Nuclear Medicine Imaging Question1 [26 Marks] A lot of radioisotopes used in nuclear medicine are produced in a cyclotron. a) Briefly describe the basic construction of a cyclotron as well as it's principle of operation. [15] b) Give few examples of isotopes produced in the cyclotron (for SPECT and PET) and write down the nuclear reactions which are used in their production. [5] c) What reactions can be used for the production of iodine 123 ? Which one of these is practically used for production of this isotope for medical use and why? [6] Question 2 [12marks] During production of a 99Mo/99mTc generator, 100 GBq of pure molybdenum 99Mo was loaded into the column on February 1-st at 12:00. Immediately after generator's preparation the first elution was made. Subsequently, the generator was delivered to the hospital and was used clinically for the first time on February 4-th at 9:00. Calculate: a) The mass of 99Mo loaded during production. [3] b) Activity of 99Mo at time of first use in the hospital [1] c) Activity of 99mTc obtained during this elution [2] d) Mass of technetium 99mTc in a syringe prepared for patient if activity in it is 500 MBq [3] Explain, why activity 99mTc obtained in practice will be lower than calculated in c. [3] Question 3 [30 marks] a) Describe the method of registration of images in positron emission tomography and the construction of the PET-scanner [15] b) Explain role of the CT scanner in PET-CT imaging device [5] c) During PET imaging beside true coincidence events another "non-true" events are registered. What are the sources of these events? How do these influence the image? How can we eliminate/minimise these effects? [10] Question 4. [8 marks] Describe briefly which physiological process is responsible for the accumulation of the radiopharmaceutical in : a) 131I uptake in thyroid during hyperthyroidism therapy [2] b) 99mTc-HMDP (biphsphonate complex) for bone scintigraphy [2] c) 99mTc pertechnetate for thyroid scintigraphy [2] d) 18F-FDG for PET scan [2] Question 5 [21marks] Localization of the sentinel lymph node with radioisotope detection is widely used in surgical practice. Please describe : a) anatomical and physiological basis of this method [5] b) radiopharmaceutical used in sentinel node procedure [4] c) intraoperative probe (construction, special requirements for use in theatre) [5] d) typical indications for this procedure [5] e) clinical role of this procedure [5]