The purpose of this study is to test whether or not a new contrast agent called Combidex, a contrast agent formulated from ultra-small superparamagnetic iron oxide (USPIO) improves the ability of Magnetic Resonance Imaging (MRI) to see lymph nodes in the pelvis. It might also help doctors tell whether or not cancer has spread to these lymph nodes. It might allow radiotherapy to be delivered more accurately.

Inclusion Criteria:

• histologically confirmed endometrial, cervix, prostate (cT1-cT3) or bladder cancer
• no distant metastases
• informed consent

Exclusion Criteria:

• confirmed prostate carcinoma and PSA less than or equal to 4 or greater than 100
• radical surgery or prior cryosurgery for prostate carcinoma, previous RT, hormonal manipulation or chemotherapy
• biopsy-proven lymph node involvement
• endometrium or cervix carcinoma who have undergone recent pelvic surgery with the exclusion of D&C or biopsy
• bladder carcinoma with recent pelvic surgery with the exclusion of TURBT
• previous or concurrent cancers other than superficial basal or squamous cell skin carcinoma unless disease-free for at least 5 yrs
• contraindication to MR imaging
• hip prosthesis
• major medical or psychiatric illness
• patients with known allergy to dextran or iron-containing compounds
• patients with cirrhosis or hemochromatosis
• patients receiving another MR contrast within 2 hrs prior to the ferumoxtran-10