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An epithermal neutron beam from the MURR and from an accelerator source compared to the beam at the BMRR

Description: An ideal neutron beam for BNCT is a beam of epithermal neutrons, forward directed, and free of gamma rays and thermal and fast neutrons. Three neutron beams were evaluated, and compared: (1) the operating Brookhaven Medical Research Reactor (BMRR) epithermal beam, (2) the designed Missouri University Research Reactor (MURR) epithermal beam, and (3) the accelerator-based epithermal neutron beam designed by Wu. These neutron beams were compared with respect to the neutron spectra, neutron and gamma fluxes and doses, and beam directionality. The epithermal neutron beams were inter-compared for different beam parameters in air at the irradiation point. The BMRR beam has the highest neutron plus gamma doses per epithermal neutron among these neutron beams but is satisfactory for patient trials by BNCT at the present time. The RBE dose delivered to the normal brain reaches the tolerance dose limit before the skin RBE dose reaches its limit, so the skin dose can be controlled under the limit. Generally speaking, a treatment can be completed in 54 minutes using the BMRR beam for irradiation at a full-power operation of the reactor. The MURR beam has better beam parameters, including lower neutron and gamma doses per epithermal neutron, higher in intensity, and also directed. The irradiation time could be 5 minutes to complete a treatment. The accelerator-based neutron beam which has shown promising beam parameters similar to the BMRR beam could be a choice in hospitals. However, a complete system at the required power has not yet been demonstrated.
Date: January 1, 1992
Creator: Liu, H.B. & Brugger, R.M.
Partner: UNT Libraries Government Documents Department

Dose calculation and treatment planning for the Brookhaven NCT Facility

Description: Consistency of the calculated to measured fluxes and doses in phantoms is important for confidence in treatment planning for Boron Neutron Capture Therapy at the Brookhaven Medical Research Reactor (BMRR). Two phantoms have been used to measure the thermal and epithermal flux and gamma dose distributions for irradiations at the BMRR and these are compared to MCNP calculations. Since MCNP calculations in phantoms or models would be lengthy if the calculations started each time with fission neutrons from the reactor core, a neutron source plane, which was verified by spectrum and flux measurements at the irradiation port, was designed. Measured doses in phantoms are especially important to verify the simulated neutron source plane. Good agreement between the calculated and measured values has been achieved and this neutron source plane is now used to predict flux and dose information for oncologists to form treatment plans as well as designing collimator and room shielding. In addition, a program using MCNP calculated results as input has been developed to predict reliable flux and dose distributions in the central coronal section of a head model for irradiation by the BMRR beam. Dosimetric comparisons and treatment examples are presented.
Date: January 1, 1992
Creator: Liu, H.B. & Brugger, R.M.
Partner: UNT Libraries Government Documents Department

Doses delivered to normal brain under different treatment protocols at Brookhaven National Laboratory

Description: As of October 31, 1996, 23 glioblastoma multiforme patients underwent BNCT under several treatment protocols at the Brookhaven Medical Research Reactor. For treatment planning and dosimetry purposes, these protocols may be divided into four groups. The first group comprises protocols that used an 8-cm collimator and allowed a peak normal brain dose of 10.5 Gy-Eq to avolume of 1 cm{sup 3} were the thermal neutron flux was maximal (even if it happened to be in the tumor volume). The second group differs from the first in that it allowed a peak normal brain dose of 12.6 Gy-Eq. The protocols of the third and fourth groups allowed the prescribed peak normal brain dose of 12.6 Gy-Eq to be outside of the tumor volume, used a 12-cm collimator and, respectively, uni- or bilateral irradiations. We describe the treatment planning procedures and report the doses delivered to various structures of the brain.
Date: December 31, 1996
Creator: Capala, J.; Coderre, J.A. & Liu, H.B.
Partner: UNT Libraries Government Documents Department

Technical aspects of boron neutron capture therapy at the BNL Medical Research Reactor

Description: The Brookhaven Medical Research Reactor, BMRR, is a 3 MW heterogeneous, tank-type, light water cooled and moderated, graphite reflected reactor, which was designed for biomedical studies. Early BNL work in Boron Neutron Capture Therapy (BNCT) used a beam of thermal neutrons for experimental treatment of brain tumors. Research elsewhere and at BNL indicated that higher energy neutrons would be required to treat deep seated brain tumors. Epithermal neutrons would be thermalized as they penetrated the brain and peak thermal neutron flux densities would occur at the depth of brain tumors. One of the two BMRR thermal port shutters was modified in 1988 to include plates of aluminum and aluminum oxide to provide an epithermal port. Lithium carbonate in polyethylene was added in 1991 around the bismuth port to reduce the neutron flux density coming from outside the port. To enhance the epithermal neutron flux density, the two vertical thimbles A-3 (core edge) and E-3 (in core) were replaced with fuel elements. There are now four fuel elements of 190 grams each and 28 fuel elements of 140 grams each for a total of 4.68 kg of {sup 235}U in the core. The authors have proposed replacing the epithermal shutter with a fission converter plate shutter. It is estimated that the new shutter would increase the epithermal neutron flux density by a factor of seven and the epithermal/fast neutron ratio by a factor of two. The modifications made to the BMRR in the past few years permit BNCT for brain tumors without the need to reflect scalp and bone flaps. Radiation workers are monitored via a TLD badge and a self-reading dosimeter during each experiment. An early concern was raised about whether workers would be subject to a significant dose rate from working with patients who have been irradiated. The gamma ...
Date: July 1, 1997
Creator: Holden, N.E.; Rorer, D.C.; Patti, F.J.; Liu, H.B.; Reciniello, R. & Chanana, A.D.
Partner: UNT Libraries Government Documents Department

