The usefulness of fully three-dimensional OSEM algorithm on lymph node metastases from lung cancer with 18F-FDG PET/CT

Ann Nucl Med. 2011 May;25(4):277-87. doi: 10.1007/s12149-010-0462-y. Epub 2011 Jan 15.


Objective: This work assessed the usefulness of fully three-dimensional ordered subset expectation maximization (3D-OSEM) algorithm for lymph node (LN) metastases from lung cancer. 3D-OSEM images were evaluated by comparing them with those reconstructed by conventional algorithms, such as conventional OSEM algorithm (2D-OSEM) for 2D acquisition and Fourier rebinning plus conventional OSEM algorithm (FORE + OSEM) for 3D acquisition.

Materials and methods: In a phantom study, the contrast ratio, the image noise and the signal-to-noise ratio (SNR) were calculated, and the detectability and the image quality of these images were visually evaluated. In a clinical study, 14 patients suffering from lung cancer with LN metastases were evaluated. The image quality and the malignancy, and the detectability were visually evaluated.

Results: The contrast ratio was significantly improved using 3D-OSEM as compared with FORE + OSEM, and it was similar to 2D-OSEM. The image noise and SNR in 3D-OSEM images were significantly improved compared with those by other algorithms (p < 0.001). In the visual assessment, the image quality was significantly improved in 3D-OSEM images compared with those by 2D-OSEM and FORE + OSEM (p < 0.001, p = 0.001, respectively). In the clinical study, the image quality and the detectability of LN metastases were improved in 3D-OSEM images compared with those by FORE + OSEM (p < 0.001, p = 0.006, respectively), and image quality and detectability were similar to those of 2D-OSEM images.

Conclusions: 3D-OSEM algorithm successfully improved the diagnostic accuracy of LN metastases in 3D-PET tests.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Algorithms*
  • Female
  • Fluorodeoxyglucose F18*
  • Humans
  • Imaging, Three-Dimensional*
  • Lung Neoplasms / diagnosis*
  • Lung Neoplasms / diagnostic imaging
  • Lung Neoplasms / pathology*
  • Lymphatic Metastasis
  • Male
  • Middle Aged
  • Phantoms, Imaging
  • Positron-Emission Tomography*
  • Retrospective Studies
  • Tomography, X-Ray Computed*


  • Fluorodeoxyglucose F18