Gaseous DetectorsAnd Scintillation :Gaseous DetectorsAnd Scintillation Group 4 Maykel Chala ,Gina Ferro, Candace Hurt, *Claudia Lola, Alex Smith


Objectives :Objectives Describe Gaseous and Scintillation Detectors What are the different types of Scintillation detectors? How does scintillation work? Pulse Height Analyzer (PHA) Why is the Dose Calibrator essential in nuclear medicine?


Gaseous Detector and Scintillation Detectors :Gaseous Detector and Scintillation Detectors Gaseous Detectors detect ionizing gas molecules being produced by radiation that has energy being detected by the gas-filled detector Scintillation detectors detect the materials that have fluors (fluorescent materials that illuminate when struck by radiation)


Pictures :Pictures


Gas Filled Detectors :Gas Filled Detectors Are gas-filled containers that use different types of gases such as helium, argon, neon, hydrogen, and air. When the gas-filled detector detects an ionizing radiation, the gas in chamber produces ion pairs, which results into free electrons that attract to anode (positive) while the positive charged gas molecules attract to the cathode (negative)


Types of Gaseous Chambers for Nuclear Medicine :Types of Gaseous Chambers for Nuclear Medicine In nuclear medicine we use : Dose calibrator Survey meters Cutie Pie Geiger Mueller (GM) Dose calibrators are used to determine the amount of radioactivity from a tube, vial, syringe, etc


Types of Gaseous Chambers for Nuclear Medicine (cont) :Types of Gaseous Chambers for Nuclear Medicine (cont) The survey meter is used to locate the source of radioactivity, the amount of radiation exerted from the source, and the exposure rate from the source We use this to estimate the exposure risk from patients, syringes, and packages During QC, the GM is used to check for hot spots


What are the Different Types of Scintillation Detectors? :What are the Different Types of Scintillation Detectors? Well counter/automatic gamma counters Detecting medium : NaI (TI) crystal Radiation Detected: X and Gamma rays Energy discrimination capability: Yes Liquid Scintillation Counters Detecting medium: one or more scintillation materials dissolved in an organic solvent. Radiation detected: Betas , low energy X and gamma rays. Energy Discrimination Capability: Yes.


How does scintillation work? :How does scintillation work? The scintillation detects the radiation being emitted The higher the energy, the brighter the scintillation The scintillation event is converted into a electric signal. The pulse height analyzer sorts the energy being recorded.


Pulse Height Analyzer (PHA) :Pulse Height Analyzer (PHA) An instrument that accepts input from a detector and categorizes the pulses on the basis of signal strength Set the window percentage according to the radioisotope being used. The larger the window, the more noise or background will be received. The smaller the window, the better quality.


Conclusion :Conclusion GM survey meter, gaseous and scintillation detectors are the most basic instrumentation of nuclear medicine The Geiger Mueller is a laboratory and personal survey instrument that must be checked daily for quality control.


Conclusion (cont’d) :Conclusion (cont’d) The dose calibrator has to be used to see the correct dose in syringe, or a vial Dose calibrator directly determines the measurement of exposure rate PHA is an instrument that accepts input from a detector and categorizes the pulses on the basis of signal strength


Questions :Questions 1- What does a PHA do and what does it stand for? 2 - Why is the Dose Calibrator essential in nuclear medicine? 3 - Name three different scintillation detectors. 4 - What is the crystal made of? 5 - Name some instruments that are gaseous detectors


Answers: :Answers: 1- PHA: Pulse Height Analyzer sorts the energy being recorded 2 – Dose calibrator measures the dose of radioactivity and exposure rate. 3 - Well counter, liquid scintillation. 4 – Crystals are made of NaI (TI)-Sodium Iodine 5 - Geiger Mueller, Dose Calibrator, Ionizing Chamber.