Background:T-cell responses contribute to the anti-tumoural effect of photodynamic therapy (PDT). For such responses to occur, dendritic cells (DCs) have to migrate to the tumour, take up tumour antigens and respond to danger signals with maturation, before they engage in T-cell activation. Here, we have studied the effect of 5-aminolevulinic acid (ALA)-mediated PDT on DCs in vitro in a human spheroid model of glioblastoma (GB).Methods:Spheroids of the GB cell lines U87 and U251 were treated with ALA/PDT, and effects on attraction, uptake of tumour antigens and maturation of DCs were studied. To block heat-shock protein-70 (HSP-70) on the spheroids, neutralising antibodies were used.Results:5-Aminolevulinic acid /PDT-treated GB spheroids attracted DCs that acquired tumour antigens from the spheroids effectively. Moreover, co-culture with ALA/PDT-treated spheroids induced DC maturation as indicated by the upregulation of CD83 and co-stimulatory molecules as well as increased T-cell stimulatory activity of the DCs. Heat-shock protein-70 was upregulated on the spheroids after ALA/PDT treatment. Uptake of tumour antigens and DC maturation induced by the ALA/PDT-treated spheroids were inhibited when HSP-70 was blocked.Conclusion:ALA/PDT treatment of glioma spheroids promotes the three initial steps of the afferent phase of adaptive immunity, which is at least partially mediated by HSP-70.

Stereotactic radiosurgery is related to the history of "radiotherapy" and "stereotactic neurosurgery". The concepts for neurosurgeons and radiooncologists have been changed during the last decade and have also transformed neurosurgery. The gamma knife and the stereotactically modified linear accelerator (LINAC) are radiosurgical equipments to treat predetermined intracranial targets through the intact skull without damaging the surrounding normal brain tissue. These technical developments allow a more precise intracranial lesion control and offer even more conformal dose plans for irregularly shaped lesions. Histological determination by stereotactic biopsy remains the basis for any otherwise undefined intracranial lesion. As a minimal approach, it allows functional preservation, low risk and high sensitivity. Long-term results have been published for various indications. The impact of radiosurgery is presented for the management of gliomas, metastases, brain stem lesions, benign tumours and vascular malformations and selected functional disorders such as trigeminal neuralgia. In AVM's it can be performed as part of a multimodality strategy including resection or endovascular embolisation. Finally, the technological advances in radiation oncology as well as stereotactic neurosurgery have led to significant improvements in radiosurgical treatment opportunities. Novel indications are currently under investigation. The combination of both, the neurosurgical and the radiooncological expertise, will help to minimize the risk for the patient while achieving a greater treatment success.

Background and purposePatients with internal carotid artery (ICA) occlusion can demonstrate impaired cerebral vascular reserve (CVR). The detection of CVR using single photon emission CT (SPECT) is nowadays widely accepted as a predictor in the diagnostic pathway in patients considered for cerebral revascularization. Recently perfusion CT (PCT) gained widely acceptance in stroke imaging The present study was aimed at comparing the results of perfusion CT (PCT) and 99mTc-HMPAO SPECT with acetazolamide challenge in patients with ICA occlusion.Methods13 patients were included in the prospective evaluation. Both PCT and 99mTc-HMPAO SPECT were performed before and after the administration of acetazolamide. In detail, regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), adapted time to peak (Tmax) and mean transit times (MTT) were compared with SPECT data.Results99mTc-HMPAO SPECT demonstrated an impairment of CVR in six patients. A preserved CVR was present in seven patients. All patients with impaired CVR proven by SPECT had a delayed MTT (mean +2.98 s) and a delayed Tmax (mean + 5.9 s), (both p < 0.005 compared with the non occluded side). 66% of patients with impaired CVR in SPECT showed a complete correlation of Tmax measurements in PCT with a high positive predictive value (PPV: 88.8%).ConclusionThe prospective study demonstrated a highly significant correlation of perfusion parameters as' detected by 99mTc-HMPAO SPECT and the Tmax as detected by PCT in patients with ICA occlusion. Therefore this easy-to-perform technique seems to be an adequate method for the evaluation of cerebral perfusion in patients with ICA occlusion.

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