RESUMO
To introduce our preliminary experience of treating locally and regionally recurrent Head and Neck cancer patients at Tsing Hua Open-Pool Reactor in Taiwan, four patients (M/F=3/1, median age 68 Y/O) were enrolled. BNCT with BPA (400 mg/kg) injected in 2 phases and prescription dose of 12-35 Gy (Eq.)/fraction for 2 fractions at 30 day interval can be given with sustained blood boron concentration and tolerable early toxicities for recurrent H & N cancer.
Assuntos
Terapia por Captura de Nêutron de Boro , Carcinoma de Células Escamosas/radioterapia , Neoplasias de Cabeça e Pescoço/radioterapia , Idoso , Terapia por Captura de Nêutron de Boro/efeitos adversos , Feminino , Humanos , Masculino , Imagem Multimodal , Recidiva Local de Neoplasia , Tomografia por Emissão de Pósitrons , Taiwan , Tomografia Computadorizada por Raios XRESUMO
THORplan is a treatment planning system developed at Tsing Hua University, Taiwan, for boron neutron capture therapy (BNCT) purpose. It is recently developed with user-friendly interface using Interactive Data Language. In this article the accuracy of THORplan is verified by comparing results of Snyder phantom calculation with the analytical model results of MCNP. Neutron source from THOR epithermal neutron beam is used as the source for the calculation. The thermal neutron flux calculated by THORplan is very close to the reference results. SERA overestimates thermal neutron flux by 2-5%. NCTPlan underestimates thermal neutron flux by 4-9% in most locations. The total weighted dose calculated by THORplan is accurate to within 3% except at the tissue interface. SERA overestimates the total weighted dose at depth >1.5 cm by 2-5%. NCTPlan underestimates the total weighted dose by approximately 10% at depth >1cm.
Assuntos
Terapia por Captura de Nêutron de Boro/estatística & dados numéricos , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Neoplasias Encefálicas/radioterapia , Humanos , Modelos Estatísticos , Imagens de Fantasmas/estatística & dados numéricos , Software , TaiwanRESUMO
This study investigates the radiation shielding design of the treatment room for boron neutron capture therapy at Tsing Hua Open-pool Reactor using "TORT-coupled MCNP" method. With this method, the computational efficiency is improved significantly by two to three orders of magnitude compared to the analog Monte Carlo MCNP calculation. This makes the calculation feasible using a single CPU in less than 1 day. Further optimization of the photon weight windows leads to additional 50-75% improvement in the overall computational efficiency.
Assuntos
Terapia por Captura de Nêutron de Boro/instrumentação , Proteção Radiológica/instrumentação , Terapia por Captura de Nêutron de Boro/estatística & dados numéricos , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Doses de Radiação , Proteção Radiológica/estatística & dados numéricos , Espalhamento de Radiação , TaiwanRESUMO
A characterization of the new Tsing Hua open-pool reactor (THOR) epithermal neutron beam designed for boron neutron capture therapy (BNCT) has been performed. The facility is currently under construction and expected in completion in March 2004. The designed epithermal neutron flux for 1 MW power is 1.7x10(9)n cm(-2)s(-1) in air at the beam exit, accompanied by photon and fast neutron absorbed dose rates of 0.21 and 0.47 mGys(-1), respectively. With (10)B concentrations in normal tissue and tumor of 11.4 and 40 ppm, the calculated advantage depth dose rate to the modified Snyder head phantom is 0.53RBE-Gymin(-1) at the advantage depth of 85 mm, giving an advantage ratio of 4.8. The dose patterns determined by the NCTPlan treatment planning system using the new THOR beam for a patient treated in the Harvard-MIT clinical trial were compared with results of the MITR-II M67 beam. The present study confirms the suitability of the new THOR beam for possible BNCT clinical trials.
Assuntos
Terapia por Captura de Nêutron de Boro/instrumentação , Terapia por Captura de Nêutron de Boro/estatística & dados numéricos , Neoplasias Encefálicas/radioterapia , Ensaios Clínicos como Assunto , Nêutrons Rápidos/uso terapêutico , Glioblastoma/radioterapia , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Planejamento da Radioterapia Assistida por Computador , TaiwanRESUMO
Heading for possible use for clinical trial, THOR (Tsing Hua Open-pool Reactor) at Taiwan was shutdown for renovation of a new epithermal neutron beam in January 2003. In November 2003, concrete cutting was finished for closer distance from core and larger treatment room. This article presents the design base that the construction of the new beam is based on. The filter/moderator design along the beam is Cd(0.1cm)+Al(10 cm)+FLUENTAL (16 cm)+Al(10 cm)+FLUENTAL(24 cm)+Void(18 cm)+Cd(0.1cm)+Bi(10 cm) with 6 cm Pb as reflector. Following the filter/moderator is an 88 cm long, 6 cm thick Bi-lined collimator with Li(2)CO(3)-PE at the end. The collimator is surrounded by Li(2)CO(3)-PE and Pb. The calculated beam parameters under 2 MW at the beam exit is phi(epi) = 3.4 x 10(9) n/cm(2)/s, Df/phi(epi) = 2.8 x 10(-11) cGy cm(2)/n, Dgamma/phi(epi) = 1.3 x 10(-11) cGy cm(2)/n, and J+/phi = 0.8. For a phantom placed 10 cm from beam exit, MCNP calculation shows that the advantage depth is 8.9 cm, and advantage ratio is 5.6 if boron concentration in tumor and normal tissue are assumed to be 65 and 18 ppm. The maximum dose rate for normal tissue is 50 cGy/min. The maximum therapeutic ratio is 6. The construction of the beam is scheduled to be finished by the end of April 2004.