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- Lindvall, Peter, 1971-
(författare)
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Hypofractionated conformal stereotactic radiotherapy in the treatment of AVMs and cerebral metastases
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hypofractionated conformal stereotactic radiotherapy (HCSRT) has been used for the treatment of AVMs at the Umeå University Hospital since 1986. From this year and onwards an increasing number of patients with single or oligo brain metastases have also been treated using this technique.In paper I we have retrospectively evaluated our treatment results of AVMs in terms of obliteration and complications. The rates of obliteration and complications seem to be comparable with SRS even if the AVM volumes in our series were larger than in most series with SRS. In paper II we have retrospectively evaluated the results in terms of local control, survival and complications in two groups of patients with single or oligo brain metastases. One group was treated with HCSRT alone and the other group was treated with whole brain radiotherapy in combination with a stereotactic boost. Controversy still exists concerning the benefit of additional use of WBRT in combination with stereotactic irradiation. The survival times were equal in the two groups and no significant difference in local control was observed. The omission of WBRT seems to carry a higher risk for development new brain metastases distant from the irradiated area. In paper III we report the treatment results in a subgroup of AVMs treated with a combination of embolisation and HCSRT. We also focus on the reduction of vascular density within the nidus of an AVM and propose a method to digitally compare images and more objectively assess a reduction in vascular density following embolisation. Obliteration rates seem comparable with other series using a combination of SRS and embolisation even if our rate of complications was higher than what is usually reported. Using luminescence as measure of vascular density all AVMs seemed to be less dense after embolisation.Treatment accuracy in terms of reproducibility of the isocenter in consecutive treatment sessions is crucial in fractionated radiotherapy. In paper IV we have radiologically evaluated the reproducibility of the isocenter in successive treatment sessions using the non invasive relocatable Fixster frame. There was a high degree of reproducibility and only small errors that most likely is of no clinical importance.A reliable dose plan is equally important as a tool to predict the dose delivered inside and outside the target volume. In paper V we have evaluated the reliability of treatment plans in HCSRT for targets of different geometry and size. A liquid ion chamber and gel dosimeter was used for assessment of dose distribution and absorbed dose. The doseplanning system proved to be accurate in predicting the absorbed dose and dose distribution for the different targets.
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- Ribom, Dan, et al.
(författare)
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Positron emission tomography 11C-methionine and survival in patients with low-grade gliomas
- 2001
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Ingår i: Cancer. - 0008-543X .- 1097-0142. ; 92:6, s. 1541-1549
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUNDConsiderable numbers of patients with low-grade gliomas experience an early malignant course and may benefit from aggressive treatment. These patients are difficult to identify using established prognostic factors. A retrospective study was performed to determine whether the 11C-methionine uptake in tumor is a survival factor in adult patients with supratentorial gliomas classified as World Health Organization Grade 2.METHODSThe authors identified 89 patients with histologically confirmed low-grade gliomas in whom an 11C-methionine positron emission tomography (PET) scan had been performed as part of the diagnostic tumor investigation from 1983 to 1998. Clinical data were collected, and the PET scans were re-evaluated according to a fixed protocol. The 11C-methionine uptake in the tumor and relevant clinical parameters were entered into univariate and multivariate survival analyses.RESULTSAt the end of the study, 49 patients (55.1%) had died. The median overall survival was 5.7 years. Low methionine uptake was significantly favorable in the multivariate survival analysis (P = 0.04) along with oligodendroglioma (P = 0.003). In the histologic subgroups, 11C-methionine uptake was an important survival factor among patients with astrocytomas (P = 0.05) and oligodendrogliomas (P = 0.03). Tumor resection was a favorable prognostic factor in patients with high methionine uptake (P = 0.01) but not in patients with low uptake.CONCLUSIONSBaseline 11C-methionine PET is a prognostic indicator in patients with low-grade gliomas. The results imply that PET is a valuable tool in the clinical management of these patients and may assist in the selection of patients for therapy.
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- Ronne-Engström, Elisabeth, et al.
(författare)
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Patients with spontaneous subarachnoid haemorrhage : presentation of a 10-year hospital series
- 2009
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Ingår i: British Journal of Neurosurgery. - : Informa UK Limited. - 0268-8697 .- 1360-046X. ; 23:5, s. 499-506
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Tidskriftsartikel (refereegranskat)abstract
- In this study we present the population-based patient material with spontaneous SAH, treated in our Neurosurgical unit during the 10 years (1997-2006) after the introduction of endovascular treatment of aneurysms (EVT) in our hospital. All patients that had a spontaneous SAH and a potential to survive were admitted. The present study comprises 1471 patients. 72 % had one or more aneurysms. AVM or other vascular pathological findings where found in 2%. Angiography was judged as normal in 21% and was not performed in 5%. 664 of the patients with aneurysms were treated by endovascular means, 333 were operated and 31 were treated with both methods. Thirty-five received no treatment. The main difference in admission parameters between the coiled and clipped aneurysms was the location of the aneurysm, with posterior circulation aneurysm exclusively being coiled and MCA aneurysms mainly clipped. The highest 6-month mortality for aneurysms presented in the untreated group (71.4%), and the lowest (3.2%) in the group treated with both clip and coil. Six-month mortality was 3.5% for the patients with a normal angiography. Of these, no one with Fisher grade 1 and 2/120 patients with Fisher 2 died. The mortality was high (89%) for those patients where angiography was not performed. The present patient group was compared to an earlier published a 12-year patient series from our clinic. The patients with aneurysmal SAH in the present series were older and had a lower 6-month mortality in our material compared to the published data from our clinic from 1981-1992. More patients were admitted in a good clinical condition in the present series, but there was also a higher proportion of patients from the worst clinical groups. The percentage of aneurysms treated had increased from 80% to 97% after EVT was introduced.
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| 5. |
- Zhao, Q, et al.
(författare)
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Conjugate chemistry, iodination and cellular binding of mEGF-dextran-tyrosine: preclinical tests in preparation for clinicaltrials
- 1998
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Ingår i: International Journal of Molecular Medicine. - : Spandidos Publications. - 1107-3756 .- 1791-244X. ; 1:4, s. 693-702
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Tidskriftsartikel (refereegranskat)abstract
- A conjugate with specific binding to the epidermal growth factor receptor, EGFR, and of interest for clinical tests was prepared using mouse epidermal growth factor, mEGF, and dextran. The mEGF was first coupled to dextran by reductive amination in which the free amino group on the N-terminal of mEGF was reacted with the aldehyde group on the reductive end of the dextran chain. The end-end coupled intermediate was further activated by the cyanopyridinium agent CDAP and tyrosines introduced to the dextran part of the conjugate. The mEGF-dextran-tyrosine conjugate was, with high efficiency, iodinated with the chloramine-T method. Approximately 25-35% of the radioactivity could be removed from the conjugate after exposure to protease K while 65-75% of the radioactivity could be removed after exposure to dextranase. Thus, the largest amount of the iodine was on the dextran part of the conjugate. The iodinated mEGF-dextran-tyrosine had EGFR specific binding since the binding to an EGFR rich human glioma cell line could be displaced by an excess of non-radioactive mEGF. The conjugate was to a large extent internalized in these cells and the administrated radioactivity was thereby retained inside the cells for at least up to 50 h.
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