nuc final exam

Why does spreading radiation doses out over longer periods of time, in addition to adding pauses in radiation, increase an organisms ability to recover from radiation damage?

Choose all that are correct

-Decreasing the dose rate (spreading dose over a longer period) decreases the number of double strand breaks in DNA

-The LET of the radiation decreases if it is given with pauses in between doses

-The total amount of free radicals formed decreases if you give the radiation over a longer period of time

-The LET of the radiation decreases if it is given over a longer period of time

-Decreasing the dose rate (spreading dose over a longer period) plus adding pauses allow for repair of single strand breaks in DNA

A and D

-Decreasing the dose rate (spreading dose over a longer period) decreases the number of double strand breaks in DNA

-Decreasing the dose rate (spreading dose over a longer period) plus adding pauses allow for repair of single strand breaks in DNA

An increase in          can cause a cell to become more radiosensitive:

Choose all that are correct

stress

senescence aging (very old age)

oxygen

rate of mitosis

water

All are correct

Which of the following is considered a long-term effect of radiation exposure:

Choose all that are correct

skin cancer

life shortening

erythemia

cataract formation

leukemia

A, B, D, and E

skin cancer

life shortening

cataract formation

leukemia

From tobacco smoke, particles containing polonium 210 and lead 210 are aspirated/breathed permanently into the lungs. These are alpha-emitting radioisotopes. Which of the following explains the high degree of damage caused to the lung tissues by these smoke particles:

None of these explanations apply

Lung tissue absorbs the alpha particles in a 360-degree radius in all three dimensions around each particle

The low penetration of alpha particles causes a high local concentration of radiation dose

All of these explanations apply

The large size and double charge of alpha particles makes them highly ionizing to atoms

D. All of these explanations apply

What is the relationship between the penetration capabilities (how far it travels before being stopped) of different types of ionizing radiation and the degree of biological harm they can cause when ingested?

The greatest harm is caused at an intermediate level of penetration

Higher penetration causes more harm

Lower penetration causes more harm

There is no direct relationship between penetration and harm

C. Lower penetration causes more harm

What is the relationship between the penetration capabilities (how far it travels before being stopped) of different types of ionizing radiation and the Linear Energy Transfer (L.E.T.) of that radiation?

As penetration increases LET increases

There is no relationship between penetration and LET

as penetration decreases LET increases

C. as penetration decreases LET increases

Damaging, free radical formation in the human body is often the end result of:

impaired carbon dioxide clearance

Double strand breaks in DNA

radiolysis/ionization of water by radiation

impaired cell proliferation

C. radiolysis/ionization of water by radiation

If a high dose of radiation is to be delivered to the patient in smaller doses over a long period of time with breaks in between, to allow for healing, it is said to be:

fractionated

radiosensitized

hormeises

prophased

A. fractionated

Which of the following cells is most radiosensitive?

muscle cells

stem cells

nerve cells

lymphocytes

B. stem cells

A deterministic effect is best defined as an effect that:

the severity is either all or none and doesn’t get worse with increased radiation

once a threshold is reached, occurs with certainty

the probability of occurrence increases with the amount of radiation but is never certain

is not effected by mitotic rate

B. once a threshold is reached, occurs with certainty

A stochastic effect is best defined as an effect that:

is not effected by mitotic rate

the severity of the effect worsens with increasing radiation

the probability of occurrence increases with the amount of radiation but is never certain

once a threshold is reached, occurs with certainty

C. the probability of occurrence increases with the amount of radiation but is never certain

The most likely dose-response curve for deterministic effects at very high doses (think in terms of measuring % deaths from radiation is the:

non-linear, threshold

non-linear, non-threshold

linear, threshold

linear, non-threshold

A. non-linear, threshold

The most commonly used dose-response curve for stochastic effects of very low levels of radiation (think in terms of measuring chance of cancer from radiation) is the:

linear, threshold

linear, non-threshold

non-linear, threshold

non-linear, non-threshold

B. linear, non-threshold

According to the law of Bergonie and Tribondeau, which cells are most sensitive to the effects of radiation?

