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Accurately counting analog events requires constructing an electronics chain that produces one count for each input pulse. In this work we review the use of Nuclear Instrumentation Module electronic units for counting neutron capture events in a 3He tube. We identify two unique types of false trigger events in a leading-edge discriminator and show how a dual timer module can be used to produce a veto window to exclude these events. We use the constructed electronics chain to build an apparatus to measure neutron pulses from a 252Cf neutron source. We compare the measurements with a Monte Carlo N-Particle (MCNP) model to determine the activity of the neutron source. Furthermore, by making additional measurements with borated polyethylene attenuators between the source and detector, we are able to determine the boron concentration of the polyethylene. This technique provides accurate determination of the source activity to a precision of 2.8% at the k = 1 level. The method used is simple, inexpensive, and requires no additional calibrated instruments.
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Californium-252 is used as a neutron calibration source for passive neutron correlation counting. Source age and isotopic information are needed to make decay corrections to the neutron emission rate due to the influence of 250Cf. Gamma-ray signatures present in the spectrum from spontaneous fission products and odd-numbered Cf isotopes can be used with high accuracy to confirm or query declared values on a technical data sheet. This method is good practice for independently verifying the content of 252Cf calibration sources.
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Well-characterized complexes of transplutonium elements are scarce because of the experimental challenges of working with these elements and the rarity of the isotopes. This leads to a lack of structural and spectroscopic data needed to understand the nature of chemical bonds in these compounds. In this work, the synthesis of Cf(DOPOq )2 (NO3 )(py) (DOPOq =2,4,6,8-tetra-tert-butyl-1-oxo-1H-phenoxazin-9-olate; py=pyridine) is reported, in which the nitrate anion is hypothesized to form through the α-radiolysis-induced reaction of pyridine and/or the ligand. Computational analysis of the electronic structure of the complex reveals that the CfIII -ligand interactions are largely ionic.
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The merging of small-scale syntheses and rapid crystallization methods have provided access to crystalline samples of berkelium (Z=97) and californium (Z=98) coordination complexes and compounds that can be interrogated with a suite of spectroscopic tools and structural elucidation approaches that have come online over the last 20â years. The combination of this experimental data with relativistic theoretical methods that capture the effects of spin-orbit coupling and scalar relativistic effects have allowed us to understand the electronic structure of berkelium and californium compounds at a level of detail that was not previously possible. The harbinger of this new era of post-curium chemistry was the synthesis and characterization of [Cf{B6 O8 (OH)5 }]. This compound possesses a structure type that is distinct from earlier actinide borates, a reduction in coordination number for californium, contracted Cf-O bond lengths, a substantially reduced magnetic moment with respect to the calculated free-ion moment and, most importantly, vibronically coupled broadband photoluminescence. Ligand-field analysis also showed that the splitting of the ground state was larger than typically found in the f-block elements, and when taken together places its overall electronic structure as a hybrid of d- and f-block components. The discovery of the unusual properties of this compound has led to the development of large families of 4f and 5f coordination complexes, in an effort to uncover the underlying origin of the electronic structure oddities, and whether there really is a sharp onset of these changes at californium. This in turn pushed the development of far more challenging berkelium chemistry (from a radiologic standpoint) because the half-life of the isotopes decreases from 351â years for 249 Cf to 330â days for 249 Bk. This short review details some of the chemistry that has been reported over the last 15 years, and its consequences for understanding the periodic table.
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The chemistry of trivalent transplutonium ions (Am3+ , Cm3+ , Bk3+ , Cf3+ , Es3+ ) is usually perceived as monotonic and paralleling that of the trivalent lanthanide series. Herein, we present the first extended X-ray absorption fine structure (EXAFS) study performed on a series of aqueous heavy actinide chelates, extending past Cm. The results obtained on diethylenetriaminepentaacetic acid (DTPA) complexes of trivalent Am, Cm, Bk, and Cf show a break to much shorter metal-oxygen nearest-neighbor bond lengths in the case of Cf3+ . Corroborating those results, density functional theory calculations, extended to Es3+ , suggest that the shorter Cf-O and Es-O bonds could arise from the departure of the coordinated water molecule and contraction of the ligand around the metal relative to the other [MIII DTPA(H2 O)]2- (M=Am, Cm, Bk) complexes. Taken together, these experimental and theoretical results demonstrate inhomogeneity within the trivalent transplutonium series that has been insinuated and debated in recent years, and that may also be leveraged for future nuclear waste reprocessing technologies.
