In vivo dosimetry in the field junction area for 3D-conformal radiation therapy in breast and head & neck cancer cases: A quality assurance study.

In vivo dosimetry in the field junction area for 3D-conformal radiation therapy in breast and head & neck cancer cases: A quality assurance study.

J BUON. 2016 Sept-Oct;21(5):1104-1112

Authors: Diamantopoulos S, Thalassinou S, Efstathopoulos E, Dilvoi M, Patatoukas G, Kouloulias V, Platoni K

Abstract
PURPOSE: To investigate the accuracy of field junctioning planning techniques (monoisocentric and rotating couch technique) for 3D-conformal radiotherapy (3D-CRT).
METHODS: In vivo dosimetry has been performed using thermo- luminescence dosimeters (TLDs) in 10 head and neck cancer patients (treated with monoisocentric technique) and 10 breast cancer patients (treated with rotating couch technique) irradiated with a 6 MV photon beam. Entrance dose measurements were performed in selected regions including the field junction area.
RESULTS: The mean deviation between measured and expected dose in the region of junction was significantly higher in breast cases compared to head and neck irradiation (-2.8±15.4% and 0.2±8.2% respectively; Mann-Whitney U test: p=0.002). A comparison between lateral head and neck fields and tangential breast fields revealed that the latter was associated with larger dose discrepancies (-2.2 ± 4.6% vs -3.5 ± 5.7% respectively; Mann-Whitney U test: p=0.029).
CONCLUSIONS: The results indicate the superiority of monoisocentric technique compared to the rotating couch technique in terms of dose delivery accuracy for treatments with field junctioning planning techniques.

PMID: 27837611 [PubMed - in process]

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