BladdEr Full OR Empty for Pelvic Radiation Therapy

Who May Qualify: - Provision of signed and dated willing to sign a consent form form - Stated willingness to comply with all study procedures and availability for the duration of the study - Persons, aged at least 18 years - Deemed eligible to undergo curative intent radiation therapy for primary GU, GI, or Gyn malignancy of the pelvis. - For participants able to become pregnant: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation - For participants able to cause a pregnancy: use of condoms or other methods to ensure effective contraception with partner Who Should NOT Join This Trial: - Pregnancy - Tumor invading the bladder, as judged by the enrolling physician based on available clinical information - Contraindications to radiotherapy, including Crohn's disease and active connective tissue disorders such as scleroderma or uncontrolled lupus - Prior radiation therapy to an area requiring treatment in the present study Always talk to your doctor about whether this trial is right for you.