nuclear med

Question 1

radiopharmaceutical

Answer 1

radioactive substance used in nuclear med imaging / treatment

Question 2

tracer

Answer 2

another name for radiopharmaceutical

Question 3

uptake

Answer 3

absorption / accumulation of a radiopharmaceutical by an organ or tissue indicating function / activity

Question 4

activity

Answer 4

the number of radioactive decays per second measured in becquerels or curies

Question 5

emission

Answer 5

release of energy or particles e.g. gamma rays, from a radioactive substance

Question 6

scintigraphy

Answer 6

process of creating images using gamma camera to detect radiation emitted by radiopharmaceutical

Question 7

hot spot / cold spot

Answer 7

hot spot- area of increased uptake of the radiopharmacetucal, indicating higher activity

cold spot- area with reduced uptake, indicating low activity or damage

Question 8

contamination

Answer 8

unintended spread of radioactive materials on surfaces, equipment or personnel.

Question 9

isotopes

Answer 9

atoms of the same element with the same no. of protons but different number of neutrons. this means same atomic number but different atomic masses

Question 10

stable v unstable isotopes: basis for radioactivity

Answer 10

stable nuclei- balanced protons and neutrons
unstable nuclei- imbalance between protons and neutrons which causes instability

atoms with unstable nuclei release more radiation to achieve stability

Question 11

radioactive decay-

Answer 11

radioactive atom becomes more stable by releasing particles and energy- this is called radioactive decay

-nuclei become stable through different radioactive decay as charged particles or photons

Question 12

types of radiation - alpha

Answer 12

-2 protons and 2 neutrons- has no electrons
-relatively large, can’t penetrate very far into other materials
-strongly ionising: easily knock electrons off any atoms they collide with

Question 13

types of radiation- beta

Answer 13

electrons- charge of -1 and has no mass
moderatley ionising as it is small- 5mm of aluminium

Question 14

types of radiation: gamma

Answer 14

-waves of electromagnetic radiation
-no mass or charge- can pass through materials
-weakly ionising, can travel long distances and can be stopped by thick sheets of lead
-emitted from a nucleus

Question 15

half life

Answer 15

time it takes for activity of the source to fall to half its original value

-short half life- (Tc-99m) ideal for imaging as there’s minimal patient exposure

-longer half life- (I-131) suitable for therapeutic purposes

e.g. tc-99m, 6 hour half life
after 6 hours, 50% of the isotope remains, after 12 hours only 25% remains

Question 16

how are isotopes produced

Answer 16

-cyclotron- machine that accelerates charged particles using magnetic fields. creates isotopes like fluorine-18 which has a very short half life. requiring quick use after production, and is often located near hospitals to minimise decay during transport.

nuclear reactor- produces isotopes e.g. molybdenum-99, parent isotope for Tc-99m . exposes suitable target material to the intense reactor neutron flux for an appropriate time
generator

generator: portable system that extracts Tc-99m daily from parent MO-99 (parent)- separates decay product from the source radionuclide.

Question 17

why are generators often used to create isotopes?

Answer 17

portable and easy to use in hospitals
provides fresh tc-99m daily for imaging.

Question 18

radiolabelling

Answer 18

process of attaching a radioisotope to a carrier molecule to create a radiopharmaceutical., e.g. Tc-99m binds to phosphates naturally accumulating in bones so this is ideal for bone scans.

radioactive compound -> linker -> targeting molecule -> target protein -> cancer cell

Question 19

what are the key functions of radiopharmaceutical preparation:

Answer 19

this takes place in a specialised hot lane, equipped with shielding and designed for safe handling and storage of radioactive materials.

key functions:

-radiopharmaceutical preparation
-quality control testing (radiochemical purity)
-dose measurement

Question 20

what are the essential tools used when preparing radiopharmaceutical d

Answer 20

-lead glass window: protects staff
-vial shelf and tongs to handle sources
-shielded containers and syringes: limits exposure when handling. also used for prep and administration of radiopharmaceuticals

Question 21

how is radiopharmaceutical dose calculated?

