Utilization of parasternal lymphoscintigraphy in radiation therapy of breast carcinoma.
In radiation therapy of patients with breast carcinoma, the ipsilateral internal mammary lymph nodes are either irradiated by a separate anterior field or included by isocentric opposing tangential fields, which also treat the breast and chest wall. To determine the acceptability of a particular treatment setup, the positions of the nodes must be determined with respect to the treatment fields. For the anterior field technique the problem is two-dimensional and is solved by simply superimposing the treatment field onto an anterior lymphoscintigram. For treatment by opposing tangential fields the problem is three-dimensional and more complex. The solution described in this note is to project the three-dimensional lymph node positions, obtained by a stereo-lymphoscintigraphic procedure, onto the tangential field radiographs. A mathematical expression is given to perform the required projection of the node positions onto the radiographs.
D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008433:Mathematics; D011877:Radionuclide Imaging / Q000295:instrumentation / Q000379:methods