cells that are more specialized in structure and function

cells that divide very slowly

cells that do not divide

cells that are less differentiated or divide rapidly

D. cells that are less differentiated or divide rapidly

Which of the following is the most accurate description of target theory:

the entire cell is a sensitive target, and any strike will lead to cell death

radiation seeks out the most sensitive targets in a cell, killing it

There are regions of cells that are more radiosensitive than other regions, which may be struck by accident causing cell death

radiation tends to avoid the most sensitive targets in a cell

C. There are regions of cells that are more radiosensitive than other regions, which may be struck by accident causing cell death

The indirect effect has occurred when:

radiation destroys the wall of mitochondria

radiation interacts with water to form non-soluble bound compounds

radiation strikes a DNA molecule and severs one of the strands

radiation interacts with water to form destructive free radicals

D. radiation interacts with water to form destructive free radicals

The reason that a fractionated dose is less biologically damaging than an equal single dose of radiation is because of:

increased GSD

increased RBE

recovery and repair of DNA

reduced OER

reduced LET

C. recovery and repair of DNA

Low-LET radiations (x-rays and gamma rays), at relatively low levels of exposure (well below 50 rem), are primarily associated with what type of cellular damage?

direct damage effects to cellular organelles

single-strand breaks in the DNA

double-strand breaks in the DNA

NVD Syndrome

B. single-strand breaks in the DNA

Radiation would have less effect upon a cell if given:

along with water around the cell

all at once

over a shorter period of time

over a longer period of time

D. over a longer period of time

Hormesis is best defined as:

a beneficial effect of radiation in low doses

the in utero damage of a fetus leading to birth defects

the formation of free radicals by radiation

the final phase of the cell cycle before cell death

A. a beneficial effect of radiation in low doses

In order to be conservative about radiation exposure, radiation limits (dose equivalent limits, DELs) are based upon what type of assumed dose response curve?

linear, non-threshold

non-linear, threshold

non-linear, non-threshold

linear, threshold

A. linear, non-threshold

For the acute radiation syndrome (ARS), symptoms appearing immediately after an acute exposure to radiation belong to which stage of the disease?

acute “prodrome” stage

manifest illness stage

latent period

proportional stage

A. acute “prodrome” stage

The very first symptom (within hours) of acute radiation syndrome (ARS) is:

incontinence

nausea, vomiting, diarrhea (NVD syndrome)

hair loss

excessive bleeding

B. nausea, vomiting, diarrhea (NVD syndrome)

The interpretation of a linear, non-threshold dose curve is that radiation damage is directly proportional to dose, and that:

only high doses cause damage

none of the above

any dose may cause damage

damage occurs only after a minimum dose has been exceeded

C. any dose may cause damage

The stage of acute radiation syndrome in which the exposed person temporarily feels that they are recovering is called the          stage:

latent period

interphase

acute “prodrome” stage

manifest illness stage

A. latent period

The minimum gonadal dose at which temporary sterility begins occur is about:

around 10-150 rad

around 350-500 rad

around .01 to .05 rad

around 1-10 millirad

A. around 10-150 rad

“LD 50/60” means that:

50% of the exposed population will die in 60 hours

50% of the exposed population will die in 60 days

50 rad will kill 60% of the population

It takes 60 days of radiation exposure to kill 50% of the population

B. 50% of the exposed population will die in 60 days

Physical defects that are caused by radiation exposure to the developing embryo/fetus after conception, but before birth, are referred to as          effects:

mutagenic

teratogenic

genetic

congenital

B. teratogenic

Hematopoietic (hematologic) syndrome is expected to occur at a whole body dose level of around:

