A clinical gamma camera-based pinhole collimated system for high resolution small animal SPECT imaging

Autor(es)

Mejia, J. ^[1] ; Galvis-Alonso, O. Y. ^[1] ; de Castro, A. A. ^[2] ; Braga, J. ^[3] ; Leite, J. P. ^[4] ; Simoes, M. V. ^[2]

Afiliação do(s) autor(es)

^[1] Fac Med Sao Jose do Rio Preto, Dept Biol Mol, BR-15090000 Sao Jose Do Rio Preto - Brazil

^[2] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Clin Med, Ribeirao Preto, SP - Brazil

^[3] Inst Nacl Pesquisas Espaciais, Div Astrofis, BR-12201 Sao Jose Dos Campos - Brazil

^[4] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Neurociencias & Ciencias Comportamento, Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 43, n. 12, p. 1160-1166, DEC 2010.
• Citações Web of Science: 12

Resumo

The main objective of the present study was to upgrade a clinical gamma camera to obtain high resolution tomographic images of small animal organs. The system is based on a clinical gamma camera to which we have adapted a special-purpose pinhole collimator and a device for positioning and rotating the target based on a computer-controlled step motor. We developed a software tool to reconstruct the target's three-dimensional distribution of emission from a set of planar projections, based on the maximum likelihood algorithm. We present details on the hardware and software implementation. We imaged phantoms and heart and kidneys of rats. When using pinhole collimators, the spatial resolution and sensitivity of the imaging system depend on parameters such as the detector-to-collimator and detector-to-target distances and pinhole diameter. In this study, we reached an object voxel size of 0.6 mm and spatial resolution better than 2.4 and 1.7 mm full width at half maximum when 1.5- and 1.0-mm diameter pinholes were used, respectively. Appropriate sensitivity to study the target of interest was attained in both cases. Additionally, we show that as few as 12 projections are sufficient to attain good quality reconstructions, a result that implies a significant reduction of acquisition time and opens the possibility for radiotracer dynamic studies. In conclusion, a high resolution single photon emission computed tomography (SPECT) system was developed using a commercial clinical gamma camera, allowing the acquisition of detailed volumetric images of small animal organs. This type of system has important implications for research areas such as Cardiology, Neurology or Oncology. (AU)

• Processo FAPESP: 07/58052-5 - Desenvolvimento de instrumentagco e de algoritimos de processamento de dados para a producao de imagens cintilograficas de pequenos animais com resolucao espacial e temporal elevadas.
• Beneficiário: Jorge Mejía Cabeza
• Modalidade de apoio: Bolsas no Brasil - Jovens Pesquisadores
• Processo FAPESP: 07/50339-3 - Desenvolvimento de instrumentação e de algoritmos de processamento de dados para a produção de imagens cintilográficas de pequenos animais com resolução espacial e temporal elevadas
• Beneficiário: Jorge Mejía Cabeza
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 05/56447-7 - Pesquisa através de imagens por ressonância magnética de alto campo destinadas a estudos em humanos
• Beneficiário: João Pereira Leite
• Modalidade de apoio: Auxílio à Pesquisa - Programa CINAPCE - Temático