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TEST BORRADO, QUIZÁS LE INTERESE: 4 Instrumentation and Quality Assurance

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Título del Test: 4 Instrumentation and Quality Assurance Descripción: 4 Instrumentation and Quality Assurance Autor: Camaleon24 OTROS TESTS DEL AUTOR Fecha de Creación: 07/10/2024 Categoría: Ocio Número Preguntas: 67

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1) How often should the COR check be performed? a. at least weekly b. before each patient c. every 6 months d. at least monthly. 2) The abbreviation COR stands for: a. circle of rotation b. center of region c. correction of rotation d. center of rotation. 3) What is the minimum number of counts that should be obtained in a uniformity correction flood for a SPECT camera? a. 10 K b. 10 million c. 30 million d. 60 million. 4) Which of the following collimators will magnify an image? a. flat field b. diverging c. converging d. high resolution. 5) Which of the following must be performed every 6 months at minimum? a. COR b. sealed source leak test c. linearity of the dose calibrator d. area survey of hot lab. 6) A dose calibrator must undergo repair or replacement if accuracy or constancy errors are: a. present b. greater than 5% c. greater than 10% d. greater than 20%. 7) Accuracy of the dose calibrator must be tested: a. on installation b. at least annually c. every six months d. both a and b. 8) Linearity of a dose calibrator must be checked: a. on installation b. quarterly c. every six months d. both a and c. 9) Constancy of the dose calibrator must be tested: a. daily b. quarterly c. weekly d. every six months. 10) A technologist wishes to evaluate the intrinsic uniformity of a camera used for planar imaging and is preparing a dose of 99mTc.How much activity is sufficient for the image? a. 2 mCi b. 200 μCi c. 20 mCi d. 10 μCi. 11) Which has an effect on the CRT appearance? a. energy of isotope b. dose calibration c. tag efficiency d. count rate. 12) The advantages of using a 57Co sheet source over a fluid filled flood source with 99mTc added include: a. it does not have to be prepared each day b. lower cost c. shorter half life d. all of the above. 13) Geometric dependence of a dose calibrator must be checked: a. at installation b. daily c. quarterly d. both a and c. 14) What happens to image resolution as the distance between a patient and a parallel hole collimator decreases? a. improves b. worsens c. does not change. 15) What happens to image size as the distance between a patient and a parallel hole collimator decreases? a. improves b. worsens c. does not change. 16) What part of an imaging system emits light when it has absorbed a photon? a. photomultiplier tube b. pulse height analyzer c. scintillation crystal d. collimator. 17) Most of the photons emitted from the radiopharmaceutical which has been administered to a patient: a. do not contribute to the final image b. are received by the sodium iodide crystal c. are converted to a voltage signal d. a and b e. b and c. 18) To obtain high resolution images of a small organ, gland or joint which collimator will be most useful? a. low energy parallel hole b. flat field c. diverging d. pinhole. 19) As septal length , septal penetration . a. increases, increases b. increases, decreases c. decreases, decreases d. decreases, increases e. both b and d. 20) Which of the following degrade images? a. septal penetration b. photon scatter in the patient c. increased patient to detector distance d. all of the above e. b and c. 21) A technologist covers the collimator (which is facing the ceiling) with absorbent paper and obtains a uniformity image using a liquid flood source with added 99mTc. A round cold spot is seen on the image. Subsequently the technologist removes the collimator, turns the camera face down and obtains another image using a point source placed on the floor. This image appears uniform. What is the most likely cause of the cold spot on the first image? a. collimator defect b. decoupled photomultiplier tube c. subtle crystal crack d. improper energy peaking. 22) The first image described in question 21 showed resolution, and the second image obtained showed resolution. a. extrinsic, intrinsic b. intrinsic, extrinsic. 23) If two photons strike a sodium iodide crystal at the same time,what will occur? a. neither event will trigger production of light b. the system will perceive only one event which will contain the summed energy of both photons c. both will be correctly perceived d. none of the above. 24) The time after a crystal has absorbed a photon before it able to respond to another event is called: a. count rate b. distortion c. dead time d. sensitivity. 