Answer 21

accurate dosing- calculated based on patients weight, height, medical needs and scan type.

Question 22

preparation of administration

Answer 22

• safe transport and handling: using shielded containers to transport radiopharmaceutical

-administration to patient: injection or oral, depending on scan requirements

-imaging procedure: immediate or delayed imaging based on radiopharmaceutical and scan type.

Question 23

what does SPECT stand for?

Answer 23

single photon emission computed tomography

Question 24

what is the definition of spect

-single photon:
-emission imaging:
-computed:
tomography:

Answer 24

single photon: detects single gamma photons that are emitted from a. tracer in the body, unlike chest XRs which just pass through

emission imaging: detects radiation emitted from the body

computed: algorithms to reconstruct images using multiple angles and enhancing details

tomography: creates 3d cross sectional images to enable precise tracer localisation

Question 25

gamma camra: spect

Answer 25

imaging device used to detect gamma rays released by radiopharmaceuticals to create an image

Question 26

gamma camera head: spect

Answer 26

camera that rotates around the patient capturing multiple angles

Question 27

SPECT computer

Answer 27

processes signals to create 3d images of tracer distribution

Question 28

what is the order of components in spect

Answer 28

-patient -gamma camera -collimator -scinitillator and pmt -computer -display

Question 29

what is a collimator in spect and what are thew 2 different types

Answer 29

-collimator made of gamma ray absorbing material e.g. lead. allows only gamma rays n the correct direction pass through and be included in the imaging process. -multihople parallel collimator -pinhole collimator

Question 30

what are the features of a multihole parallel collimator:

Answer 30

-widely used and accessible in clinics -different options to choose from based on tracer energy and resolution needed -its like changing lens on a camera -stored nearby, easy to swap and change

Question 31

what are the features of a pinhole collimator:

Answer 31

-single aperture / pinhole -allows you to focus on smaller/ specific areas e.g. thyroid -works like a magnifying glass

Question 32

what is the purpose of scintillation and pmt

Answer 32

transform gamma radiation into a digital image

Question 33

outline the process of scintillation and pmt

Answer 33

scintillator- uses crystals (often sodium iodide) converts gamma rays into visible light photomultiplier tubes- detects this visible light ad converts it into electrical signals computer: detects electrical signals, processes and converts them to create digital images

Question 34

SPECT vs planar imaging

Answer 34

planar imaging: single 2d projection, gamma camera does not rotate useful for quick assessments, but lacks depth information types of planar imaging: static: single image e.g. thyroid dynamic: rapid frames to track changes overtime e.g renal studies whole body: a single image of the entire body by moving camera e.g. bone scans

Question 35

what is SPECT/CT

Answer 35

- hybrid imaging: combines sect for function and CT for structure, in one scan -benefit: provides both anatomical and functional information -clinical utility: enhances localisation of abnormalities

Question 36

what is PET?

Answer 36

-nuclear med technique- visualises cellular and molecular activity uses radioactive tracers e.g fluorine18- emits positrons detectable by PET scanner -highly sensitive for detecting disease activity in: -oncology -neurology -cardiology

Question 37

mechanism of pet imaging

Answer 37

positron emission: tracer releases positron's that interact with electrons in the body annihilation event: results in two gamma was emitted 180 degrees apart

Question 38

PET detection system

Answer 38

no collimator needed: detect photons from annihilation events, improving sensitivity. ring of detectors: 360 degree detector ring to capture paired gamma rays coincidence detection: paired gamma rays are detected simultaneously to pinpoint annihilation point LOR: path connecting two detectors receiving the paired photons, indicating A.E location.

Question 39

image formation in PET

Answer 39

data collection: thousands of LORs captured during the scan image reconstruction: software uses LORs to create a 3d map of metabolic activity result: final images help diagnose cancer, brain and heart disease