ABSTRACT
PURPOSE: The aim of this study was to evaluate the effect of decreasing the irradiated cardiac volume in breast-conserving therapy (BCT) using breath-adapted radiation therapy (BART). MATERIALS AND METHODS: The radiation therapy (RT)-computed tomography (CT) of 21 patients with left breast cancer during free breathing (FB), end-inspiration gating (IG) with audio-prompting, and deep inspiration breath-hold (DIBH) were subjected to BART planning analysis. Respiratory movement was monitored during CT scanning with the respiratory-gating system. The opposing tangential fields were planned for each respiratory-gated CT. The dose-volume histograms (DVHs) of the heart, lung, and breast of each respiratory phase were compared. RESULTS: The median respiratory movement of the right chest wall was 5.6 mm with FB CT, 10.9 mm with audioprompting CT, and 21.3 mm from end-inspiration to DIBH. The median left ventricular volume receiving >50% of the prescribed dose was 2.9% for FB, 0.2% for IG, and 0% for DIBH. DIBH led to significant cardiac spattering effect compared with FB or IG (P < 0.01). The median lung volume receiving 20 Gy or more was 5.0% for FB, 4.7% for IG, and 4.3% for DIBH. There were no significant differences between each respiratory phase. CONCLUSION: We concluded that radiotherapy on the DIBH facilitates a reduction of the irradiated heart volume compared to FB and IG.
Subject(s)
Breast Neoplasms/radiotherapy , Heart/radiation effects , Radiation Injuries/prevention & control , Adult , Breast Neoplasms/diagnostic imaging , Female , Heart/diagnostic imaging , Humans , Middle Aged , Radiation Injuries/diagnostic imaging , Radiotherapy Dosage , Respiratory-Gated Imaging Techniques , Statistics, Nonparametric , Tomography, X-Ray ComputedABSTRACT
BACKGROUND: High-dose-rate interstitial radiation therapy is a newly introduced modality, and its role in the management of gynecologic malignancies remains to be studied. Clinical experience in high-dose-rate interstitial radiation therapy was retrospectively investigated. PATIENTS AND METHODS: Eight patients with primary and nine with recurrent gynecologic malignancies underwent high-dose-rate interstitial radiation therapy with/without external-beam irradiation. Fractional dose of the high-dose-rate interstitial radiation therapy ranged between 4 and 6 Gy with total doses of 15-54 Gy. Interstitial irradiation was performed twice daily with an interval of > 6 h. RESULTS: 2-year local control rate was 75% for primary treatment and 47% for treatment of recurrence (p = 0.46). Maximum tumor size had a statistically significant impact on local control (p < 0.002). Grade 2 and 4 late complications were seen in five patients, and the incidence was significantly higher in patients with a larger volume enclosed by the prescribed fractional dose of high-dose-rate interstitial radiation therapy. The incidence of grade 2 and 4 complications at 18 months was 78% and 0% with a volume > 100 cm(3) and < or = 100 cm(3), respectively (p < 0.04). CONCLUSION: Although high-dose-rate interstitial radiation therapy is a promising modality, it must be applied cautiously to patients with bulky tumors because of the high incidence of serious complications.