25) The Z component of the signal in the photomultiplier tube will: a. be processed by the pulse height analyzer b. be recorded on the CRT c. be removed by the PMT d. all of the above. 26) The purpose of the photomultiplier tube is to: a. keep any of the electrical signal which resulted from scatter or background from contributing to the final image b. to convert light into an electrical signal and to magnify that signal c. to convert radioactivity into light d. to filter out photons which strike the crystal from oblique angles. 27) The purpose of the pulse height analyzer is to: a. keep any of the electrical signal which resulted from scatter or background from contributing to the final image b. to convert light into an electrical signal and to magnify that signal c. to convert radioactivity into light d. to filter out photons which strike the crystal from oblique angles. 28) A camera with three pulse height analyzers will be most useful for imaging: a. 99mTc b. 67Ga c. 111In d. 133Xe e. b and d. 29) A technologist has set a 15% symmetric window for a 140 keV photopeak.What will happen to a 158 keV signal? a. it will be accepted by the pulse height analyzer b. it will be rejected by the pulse height analyzer. 30) A typical energy spectrum of 99mTc from a patient contains a broad peak around 90–140 keV that is not present on the energy spectrum from a point source of the same isotope. This represents: a. the iodine escape peak b. the signal from 99mTc c. lead X-ray peak d. Compton scatter. 31) Image exposure time may be determined by: a. a preset number of counts b. a preset time c. information density d. all of the above. 32) Which of the following is measured in millimeters? a. energy resolution b. spatial resolution c. field uniformity d. temporal resolution. 33) The spatial resolution of an image is better with a energy isotope than with a energy isotope. a. higher, lower b. lower, higher. 34) If the energy range for 137Cs at half maximum ranges from 620–695,what is the percent energy resolution, and is the system operating within acceptable limits? a. 7.5, no b. 10.8, yes c. 11.3, yes d. 13.5, no. 35) According to the curve for 137Cs shown in Figure 4.1, what is the energy resolution of the system? a. 6.9 b. 8.2 c. 10.5 d. 11.6. 36) Of the following types of transmission phantoms, which one requires the fewest images to test the spatial resolution over the entire detector face? a. Hine-Duley phantom b. four quadrant bar phantom c. parallel line equal space phantom d. orthogonal hole phantom. 37) An orthogonal hole phantom cannot be used to test spatial linearity since it does not contain lead bars. a. true b. false. 38) When using a 150 μCi source of 99mTc to check uniformity, a technologist measures the counts in one minute as 53,125. If the background in the room is 352 cpm,what is the sensitivity of the system? a. 351 cpm/μCi b. 354 cpm/μCi c. 356 cpm/μCi d. 360 cpm/μCi. 39) A technologist performs an extrinsic uniformity correction on Monday and it shows a nonuniformity of 3%. On Tuesday, it is 8%.What would be the next step? a. check the photopeak b. call for service on machine c. remove the collimator and obtain intrinsic uniformity flood d. a or c. 40) For a system with inverse gain control, and a gain setting of 4, each division on the pulse height analyzer dials corresponds to: a. 0.5 keV/division b. 1.0 keV/division c. 2.0 keV/division d. none of the above. 41) For a system with true gain control , and a gain setting of 4, each division on the pulse height analyzer dial corresponds to: a. 0.5 keV/division b. 1.0 keV/division c. 2.0 keV/division. 42) An uptake probe operates with true gain and was calibrated with a gain setting of 8. If the gain setting is 16, and energies accepted by the pulse height analyzer are 294–342,what is the isotope under study? a. 99mTc b. 123I c. 210Tl d. 133Xe. 43) Why might a technologist use an asymmetric window around a photopeak? a. to include other emissions b. to exclude the Compton edge c. to exclude Compton scatter d. none of the above. 44) What energies are included if a 20% symmetric window is used for the 364 keV photopeak of 131I? a. 191–437 b. 328–400 c. 337–391 d. 344–384. 45) The images acquired as a SPECT camera rotates around a patient are called: a. reconstructions b. arcs c. projections d. azimuth stops. 46) With a matrix size of 64 ¥ 64, and two sources placed 30 cm apart there are 44 pixels between the activity peaks on the activity profile that is generated.What is the pixel size? a. 6.8 cm/pixel b. 6.8 mm/pixel c. 1.4 mm/pixel d. 0.14 cm/pixel e. none of the above. 