Functional magnetic resonance imaging aided radiation treatment planning

Abstract

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.

Role of stereotactic radiosurgery and fractionated stereotactic radiotherapy for the treatment of recurrent glioblastoma multiforme

“…Preliminary experience with the definition of biological target volumes using metabolic imaging has resulted in substantial changes in target volumes for the planning of radiation therapy. 13,45 Diffusion tensor imaging, a technique that displays the distribution and abnormalities of white matter fibers resulting from tumor infiltration, has also been included in the treatment planning for gliomas. In one study elongated treatment margins along the paths of increased water diffusion and altered metabolic activity were included in the treatment volume, to some extent creating a model of tumor diffusion.…”

Integration of functional brain information into stereotactic irradiation treatment planning using magnetoencephalography and magnetic resonance axonography

“…Apart from MEG, functional MRI (fMRI) and positron emission tomography (PET) AOYAMA H, et al, 13 is reported to be useful functional imaging modalities and fMRI is used for radiotherapy-treatment planning [14,15]. MEG provides the direct measure of neuronal electric activity.…”

“…They reported that this technique may reduce the risks associated with embolization treatment [13]. A group in New Jersey used fMRI for radiosurgical planning and succeeded at reducing the maximum dose to the functional AOYAMA H, et al, 14 area in three patients in the treatment planning with an average dose reduction of 32% [14,15].…”

“…Recently, imaging modalities that enable the identification of functional brain areas have emerged as clinically significant [8][9][10][11][12][13][14][15][16][17][18]. Magnetoencephalography (MEG) is used AOYAMA H, et al, 5 to detect the magnetic field associated with intracranial neuronal electric activity itself.…”

Clinical applications of imaging biomarkers. Part 3. The neuro-oncologist's perspective

“…They concluded that MRSI would optimise the target volume with the potential to improve local control while reducing complications. Liu et al [9] showed, …”