Inclusion Criteria:

- Must have pathologically confirmed invasive adenocarcinoma or ductal carcinoma in
situ of the breast.

- Patients must have undergone segmental mastectomy (i.e., lumpectomy).

- Patients must not have received prior radiation therapy to the breast.

- Patients must not have active local-regional disease prior to registration.

- Patients must not be pregnant because of the potential for fetal harm as a result of
radiation treatment. Women of child-bearing age will be given a serum pregnancy test
prior to study entry to ensure they are not pregnant. They will also be counseled on
the importance of avoiding pregnancy and hormonal contraception while undergoing
radiation therapy.

- Patients must not have a serious medical or psychiatric illness which prevents
informed consent or compliance with treatment.

- All patients must be informed of the investigational nature of this study and give
written informed consent in accordance with institutional and federal guidelines.

Exclusion Criteria:

- Visible skin pathology, excessive freckles, or skin blemishes in the test area.

- History of skin disease or hypersensitivity and repeated contact allergies.

- Sarcoma or squamous cell histology.

- Metastatic disease to the breast.

- Current tobacco use.