Gamma probe-assisted brain tumor microsurgical resection: a new technique

Abstract

-Objectives: The pioneering performance of gamma probe-assisted surgery (GPAS) for brain tumors, aiming not only an improvement of tumor detection, but mainly assurance of its complete removal and the study of the usual distribution of the 99m Tc-MIBI in the brain SPECT of normal individuals. Method: Patient's informed consent and demonstration of the tumor by the preoperative MIBI SPECT were the inclusion criteria adopted for GPAS, which was performed in one patient with a right parietal lobe metastatic tumor. The radiotracer ( 99m Tc-MIBI) was injected in a peripheral vein 5 hours before the operation. A tumor to-normal tissue count ratio equal to or greater than 2/1 was considered indicative of tumor. MIBI SPECT was performed in five normal individuals in a pilot study. Results: The gamma probe greatly facilitated intraoperative tumor detection (tumor to-normal brain count ratio was 5/1) and indicated a small piece of residual tumor after what was thought to be a complete tumor removal, allowing its resection, which, otherwise, would have been left behind. Postoperative CT confirmed complete tumor resection. The MIBI SPECT in normal individuals showed an increased uptake by the hypophisis, choroid plexus, skull, scalp and salivary glands and absence of uptake by the normal brain tissue. There were no complications. Conclusion: GPAS proved to be, in this single case, a safe and reliable technique to improve brain tumor detection and to confirm the presence or absence of residual tumor.KEY WORDS: radioguided surgery, gamma probe, gamma probe-assisted surgery, 99m Tc-MIBI, SPECT, brain tumor, brain neoplasm.Ressecção microcirúrgica de tumor cerebral assistida por detector gama: uma nova técnica RESUMO -Objetivos: A realização pioneira de cirurgia assistida por detector gama (CADG) para tumores cerebrais, objetivando-se não apenas a identificação do tumor, mas, sobretudo, assegurar-se quanto à sua completa ressecção e estudar a distribuição usual do 99m Tc-MIBI no SPECT cerebral de indivíduos normais. Método: O consentimento informado do paciente e a demonstração do tumor pelo SPECT pré-operatório com MIBI foram os critérios de inclusão adotados para a CADG, a qual foi realizada em um paciente com metástase para lobo parietal direito. O radiotraçador ( 99m Tc-MIBI) foi injetado em uma veia periférica 5 horas antes da cirurgia. Uma relação ≥ 2/1 entre a radiação gama emitida pelo tumor e pelo tecido normal foi considerada como indicativa de presença tumoral. Em um estudo piloto, SPECT cerebral com MIBI foi realizado em cinco pacientes normais. Resultados: O detector gama em muito facilitou a detecção per-operatória do tumor e demonstrou a presença de um pequeno resíduo tumoral após o que se pensou tratar-se de uma completa ressecção; tal resíduo, de outro modo, não teria sido percebido, o que teria impossibilitado sua exérese. Tomografia computorizada pós-operatória confirmou a completa ressecção do tumor. O SPECT com MIBI de indivíduos normais mostrou sua captação pela hipófise, plexo coróide, crânio, co...

The value of gamma probe in the detection of epileptogenic focus

“…In neurosurgery, the utilization of such a method is more recent (4,5) . As the radiotracer remains concentrated in the abnormal area for several hours (up to ten hours), it may be intravenously injected before the surgical procedure and, during the surgery, the gamma probe detects the abnormal activity.…”

A comprehensive overview of radioguided surgery using gamma detection probe technology

“…Radioguided surgical resection of brain tumors has been investigated in a very limited fashion [ 723 - 727 ]. In 2002, Vilela Filho and Carneiro Filho [ 723 ] first described use of 99m Tc-MIBI, in a dose of 30 mCi (1110 MBq), for gamma probe-assisted resection of a metastatic renal cell carcinoma to the right parietal lobe.…”

“…Radioguided surgical resection of brain tumors has been investigated in a very limited fashion [ 723 - 727 ]. In 2002, Vilela Filho and Carneiro Filho [ 723 ] first described use of 99m Tc-MIBI, in a dose of 30 mCi (1110 MBq), for gamma probe-assisted resection of a metastatic renal cell carcinoma to the right parietal lobe. In 2004, Kojima et al [ 724 ] reported on the use of 99m Tc-MIBI, in an unknown dose, for gamma probe-assisted resection in 13 patients with either primary or recurrent astrocytomas or metastatic brain lesions.…”

A new method for intraoperative localization of epilepsy focus by means of a gamma probe

“…The use of gamma probe in brain surgery that is known as gamma probe-assisted surgery was first introduced into the clinical practice to guide the resection of brain tumors (8) . Considering that ictal brain SPECT can detect EFs and that the radiotracer remains in the abnormal cortical area for many hours, the authors have considered the hypothesis that the gamma probe might allow the intraoperative identification of the origination point of the epileptic seizures ( Figure 1) .…”