 The first phase of study Stage I will use FI coregistered with pMR, iUS and iSV images to test the overall hypothesis that there is a high degree of spatial correlation between local tissue FI signal and coregistered conventional imaging and corresponding histopathology. Additionally, coregistered probe measurements and biopsy specimens will be acquired intraoperatively. Biopsy specimens will be processed post-operatively via fluorescence microscopy and chemical spectrofluorimetry to assess PpIX concentration which will allow direct comparisons of FI signal strength with PpIX production based on both in vivo probe data and ex vivo histological quantification as a function of histological grade. The study protocol is outlined below. Because of the overall interest and importance of relating this data to the existing body of literature and the excellent safety record of oral administration of ALA reported in these trials 1, 33-36, we will use the same dosetime schedule described in 1, 33. The operative procedures will follow existing practice at Dartmouth for image-guided resection of meningiomas, pituitary adenomas and metastases with additional acquisition of FI and biopsy data at predefined time points that are related to the expected volume of tumor tissue. In this first phase of the study, resection decisions will not be made based on FI data alone. Should residual fluorescence remain after the intended resection volume has been removed further excisions will require biopsy confirmation in the OR. It is anticipated that 234 patients will be enrolled in Stage I. 