Eur J Nucl Med Mol Imaging (2010) 37:1616 DOI 10.1007/s00259-010-1487-0
LETTER TO THE EDITOR
Our experience in thymic hyperplasia using 111 In-pentetreotide and 201Tl-chloride
67
Ga-citrate,
Pier Francesco Rambaldi & Vincenzo Cuccurullo & Giuseppe Lucio Cascini & Luigi Mansi
Received: 20 April 2010 / Accepted: 25 April 2010 / Published online: 27 May 2010 # Springer-Verlag 2010
Dear Sir, We read with great interest the paper “Time-dependent changes in 18F-FDG activity in the thymus and bone marrow following combination chemotherapy in paediatric patients with lymphoma” by Goethals et al. recently published in the European Journal of Nuclear Medicine and Molecular Imaging [1]. The reason was due to the opportunity to report our research in the field, using different radiotracers with respect to 18F-fluorodeoxyglucose (FDG), presented at international congresses almost 15 years ago, but never published in peer-reviewed journals [2, 3]. In our experience in the 1990s we evaluated a series of paediatric patients after treatment for lymphoma using 67Ga scintigraphy. In seven of them, an intense 67Ga mediastinal uptake was observed without evidence of other pathological locations. In this restricted population we also performed, on different days, 111In-pentetreotide (OCT) scintigraphy, at 4 and 24 h after injection, and using 201Tl-chloride, 15 min after i.v. administration. At OCT imaging, a slight diffuse thymic uptake was observed at 4 h, more evident at 24 h, although a decrease in target to non-target ratio was noted.
P. F. Rambaldi : V. Cuccurullo : L. Mansi (*) U.O.C. Nuclear Medicine, Second University of Naples, P.zza Miraglia 2, 80138 Naples, Italy e-mail:
[email protected] G. L. Cascini Nuclear Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
No uptake was seen in all of the patients undergoing 201Tl imaging. Also on the basis of the clinical pattern, a diagnosis of thymic hyperplasia was defined, avoiding mediastinoscopy and biopsy. All of the seven children were alive and free of disease over a period ranging between 29 and 55 months after the study. Therefore, since the OCT uptake is not easily differentiable with respect to lymphoma lesions, we concluded that 201Tl was the best radiotracer for a differential diagnosis of thymic hyperplasia with respect to recurrence or residual disease in patients with lymphoma [3]. This conclusion was further stressed as the best choice, also in the presence of availability of a PET centre, considering false-positive results obtained with FDG, showing uptake both in lymphoma and in thymic hyperplasia, as also reported in the article by Goethals et al. [1].
References 1. Goethals I, Hoste P, De Vriendt C, Smeets P, Verlooy J, Ham H. Time-dependent changes in 18F-FDG activity in the thymus and bone marrow following combination chemotherapy in paediatric patients with lymphoma. Eur J Nucl Med Mol Imaging 2010;37 (3):462–7. 2. Mansi L, Rambaldi PF, Casale F, Masone M, Indolfi P, Murano A, et al. In-111 pentetreotide and Ga-67 citrate uptake in benign thymic hyperplasia after chemotherapy in children with lymphoma. J Nucl Med 1996;37:256P. 3. Rambaldi PF, Cascini GL, Casale F, Murano A, Fallanca F, Indolfi P, et al. In111 OCT and TL201 scintigraphy in thymic rebound after chemotheraphy in children with lymphoma. Eur J Nucl Med 1998;25:OS-50P.
