The goal of this clinical research study is to use CT scans to find any changes in position of the vagina and pelvic lymph node areas during the course of IMRT radiation therapy. Treatment can then be adjusted in order to "spare" as much normal tissue as possible during radiation therapy. Another goal is to study the side effects of IMRT radiation therapy.

The standard radiotherapy technique for delivering radiation therapy to the pelvis following a hysterectomy involves a technique which also causes a large amount of normal tissue to receive radiation. This can cause both early and late side effects, which may be severe. The new technique of intensity modulated radiotherapy (IMRT) has been used to help spare normal tissue, especially tissue of the small bowel. This is an advanced new technology that delivers the high-dose of radiation to the target area but avoids the normal tissue. Using CT scans, the target is outlined by the doctors before treatment. However, sometimes organs in the pelvis move throughout the course of treatment. Using CT scans during treatment and re-outlining the target may help to deliver more radiation to the cancer tissues and less to the surrounding normal areas.

During the study, you will have additional CT scans that will be performed on a special scanner in the radiation treatment room. You also will have additional CT scans twice a week during the 5 weeks of radiation treatment. The first 12 participants enrolled will receive the standard radiation therapy taking into account the maximum possible movements of the bladder. No adjustments will be made according to the results of the additional CT scans. The next 12 participants may have their radiation therapy adjusted according to the CT scans in an effort to target less of the normal tissue without missing cancer tissue. To reduce movement of your bladder due to different amounts of fluid in your bladder, you will be asked to drink 3 glasses of water before treatment and to come for treatment with a full bladder.

The volumes of your bladder and rectum will also be studied, and any side effects of the treatment will be recorded. You will be asked to fill out a short questionnaire about the side effects of your treatment 3 times per week during treatment. It should take around 5 minutes to complete the questionnaire.

Patients will be followed for at least 2 years. (Every 3 months for 1 year and 4 months for second year according to usual clinic practice.)

This is an investigational study. IMRT radiation therapy is an approved method of treating some types of cancer. However, adjusting the radiation treatment according to the movement of the internal organs is investigational. Initial CT scans for treatment planning are part of standard treatment. Up to 24 participants will take part in this study. All will be enrolled at M. D. Anderson.

Inclusion Criteria:

1. Patients who have been treated with a hysterectomy for carcinoma of the uterine cervix or endometrium who require post-operative radiation or chemoradiation therapy because of positive pelvic lymph nodes or other high-risk local findings.
2. Patients must have no evidence of metastatic disease outside of the pelvis.
3. Patients must have a Karnofsky Performance Status of >60.
4. The patient must be able to understand the protocol and sign a study-specific informed consent. .

Exclusion Criteria:

1. Karnofsky Performance Status < 60.
2. Patients with para-aortic nodal disease or who require extended field radiotherapy beyond the pelvis.
3. Obese patients who exceed the size limits of hte treatment table or CT scanner.
4. Mental status changes or bladder control problems that make the patient unable to comply with bladder-filling instructions.

Women treated with a hysterectomy for carcinoma of the uterine cervix or endometrium who require post-operative radiation or chemoradiation therapy because of positive pelvic lymph nodes or other high-risk local findings.