nuclear medicine imaging and therapies

Question 1

wha are 4 imaging techniques in nuclear medicine

Answer 1

static
dynamic
wholebody
SPECT

Question 2

static, dynamic, whole body are planar imaging techniques

Question 3

explain how radiation dose and exposure time must be compromised in nuclear medicine

Answer 3

• low-level radiation can be used with increased exposure time vice versa

Question 4

describe how exposure time correlates with resolution in nuclear med

Answer 4

longer exposure time the greater the resolution

Question 5

how long are marker images usually

Answer 5

30 seconds

Question 6

how long do diagnostic images take

Answer 6

2-10 mins

Question 7

how can the time acquired be decided upon

Answer 7

either by a set time or dependant on counts

Question 8

What is a DMSA scan

Answer 8

Dimercaptosuccinic acid

• scan used to assess function and location of kidneys

Question 9

what is IV bolus

Answer 9

the administration of a concentrated dose of medication or fluid directly into a vein

Question 10

describe the administration/prep procedure for nuclear med scan for the kidneys

Answer 10

• IV bolus off 80 MBq Tc99m DMSA given 2-4 hrs before scan

Question 11

DMSA scan can provide quantification values, e.g mean percentage of each kidney function

Question 12

what are counts in nuclear med

Answer 12

the number of events detected, but dose rate relates to the amount of ionising energy deposited in the sensor of the radiation detector

Question 13

how do you quantify anatomical structure in nuclear med

Answer 13

compare the counts between structures

Question 14

what is a HIDA scan

Answer 14

hepatobiliary iminodiacetic acid (HIDA) scan

• is an imaging procedure used to diagnose problems of the liver, gallbladder and bile ducts

Question 15

why would you choose radionuclide renographyh over intravenous urogram

Answer 15

• to asses the physiological function of the kidneys
• renography offers quantitation of both impaired clearance and subsequent effect on renal function

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Question 16

why is checking quantitation beneficial

Answer 16

useful for follow up comparison i.e pre and post operation

Question 17

what is the effective dose of a MAG-3 renogram

Answer 17

0.7 mSv

Question 18

what is the difference between absorbed, equivilant and effective dose

Answer 18

absorbed = Absorbed dose is the amount of energy deposited by radiation in a mass.

equivalent = absorbed dose to an organ, adjusted to account for the effectiveness of the type of radiation.

effective = ddition of equivalent doses to all organs, each adjusted to account for the sensitivity of the organ to radiation.

Question 19

how can dehydration effect a nuclear med scan

Answer 19

• delayed peak activity
• delayer parenchymal clearance
• election of excretion slope

Question 20

how much water should you drink for nuclear med scan

Answer 20

1 l

Question 21

patient must empty bladder immediately prior to scan

Question 22

for a renogram, midway or at the start of scan, an intravenous dose of diuretic is given. what is this and type and what dosage is given

Answer 22

• medicines that help reduce fluid buildup in the body.
• frusemide
• 20-40mg administered

Question 23

what range of fluid production by kidney indicated a form of obstruction by either stone or sedimen

Answer 23

under 5ml per min

Question 24

what filters/clears out the radionuclide substance in the body

Answer 24

• glomerular filtration and tubular secretion in kidney

Question 25

what percentage of the radionuclide is excreted within 30 mins

Answer 25

70%

Question 26

what type of graph is generated by the computer to analyse kidney function

Answer 26

• computer plots curve of activity against time for each region
• curve shape determines how kidneys are behaving

Question 27

what is stasis

Answer 27

slow urine flow leads to build of debris (stone) or potentiates infection

Question 28

what is the output efficincy of the kidneys in percentage to be considered obstructed or not

Answer 28

output efficincy of kidneys over 78% = no obstruction

under 70% = obsturction

Question 29

why are patients asked to go toilet before scan

Answer 29

• intense uptake in urine can obscure views of hips/pelivs and legs

Question 30

how does patient size affect image quality

Answer 30

increasing size decreases resolution due to more attenuation

Question 31

how does motion affect image quality

Answer 31

• reduced spacial resolution

Question 32

be aware of indirect contamination of camera detector, floors, skin, beds from patient, also urine leak from renogram

Question 33

artefacts can be caused by issues with the gammea camera for example?

Answer 33

• wrong energy window, doesnt receive incoming rays
• flood not flat
• damage to crystals

Question 34

if the uniformity are within limits but the visual image looks abnormal, what can this indicate an issue of

Answer 34

Photomultiplier tube off-peak artifactual apperance

uniformity map needs recalibrating

Question 35

why is iodine 131 used in nuclear med for thyroid issues

Answer 35

• it gets in blood stream and deposits in functioning thyroid tissueh

Question 36

what ion is taken up into thyrocytre and via what

Answer 36

I- ion taken up into thyrocyte via sodium-iodide symporter

Question 37

what dose of iodine 131 required the patient to be isolated in hospital

Answer 37

over 800 MBq

Question 38

not all radioactivity administered is taken up by thyroid, some excreted, urine, sweat, saliva

Question 39

how can you ensure accumulation of the radionuclide is in the correct place

Answer 39

attach it to a pharmaceutical which has an affinity to the target area

Question 40

length of stay depends on activity given and how quickly individual excretes the radiation