Thomas H. Newton

A Critical Examination of the Results from the Harvard-MIT NCT Program Phase I Clinical Trial of Neutron Capture Therapy for Intracranial Disease

SummaryA phase I trial was designed to evaluate normal tissue tolerance to neutron capture therapy (NCT); tumor response was also followed as a secondary endpoint. Between July 1996 and May 1999, 24 subjects were entered into a phase 1 trial evaluating cranial NCT in subjects with primary or metastatic brain tumors. Two subjects were excluded due to a decline in their performance status and 22 subjects were irradiated at the MIT Nuclear Reactor Laboratory. The median age was 56 years (range 24–78). All subjects had a pathologically confirmed diagnosis of either glioblastoma (20) or melanoma (2) and a Karnofsky of 70 or higher. Neutron irradiation was delivered with a 15 cm diameter epithermal beam. Treatment plans varied from 1 to 3 fields depending upon the size and location of the tumor. The10B carrier,l-p-boronophenylalanine-fructose (BPA-f), was infused through a central venous catheter at doses of 250 mg kg−1 over 1 h (10 subjects), 300 mg kg−1 over 1.5 h (two subjects), or 350 mg kg−1 over 1.5–2 h (10 subjects). The pharmacokinetic profile of10B in blood was very reproducible and permitted a predictive model to be developed. Cranial NCT can be delivered at doses high enough to exhibit a clinical response with an acceptable level of toxicity. Acute toxicity was primarily associated with increased intracranial pressure; late pulmonary effects were seen in two subjects. Factors such as average brain dose, tumor volume, and skin, mucosa, and lung dose may have a greater impact on tolerance than peak dose alone. Two subjects exhibited a complete radiographic response and 13 of 17 evaluable subjects had a measurable reduction in enhanced tumor volume following NCT.

Startup of the fission converter epithermal neutron irradiation facility at the mit reactor

Abstract A new epithermal neutron irradiation facility, based on a fission converter assembly placed in the thermal column outside the reactor core, has been put into operation at the Massachusetts Institute of Technology Research Reactor (MITR). This facility was constructed to provide a high-intensity, forward-directed beam for use in neutron capture therapy with an epithermal flux of ≈ 1010 n/cm2·s at the medical room entrance with negligible fast neutron and gamma-ray contamination. The fission converter assembly consists of 10 or 11 MITR fuel elements placed in an aluminum tank and cooled with D2O. Thermal-hydraulic criteria were established based on heat deposition calculations. Various startup tests were performed to verify expected neutronic and thermal-hydraulic behavior. Flow testing showed an almost flat flow distribution across the fuel elements with <5% bypass flow. The total reactivity change caused by operation of the facility was measured at 0.014 ± 0.002% ΔK/K. Thermal power produced by the facility was measured to be 83.1 ± 4.2 kW. All of these test results satisfied the thermal-hydraulic safety criteria. In addition, radiation shielding design measurements were made that verified design calculations for the neutronic performance.

Neutronic Analysis and Fuel Cycle Simulation of the MIT Reactor Using MCODE-FM and Experimental Validation

A neutronic analysis of the Massachusetts Institute of Technology Research Reactor (MITR) is performed using state-of-the-art computational tools: the continuous-energy Monte Carlo code MCNP5 and the point-depletion code ORIGEN2.2. These codes are externally coupled by the in-house code package, MCODE (MCNP-ORIGEN Coupled Depletion Program), more recently, it being extended to MCODE-FM (Fuel Management). The latter features automated input file generation, data manipulation, and post-processing of the output data for the fuel cycle analysis, so that it is used to simulate the fuel management of the MITR. MCODE-FM also has an optional criticality search algorithm to simulate control blade movement.The code validation is carried out by comparing the calculated results to experimental data. Two sets of the comparisons are made in the present paper: 1) the Xe-135 reactivity effect during the reactor start-up and shutdown and 2) the thermal and fast neutron flux in an irradiation capsule in the reactor core. Good agreements have been found.The validated MCODE-FM is therefore useful for neutronic analysis and the fuel cycle simulation of the MITR. The time dependent variation of the key parameters, viz. the control blades’ axial position (maintaining criticality) and the fissile inventory in the fuel, is presented.Copyright