الفهرس Only 14 pages are availabe for public view
 |  | from | 181 |  |  |
| | | from | 181 | | |
Abstract
In adults, brain tumors account for approximately 2% of all malignant tumors. Primary brain tumors continue to be among the top 10 causes of cancer-related death in the United States, despite a comparatively low incidence to other cancers.
Treatment of malignant brain tumors usually consists of a combination of a surgery and radiation therapy followed by adjuvant chemotherapy.
Monitoring treatment after therapy is very crucial so as to discontinue ineffective treatment and apply alternative therapies if the treatment is found to be resistant to the first line of therapies.
The current gold standard, conventional MRI, provides superior structural detail but poor specificity in identifying viable tumors in brain treated with surgery, radiation or chemotherapy. Besides, monitoring of response using conventional anatomical methods depends on changes occurring in tumor volume that may occur late in the course of therapy.
The radiologist’s major challenge is to differentiate residual or recurrent tumor from post-radiation necrosis.
Physiological imaging techniques, which can potentially differentiate neoplastic from non-neoplastic brain tissue based on functional rather than purely anatomic or structural parameters, have become an important area of investigation. These ”functional” imaging modalities include not only the nuclear medicine methodologies such as positron-emission tomography (PET) and single-photon-emission computed tomography (SPECT), but also functional MRI methods such as MR spectroscopy, diffusion-weighted imaging and MR perfusion techniques.