Generators

Generator Systems :Generator Systems Group #1 Members: Jason Chok (el Capitan), Daniel Ferro and Jessica Castillo


Objectives :Objectives To know what generator systems are and what is transient and secular equilibrium To know about some generators e.g Mo99-Tc99m, and Sn113-In113m Know what are wet and dry column generators


What are generator systems? :What are generator systems? Long-lived parent produces a continuous supply of short-lived daughter radionuclide


Types of generator systems? :Types of generator systems? There are two types of parent-daughter relationships Transient and secular equilibrium


Transient equilibrium :Transient equilibrium In this system the half-life of the parent is a factor 10 to 100 times Where the parent is 10 and is 100 times greater than the daughter Example of this is the mo99 to Tc99m where it is 67-hrs to 6 hrs respectively


Secular equilibrium :Secular equilibrium In this system the half-life of the parent is 100 to 1000 times greater than the daughter An example is the Sn113(t1/2=115days)- In113m(t1/2=1.7hrs)


Transient and Secular Equilibrium :Transient and Secular Equilibrium


Mo99-Tc99m Generator :Mo99-Tc99m Generator Is commonly used in Nuclear Medicine because of the ideal half-life(6hrs) and optimum energy 140 keV Radiopharmaceuticals are made with Tc99


Wet and dry column generators :Wet and dry column generators Wet column Has saline remained on the column after elution This forms water radiolysis products, which are reducing agents Dry Column Removes saline from column after elution Decreases the amount of water radiolysis products


Wet and dry column generators :Wet and dry column generators


Sn113-In113m Generator :Sn113-In113m Generator In113m can be used in imaging lungs, liver, brain, and kidneys Sn113(115days) and In113m(1.7hrs) In113 has a photon energy of 393keV which is not ideal for use with the gamma camera This type of generator has largely been replaced by the Mo99-Tc99m generator


82Rb-82Sr Generator :82Rb-82Sr Generator T ½ = 76 seconds Rubidium 82 is a positron-emitting radionuclide Is used primarily as a myocardial perfusion agent for PET imaging. This generator is radiopharmaceutical approved by the (FDA)


Slide 13 :T 1/2 =25 days Is accelerator produced by bombardment of molybdenum target with 700- to-800 Mev protons Is produced as a radionuclide impurity


81Rb-81mKr :81Rb-81mKr A gamma ray emitting nuclide Is used as a lung imaging agent T ½ =13 seconds Is eluted by passing humidified oxygen over the generator column. 82mKr and O2 is delivered through a nonre-breathing mask to the patient.


Slide 15 :T ½ = 4.7 hours Is loaded onto the generator column containing a strong cation-exchange resin. Mayor disadvantage of 81Rb-81Kr generator are the high cost and the 12-hour expiration time due to the half-life of the parent isotope, which limits the generator to the day of use only.


68Ge - 68Ga generator :68Ge - 68Ga generator Gallium-68 (t1/2 = 68 minutes) emits a 2.92 – MeV positron in 89% abundance Not FDA approved Useful in PET imaging Alluted using 1 M HCL.25


68Ge - 68Ga generatordisadvantages :68Ge - 68Ga generatordisadvantages Large elution volume (3 ml) and the high acid concentration The presence of trace metals made complexation of Ga68 challenging


62Zn – 62Cu generator :62Zn – 62Cu generator Copper–62 is a positron-emitting radionuclide (98% abundance) with a 1.7 minute half life Attractive radionuclide for PET imaging Used in clinical investigation for heart and brain blood flow measurement


62Zn – 62Cu generatordisadvantage :62Zn – 62Cu generatordisadvantage Short half-life of Zn62 (9.3 hours) Requires generator replacement at one or two day intervals Radiopharmaceutical synthesis time is the 40 second period required for general elution


Summary :Summary Generator Systems Transient and secular equilibrium Wet and dry column generators Mo99-Tc99m, Sn113-In113m 82Rb-82Sr,81Rb-81mKr 68Ge-68Ga,62Zn-62Cu


Questions #1 :Questions #1 What are Generators? What is Transient Equilibrium? Which Equilibrium does a 100 to 1000 Factor belong? What is the difference between a Wet and a Dry column Generator, in terms of what happens after Elution?


Question #2 :Question #2 Is the Mo99-Tc99m Generator a Transient or Secular generator? What is the photon energy of In113m, and is it ideal for use with the gamma camera


Questions #3 :Questions #3 Rubidium is what kind of radionuclide? Name a disadvantage to the 81Rb-81Kr generator.


Questions #4 :Questions #4 Is Ge 68- Ga68 generator approved by the FDA? What main organs are targeted with the use of copper 62?