New technologies have enabled students to become active participants in computational simulations of dynamic and complex systems (called Participatory Simulations), providing a "first-person" perspective on complex systems. However, most existing Participatory Simulations have targeted older children, teens, and adults assuming that such concepts are too challenging for younger age groups. This paper, by contrast, presents a design for a Participatory Simulation, called BeeSim, which makes use of wearable computers and targets young children (7-8 years old) to model the behaviors of honeybee nectar collection. In our preliminary user studies, we found that BeeSim contributed to systems understanding and more easily managed group dynamics.

Objective and Importance: Anosmia is a frequent complication of surgical treatment of olfactory groove meningiomas (OGMs). The loss of olfaction can significantly impact on patient quality of life. We present 3 patients with incidentally discovered small OGMs who were treated with stereotactic radiosurgery (SRS). All patients have had tumor control and have not suffered from olfactory loss. This is the first study to elaborate on the safety of SRS in relation to the first cranial nerve. Clinical Case Presentation: Three women, aged 46, 62 and 52 years, presented with incidentally discovered OGMs. They were all asymptomatic from these tumors and had intact olfaction. Intervention: Two patients received single session SRS, 1 with 2,000 cGy to the 85th percentile line, and the other 1,500 cGy to the 85th percentile line. The third patient chose hypofractionated SRS because she was an employee of the hospital and did not wish her colleagues to see her with a frame. She received 2,600 cGy in five daily fractions. All 3 patients have had tumor control with no complications and remain symptom-free with intact olfaction. Conclusion: SRS provides an excellent treatment alternative for a select group of patients with OGMs who wish to maintain their sense of smell.

INTRODUCTION:For many patients with brain tumors, the ideal management strategy may be a planned subtotal resection followed by stereotactic radiosurgery (SRS). However, intraoperative visual inspection may be an inadequate measure of the amount of residual lesion. Intraoperative MRI (IMRI) may help to ensure that the goals of surgery have been achieved and that the best possible target for SRS remains.PATIENTS AND METHODS:We have operated on 68 patients using the PoleStar N-10 IMRI system (Odin Medical Technologies, Yokne'am, Israel). Benign extraaxial lesions were present in 34 patients. In 12 patients subtotal resection and adjuvant SRS were planned. Diagnoses included 5 pituitary adenomas, 4 meningiomas, 2 vestibular schwannomas, and 1 trigeminal schwannoma. Tumor resection was performed until critical structures (e.g. superior sagittal sinus) were being approached and IMRI demonstrated that the lesion was as small as possible.RESULTS:In 1 patient a surgical resection was completed, while in 11 others the plan for subtotal resection was carried out. One patient with an extensive meningioma was treated with fractionated 3-dimensional conformal fractionated radiation therapy, as her tumor remained too large for SRS. In the remaining 10 patients an ideally small target remained for SRS; 3 patients have been treated so far.CONCLUSIONS:Adjuvant SRS after subtotal tumor resection is an excellent management strategy for many patients with intracranial tumors. IMRI can ensure that the surgical goals have been reached. Future comparison of target volumes, integral volume doses, and patient outcomes are planned.

Functional MRI (magnetic resonance imaging) allows one to noninvasively identify various eloquent cortices in the brain. The integration of cortical activation information into radiosurgical treatment planning may provide an alternative to prevent or minimize radiation damage to eloquent cortex. A novel approach of directly integrating the fMRI (functional magnetic resonance imaging) brain map into treatment planning is proposed. Three brain tumor patients have been studied using this method with motor and/or visual paradigms. Brain activation was demonstrated in eloquent cortex at the precentral gyrus (motor area) and medial occipital lobe (visual area). The activation maps were transferred to a treatment planning workstation, (XKnife), and 3D (three-dimensional) activation maps were generated and co-registered to a 3D CT (computed tomography) anatomical data set, which provided the calibration localizer, for treatment planning. Radiosurgery was designed based on both functional and structural information by the medical team consisting of a radiation oncologist, a neurosurgeon and a physicist. The average maximum dose for the tumor was 2113 cGy. The average maximum dose for tissue surrounding the tumor was 1600 cGy. The average dose with fMRI information to the eloquent cortex was 163.4 cGy over three patients, while without fMRI information it was 240.5 cGy. The average percentage dose reduction over three patients is 32%. The results suggest that using this method can reduce the dose to the eloquent cortex. This approach provides the physician with additional information for treatment planning and may spare the patient unnecessary radiation exposure to adjacent eloquent cortices.

OBJECTIVE:To assess the effect of functional magnetic resonance imaging (fMRI) on stereotactic radiosurgical (SRS) dose planning.METHODS:Patients included those undergoing SRS whose lesions were in or near areas that could be identified with fMRI. After processing, an fMR scan was registered to the anatomic scan, and this dataset was registered to a stereotactic CT scan. The imaged functional areas were contoured along with standard anatomical targets. Dose planning was done at first with the functional volumes rendered invisible; the plans were then adjusted as needed using the functional targets. Doses were measured using a dose-volume histogram tool.RESULTS:SRS was performed in 12 patients, 1 of whom also underwent SRT. Functional volumes studied included motor cortex in 8 patients, visual in 6 and language in 3; a total of 33 functional targets were imaged. Prescription doses ranged from 12 to 22.5 Gy (mean 19.5 Gy), and the maximum dose to functional volumes from 8 cGy to 18.5 Gy (mean 2.9 Gy). In 6 patients, arc adjustment using functional targets yielded a >50% reduction in dose to at least one functional volume; in all patients, the dose reduction to 50 and 75% of functional volumes averaged 4% (12 cGy) and 13% (30 cGy), respectively, while the reduction of maximal dose averaged 24% (50 cGy).CONCLUSIONS:fMRI can be used in SRS to reduce irradiation of eloquent brain using standard prescription doses. Appropriate arc adjustment may allow for escalation of the dose to the targeted lesion.