The place of interstitial brachytherapy and radiosurgery for low-grade gliomas.

Even though stereotactic brachytherapy has been used for treatment of complex located low-grade glioma for many years, its place within modern treatment concepts is still debated and only a few centers have gained experience with this complex treatment modality. The current article reviews selection criteria, treatment protocols, radiobiology, treatment effects, risk models and side effects of stereotactic brachytherapy. Potentially alternative techniques such as radiosurgery were also reviewed under consideration of radiobiological similarities and differences.

Surgical resection plus stereotactic 125I brachytherapy in adult patients with eloquently located supratentorial WHO grade II glioma - feasibility and outcome of a combined local treatment concept.

OBJECTIVE: The current pilot study analyzed feasibility, risk and effectiveness of 1) microsurgery plus stereotactic iodine-125 ((125)I) brachytherapy (SBT) for large (diameter > 4 cm), circumscribed, and complex located WHO grade II glioma and 2) SBT alone for small (diameter < 4 cm), and complex located recurrences. METHODS: Lowactivity temporary (125)I seeds were used. The applied reference dose was 54 Gy and the dose rate was low (median, 10 cGy/h). Time to progression and time to additional external beam radiation (EBR) and/or chemotherapy were estimated with the Kaplan-Meier method. Any adverse sequel potentially attributable to treatment was classified as morbidity. Treatment effects of SBT were estimated according to the modified MacDonald criteria. RESULTS: Thirtyone patients (de novo group: n = 18, recurrence group: n = 13) were included. The median tumor volume before surgery was 66 ml. A planned partial tumor resection achieved eligibility for SBT in all patients. Transient morbidity of microsurgery and SBT was 27.8 % and 6.4 %, respectively. There was no permanent morbidity. Radiogenic complications did not occur. Complete response, partial response, and stable disease were seen in 8, 9, and 14 patients, respectively. Ten patients exhibited tumor progression (overall 5-year progression- free survival > 60 %). The 5-year probability to receive chemotherapy and/or EBR was 18 %. CONCLUSION: A planned partial tumor resection of large and complex located WHO grade II glioma is safe. SBT of small and complex located residual of recurrent tumors is safe and minimally invasive. Combined treatment may provide the possibility to withhold EBR and/or chemotherapy for a considerable number of patients and deserves further prospective evaluation.

Interstitial iodine-125 radiosurgery alone or in combination with microsurgery for pediatric patients with eloquently located low-grade glioma: a pilot study.

PURPOSE: The optimal therapeutic management of children with World Health Organization grade I and II gliomas not accessible to complete resection is poorly defined. Radical surgical resection is the first-line treatment for large hemispheric tumors, whereas interstitial iodine-125 radiosurgery (IRS) might be an attractive treatment concept for selected patients with small (tumor diameter in the range of 4 cm) and circumscribed tumors in any location of the brain. Precise high-dose application, maximal sparing of surrounding normal tissue, and the absence of long-term complications have been reported to be the hallmark of IRS. Therefore, the therapeutic impact and the risk of IRS alone or in combination with microsurgery (in case of larger tumor volumes) were prospectively examined. METHODS: Seven boys and four girls were included (mean age, 6.8 years; range, 11 months to 16 years). IRS (after stereotactic biopsy) was considered to be indicated for circumscribed tumors with a diameter in the range of 4 cm (four cases). For larger tumors, a combined microsurgical/radiosurgical approach was preferred (seven patients). Temporary iodine-125 seeds were used exclusively (tumor dose calculated to the boundary, 54 Gy; dose rate, 10 cGy/h). Tumor location was hypothalamic/suprasellar in four, lobar in three, deep (thalamus and pineal gland) in two, and within the brain stem in two children. Treatment effects of IRS were estimated according to the MacDonald criteria. RESULTS: A complete response after IRS was seen in four patients, and a partial response was seen in seven patients (median follow-up, 31.5 months). There was no perioperative morbidity after microsurgery and/or IRS, and no radiogenic complications occurred during the follow-up period. Five patients experienced an improvement in their deficits, and no deterioration in neurological/endocrine function was seen in any of the patients at the time of last follow-up evaluation. CONCLUSION: IRS alone or in combination with microsurgery (in the case of larger tumors) is a safe, effective, and minimally invasive treatment strategy for eloquently located pediatric low-grade gliomas and deserves further prospective evaluation.

Types and tokens in transsaccadic object identification: effects of spatial position and left-right orientation.

What types of representations support our ability to integrate information acquired during one eye fixation with information acquired during the next fixation? In Experiment 1, transsaccadic integration was explored by manipulating whether or not the relative position of a picture of an object was maintained across a saccade. In Experiment 2, the degree to which visual details of a picture are coded in a position-specific representational system was explored by manipulating whether or not both the relative position and the left-right orientation of the picture were maintained across a saccade. Position-specific and nonspecific preview benefits were observed in both experiments. Only the position-specific benefits were influenced by the number of task-relevant pictures presented in the preview display (Experiment 1) and the left-right orientation of the picture presented in the preview display (Experiment 2). The results support a model of transsaccadic integration based on two independent representational systems. One system codes abstract, prestored object types, and the other codes episodic tokens consisting of stimulus properties linked to scene- or configuration-based position markers.

Monitoring of blood-10B concentration for boron neutron capture therapy using prompt gamma-ray analysis.

The aim of the present study was to monitor the blood-10B concentration of laboratory dogs receiving boron neutron capture therapy, in order to obtain optimal agreement between prescribed and actual dose. A prompt gamma-ray analysis system was developed for this purpose at the High Flux Reactor in Petten. The technique was compared with inductively coupled plasma-atomic emission spectrometry and showed good agreement. A substantial variation in 10B clearance pattern after administration of borocaptate sodium was found between the different dogs. Consequently, the irradiation commencement was adjusted to the individually determined boron elimination curve. Mean blood-10B concentrations during irradiation of 25.8 +/- 2.2 micrograms/g (1 SD, n = 18) and 49.3 +/- 5.3 micrograms/g (1 SD, n = 17) were obtained for intended concentrations of 25 micrograms/g and 50 micrograms/g, respectively. These variations are a factor of two smaller than irradiations performed at a uniform post-infusion irradiation starting time. Such a careful blood-10B monitoring procedure is a prerequisite for accurately obtaining such steep dose-response curves as observed during the dog study.

HLA B27 positive helicopter pilot with reactive arthritis responsive to sulfasalazine.

An aviator with prolonged right sided low back pain is described. The diagnostic workup is presented leading to diagnosis of HLA B27 positive reactive sacroiliitis. Trial of sulfasalazine lead to resolution of his pain. The spondylarthropathies are briefly reviewed. Implications on his aeromedical status are discussed.