Gadolinium as an element for neutron capture therapy

Description: At BNL, preparations are being made to test in vitro compounds containing Gd and compare their response to the response of GD-DTPA to determine if one or several compounds can be located that enter the cells and enhance the Auger effect. Two similar rotators with positions for cell vials that have been constructed for these tests. The first rotator is made of only paraffin which simulates healthy tissue and provides control curves. The second rotator has 135 ppM of Gd-157 in the paraffin to simulate a Gd loaded tumor. Cells are irradiated in vials in the paraffin rotator and in the Gd-paraffin rotator at the epithermal beam of the Brookhaven Medical Research Reactor (BMRR). This produces an irradiation similar to what a patient would receive In an actual treatment. A combination of irradiations are made with both rotators; with no Gd compound or IdUrd In the cell media, with only Gd compound in the cell media and with both Gd compound and IdUrd in the cell media. The first set shows the effects of gamma rays from the H(n,gamma) reaction and the prompt gamma rays from capture of neutrons by Gd. The second set shows if there is any effect of Gd being in the cell media or inside the cells, i.e., an Auger effect. The third set shows the effect of enhancement by the IdUrd produced by the gamma rays from neutrons captured by either H or Gd. The fourth set combines all of the reactions and enhancements. Preliminary calculations and physical measurements of the doses that the cells will receive In these rotators have been made.
Date: January 1, 1992
Creator: Brugger, R.M.; Liu, H.B.; Laster, B.H.; Gordon, C.R.; Greenberg, D.D. & Warkentien, L.S.
Partner: UNT Libraries Government Documents Department

Boron neutron capture therapy of glioblastoma multiforme using the p- boronophenylalanine-fructose complex and epithermal neutrons

Description: The amino acid analogue p-boronophenylalanine (BPA) is under investigation as a neutron capture agent for BNCT of glioblastoma multiforme. A series of patients undergoing surgical removal of tumor received BPA orally as the free amino acid. Favorable tumor/blood boron concentration ratios were obtained but the absolute amount of boron in the tumor would have been insufficient for BNCT. BPA can be solubilized at neutral pH by complexation with fructose (BPA-F). Studies with rats suggest that intraperitoneal injection of BPA-F complex produces a much higher tumor boron concentration to rat intracerebral 9L gliosarcoma that were possible with oral BPA. Higher boron concentrations have allowed higher tumor radiation doses to be delivered while maintaining the dose to the normal brain vascular endothelium below the threshold of tolerance. The experience to date of the administration of BPA-F to one patient is provided in this report.
Date: December 31, 1994
Creator: Coderre, J.A.; Chanana, A.D.; Joel, D.D.; Liu, H.B.; Slatkin, D.N.; Wielopolski, L. et al.
Partner: UNT Libraries Government Documents Department

A comparison of the dose RBE and the biological dosimetry approaches for treatment planning in BNCT

Description: Treatment planning for clinical trials with boron neutron capture therapy (BNCT) is complicated substantially by the fact that the radiation field generated by the activating external neutron beam is composed of several different types of radiation, i.e., fast neutrons, recoil protons from elastic collisions with hydrogen, gamma rays from the reactor and from neutron capture by body hydrogen, protons from nitrogen capture, and the products of the NCT interaction. Furthermore, the relative contribution of each type of radiation varies with depth in tissue. Because each of these radiations has its own RBE, and the RBE of the fast neutron component will not be constant as the neutron spectrum changes with depth, the problem of predicting the severity of the biological effect, in depth, becomes complex indeed. In order to attack this problem, Monte Carlo calculations of dose, checked against benchmark measurements, are employed. Two approaches are then used to assess the severity of the effect. In the first, the effective dose (D[sub EF]) is determined by summing the products of (D[center dot]RBE) for each radiation. The other approach involves placing cells at the location for which the D[sub EF] was calculated. Using a dose-response curvefrom a low-LET radiation, e.g. [sup 137]Cs gamma rays (D[sub [gamma]Ca]), the photon equivalent dose (PED, or D[sub P]) can be determined. If the RBE values used are correct, the D[sub EF] and the D[sub P] should be essentially identical.
Date: January 1, 1992
Creator: Laster, B.H. (Brookhaven National Lab., Upton, NY (United States) University Hospital, Stony Brook, NY (United States). Dept. of Radiation Oncology); Liu, H.B.; Gordon, C.R. & Bond, V.P. (Brookhaven National Lab., Upton, NY (United States))
Partner: UNT Libraries Government Documents Department