300-1000 rads

more than 5000 rads

1000-3000 rads

1-50 rads

A. 300-1000 rads

Erythema is the:

reddening of the skin

feeling of well-being

ulceration of the skin

loss of hair

A. reddening of the skin

Which of the following represents the greatest risk to patients suffering from the hematopoietic syndrome?

infection

seizures

diarrhea

excessive vomiting

A. infection

Acute radiation syndrome (ARS) includes all of the following forms of syndrome except:

gastrointestinal

hematopoietic

respiratory

central nervous system

C. respiratory

The human LD 50/60 is currently estimated to be about:

700 rads

1000 rads

350 rads

5000 rads

100 rads

C. 350 rads

In which phase of the cell cycle is DNA damage repaired?

S

G2

G1

Mitosis

A. S

Damage to the DNA that would most likely result in mutation instead of cell death occurs in which phase of the cell cycle?

Mitosis

S

G1

G2

B. S

The damaging free radicals formed by radiation in cells predominantly come from what compounds?

Ions like Iron, Calcium, and Phosphorous

ATP and Cyclic AMP

Oxygen and Water

Carbon Dioxide and Glucose

C. Oxygen and Water

In Missouri, a typical member of the public receives how much dose per year from background radiation?

3-4 rem

3-4 mrem

300-400 rem

30-40 mrem

300-400 mrem

D. 300-400 mrem

In the United States, what is the most common source of man-made radiation dose above background radiation that the general public receives?

Living close to nuclear reactors

Radon gas

Medical procedures

Radioactive contaminants in the food supply

C. Medical procedures

In the United States, what is the most common source of naturally occurring background radiation that the general public receives?

Radioactive contaminants in the food supply

Radon gas

Cosmic Radiation

Uranium byproducts in drinking water

B. Radon gas

A reading of “M” on a radiation dosimetry report, in place of a numerical value, indicates:

maximum exposure

mandatory exposure

the badge could not be read

zero exposure

minimal exposure

E. minimal exposure

T/F: An x-ray technologist trips and injures their arm while at work and must receive x-rays to rule out a fracture. Since this occurred at work, the technologist should continue to wear their dosimetry badges while they receive their x-rays.

False

A nuclear medicine technologist who is 39 years old has been working in a high radiation lab for the last 20 years. Each year they have been in their job they have received 2 rem which has given them a cumulative lifetime exposure of 40 rem. As they turn 40, three months later, upon reviewing their records you discover that they now have a cumulative lifetime exposure of 42 rem. Which of the following statements is accurate:

Action is strongly suggested to limit them to 3 rem over the next 12 months

No action is required since they haven't exceeded their lifetime exposure yet

Action is mandatory and they must be limited to 1 rem over the next 12 months

As long as they don't exceed 5 rem in the next year, no action should be taken

C. Action is mandatory and they must be limited to 1 rem over the next 12 months

A nuclear medicine technologist who is 31 years old has been working in a high radiation lab for the last 10 years. Each year they have been in their job they have received 3 rem which has given them a cumulative lifetime exposure of 30 rem. As they turn 32, three months later, upon reviewing their records you discover that they now have a cumulative lifetime exposure of 32 rem. Which of the following statements is accurate:

-Even though the technologist's exposure is high, they have never exceeded their prospective annual limit

-As long as the technologist continues to receive only 3 rem per year they should be ok to continue to work in this area

-This technologist has consistantly exceeded their prospective annual limit

-If this is a pregnant radiation worker who has not yet declared their pregnancy in writing, they must be reasigned to a different area regardless of the status of their paperwork

A. Even though the technologist's exposure is high, they have never exceeded their prospective annual limit

T/F: A pregnant x-ray technologist who is close to exceeding the annual fetal dose limit can “undeclare” her pregnancy so she can continue to work in a higher radiation area even though she is only in the 4^th month of her pregnancy.

True

How often should you do area surveys with a geiger counter in places where radioactive drugs are used or given to patients?

Weekly

Monthly

Daily

Quaterly

C. Daily

How often should you do removable contamination surveys with wipes in places where radioactive waste is stored?

