Radiosurgery with the Gamma Knife was performed in 12 patients with parkinsonism. In 9 patients small lesions were created in the head of the caudate nucleus bilaterally. Two patients underwent radiosurgical thalamotomy, and 1 patient was treated with caudatotomy and thalamotomy. After a follow-up period of 1–12 months, 9 patients of the caudatotomy group and all patients with thalamotomies showed clear benefit. There was no complication or side effect that could be related to the treatment. Pre- and postoperative testing was performed with the Unified Parkinson Rating Scale and with objective motor tasks. Caudatotomy proved to be an effective treatment for bradykinesia and rigidity, while tremor was ameliorated by thalamotomy. Functional neurosurgery with the Gamma Knife would seem to be a good alternative to open procedures with low morbidity and no mortality. Advantages and drawbacks of radiosurgical techniques for the treatment of parkinsonism are discussed.
The radiobiologic changes induced by cobalt-60 gamma irradiation in cerebral arteriovenous malformations (AVMs) is a torpid process. Complete obliteration may take 1 or 2 years or even longer. Neuroradiological modalities like magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) do not provide sufficient information to comprehend this process. Digital subtraction angiography represents an invasive method and is therefore most often performed when complete obliteration is expected. The purpose of this study was to investigate the value of blood pool scintigraphy and functional imaging, such as single photon emission computed tomography (SPECT), to gain more knowledge about the volumetric changes of AVMs treated by radiosurgery. Twenty consecutive candidates for Gamma Knife treatment were selected for comparative MRI/ MRA and scintigraphic studies. All lesions ranging from 0.6 to 18.6 cm3 could be identified on blood pool and SPECT images. Seven patients had repetitive examinations at 3-month intervals to compare the relative volumetric change of the lesion. In 5 cases, a marked decrease in blood pooling was noticed after 3 months, and in 2 patients no significant change was evident. In contrast, MRI/MRA scans done at the same time did not similarly indicate progressive obliteration changes. This preliminary result indicates that scintigraphic evaluation using the blood pool technique is a very sensitive method to describe the relative volumetric change of radiosurgically treated AVMs.
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