السلام عليكم الناهرده هاتكمل عن اذاى تخبر ال Dose calibrator فى المعمل وتتاكد من كفائته وده هايتم عن طريق الاختبارات التاليه :- 1. Accuracy at installation :- 2. Constancy daily test 3. Linearity 4. Geometry at installation Accuracy at installation 1- انا عايز اتاكدان ال dose calibrator قرائته سليمه فبالتالى محتاج مصدر معلوم القوه الاشعاعيه مثل ( (57Co, 133Ba and 137Cs ويكون له long half live وابتدى احسب القوه الاشعاعيه للمصدر فى تاريخ القياس بمعلومية نشاطه الاشعاعى فى تاريخ سابق يبقى انا كده عندى ال original activity( A0) ومحتاج احسب النشاط الاشعاعى عند زمن القياس A(t) وممكن تستخدم المعادلات التاليه :- A(t)=A(0)/2*n n = (no of days left from the activity measurment day) /T 1/2 2- يمك...
Dose represents the energy deposited per unit mass; in CT, this is represented by the CTDI. Dose depends on mA, kV, and pitch. The total energy deposted is the dose-length product. DLP = CTDI * scan length . The DLP can be converted into an estimate of the effective dose, which represents an average risk for stochastic radiation effects (i.e. cancer). However , the CTDI, DLP, and effective dose are not accurate for large or small patients. For the same technique, large patients will have lower doses and smaller patients will have higher doses. This illustrates the importance of adjusting the scan settings (mA and kV) for pediatric and obese patients. Automated exposure control (tube current modulation) can perform some of these adjustments for you by using the CT topogram to estimate the patient's attenuation. Decreasing the kV can improve contrast and decrease dose, but this is only effective in small and normal-sized patients. Very large patient...
The physics of Nuclear Imaging part 1 Outlines: 1-Radiopharmaceuticals 2-Radiopharmaceutical QC 3-Dose Calibrator QC 1-Radiopharmaceuticals: · Definition: Radiopharmaceuticals consist of a radioactive isotope, which creates the image, and a pharmaceutical, which determines the physiological behavior of the compound and, therefore, where the signal accumulates to form the image. · Properties of ideal radiopharmaceuticals: 1. Easily and firmly attached to the pharmaceutical at room temperature but has no effect on its metabolism. 2. Readily available at the hospital site. 3. A high-specific activity 4. High target: non-target uptake ratio 5. Easy and cheap to produce 6. Non-toxic 7. Does not alter physiolog...
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