Weekly

Monthly

Daily

Quarterly

A. Weekly

When performing radiographic exams which of the following strategies is NOT considered appropriate to reduce an employees radiation exposure?

Use timers on the switches that turn on fluroscopic units

Increase the distance between patients and staff when imaging

decrease KVp and increase MAS settings whenever possible

Stand behind shielded walls when imaging

C. decrease KVp and increase MAS settings whenever possible

What is occurring during Compton scattering?

-a primary photon interacts with an electron but there is no loss of energy by the primary photon, just a deflection of its path of travel

-a primary photon is totally absorbed by an electron which then emits a secondary photon

-a primary photon is totally absorbed by an electron which is then ejected

-a primary photon interacts with an electron which gets ejected and the primary photon loses energy and its path of travel is deflected

D. a primary photon interacts with an electron which gets ejected and the primary photon loses energy and its path of travel is deflected

When energetic electrons interact with the inner-shell electrons of a target atom, it produces _____ radiation.

Alpha particles

Gamma rays

Beta particles

Bremsstrahlung and characteristic x-rays

D. Bremsstrahlung and characteristic x-rays

⁹⁹Tc    versus   ^99mTc are considered to be ________ of each other

Isotopes

Isomers

Isobars

Isotones

B. Isomers

¹³¹I   versus   ¹²³I are considered to be ________ of each other

Isotopes

Isomers

Isotones

Isobars

A. Isotopes

How do we protect ourselves from radiation?

All of these

By being knowledgable about radiation and it's dangers

Use time, distance, and shielding to protect us

Use ALARA work practices

Monitor your radiation exposure and change your work practices when neccesary

A. All of these

You have been monitoring your monthly radiation exposure readings and you have noticed they have been high. Normally when you are assisting in the special procedures room during angiography work, you have been standing roughly 2 feet away from the x-ray tube. You bring a radiation detector into the room and discover that the radiation levels at that distance are 15 mR/hr. 

How far away from the x-ray tube would you need to stand to have the exposure reduced to < 1 mR/hr?

> 3.94 feet

> 7.75 feet

> 3.75 feet

> 60 feet

B. > 7.75 feet

The attenuation coefficient for tungsten when using a 100 kV x-ray is 0.21 mm^-1.

What is the half value layer for tungsten when using 100 kV x-rays?

0.145 mm

3.3 mm

0.6 mm

0.3 mm

B. 3.3 mm

The attenuation coefficient for tungsten when using a 100 kV x-ray is 0.21 mm^-1

 How much tungsten will it require to reduce a beam's dose to 30% of its original strength when using 100 kV x-rays?

3.8 mm

1.7 mm

5.7 mm

0.7 mm

C. 5.7 mm

You have been monitoring your monthly radiation exposure readings and you have noticed they have been high. Normally when you are assisting in the special procedures room during angiography work, you have been standing roughly 3 feet away from the x-ray tube. You bring a radiation detector into the room and discover that the radiation levels at that distance are 10 mR/hr. 

What would you expect the radiation levels to be if you step back to 5 feet away from the x-ray tube?

2.0 mR/hr

3.6 mR/hr

6 mR/hr

27.7 mR/hr

B. 3.6 mR/hr

A sample is measured in a radiation detector and a total of 2.22 x 10¹⁰ radioactive decays are measured in 1 minutes (for now don’t worry about background radiation). How many mCi of radioactivity does the sample contain?

600 mCi

0.6 mCi

10 mCi

0.01 mCi

C. 10 mCi

You have been given a 30 mCi of a radiopharmaceutical in a 5 ml vial. What is the specific activity of the sample

150 mCi/ml

40 mCi/ml

0.17 mCi/ml

6 mCi/ml

D. 6 mCi/ml

You are given a vial with an unknown total volume. When you measure the vial in a radiation detector, it contains a total of 500 mCi of radioactivity. When you withdraw a sample containing 1 ml, it measures 25 mCi. What was the total volume of radioactivity in the vial?

