Craniospinal radiotherapy in an advanced technique.
OBJECTIVE
Whole craniospinal irradiation cannot be achieved in one field at a normal treatment distance for adults. The aim of this newly developed technique is to minimize problems of matching fields and to maximize precision of craniospinal radiotherapy.


METHODS
Twelve patients (3-59 years) had craniospinal irradiation in supine position. The head was treated with lateral opposed isocentric fields with collimator rotation and isocentric table rotation. Using an extended source-skin distance of 160 cm only one dorsal field is necessary to cover the whole spinal axis. To avoid systematic under- or overdosage, junction field edges were moved twice by 1.5 cm. Treatment planning was performed based on CT scans. For visual verification of field matching an additional line laser was first adjusted to the caudal edge of one lateral light field and then checked against the light field of the spinal field under the table.


RESULTS
Control films show good homogeneity in the junction between lateral and vertical fields. Reproducibility of table movements is acceptable. Total time needed for one fraction is about 15-20 min.


CONCLUSIONS
The described technique is now well established, feasible and leads to less risk of dose uncertainties.
Christ
Gunter
G
Medical Physics, Department of Radiooncology, University of Tübingen, Tübingen, Germany. gunter.christ@med.uni-tuebingen.de
Denninger
Daniel
D
Dohm
Oliver Steffen
OS
Weigel
Bernd
B
Hönes
Andreas
A
Paulsen
Frank
F
D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D004806:Ependymoma / Q000000981:diagnostic imaging / Q000532:radiotherapy; D005260:Female; D018237:Germinoma / Q000000981:diagnostic imaging / Q000532:radiotherapy; D006801:Humans; D007834:Lasers; D008297:Male; D008527:Medulloblastoma / Q000000981:diagnostic imaging / Q000532:radiotherapy; D008875:Middle Aged; D018242:Neuroectodermal Tumors, Primitive / Q000000981:diagnostic imaging / Q000532:radiotherapy; D010870:Pineal Gland / Q000000981:diagnostic imaging / Q000528:radiation effects; D010871:Pinealoma / Q000000981:diagnostic imaging / Q000532:radiotherapy; D011832:Radiation Injuries / Q000209:etiology; D011878:Radiotherapy; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation*; D013120:Spinal Cord Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed