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2.
Artículo en Inglés | WPRIM | ID: wpr-124665

RESUMEN

This study was conducted to assess the feasibility of image guided radiotherapy (IGRT) for orthotopic 4T1 mouse mammary tumor using linear accelerator (LINAC). Eighteen Balb/C mice were inoculated with 4T1 cells on left mammary fat pad and nine of them were irradiated using LINAC. Tumors, planning target volumes (PTV), bowels adjacent to tumors, bones and lungs were delineated on planning CT images. IGRT plans were generated to irradiate prescription dose to at least 90% of the PTV and then compared with conventional 2-dimensional plans with anterior-posterior and posterior-anterior beams with 5 mm margins (2D AP/PA plan). Homemade dose-build-up-cradle was designed to encompass mouse bed for homogeneous dose build up. To confirm the irradiated dose, tumor doses were measured using diode detector placed on the surface of tumors. Plan comparison demonstrated equivalent doses to PTV while sparing more doses to normal tissues including bowel (from 90.9% to 40.5%, median value of mean doses) and bone marrow (from 12.9% to 4.7%, median value of mean doses) than 2D AP/PA plan. Quality assurance using diode detector confirmed that IGRT could deliver 95.3-105.3% of the planned doses to PTV. Tumors grew 505.2-1185.8% (mean 873.3%) in the control group and 436.1-771.8% (mean 615.5%) in the irradiated group. These results demonstrate that LINAC-based IGRT provides a reliable approach with accurate dose delivery in the radiobiological study for orthotropic tumor model maintaining tumor microenvironment.


Asunto(s)
Animales , Ratones , Tejido Adiposo , Médula Ósea , Pulmón , Aceleradores de Partículas , Prescripciones , Radioterapia , Microambiente Tumoral
3.
Artículo en Inglés | WPRIM | ID: wpr-8698

RESUMEN

PURPOSE: To determine feasibility of RapidArc in sequential or simultaneous integrated tumor boost in whole brain radiation therapy (WBRT) for poor prognostic patients with four or more brain metastases. MATERIALS AND METHODS: Nine patients with multiple (> or =4) brain metastases were analyzed. Three patients were classified as class II in recursive partitioning analysis and 6 were class III. The class III patients presented with hemiparesis, cognitive deficit, or apraxia. The ratio of tumor to whole brain volume was 0.8-7.9%. Six patients received 2-dimensional bilateral WBRT, (30 Gy/10-12 fractions), followed by sequential RapidArc tumor boost (15-30 Gy/4-10 fractions). Three patients received RapidArc WBRT with simultaneous integrated boost to tumors (48-50 Gy) in 10-20 fractions. RESULTS: The median biologically effective dose to metastatic tumors was 68.1 Gy10 and 67.2 Gy10 and the median brain volume irradiated more than 100 Gy3 were 1.9% (24 cm3) and 0.8% (13 cm3) for each group. With less than 3 minutes of treatment time, RapidArc was easily applied to the patients with poor performance status. The follow-up period was 0.3-16.5 months. Tumor responses among the 6 patients who underwent follow-up magnetic resonance imaging were partial and stable in 3 and 3, respectively. Overall survival at 6 and 12 months were 66.7% and 41.7%, respectively. The local progression-free survival at 6 and 12 months were 100% and 62.5%, respectively. CONCLUSION: RapidArc as a component in whole brain radiation therapy for poor prognostic, multiple brain metastases is an effective and safe modality with easy application.


Asunto(s)
Humanos , Apraxias , Encéfalo , Supervivencia sin Enfermedad , Estudios de Seguimiento , Imagen por Resonancia Magnética , Metástasis de la Neoplasia , Paresia , Radioterapia de Intensidad Modulada
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