Nuclear Medicine Physics Jerry Allison, Ph.D. Department of Radiology Medical College of Georgia Image Artifacts in Nuclear Medicine Part A

A note of thanks to Z. J. Cao, Ph.D. Medical College of Georgia And Sameer Tipnis, Ph.D. G. Donald Frey, Ph.D. Medical University of South Carolina for Sharing nuclear medicine presentation content

Department of Radiology Medical Physics Resources Medical Physics Course  Calendar  Handouts

What to learn? ABR Core Exam Study Guide  Physics: Section 17) Nuclear Medicine and Instrumentation  Radioisotope Safety Examination (RISE) media/pdf/CORE_Exam_Study_Guide_FINAL%28V10%29.pdf

What to learn? ABR Core Exam Sample Content  A compilation of topics seen on previous Core Exams. media/pdf/Core_Exam_Sample_Content.pdf

Nuclear Medicine Physics : A Handbook for Teachers and Students Diagnostic Radiology Physics: A Handbook for Teachers and Students International Atomic Energy Agency, including-dosimetry- Wonderful new books (FREE)!

Artifacts in NM images  Defects of gamma camera or suboptimal data acquisition  Photon attenuation  Compensation of photon attenuation in PET/CT and SPECT/CT  Patient motion  Undesired uptake of radiopharmaceutical 7

Defects of gamma camera  Defect of collimator or detector  Bad PMT  Shift of energy peak out of energy window  High count rate (> 40,000 counts/sec)  SPECT artifacts 8

Effect of counts on perceived noise Rzeszotarski M S Radiographics 1999;19: ©1999 by Radiological Society of North America Image of a brain phantom. As counts increase, noise decreases.

Effect of counts on contrast End –diastole image Rzeszotarski M S Radiographics 1999;19: ©1999 by Radiological Society of North America

11 Small dot: collimator defect

12 One PMT  a defective PMT Multiple PMTs  offset of energy peak

13 Shift of energy peak

14 A defective PMT in SPECT

15 Line: cracked detector Caused by mechanical impact

16 High count rate  pile-up time pulse height

17 High count rate

18 COR shift in SPECT

19 3 foci of uptake that could be mistaken for a neoplastic process Contamination of the patient's clothing with radioactivity

20 Attenuation by left breast  an apparent defect in the anterior wall