Magnetic resonance imaging (MRI) is a diagnostic study that makes pictures of organs of the body using magnetic field and radio frequency pulses that can not be felt. The purpose of this study is to determine if a new MR imaging method can help tumor evaluation in head and neck cancer or prostate cancer. The extra images will be obtained using Diffusion-weighted Magnetic Resonance Imaging which provides image contrast through detection of small restrictions in the movement of water molecules. This study may help us provide additional information about the tumor along with the picture of the organ.

Inclusion Criteria:

• Adults aged 18 and over.
• Men and women without regard to ethnic background.
• Patients/Subjects able to give informed consent
• Patients/Subjects whose weight does not exceed 275 lbs.
• Patient with a known or suspected head and neck cancer or prostate cancer scheduled for an MRI scan as part of their routine care --OR--
• Volunteer with no history of the disease in that category.

Exclusion Criteria:

• Patients who are unwilling or unable to undergo MRI including patients with contra-indications to MRI such as the presence of cardiac pacemakers or non-compatible intracranial vascular clips.

The radiologists on the study will identify potential research participants from those patients who are scheduled for MRI examination as part of their routine clinical care.