nuclear med

Question 1

what is the main drug used in nuclear med

Answer 1

technetium-99m

Question 2

what regulates radio pharmacy prep

Answer 2

MHRA

Medicines and Healthcare products Regulatory Agency

Question 3

note: external dose rate of technetium generator must be measured to check if theres damage or leakage from box

Question 4

what are isolators and isolator readings

Answer 4

isolator= contained environment used for sterile prep of drug

readings = measurement and monitoring of environmental conditions in isolator

Question 5

trolley used to load 22kg generator into isolator.

outside of generator is sanitised with 70% alcohol prior

Question 6

what is a radionuclide assay calibrator

Answer 6

also knowns as ionization chamber / dose calibrator

• measures radioactivity of radioactive sample

Question 7

constancy (dependable) check of the calibrator is done using what chemical

Answer 7

caesium-137

Question 8

what gas is inside the isolator for sterilization

Answer 8

hydrogen peroxide vapour

Question 9

to form technetium-99m from molybdenum-99m is via elution, explain the process

Answer 9

• vial (containing eluent) (sterile saline) placed onto generator
• saline draws thru molybdenum/alumina Column causing ion-exchange
• this forms solution of technetium 99m in form of pertechnetate anions in collection vial

Question 10

what controls the volume of technetium 99m formation

Answer 10

the volume of saline in the evacuated vile (the vile that is placed onto the generator holding sterile saline)

Question 11

what is done with the collected technetium 99m

Answer 11

radioactivity measures and entered on data base along with volume

Question 12

what material is the collected technetium 99 vial placed in

Answer 12

thick tungsten shield

Question 13

what is the average eluted activity from technetium

Answer 13

110GBq

Question 14

dose rate to internal walls of tungsten shield = 1Gy/hr

Question 15

1 Bq = 1 radioactive decay per sec,
bone scan has 600 mill per sec so how much Bq is this

Answer 15

600MBq

Question 16

what is done to the collected vial of pertechnetate in order for it to become usable as technetium 99m

Answer 16

pertechnetate is a water soluble isotope of technetium 99m

• this is added to a cold kit
• this kit has all ingredients needed for formation of technetium 99m from pertechnetate / for technetium 99m to be reduced from pertechnetate to form oxidation state for binding to molecules (needed in NM)

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Question 17

How is the volume of pertechnetate to be added into each kit vial calculated

Answer 17

determine by radioactive conc of pertechnetate which data base calculates from activity and volume measured earlier

(auto corrects for decay as session proceeds)

Question 18

what dosage to fingers are received when handling the technetium cold kits

Answer 18

1mSv per session

Question 19

kits have limits on max activity that can be added

activity of prepared technetium is measured with what

Answer 19

assay calibrator

• then entered onto database with volume of pertechnetate added

Question 20

what is product release

Answer 20

kits being checked by another staff member not involved in drug prep prior to injecting for patients

Question 21

what is checked during product release

Answer 21

• correct apperance
• radioactivity
• volume
• lot number matching vial
• expiration

Question 22

what is a molybdenum breakthrough test, how’s it done

Answer 22

checking of molybdenum ‘breakthrough’ in 1st elution

• equate measured in lead pot
• this pot completely attenuated technetium99m gamma but allows gamma rays from molybdenum thru
• this allows measuring of molybdenum 99m activity contribution

Question 23

what is a aluminium breakthrough test, how’s it done

Answer 23

• checks for aluminium breakthrough in 1st elution
• eluate spotted onto indicator paper with standard aluminium solution
• if pink, its present (although if its pink but intensity is less than standard aluminium solution its ok)

Question 24

if aluminium is present in eluate (high conc), can cause clumping impairing in-vivo behaviour

Question 25

what is used to draw up patient injections and where is it stored

Answer 25

shielded syringe - put into lead lined boxed at room temp or fridge

Question 26

injections are double checked with assay calibrator to ensure radioactivity is within 10% of calculated activity

Question 27

how frequency is QC done in radiopharmaceutical

Answer 27

every morning

Question 28

what is checked in QC

Answer 28

- pressure pads (reset) - camera movement (reset) - peak, uniformity

Question 29

4 scans in NM are eluate, technescan HDP, nano scan, pulmocis (MAA): what are these scans for and what does it used

Answer 29

eluate = use pertechnetate (from elution), creates technegas for lung ventilation imaging technescan HDP = hydroxydiphosphonate bone scanning agent nanoscan = nano colloid image lymphatic flow pulcomis (MAA) = macroaggevated albumin, suspension to image blood flow in lungs

Question 30

how much technetium is give to sentinel node scan / nano scan and whats seen and how is the procedure done

Answer 30

10MBq injected - image tracked to see lymphatic drainage to first sentinel lymph node - radiation probe used in theatre to guide surgeon to node - node examined for metastatic cancer (if positive, continue removing)

Question 31

for NM bone scans/ HDP, how long must be waited before scan is done after injection of technetium

Answer 31

3 hrs, to wait for bone to uptake tracer

Question 32

IV injections for the bone scan is done where

Answer 32

peripheral vein

Question 33

why are patients encourages to drink lots of fluid and frequently pee

Answer 33

flush excess radiopharmaceutical out of soft tissue and decreases radiation dose to bladder wall

Question 34

what is the contamination limit (if there is technetium 99m spill)

Answer 34

50cps (counts per sec)

Question 35

what is a V/Q scan

Answer 35

A VQ scan, also called a Ventilation (V) Perfusion (Q) scan, is made up of two scans that examine air flow and blood flow in your lungs - find PE'S

Question 36

why is a v/q scan preferred to a CTPA in young women

Answer 36

dose to breast tissue is lower

Question 37

chest xray done prior to v/q why

Answer 37

rule out changes that explain symptom or make interpretation of v/q hard

Question 38

v/q scan requires process call simmering, what is thsi

Answer 38

0.14ml pertechnetate added to carbon crucible (container) and heated to boil off water solvent (2750 degrees Celsius)

Question 39

how is the ventilation part of v/q scan done and imaged

Answer 39

- patient inhales technegas through mouthpiece with nose clip - inhaled over camera monitoring lung activity until correct count rate reached - images using SPECT (single photon emission)

Question 40

how is the perfusion part of v/q scan done and imaged

Answer 40

- IV injection of 100MBq technetium 99m macroaggravated albumin - given over camera to ensure amount injected reaches MMA activity level x4 of technegas - SPECT imaging to form 3D rep of blood flow in lung

Question 41

how do u use the ventilation and perfusion scan to identify abnomality

Answer 41

images get compared - ventilation scan should mirror chest xray and perfusion (normal) - if areas of absent in perfusion scan where seen normal in ventilation scan, can prove ACUTE PE

Question 42

though SPECT has good sensitivity and specificity, it takes x2 as long for planar whole body scan

Question 43

what is symbia camera

Answer 43

hybrid device - performed single slice low dose CT scan

Question 44

typical scanning regions: - SPECT (head/neck, chest/abdomen, abdomen/pelvis) -AP/PA planar of lower limbs - all these get combined to form whole body SPECT study 9can be seen in axial, sag, coronal) or 3d rendering with MIP

Question 45

how does motion affect SPECT image quality

Answer 45

reduced spatial resolution

Question 46

for items that cant be cleaned, how is the radioactivity dealt with (if over 50cps)

Answer 46

transferred to radioactive waste store to decay before back in service - or just covered and left to decay

Question 47

bathroom is left till next morning to be cleaned to allow decay