges - can happen in both

common beam energies for linear accelerators range from

4 MV - 25 MV

Characteristic X-rays only occur in

Diagnostic Radiograph NOT radiation therapy

what is characteristic x-ray ?

incoming electrons interacts with an inner shell electron causing the inner shell electron to be ejcted - outer shell electron fills the new vacancy

particles

particle beam raditherapy includes high- energy charged particles, such as protons, alpha particles and carbon ions

What is a cyclotron?

charged particle acclerator - used in proton therapy to speed up protons - proton speed determines the energy

Bragg peak

the dose curve of a proton beam starts off is low at the beggining rises rapidly and instantly dies off

what is an Isotope

same protons

what is isotones

same neutrons

Isobars

same # of nucleons

Isomers

different energy states