85% water proteins carbohydrates lipids nucleus acids

must be used when gonads are w/in 5cm of beam lead must be 0.5mm Pb equivalent

protects against scatter/leakage stationary fixed barriers, viewing window

Quiz 7 Flashcards by Ele 101

Diff. Between 3phase 6pulse & 3phase 12pulse

reduced ripple with 12 pulse generator 3-10% ripple

* 6pulse 13-25% ripple

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Ripple factor constant potential?

•less than 2% ripple

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3phase generators or high frequency is approximately __% increase in kVp or almost ___ mAs over single phase power

* doubling mAs

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Generator with least ripple

constant potential

* less than 2%

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Generator with greatest exposure to patient

•single phase 100% ripple

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Dose response curve for X-rays

•linear non threshold curve /

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Cell biology

85% water
proteins
carbohydrates
lipids
nucleus acids

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Gonadal shielding

must be used when gonads are w/in 5cm of beam

* lead must be 0.5mm Pb equivalent

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Cardinal principles of radiation protection?

TIME-keep time to a minimum (directly proportional)
DISTANCE-inverse square law the further u r the less exposure
SHIELDING-lead aprons, thyroid shields, gloves 0.25mm Pb equivalent

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Primary barrier

•protects anything the primary beam hits (wall, structure)

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Secondary barriers

protects against scatter/leakage

* stationary fixed barriers, viewing window

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Whole body dose limits (occupational)

•5rem (50msv)

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Extremities dose limits

•50rem (500mSv)

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Lens of eye dose limits

•15rem (150mSv)

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Accumulated dose limits

•1rem X age (in years)

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Whole body dose frequent (public)

•0.1rem (1mSv)

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Fetus total dose limit/ per month

total 0.5rem (5mSv)

* month 0.05rem (0.5mSv)

Law of Bergonoie & Tribondeau

some tissues are more radiosensitive than others depends on:
primitive or stem cells *
rapidly dividing cells *
mitotic rate *
high metabolic rate
high proliferation

(Linear energy transfer)LET

energy transferred per unit of path length

* Measures the rate of energy transferred from ionizing radiation to tissue

Low LET

sub lethal
not highly ionizing
travel far

High LET

highly ionizing

* poorly penetrating

Direct damage

results in damage of cell

* occurs only when direct interaction with essential molecule/DNA/target molecule

Indirect damage

results in no damage

* ionization of water

Doubling dose

•amount of radiation required to double frequency of mutation

Mitosis

* cell division * 4 phases * prophase * metaphase * anaphase * telophase

Interphase

* period between divisions | * mitosis-G1-(S)phase-G2

1rem = ?sV

•10Sv

1Gy = ?Rad

•100rads

Ionized water creates free radicals that combine to creat hydrogen peroxide, causes breakdown of membrane permeability

•Radioloysis of water(indirect effect)

The primary beam is made up of what photons

•photoelectric

LD 50/60

•50% of the population will die with in 60 days

Most radiosensitive cell cycle

* mitosis * late G1 * early S-phase

What is more radiosensitive high or low mitotic

•high mitotic

Relationship increase in LET= increase in?

•RBE

Relationship OER increase =

•indirect effects of radiation

Prodromal syndrome

•initial stage of disease

Latent period

•symptom free

Most radiosensitive fetal stage

•the first trimester

Somatic cell? Mitosis or meiosis?

•mitoses

Germ cell mitosis or Meiosis?

•meiosis

Vest shielding

•0.25mm Pb

What kind of interaction is produced my characteristic radiation

•photoelectric