Presentation is loading. Please wait.

Presentation is loading. Please wait.

Instruments & Radiopharmaceutical Production

Similar presentations

Presentation on theme: "Instruments & Radiopharmaceutical Production"— Presentation transcript:

1 Instruments & Radiopharmaceutical Production
NM 4103 Section II Instruments & Radiopharmaceutical Production

2 Gas Filled Detectors Ionization chambers Geiger-Muller counters
Operate on V Dose Calibrator Geiger-Muller counters Operate around 1000V

3 Dose Calibrator Sealed chamber Filled with argon & halogen
Operating voltage around 150 V Used for measuring activity of radiopharmaceuticals

4 Geiger-Muller Counter
Used to detect beta and gamma radiations Usually operates as a ratemeter Readings can be given in: uR/hour mR / hour R / hour Cpm Used for area survey (contamination) Calibrated annually with 226Ra or 137Cs Ur/hr = micro-roentgen per hour mR/hr = Milli-roentgen per hour R / hr = Roetngen per hour Cpm = counts per minute

5 Scintillation Detectors
Well counter Thyroid probe Gamma camera Gamma rays interact in the sodium iodide detector and light photons are emitted.

6 Detectors Sodium iodide crystals (most common)
Light generated in the crystal is then directed at the PM tube Sodium Iodide crystals are very Fragile

7 Collimators Covers the sodium iodide detector
Purpose is to limit the field of view Made of lead Holes of different shapes and sizes Increased number of holes = increased sensitivity (but loss of resolution)

8 Thyroid Probe Collimator
Single bore Cylinder shaped One PM tube

9 Scintillation Camera Collimators
Parallel : most common Diverging : organ larger than the size of the detector Pinhole : small organs/areas (thyroid) Converging : organ smaller than the size of the detector

10 Parallel-hole Collimator
Can be high-resolution, all purpose or high-sensitivity Size and number of holes the same, change thickness High sensitivity = smallest thickness High resolution = thickest All purpose = middle *want to imaged close to the patient *spatial resolution is best at the collimator face

11 Photomultiplier Tube Fixed to the sodium iodide crystal
Photocathode / series of dynodes / anode (all in a vacuum glass tube) *when a pm tube goes out, you will see a dark circle on your daily uniformity flood

12 Cyclotron Charged particles are accelerated in circular paths under vacuum by an electromagnetic field Radionuclides are usually neutron deficient and decay by + emission or electron capture Examples: Gallium-67 Iodine-67 Indium-111 Thallium-201 PET radiopharmaceuticals (Carbon-11,Nitrogen-13,Oxygen-15,Fluorine-18) Elements in Nature with an atomic number greater than 83 are Radioactive Radionuclides used in nuclear medicine are mostly artificial B+ : Positron


14 Reactor Constructed with fuel rods that undergo spontaneous fission
Radionuclides are usually neutron rich and decay by - emission Examples: Iodine-131 Molybemum-99 Xenon-133 Cesium-137 Fission = breakup of a heavy nucleus into two fragments accompanied by the emission of two to three neutrons B- : Beta

15 Specific Activity Radioactivity per unit mass Expressed in mCi / mg
Accurate only at the date and time of calibration On the radipharmacy label

16 Concentration Radioactivity per unit volume Expressed in mCi / ml
Accurate only at the date and time of calibration Found on the radiopharmacy label

17 Generator Long lived parent radionuclide continually decays to a shorter lived daughter radionuclide Chemical properties must be different, so they can be easily separated from one another Generator must be sterile and pyrogen-free Used for humans


19 Parent/Daughter relationship
Daughter grows as a result of the decay of the parent until equilibrium is reached Daughter activity is eluted, leaving the parent on the column After elution, the daughter activity starts to grow again

20 99Mo - 99mTc Generator 99Mo has a half-life of 66 hours & decays by - emission 99mTc has a half-life of 6 hours & decays by isomeric transition Liquid or solid column Liquid is rarely used in nuclear medicine B- : beta

21 Solid column generator
Alumina oxide on a column (encased in lead) 99mTc builds up until the maximum activity is reached (usually 4 half-lives) Wet or dry column generators Dry : after elution, the leftover saline in the column is drawn out with vial 4 half-lives is 24 hours = for maxiumum buildup


23 ~QC testing ~ 99Mo Breakthrough
Radionuclide purity Molybdemum contamination in the elution Limit: 0.15 uCi of 99Mo / 1 mCi of 99mTc

24 ~QC testing~ Aluminum Breakthrough
Aluminum contamination Limit 10 ug Aluminum ion / ml 99mTc eluate Aluminum interferes with tagging sulfur colloid and RBC’s

25 ~QC testing~ pH Should be between 4.5 and 7.5

Download ppt "Instruments & Radiopharmaceutical Production"

Similar presentations

Ads by Google