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PURPOSE: The aim of this study was to retrospectively observe and analyze the long-term treatment outcomes of 96 elderly patients with gastroesophageal junction adenocarcinoma (GEJAC) who were treated with californium-252 (252Cf) neutron brachytherapy (NBT) in combination with external beam radiotherapy (EBRT) with or without chemotherapy. MATERIAL AND METHODS: From January 2002 to November 2012, 96 patients with GEJAC underwent treatment. The total radiation dose to the reference point via NBT was 8-25 Gy-eq in 2 to 5 fractions, with 1 fraction per week. The total dose via EBRT was 40-54 Gy, which was delivered over a period of 4 to 5.5 weeks with normal fraction. RESULTS: The median survival time for the 96 patients was 15.3 months, and the 1-, 2-, 3-, and 5-year rates of overall survival (OS) were 62.5%, 33.7%, 20.1%, and 7.9%, respectively. The 1-, 2-, 3-, and 5-year rates for local-regional control (LRC) were 78.7%, 57.9%, 41.8%, and 26.4%, respectively. The patients' age was an independent factor that was significantly associated with OS (p = 0.006) and LRC (p = 0.0005), according to univariate analysis. The 3-year OS (LRC) was 31.9% (62.9%) for patients aged 70-74 years and 16.1% (19.5%) for patients aged ≥ 75 years. From the time of treatment completion to the development of local-regional recurrence or death, 5 (5.2%) patients experienced fistula and 7 (7.3%) experienced massive bleeding. CONCLUSIONS: The clinical data indicated that NBT in combination with EBRT produced favorable local control and long-term survival rates for elderly patients with GEJAC, and that the side effects were tolerable. The patient's age could be used to select the appropriate treatment in an elderly patient.
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Coincidence and time-of-flight measurement techniques are employed to tag fission neutrons emitted from a 252Cf source sealed on one side with a very thin layer of Au. The source is positioned within a gaseous 4He scintillator detector. Together with α particles, both light and heavy fission fragments pass through the thin layer of Au and are detected. The fragments enable the corresponding fission neutrons, which are detected in a NE-213 liquid-scintillator detector, to be tagged. The resulting continuous polychromatic beam of tagged neutrons has an energy dependence that agrees qualitatively with expectations. We anticipate that this technique will provide a cost-effective means for the characterization of neutron-detector efficiency in the energy range 1-6MeV.
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BACKGROUND: Cervical cancer is the sixth most common cancer in Chinese women. A standard treatment modality for cervical cancer is the combination of surgery, chemotherapy, external-beam radiotherapy and intracavitary brachytherapy. The aim of this study was to retrospectively assess the long-term treatment outcomes of patients with cervical cancer who were treated with californium-252 neutron brachytherapy combined with external-beam radiotherapy plus concurrent chemotherapy. METHODS: We retrospectively analyzed the medical records of 150 patients with primary stages IB-IVB cervical cancer who received neutron brachytherapy combined with external-beam radiotherapy concurrently with cisplatin chemotherapy. All patients were followed up. Using an actuarial analysis, patient outcomes and treatment-related adverse effects were evaluated and compared. RESULTS: The median overall survival (OS) was 33.2 months. The 3-year progression-free survival rates for patients with stages I-II, III, and IV diseases were 81.0% (68/84), 65.0% (39/60), and 0% (0/6), respectively; the 3-year OS rates were 90.5% (76/84), 85.0% (51/60), and 16.7% (1/6), respectively. Vaginal bleeding was controlled within the median time of 4.0 days. One month after treatment, 97.3% of patients achieved short-term local control. The local recurrence rates for patients with stages I-II, III, and IV disease were 4.8% (4/84), 11.7% (7/60), and 33.3% (2/6), respectively, and the occurrence rates of distant metastasis were 16.7% (14/84), 25.0% (15/60), and 100.0% (6/6), respectively. Cancer stage, tumor size, and lymph node metastasis were identified as prognostic risk factors, but only lymph node metastasis was found to be an independent prognostic factor. The most common adverse effects during treatment were grades 1 and 2 irradiation-related proctitis and radiocystitis. CONCLUSION: For patients with cervical cancer, neutron brachytherapy combined with external-beam radiotherapy plus concurrent chemotherapy produces a rapid response and greatly improves local control and long-term survival rates with tolerable adverse effects.
