Artifacts and Images

Question 1

Question 2

A dynamic series of analogue consecutive intrinsic spatial resolution images using 99mTc were made to check the consistency of the image formatter. The energy window had been centred over the photopeak of 99mTc prior to the check.

Answer 2

energy window over the photopeak has shifted, resulting in patchiness

Question 3

Tc DTPA of kidney

Answer 3

Poor energy window position, note appearance of PM tubes

Question 4

Answer 4

good uniformity image, intrinsic, 3M counts, Tc - 99m

Question 5

Answer 5

septal penetration

streak artifacts appear along directions where septa is thinnest and can extend over many cm indicating penetration of many holes

In this image a high energy collimator with hexagonal holes was used

Question 6

Answer 6

PMT voltage drift causing peak shift and difference in sensitivity

Question 7

High count rates can lead to a loss of

Question 8

Intrinsic flood image

Question 9

Answer 9

crushed lead septa; lead foil separation

Question 10

Answer 10

cracked crystal (mechanical shock or thermal shock - when changing temp by more than 10 deg / hr)

Question 11

Answer 11

truncation artifact

Question 12

Which set of images was performed with a 360 vs a 180 degree acquisition arc?

Answer 12

bottom

Question 13

Which is a low resolution SPECT image, 60 images at 6 degree steps or 120 images at 3 degree steps?

Answer 13

60 images at 6 degree steps

Question 14

The typical number of counts in a spect study range from

Answer 14

2 - 8 M

Question 15

To reduce high frequency noise in a FBP image, use a

Answer 15

low pass filter such as hannning or butterworth

Question 16

Answer 16

bulls eye artifact due to poor uniformity

Question 17

Answer 17

serial ring artifact

Question 18

Answer 18

COR artifact