5 ml

0.25 ml

20 ml

there is not enough information to answer this question

C. 20 ml

A patient is given a new drug being developed to treat cancer. To measure how fast it leaves the blood stream, it is labeled with Tc-99m which has a 6 hour physical half life. Blood samples are drawn from the patient every 10 minutes and it is determined that it takes 3 hours for the amount of radiation in the blood stream to decrease by 1/2.

Calculate the Biologic T_1/2 (half life) for the new drug.

Given:

(1 / T½ _(E) )= (1 / T½ _(P) )  +  (1 / T½ _(B))

A_t= A_o x e^{-[ lambda x t ]}

lambda = ln(2) / T½

0.33 hours

6 hours

0.16 hours

3 hours

B. 6 hours

At 8 AM you have a 6 ml vial which contains a total of 250 mCi of a radioactive imaging agent, which has a 6 hour physical half life. You have a patient scheduled to receive an injection of 25 mCi of the agent at 2 PM. How many ml should you withdraw at 8 AM so the syringe will contain enough agent to give 25 mCi at 2 PM?

Given:

(1 / T½ _(E) )= (1 / T½ _(P) )  +  (1 / T½ _(B))

A_t= A_o x e^{-[ lambda x t ]}

lambda = ln(2) / T½

1.2 ml

1.7 ml

5 ml

0.6 ml

A. 1.2 ml

Match the following with the best description

Beta Particle

Alpha Particle

Compton Scatter

Characteristic X-Ray

Bremsstrahlung X-Ray

Cherenkov Effect

What are the maximum 1 year (unless stated otherwise)  radiation dose limits (in mR) for each of the following?

An x-ray technologist over a 1 year period of time

A patient transporter/holder who works solely in radiology and nuclear medicine over any given 3 month period

The annual hand exposure to a nuclear medicine worker

A payroll accountant who works for the hospital

The exposure to the lens of the eye of a radiologist performing fluoroscopy

A nuclear medicine technologist who has declared her pregnancy and is in her first month of gestation (limit for the entire gestation period)

A. 5000 mrem

B. 3000 mrem

C. 50,000 mrem

D. 100 mrem

E. 15,000 mrem

F. 500 mrem

Other equations to know

c = 3.0 x 10⁸ m/s (the speed of light)

        E _{(in joules)} = m _{(in kg)} x c²

        1 eV = 1.6 x 10^-19 Joules

        Planks constant _{(in j)}      h = 6.63 x 10^-34 J-s

        Planks constant _{(in eV)}   h = 4.14 x 10^-15 eV-s

        E = h x f _{(in Hz)}

        E_{(in keV)}  = 1.24 / l _{(in nanometers or angstroms)}

        c = l _{(in meters)} x f _{(in Hz)}

        Inverse square law (I = intensity, D = distance)

        (I_(original) / I_(new)) = ((D_(new))² / (D_(original))²)

        A_n= A_o x e^{-[lambda x t]}

        lambda= decay constant, T½=half life, t=time passed

        lamda=ln(2)/ T½

        I_d= I_o x e^{-[u x d]}

        u=attenuation constant, HVL= Half Value Layer

        u=ln(2)/ HVL

        (1 / T½ _(E) )= (1 / T½ _(P) )  +  (1 / T½ _(B))

        1 Bq = 1 disintegration per second (dps)

        1 Ci = 3.7 x 10¹⁰ Bq

        1 mCi = 37 MBq

        1 AMU = 1.66 x 10^-27 kg

        Mass of e^- = 0.00054858 AMU

        Mass of e^- = 9.11 × 10^-31 kg

        Mass of p⁺ = 1.007276 AMU

        Mass of p⁺ = 1.673× 10^-27 kg

        Mass of n⁰ = 1.008664 AMU

        Mass of n⁰ = 1.675× 10^-27 kg