Subject(s)
Antineoplastic Agents/therapeutic use , Californium/therapeutic use , Cisplatin/therapeutic use , Neutrons/therapeutic use , Uterine Cervical Neoplasms/therapy , Adult , Aged , Brachytherapy , Chemoradiotherapy , Disease-Free Survival , Female , Humans , Kaplan-Meier Estimate , Middle Aged , Pelvis , Uterine Cervical Neoplasms/radiotherapyABSTRACT
PURPOSE: The aim of this study was to retrospectively observe and analyze the long-term treatment outcomes of 191 elderly patients with esophageal squamous cell cancer (ESCC) who were treated with californium-252 (252Cf) neutron brachytherapy (NBT) in combination with external beam radiotherapy (EBRT). MATERIAL AND METHODS: From January 2002 to November 2012, 191 patients with ESCC underwent NBT in combination with EBRT. The total radiation dose to the reference point via NBT was 8-25 Gy-eq in two to five fractions with one fraction per week. The total dose via EBRT was 50-60 Gy, which was delivered over a period of 5 to 6 weeks with normal fractionation. RESULTS: The median survival time for the 191 patients was 23.6 months, and the 5-year rates for overall survival (OS) and local-regional control (LRC) were 28.7% and 54.2%, respectively. The patients' age was a factor that was significantly associated with OS (p = 0.010), according to univariate analysis. The 5-year OS (LRC) was 37.3% (58.6%) for patients aged 70-74 years and 14.5% (47.9%) for patients aged > 74 years (p = 0.010 and p = 0.038). In multivariate analysis, age and clinical N stage were associated with OS and LRC (p = 0.011 [0.041] and p = 0.005 [0.005]). From the time of treatment completion to the development of local-regional recurrence or death, 5 (2.6%) patients experienced fistula and 15 (7.9%) experienced massive bleeding. The incidence of severe late complications was related to older age (p = 0.027), higher NBT dose/fraction (20-25 Gy/5 fractions), and higher total dose (> 66 Gy). CONCLUSIONS: The clinical data indicated that NBT in combination with EBRT produced favorable local control and long-term survival rates for elderly patients with ESCC, and that the side effects were tolerable. Patient's age, clinical stage N status, and radiation dose could be used to select the appropriate treatment for elderly patients.
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PURPOSE: The aim of this work was to compare the long-term curative effects and complications of patients diagnosed with cervical cancer International Federation of Gynecology and Obstetrics IIIB (n = 430) as treated with Californium-252 ((252)Cf) or cobalt-60 ((60)Co) intracavitary brachytherapy (ICBT) combined with external beam radiotherapy (EBRT). METHODS AND MATERIALS: Cervical cancer cases with a history of treatment with (252)Cf or (60)Co ICBT combined with EBRT were selected from the Lithuanian National Cancer Institute database. Complications and second primary malignancies were compared in both patients groups. Estimates of the 5-, 10-, and 15-year overall survival and disease-free survival rates were computed with the Kaplan-Meier method and a Cox proportional hazards model applied using STATA software. RESULTS: At 5, 10, and 15 years, the overall survival rates were 46.9%, 39.3%, and 34.6% for the (252)Cf group and 35.4%, 26.9%, and 22.5% for the (60)Co group (p = 0.004), respectively. The disease-free survival rates were 42.1%, 35.0%, and 31.0% for the (252)Cf group and 32.0%, 25.1%, and 21.4% for the (60)Co group (p = 0.009), respectively. Histopathologic type of adenocarcinoma increased the risk of death for the (252)Cf group (hazard ratio 3.62). Histopathologic tumor type (hazard ratio 7.48) and recurrence (hazard ratio 2.83) were factors that statistically and significantly influenced the patient prognosis for the (60)Co group. CONCLUSIONS: Applying (252)Cf ICBT with EBRT was effective for International Federation of Gynecology and Obstetrics IIIB cervical cancer patients. Moreover, long-term followup data demonstrated higher survival rates in patients treated with (252)Cf ICBT than (60)Co ICBT. Complications in patients treated with neutron ICBT were not more frequent or severe than those treated with (60)Co ICBT.
Subject(s)
Adenocarcinoma/radiotherapy , Brachytherapy/methods , Californium/therapeutic use , Cobalt Radioisotopes/therapeutic use , Neoplasm Recurrence, Local/pathology , Neoplasms, Second Primary/diagnosis , Uterine Cervical Neoplasms/radiotherapy , Adenocarcinoma/pathology , Adult , Aged , Brachytherapy/adverse effects , Californium/adverse effects , Cobalt Radioisotopes/adverse effects , Disease-Free Survival , Female , Humans , Middle Aged , Neoplasm Staging , Radiotherapy Dosage , Survival Rate , Time Factors , Uterine Cervical Neoplasms/pathologyABSTRACT
OBJECTIVE: The aim of this study was to determine the efficacy of 252Californium neutron intracavitary brachytherapy using a two-channel Y applicator combined with external beam radiotherapy for the treatment of endometrial cancer. METHODS: Thirty-one patients with stage I-III endometrial cancer were recruited for this study. The stage I patients received only 252Californium neutron intracavitary brachytherapy with a two-channel applicator. The stage II and III patients received both 252Californium neutron intracavitary brachytherapy using a two-channel applicator and parallel-opposed whole pelvic radiotherapy. RESULTS: The five-year local control rate was 80.6% (25/31), the overall survival rate was 51.6% (16/31), and the disease-free survival rate was 54.8% (17/31). The incidence of serious late complications was 12.9% (4/31). CONCLUSIONS: 252Californium neutron intracavitary brachytherapy using a two-channel applicator combined with external beam radiotherapy was effective for treating endometrial cancer and the incidence of serious late complications related to this combination was within an acceptable range.
