Source PUB MED via http://www.ncbi.nlm.nih.gov/pubmed/
Kubas A, Chapet O, Merle P, Lorchel F, d'Hombres A, Mornex F.
Cancer Radiother. 2009 Jan;13(1):24-9. Epub 2008 Dec 13.
Service de radiothérapie-oncologie, centre hospitalier Lyon-Sud Pierre-Bénite, 165, chemin du Grand-Revoyet, 69495 Pierre-Bénite cedex, France.
OBJECTIVE: To evaluate the dosimetric impact of breath-hold during radiotherapy of hepatocellular carcinoma (HCC) and to determinate the optimal respiratory phase for treatment (exhale or inhale). PATIENTS AND METHODS: Two CT scans were performed in inhale and in exhale in 20 patients with HCC. The GTV was delineated slice by slice on the inspiration breath hold acquisition (GTV(insp)) and on the expiration breath hold acquisition (GTV(exp)). The superposition of two GTV allowed to obtain the global GTV (free respiration). PTV was defined by adding a margin of 1cm around each GTV. The liver, the duodenum, the two kidneys, the stomach and the spinal cord were delineated on each acquisition as organs at risk (OAR). Three dosimetric plans were created on inspiration, expiration and on global PTV. RESULTS: The mean reduction in the volume of PTV with conformal radiation therapy (3D-CRT) in the hold-breath group compared to the free respiration group was of 33.5+/-11.9%. The average difference of V50%, V20, V30, V40 and V50 were around 4% in favor of the breath hold. The average value of NTCP was 8.9% in free respiration, 4.5% in expiration and 3.2% in inspiration. Further improvement in the OARs dosimetric parameters for the breath hold was observed. CONCLUSION: Compared to the conformal radiotherapy with free respiration, the breath-hold allows reducing the volume of the PTV and the doses to the healthy liver and organs at risk. The use of this modality during different radiotherapy techniques (3D-CRT, IMRT and stereotactic) may be recommended. No difference in dosimetric value has been observed between the breath hold in expiratory and inspiratory phases.