Partial volume effect in SPECT & PET imaging and impact on radionuclide dosimetry estimates

Document Type : Original Article


1 Sydney Vital Translational Cancer Research Centre, Sydney, Australia

2 Institute of Medical Physics, University of Sydney, Sydney, Australia

3 Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia


Objective(s): The spatial resolution of emission tomographic imaging systems can lead to a significant underestimation in the apparent radioactivity concentration in objects of size comparable to the resolution volume of the system. The aim of this study was to investigate the impact of the partial volume effect (PVE) on clinical imaging in PET and SPECT with current state-of-the-art instrumentation and the implications that this has for radionuclide dosimetry estimates.
Methods: Using the IEC Image Quality Phantom we have measured the underestimation in observed uptake in objects of various sizes for both PET and SPECT imaging conditions. Both single pixel measures (i.e., SUVmax) and region of interest mean values were examined over a range of object sizes. We have further examined the impact of the PVE on dosimetry estimates in OLINDA in 177Lu SPECT imaging based on a subject with multiple somatostatin receptor positive paragangliomas in the head and neck.
Results: In PET, single pixel estimates of uptake are affected for objects less than approximately 18 mm in minor axis with existing systems. In SPECT imaging with medium energy collimators (e.g., for 177Lu imaging), however, the underestimates are far greater, where single pixel estimates in objects less than 2-3×the resolution volume are significantly impacted. In SPECT, region of interest mean values are underestimated in objects less than 10 cm in diameter. In the clinical case example, the dosimetry measured with SPECT ranged from more than 60% underestimate in the largest lesion (28×22 mm in maximal cross-section; 10.2 cc volume) to >99% underestimate in the smallest lesion (4×5 mm; 0.06 cc).
Conclusion: The partial volume effect remains a significant factor when estimating radionuclide uptake in vivo, especially in small volumes. Accurate estimates of absorbed dose from radionuclide therapy will be particularly challenging until robust solutions to correct for the PVE are found.


Main Subjects

  1. Haugen BR, Alexander EK, Bible KC, Doherty GM, Mandel SJ, Nikiforov YE, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid: official journal of the American Thyroid Association. 2016; 26(1):1-133.
  2. Strigari L, Konijnenberg M, Chiesa C, Bardies M, Du Y, Gleisner KS, et al. The evidence base for the use of internal dosimetry in the clinical practice of molecular radiotherapy. Eur J Nucl Med Mol Imaging. 2014; 41(10):1976-88.
  3. Sundlov A, Sjogreen-Gleisner K, Svensson J, Ljungberg M, Olsson T, Bernhardt P, et al. Individualised 177Lu-DOTATATE treatment of neuroendocrine tumours based on kidney dosimetry. Eur J Nucl Med Mol Imaging. 2017; 44(9):1480-9.
  4. Jackson PA, Hofman MS, Hicks RJ, Scalzo M, Violet J. Radiation Dosimetry in (177)Lu-PSMA-617 Therapy Using a Single Posttreatment SPECT/CT Scan: A Novel Methodology to Generate Time- and Tissue-Specific Dose Factors. J Nucl Med. 2020; 61(7):1030-6.
  5. Tran-Gia J, Salas-Ramirez M, Lassmann M. What You See Is Not What You Get: On the Accuracy of Voxel-Based Dosimetry in Molecular Radiotherapy. Journal of Nuclear Medicine. 2020; 61(8):1178-86.
  6. Erlandsson K, Buvat I, Pretorius PH, Thomas BA, Hutton BF. A review of partial volume correction techniques for emission tomography and their applications in neurology, cardiology and oncology. Phys Med Biol. 2012; 57(21):R119-59.
  7. Phelps ME, Mazziotta JC, Shelbert HR. Positron Emission Tomography and Autoradiography. Principles and Applications for the Brain and Heart. New York: Raven Press; 1986.
  8. Hoffman EJ, Huang SC, Phelps ME. Quantitation in positron emission tomography: 1. Effect of object size. J Comput Assist Tomogr. 1979; 3(3):299-308.
  9. Cherry SR, Sorensen JA, Phelps ME. Physics in Nuclear Medicine. 4th ed. Philadelphia, PA: Elsevier Saunders; 2012.
  10. Ryu H, Meikle SR, Willowson KP, Eslick EM, Bailey DL. Performance evaluation of quantitative SPECT/CT using NEMA NU 2 PET methodology. Phys Med Biol. 2019; 64(14):145017.
  11. Bailey DL, Hennessy TM, Willowson KP, Henry EC, Chan DLH, Aslani A, et al. In Vivo Measurement and Characterisation of a Novel Formulation of [177Lu]-Dota-Octreotate. Asia Oceania J Nucl Med Biol. 2015; 4(1):30-7.
  12. Erdi YE, Wessels BW, Loew MH, Erdi AK. Threshold estimation in single photon emission computed tomography and planar imaging for clinical radio-immunotherapy. Cancer Res. 1995; 55(23 Suppl):5823s-6s.
  13. Hellwig D, Graeter TP, Ukena D, Groeschel A, Sybrecht GW, Schaefers HJ, et al. 18F-FDG PET for mediastinal staging of lung cancer: which SUV threshold makes sense? J Nucl Med. 2007; 48(11):1761-6.
  14. Bailey DL, Schembri GP, Willowson KP, Hedt A, Lengyelova E, Harris M. A Novel Theranostic Trial Design Using 64Cu/67Cu with Fully 3D Pre-Treatment Dosimetry. J Nucl Med. 2019; 60(Suppl. 1):204 (Abstract).
  15. Bailey DL, Hennessy TM, Willowson KP, Henry EC, Chan DLH, Roach PJ. In Vivo Quantification of 177Lu with Planar Whole-Body and SPECT/CT Gamma Camera Imaging. Eur J Nucl Med Mol Imag Physics. 2015; 2:20.
  16. Stabin MG, Sparks RB, Crowe E. OLINDA/EXM: the second-generation personal computer software for internal dose assessment in nuclear medicine. J Nucl Med. 2005; 46(6):1023-7.
  17. Cremonesi M, Ferrari M, Bodei L, Tosi G, Paganelli G. Dosimetry in Peptide radionuclide receptor therapy: a review. J Nucl Med. 2006; 47(9):1467-75.
  18. Ardekani BA, Braun M, Hutton BF. Improved quantification with the use of anatomical information in PET image reconstruction. In: Uemura K, Lassen NA, Jones T, Kanno I, editors. Quantification of Brain Function: Tracer Kinetics and Image Analysis in Brain PET: Elsevier; 1993. p. 351-62.
  19. Labbé C, Froment JC, Kennedy A, Ashburner J, Cinotto L. Positron emission tomography metabolic data correction for cortical atrophy using magnetic resonance imaging. Alzheimer Dis & Assoc Disord. 1996; 10(3):141-70.
  20. Vija AH. Introduction to xSPECT* Technology: Evolving Multi-modal SPECT to Become Context-based and Quantitative. Chicago: Siemens Healthcare; 2015.
  21. Duncan I, Ingold N. The clinical value of xSPECT/CT Bone versus SPECT/CT. A prospective comparison of 200 scans. Eur J Hybrid Imaging. 2018; 2(1):4.
  22. Deidda D, Karakatsanis NA, Robson PM, Tsai Y-J, Efthimiou N, Thielemans K, et al. Hybrid PET-MR list-mode kernelized expectation maximization reconstruction. Inverse Prob. 2019; 35(4):044001.
  23. Marquis H, Deidda D, Gillman A, Willowson KP, Gholami Y, Hioki T, et al. Theranostic SPECT reconstruction for improved resolution: application to radionuclide therapy dosimetry. EJNMMI Physics. 2021; 8(1):16.