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Flashcards in Nuclear Medicine Midterm Deck (69)
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1

What is the proper name for an electron ejected from an atom by a gamma ray emitted from the nucleus of the same atom?

Conversion electrons

2

What is the difference between isotopes, isotones, isobars and isomers?

Isotopes: Same # of protons

Isotones: Same # of neutrons

Isobars: Same A value

Isomers: Everything is same except energy

3

Conventional and SI units for dose?

Conventional: 1 rad = 100 erg/gm

SI: 1 Gy = 100 rad

4

True or false, for "Nuclear Medicine" radiations, D(rad) = X(R)?

True

5

What are the units of LET?

Energy deposited/distance. Often described as,

keV/µ

6

What is the number that expresses differences among different radiations in producing biological effects?

Relative Biological Effectiveness (RBE)

 

RBE = Dstandard radiation/Dtest radiation

7

Units of dose equivalent?

H = wrD

Conventional: 1 rem = 100 erg/gm

SI: 1 Sv = 100 rem = 1 J/kg

8

Units of effective dose?

E = ΣwTHT

Conventional: 1 rem = 100 erg/gm

SI: 1 Sv = 100 rem

9

What number is used to describe the relative sensitivity of tissue to radiogenic cancer or hereditary damage?

Tissue weighting factor (wT)

10

Above what Z value are all isotopes radioactive?

Z >= 90

11

What the is process called in which an emitted gamma ray ejects an orbital electron?

Internal Conversion (it's essentially the nucleus equivalent of Auger electrons)

12

Which of the following reactions are isobaric?

A) Alpha decay
B) Negatron decay

C) Electron capture
D) Positron Decay

B,C and D

13

What is the mathematical definition fo activity?

A = (lambda)N

14

Equation for effective half-life

Te = TpTb/(Tp+Tb)

Where Tp is physical half-life and Tb is biological half-life

15

Average life equation

(tau) = 1/(lambda)

16

Condition for secular equilibrium to occur

Tp >> Td

17

Formulas for standard deviation and percent standard deviation/variance.

SD = sqrt(N)

%SD or V = 100%/sqrt(N) = sqrt(N)/N

18

What variable is often taken to express the "noise" of an imagine?

%SD

19

If you take a  512x512 image, then convert it to 256x256 but retain all the data,

What happens to the pixel size?

What happens to the counts per pixel?

What happens to noise?

Pixel size is doubled

Counts per pixel is quadrupled

Noise is halved

20

What is the pixel dimension requirement for the Nyquist criterion?

Dimension of each pixel ~ 1/3 FWHM

21

What is the ideal pixel setup in the Nyquist crierion?

Use the coarsest matrix (ie largest pixels) that are compatible with the practically achievable spatial resolution.

22

Typical speed of a whole body scan?

5-15 cm/min

23

Difference between Un-gated and gate dynamic imaging?

Un-gated: images or frames acquired sequentially from beginning to end of acquisition. No summation of frames.

 

Gates: images or frames at different points of recurring process. 1 temporally summed image per time point.

24

Definition of count rate,

Standard deviation of count rate,

Standard deviation of NET count rate.

R = N/(delta)t

SDR = sqrt(R)

SDRn = sqrt(Rg/(delta)tg + Rb/(delta)tb​)

25

Detection efficiency = gp x (epsilon) x Escape Fraction x fp

 

About what is the value of the detection efficiency? What contirbutes the most loss?

D ~ 0.001 - 0.01

 

Geometric efficiency

26

Name one use for each of the following ionization detectors.

Ionization Chamber

Proportional Counter

Geiger counter

Solid-state ionization detector

Ionization Chamber - calibration chamber, dose calibrator

Proportional Counter - research

Geiger counter - survey meter

Solid-state ionization detector - intraoperative probe or gamma cameras

27

How often are accuracy and constancy quality control checked for?

Daily and/or after servicing

28

How often is linearity checked for? What are the two methods used to check linearity?

Quarterly and/or after servicing

 

Decay method using Tc-99m or Shield method

29

How often should any geometry quality control be performed?

What are the two types of geometry quality controls?

At installation

 

Volume and Position

30

Be able to identify this entire image and the parts,