Synthesis of enriched boron nitride nanocrystals: A potential element for biomedical applications.

The shortcomings in Boron neutron capture therapy (BNCT) and Hyperthermia for killing the tumor cell desired for the synthesis of a new kind of material suitable to be first used in BNCT and later on enable the conditions for Hyperthermia to destroy the tumor cell. The desire led to the synthesis of large band gap semiconductor nano-size Boron-10 enriched crystals of hexagonal boron nitride (10BNNCs). The contents of 10BNNCs are analyzed with the help of x-ray photoelectron spectroscopy (XPS) and counter checked with Raman and XRD. The 10B-contents in 10BNNCs produce 7Li and 4He nuclei. A Part of the 7Li and 4He particles released in the cell is allowed to kill the tumor (via BNCT) whereas the rest produce electron-hole pairs in the semiconductor layer of 10BNNCs suggested to work in Hyperthermia with an externally applied field.

[Tumor regression in malignant choroidal melanomas after transpupillary thermotherapy (TTT) versus ruthenium brachytherapy and sandwich therapy - a comparative analysis]. / Tumorregression maligner Aderhautmelanome nach Transpupillarer Thermotherapie (TTT) versus Ruthenium-Brachytherapie und Sandwichtherapie - eine vergleichende Analyse.

PURPOSE: The aim of this study was to evaluate tumour regression in a large series of choroidal melanomas, which were treated with three different eye-sparing treatment modalities. PATIENTS AND METHODS: Retrospective review of the treatment results in all eyes with malignant choroidal melanoma, which were treated in the University Eye Clinic of Mainz consecutively in the time span 1.1992 to 12.2000 with transpupillary thermotherapy (TTT, standard protocol Oosterhuis JA 1995), ruthenium brachytherapy (RB, tumor apex dose 150 Gy) or sandwich therapy (ST). One-step ST was defined as TTT followed by RB with 100 Gy tumor apex dose within 48 hours. The treatment of residual prominences with TTT secondary to RB after different time spans was called two-step ST. Follow-up was 2 years. RESULTS: 131 eyes with malignant choroidal melanoma (mean tumour thickness: 4.5 mm) were treated with RB (66 eyes), TTT (26 eyes) or ST (39 eyes). Preservation of the globe was achieved in 109 eyes (81 %). Local tumour control was found in small melanomas (prominence up to 3 mm) in 89 %, in large tumors (prominence 8 mm and higher) in 50 %. In a subgroup of small posterior melanomas (n = 70 eyes, prominence up to 4.5 mm, located posterior to the equator) local tumour control was noted in 91 %. The time span to reach local tumour control (Kaplan-Meier estimates) was the shortest after TTT (median: 20 weeks), compared with RB (48 weeks) and one-step ST (29 weeks). CONCLUSIONS: In choroidal melanomas the chance of local tumour control and preservation of the globe decreases with increase of the tumour prominence. In small choroidal melanomas with posterior location local tumour control was achieved significantly faster after TTT than after RB.

Boron neutron capture therapy (BNCT) for the treatment of spontaneous nasal planum squamous cell carcinoma in felines.

Recently, Boron neutron capture therapy (BNCT) was successfully applied to treat experimental squamous cell carcinomas (SCC) of the hamster cheek pouch mucosa, with no damage to normal tissue. It was also shown that treating spontaneous nasal planum SCC in terminal feline patients with low dose BNCT is safe and feasible. In an extension of this work, the present study aimed at evaluation of the response of tumor and dose-limiting normal tissues to potentially therapeutic BNCT doses. Biodistribution studies with (10)B-boronophenylalanine (BPA enriched in (10)B) as a (10)B carrier were performed on three felines that showed advanced nasal planum SCC without any standard therapeutic option. Following the biodistribution studies, BNCT mediated by (10)BPA was done using the thermalized epithermal neutron beam at the RA-6 Nuclear Reactor. Follow-up included clinical evaluation, assessment of macroscopic tumor and normal tissue response and biopsies for histopathological analysis. The treated animals did not show any apparent radiation-induced toxicity. All three animals exhibited partial tumor control and an improvement in clinical condition. Enhanced therapeutic efficacy was associated with a high (10)B content of the tumor and a small tumor size. BNCT is therefore believed to be potentially effective in the treatment of spontaneous SCC. However, improvement in targeting (10)B into all tumor cells and delivering a sufficient dose at a greater depth are still required for the treatment of deep-seated, large tumors. Future studies are needed to evaluate the potential efficacy of the dual mode cellular (e.g. BPA-BNCT) and vascular (e.g. GB-10-BNCT) targeting protocol in a preclinical scenario, employing combinations of (10)B compounds with different properties and complementary uptake mechanisms.

Brachytherapy in men aged < or = 54 years with clinically localized prostate cancer.

