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Adv Imaging Unit 4
Overview
| Question | Answer |
|---|---|
| cancer | common in ppl older than 55 men - prostate, lung, colorectal women - breast, lung, colorectal |
| Nucmed physical principles (part1) | radiopharmaceutical agents have 2 components: radionuclide & pharmaceutical Pharmaceutical based on its role in organ's physiologic function Radionuclide is tagged to a pharmaceutical |
| Nucmed physical principles (part2) | radiopharmaceutical is administered to the patient the target organ is localized and the radiation emitted from it can be detected by imaging instruments, or gamma cameras Technetium-99 (99mTc) —the most commonly used radionuclide in NM |
| Preferred Radiopharmaceutical Characteristics part1 | easily produced, readily available, low cost, low radiation dose, primary photon btwn 100-400 keV, half life greater than injection preparation time, effective half life longer than exam time, rapid localization, diff uptake in structure to be detected |
| Preferred Radiopharmaceutical Characteristics part2 | low toxicity, stability or near stability |
| Nucmed radiation safety | radionuclides continuously emit radiation after administration Preparation area in nuclear pharmacy contains, Isolated ventilation. Protective lead or glass shielding for vials &syringes. Gloves &lead syringe shield required to reduce exposure to hands |
| crystal and light pipe | light pipe- disk of optically transparent material, helps direct photons from the crystal into the PMTs (may be used to attach crystals to PMTs) |
| detector electronics part1 | PMTs detect and convert light from crystal into electronic signal and amplify signal 10^7 , PMT array attached to back of crystal or light pipe, typical gamma camera detector head contains 80 to 100 PMTs |
| detector electronics part2 | PMTs processing steps -location (x,y) of original photon and amplitude/energy (z) , pulse height analyzer eliminates z signals , reduce scattered lower energy (noise) , processed data are transmitted to the display system |
| gamma cameras | originally single detector head systems newer may have up to 3 heads multicrytsal gamma cameras- utilize an array of crystals that are coupled to position sensitive PMTs or photodiodes |
| PET principles PET is a multidisciplinary technique with four processes: Radionuclide production | Radiopharmaceutical production Data acquisition (PET scanner or tomograph) Combination of image reconstruction and image processing to create images that depict tissue function |
| Clinical PET | Oncology imaging Neurologic imaging Cardiology imaging |
| Future of NucMed | Radioimmunotherapy Hybrid imaging |
| Radiation Oncology theory part1 | biologic effectiveness of ionizing radiation in living tissue depends partially on the amount of energy that is deposited within tissue and partially on the condition of the bio system |
| LET and RBE | energy effect is described as linear energy transfer (LET) and relative biologic effectiveness (RBE) LET increase = RBE increase |
| Radiation Oncology theory part2 | State of the biologic system is based on Law of Bergonié and Tribondeau Radiosensitivity of tissue depends on Cell differentiation Mitotic rate Length of time in mitosis |
| Radiation Oncology theory part3 | 1. led to tumor radiosensitivity rating - very radiosensitive, moderately radiosensitive, &relatively radioresistant 2. very radiosensitive - gonadal germ cell tumors, lymphomas, embryonal tumors |
| Radiation Oncology Clinical Applications | Lung cancer Prostate cancer Head and neck cancers Cervical cancer Hodgkin’s lymphoma Breast cancer Laryngeal cancer Skin cancer Medulloblastoma |
| Future Trends in Radiation Oncology part1 | Intensity-modulated radiation therapy expansion Newest is volumetric-modulated arc therapy (VMAT) |
| Future Trends in Radiation Oncology part2 | Image-guided radiation therapy expansion Proton beam therapy, Not new, but gaining popularity as a result of normal-tissue savings, Cost and space constraints are still issues |