47) What steps should be taken to reduce of remove a star artifact from reconstructed SPECT images? a. decrease the matrix size b. increase the time per projection c. increase the radius of projection d. increase the number of projections. 48) The method of SPECT acquisition requires slightly more time, but has less blurring than the method. a. step and shoot, continuous rotation b. continuous rotation, step and shoot. 49) As matrix size increases,what must also increase? a. total imaging time b. computer memory used c. number of projections d. all of the above e. a and b. 50) If the distance between 2 point sources placed on the camera surface is 35 mm, and the number of pixels between their activity profile peaks is 52 in the x axis and 55 in the y axis, are the pixel dimensions in the x and y direction within 0.5 mm of one another? a. yes b. no. 51) A technologist measures a standard of known activity in the dose calibrator three times. She subtracts background from each measurement and compares these measurements to the decay corrected activity of the standard. This was a test of: a. constancy b. linearity c. accuracy d. geometric dependence. 52) Records of dose calibrator checks must be kept for: a. 3 years b. 5 years c. 10 years d. as long as the license is valid. 53) Survey meters must be calibrated: a. before first use b. annually c. following repair d. all of the above. 54) Survey meters must be checked for proper operation against a sealed source: a. before each day of use b. weekly c. monthly d. every six months. 55) Which of the following would be used to perform a survey of an area in which a small amount of radioactivity is expected to be present? a. ionization chamber b. Geiger-Muller counter c. well counter d. single probe counting system. 56) An ionization chamber with a relatively low applied voltage from the anode to the cathode has a low efficiency and is therefore best for measuring: a. low exposure rates b. high exposure rates c. background radiation d. absorbed dose. 57) Most well counters measure radioactivity by use of: a. an applied voltage from anode to cathode b. a sodium iodide crystal c. a silver halide layer d. thermoluminescent crystals. 58) Which of the following is a consideration when measuring samples in a well counter? a. sample volume should be kept small and consistent among samples b. samples should be contained in identical tubes c. amount of radioactivity should be low d. all of the above e. all except d. 59) A dose calibrator is received in the Nuclear Medicine department following repair.A linearity test is performed on the dose calibrator, and the results are as follows. 33.9 mCi 17-Jan 08:00 30.3 mCi 17-Jan 09:00 9.2 mCi 17-Jan 19:00 2.3 mCi 18-Jan 07:00 0.5 mCi 18-Jan 20:00 0.2 mCi 19-Jan 03:00 What is the next step the technologist should take? a. send the instrument for further repair b. accept the instrument for use c. reject the instrument for use d. change the battery. 60) What is the sensitivity of a camera that registers 28,137 cpm from a 120 μCi source if the background is 705 cpm? a. 40 cpm/μCi b. 203 cpm/μCi c. 228 cpm/μCi d. 234 cpm/μCi e. 240 cpm/μCi. 61) A check source is calibrated for June 13, 1995 at noon and contains 145 μCi of 137Cs (Tp = 30 years). If a dose calibrator is used to measure that dose on June 13, 2001, what is the range of acceptable activities to prove that the accuracy is within 10%? a. 115–130 μCi b. 119–125 μCi c. 120–133 μCi d. 125–140 μCi. 62) One ml of a solution is assayed and contains 206 mCi. If the solution is diluted to 9 ml, and the activity is now 170,what is the geometric correction factor? a. 0.65 b. 1.2 c. 10.9 d. 18. 63) Because of the relatively high energy of the photon detected in PET imaging, attenuation correction does not need to be performed. a. True b. False. 64) Which of the following can not be used for PET scanning? a. a SPECT camera with high energy collimation b. a dedicated PET scanner c. a SPECT camera with coincidence counting d. CT scanner. 65) What part of a PET scanner quality control regimen is necessary for the computation of attenuation factors? a. coincidence timing calibration b. normalization correction c. PMT gain adjustment d. blank scan. 66) Which of the following describes random coincidence? a. the simultaneous detection of annihilation photons originating from a single positron. b. the simultaneous detection of annihilation photons originating from a single positron although one of the photons has been scattered before reaching the detector. c. the simultaneous detection of photons originating from different positrons. d. none of the above. 67) Scintillation crystals for PET scanners are not made of: a. sodium iodide b. lutetiumoxyorthosilicate c. bismuth germinate d. lead sulfate e. b and d.

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