OBJECTIVE: To report the biochemical progression-free survival (BPFS) in hormone-naive men aged < or = 54 years who underwent brachytherapy with or without supplemental external beam radiation therapy (EBRT), as despite favourable biochemical control rates with brachytherapy, there remains a reluctance to recommend non-extirpative approaches for young men with clinically localized prostate cancer. PATIENTS AND METHODS: From April 1995 to October 2002, 108 hormone-naive patients aged < or = 54 years (median 52 years, range 45-54) had permanent interstitial brachytherapy for clinical stage T1c-T2c NXM0 (2002 American Joint Committee on Cancer staging) prostate cancer. No patient had a seminal vesicle biopsy or pathological lymph node staging. The mean (sd, median) follow-up was 5.3 (1.8, 4.8) years. BPFS was defined by a prostate-specific antigen (PSA) level of < or = 0.40 ng/mL after the nadir. Risk groups were assigned using the Memorial Sloan-Kettering Cancer Center criteria. Several clinical, treatment and dosimetric variables were evaluated for their effect on BPFS. RESULTS: For the entire group, the actuarial 8-year BPFS was 96%; for low- (57 men), intermediate- (47) and high- (four) risk patients, the BPFS rates were 96%, 100% and three of four, respectively. For biochemically disease-free patients, the median PSA level after treatment was 0.05 ng/mL. In a multivariate analysis, only pretreatment PSA level predicted biochemical control, while dosimetry variables after treatment were almost statistically significant. CONCLUSIONS: Hormone-naive patients aged < or = 54 years have a high probability of a good 8-year BPFS after permanent interstitial brachytherapy with or without supplemental EBRT.

Biodistribution of 10B in a rat liver tumor model following intra-arterial administration of sodium borocaptate (BSH)/degradable starch microspheres (DSM) emulsion.

We reported that intra-arterial administration of borocaptate sodium (BSH)/lipiodol emulsion provided selectively high (10)B concentrations (approximately 200 ppm 6 h after administration) in experimental liver tumors. In the present study, we investigated the pharmacokinetics of BSH following intra-arterial administration of BSH with other embolizing agent, degradable starch microspheres (DSM). The (10)B concentration in the tumor at 1 h after administration of BSH with DSM was 231 ppm. At 6 h, the (10)B concentration in the tumor in BSH with DSM group was 81.5 ppm. The (10)B concentration in the liver at 1 h after administration of BSH with DSM was 184 ppm. At 6 h, the(10)B concentration in the liver in BSH with DSM group was 78 ppm. The tumor/liver (10)B concentration ratios (T/L ratio) in the "BSH+DSM" group were significantly smaller than those in the "BSH+lipiodol" group at 1 h (1.4 vs. 3.6) and 6h (1.1 vs. 14.9). BSH/DSM-boron neutron capture therapy (BNCT) was not suitable for treatment of multiple liver tumors due to the low T/L (10)B concentration ratio. However, the high (10)B accumulation in the liver tumors following intra-arterial administration of BSH/DSM emulsion suggests that BSH/DSM-BNCT has the potential for application to malignant tumors in other sites.

Nuclear and isotopic techniques applied to supporting nutritional studies in East Asia and Pacific Countries: IAEA's contributions over 20 years.

The world's scientific community has recognized that isotopic techniques play a vital role in monitoring the effectiveness of nutrition intervention by providing precise data on absorption, bioavailablity and interaction of various micronutrients in a cost effective manner. The International Atomic Energy Agency (IAEA) has been supporting many such health related studies in Member States from developing countries using nuclear and isotopic methods for over 20 years. This report documents the Agency's support for a variety of projects in East Asia and Pacific countries to assess body composition, total energy expenditure, nutrient intake, osteoporosis, infection, vitamin and mineral bioavailability as well as food composition. The IAEA spent a total of 10,302,356 US dollars through Coordinated Research Projects (CRP) and Technical Cooperation Projects (TCP) over the past 20 years. Out of this only 2,732,802, US dollars or 26.5% was used by the East Asia and Pacific countries. While the participation of East Asia and Pacific countries was strong in CRPs and moderate in regional TCPs, they did not participate in national TCPs at all. The non-participation under national TCPs is a serious deficiency when compared with Latin American and African regions and therefore, more participation from the East Asia and Pacific countries in national TCPs is strongly encouraged in the future.

Computational assessment of improved cell-kill by gadolinium-supplemented boron neutron capture therapy.

Potential improvement in neutron capture therapy (NCT) by utilizing both 157Gd and 10B is assessed considering two parameters calculated in transport models in MCNP4B, the dose to quiescent cells and the therapeutic ratio. Improved sterilization of quiescent or more generally non-uptaking cells is demonstrated with the addition of 157Gd to conventional 10B loading. The improved dose delivery to non-uptaking cells from concurrent administration of 157Gd and 10B is weighed against a second index, degradation in the therapeutic ratio resulting from the longer interaction lengths of the 157Gd capture products. Optimal concentrations of 157Gd are determined considering varying assumptions for boron uptake levels and selectivity. By analysing the dosimetry results of varying 157Gd concentrations applied concurrently with BPA-delivered boron in NCT, this work seeks to determine a balance between the high tumour-specific dose provided by BPA and the high dose to quiescent cells provided by potential gadolinium agents. Depending upon the assumptions for drug specificity, tumour size and fraction of quiescent cells, NCT with low levels of 157Gd (125 microg g(-1)) supplementing 10B loadings was shown to be superior to treatments applying 10B alone.