HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tang, H. R. Articles by Hasegawa, B. H. Search for Related Content PubMed PubMed Citation Articles by Tang, H. R. Articles by Hasegawa, B. H.

Neuroblastoma Imaging Using a Combined CT Scanner–Scintillation Camera and ¹³¹I-MIBG

Departments of Radiology and Pediatrics, University of California, San Francisco, California

High-dose administration of ¹³¹I-metaiodobenzylguanidine (¹³¹I-MIBG) continues to be a promising treatment for neuroblastoma. However, currently used methods of estimating ¹³¹I-MIBG uptake in vivo may be too inaccurate to properly monitor patient radiation exposure doses. To improve localization and uptake measurements over currently practiced techniques, we evaluated different methodologies that take advantage of the correlated patient data available from a combined CT–scintillation camera imaging system. Methods: Serial CT and radionuclide scans of three patients were obtained on a combined imaging system. SPECT images were reconstructed using both filtered backprojection and maximum-likelihood expectation maximization (MLEM). Volumes of interest (VOIs) were defined on anatomic images and automatically correlated to spatial volumes in reconstructed SPECT images. Several radionuclide quantification methods were then compared. First, the mean reconstructed values within coregistered SPECT VOIs were estimated from MLEM reconstructed images. Next, we assumed that reconstructed activity in SPECT voxels were linear combinations of activities present in individual objects, weighted by geometric factors derived from CT images. After calculating the weight factors by modeling the SPECT imaging process with anatomically defined VOIs, least-squares fitting was used to estimate the activities within lesion volumes. We also estimated the lesion activities directly from planar radionuclide images of the patients using similar linearity assumptions. Finally, for comparison, lesion activities were estimated using a standard conjugate view method. Results: Activities were quantified from three patients having a total of six lesions with volumes ranging from 0.67 to 117 mL. Methods that used CT data to quantify lesion activities gave similar results for planar and tomographic radionuclide data. Estimating activity directly from mean VOI values in MLEM-reconstructed images alone consistently provided estimates lower than CT-aided methods because of the limited spatial resolution of SPECT. Values obtained with conjugate views produced differences up to fivefold in comparison with CT-aided methods. Conclusion: These results show that anatomic information available from coregistered CT images may improve in vivo localization and measurement of ¹³¹I-MIBG uptake in tumors.

Key Words: correlated imaging • combined imaging system • absolute quantitation • SPECT • ¹³¹I-MIBG

This article has been cited by other articles:

				B.-K. Teo, Y. Seo, S. L. Bacharach, J. A. Carrasquillo, S. K. Libutti, H. Shukla, B. H. Hasegawa, R. A. Hawkins, and B. L. Franc Partial-Volume Correction in PET: Validation of an Iterative Postreconstruction Method with Phantom and Patient Data J. Nucl. Med., May 1, 2007; 48(5): 802 - 810. [Abstract] [Full Text] [PDF]

				H. Zaidi and B. Hasegawa Determination of the Attenuation Map in Emission Tomography J. Nucl. Med., February 1, 2003; 44(2): 291 - 315. [Abstract] [Full Text] [PDF]

				K. K. Matthay, C. Panina, J. Huberty, D. Price, D. V. Glidden, H. R. Tang, R. A. Hawkins, J. Veatch, and B. Hasegawa Correlation of Tumor and Whole-Body Dosimetry with Tumor Response and Toxicity in Refractory Neuroblastoma Treated with 131I-MIBG J. Nucl. Med., November 1, 2001; 42(11): 1713 - 1721. [Abstract] [Full Text] [PDF]