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1.
J Cancer Res Ther ; 11(2): 358-63, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26148600

RESUMO

AIMS: To evaluate current focal high precision radiotherapy (RT) techniques to spare hippocampi most optimally, in view of mounting clinical evidence to preserve neurocognition. MATERIALS AND METHODS: Computed tomography/magnetic resonance imaging (CT/MRI) datasets of 10 patients with benign/low-grade brain tumors, treated with focal conformal RT were replanned with helical tomotherapy (Tomo), intensity-modulated radiotherapy (IMRT) with high definition multileaf collimator (HD-MLC), and forward planning stereotactic conformal radiotherapy (SCRT). The primary planning objective was to encompass 99% of planning target volume (PTV) by 95% of prescribed dose (54 Gy/30#). Assessments included target coverage (TC), homogeneity index (HI), and maximum (max) and minimum (min) dose. Hippocampal dose was assessed with mean, maximum, minimum, median dosem and various dose levels. RESULTS: Mean V 95 for PTV coverage in Tomo, IMRT, and SCRT were 99.7, 99.4, and 98.3%, respectively. PTV coverage was significantly better in Tomo and IMRT compared to SCRT (P = 0.03). Tomotherapy (HI ≤ 0.06) and IMRT (HI ≤ 0.06) plans were more homogenous than SCRT (HI > 0.7) (P = 0.00). Right hippocampus mean dose with Tomo (20Gy) was 18.5% less than SCRT (30 Gy); but for left hippocampus, difference decreased to 3.3% (Tomo-32.2Gy and SCRT-34Gy). At 30% dose level, 9% more volume of right hippocampus was treated in IMRT and 20% in SCRT when compared to Tomo plan. At 80% dose, 6 and 12% more volumes were treated with IMRT and SCRT, respectively, in comparison to Tomo plan. For left hippocampus all three techniques were comparable. CONCLUSION: Tomotherapy and Linear accelerator (LINAC)-based IMRT achieved significantly better PTV coverage than forward planned SCRT. Tomo as compared to SCRT and IMRT plans showed trend towards significant sparing of the contralateral hippocampus, in eccentrically located tumors.


Assuntos
Hipocampo/patologia , Imageamento por Ressonância Magnética/métodos , Radioterapia de Intensidade Modulada/métodos , Tomografia Computadorizada por Raios X/métodos , Adolescente , Adulto , Neoplasias Encefálicas/patologia , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Adulto Jovem
2.
J Cancer Res Ther ; 7(3): 292-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22044810

RESUMO

PURPOSE: This study was designed to evaluate inter and intraobserver concordance in gross tumor volume (GTV) delineation on megavoltage CT (MVCT) images in patients with postoperative vault recurrences. MATERIALS AND METHODS: Three observers delineated GTV on MVCT and CECT and two observers recontoured on MVCT images. Tumor volumes were calculated and correlated using Spearman correlation. The standard deviation of centre of mass was averaged on per patient basis. The ratio of common volume and encompassing volume was used to determine intra and interobserver spatial concordance. Lack of difference in spatial concordance ratio between MVCT and CECT images was used as an index of usability of MVCT images. RESULTS: Thirty six datasets were available for seven patients. High intraobserver GTV correlation was recorded for observer 1 and 2 (r = 0.93 and r = 0.98; P=0.03 and 0.0001). The average intraobserver spatial concordance ratio was 0.57 and 0.62 respectively. The mean GTV of observers 1, 2 and 3 were 31.6 (18.7-52.2); 28.2 (16.7-51.8) and 46.3 cc (29.1-90.5) respectively. Average standard deviation of centre of mass of all observers was less than 5 mm in either direction. Largest interobserver discordance was observed in anterior, inferior and lateral direction. The interobserver spatial concordance of GTV on MVCT and CECT images was 0.34 and 0.36 (P=0.24) respectively. CONCLUSION: Moderate to good inter and intraobserver GTV correlation was observed on MVCT images, however, was associated with low interobserver spatial concordance on both MVCT and CECT images. Strategies to improve contouring reproducibility on MVCT and KVCT images are desirable.


Assuntos
Neoplasias/patologia , Neoplasias/radioterapia , Radioterapia Guiada por Imagem/métodos , Tomografia Computadorizada por Raios X , Carga Tumoral , Feminino , Humanos , Masculino , Variações Dependentes do Observador , Reprodutibilidade dos Testes
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