Radiation planning in breast cancer. What is the depth of the internal mammary lymph nodes

: For irradiation of the parasternal lymph nodes by high-energy electrons the target volume depth, i.e. the depth of the parasternal nodes below the skin surface, was determined by CT in 25 consecutive female patients with a sternal irradiation field. On measurement at the cranial end of the sternum, at a middle level, and at the caudal part of the sternal field, intraindividual differences were low, whereas interindividual findings differed markedly--depending on thickness of subcutaneous fatty tissue. For individual treatment planning, we recommend measuring target volume depth by CT.