Subject(s)
Adult , Aged , Female , Humans , Middle Aged , Adenocarcinoma/radiotherapy , Brachytherapy/methods , Californium/therapeutic use , Endometrial Neoplasms/radiotherapy , Adenocarcinoma/mortality , Adenocarcinoma/pathology , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Brachytherapy/instrumentation , Combined Modality Therapy , Carmustine/therapeutic use , Cytarabine/therapeutic use , Endometrial Neoplasms/mortality , Endometrial Neoplasms/pathology , Follow-Up Studies , Melphalan/therapeutic use , Podophyllotoxin/therapeutic use , Survival Rate , Treatment OutcomeABSTRACT
The reactions of trivalent lanthanides and actinides with molten boric acid in high chloride concentrations result in the formation of M4[B16O26(OH)4(H2O)3Cl4] (M = Sm, Eu, Gd, Pu, Am, Cm, Cf). This cubic structure type is remarkably complex and displays both chirality and polarity. The polymeric borate network forms helical features that are linked via two different types of nine-coordinate f-element environments. The f-f transitions are unusually intense and result in dark coloration of these compounds with actinides.
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PURPOSE: The aim of this study was to retrospectively observe and analyze the long-term treatment outcomes for a total of 952 esophageal cancer patients who were treated with (252)Cf neutron brachytherapy (NBT) in combination with external beam radiotherapy (EBRT). METHODS AND MATERIALS: From November 2001 to March 2012, 952 patients with esophageal cancer underwent NBT in combination with EBRT. The patient numbers distributed over various cancer Stages I, IIA, IIB, III, and IVA were 9, 290, 51, 579, and 23, respectively. The total radiation dose to the reference point via NBT was 8-25 Gy-eq in three to five fractions with one fraction/week. The total dose via EBRT was 40-60 Gy delivered over a period of 5-6 weeks with normal fractionation. RESULTS: The overall median survival time was 20.3 months. The 1-, 3-, and 5-year survival rates were 67.1%, 36.3%, and 26.6%, respectively. These results compare favorably with the results obtained from conventional high-dose rate in combination with EBRT. Although a majority of the patients (860 or 90.3%) developed Grades 1 and 2 esophagitis during treatment, the symptoms were effectively relieved after the application of antacid and surface anesthesia. CONCLUSIONS: The clinical data show that NBT in combination with EBRT produced favorable local control and long-term survival rates for patients with esophageal cancer and that the side effects are tolerable. As such, we conclude that this dual-modality method is an effective and safe way for treating esophageal cancer.
Subject(s)
Brachytherapy/methods , Californium/therapeutic use , Carcinoma/radiotherapy , Esophageal Neoplasms/radiotherapy , Neutrons/therapeutic use , Radiopharmaceuticals/therapeutic use , Adult , Aged , Aged, 80 and over , Carcinoma/mortality , Combined Modality Therapy , Dose Fractionation, Radiation , Esophageal Neoplasms/mortality , Female , Follow-Up Studies , Humans , Male , Middle Aged , Radiation Dosage , Retrospective Studies , Survival Rate , Treatment OutcomeABSTRACT
Objective To observe and analyze the long-term curative effects and complications for early stage thoracic esophageal cancer patients treated with external beam radiotherapy (EBRT) and 252Cf neutron brachytherapy (NBT).Methods From May 2002 to May 2012,26 patients with early stage squamous cell carcinoma who underwent EBRT and 252Cf NBT were respectively analyzed.Patients were treated 5 days per week at 2 Gy/day for a total dose of 50 Gy with EBRT.The total radiation dose to the reference point was 12-16 Gy-eq in 3-4 fractions with 4 Gy-eq/fraction with 252Cf NBT.The 1-,3-and 5-year follow-up rates were all 100 ％.Results The 1-,3-and 5-year survival rates were 95.5 ％,95.5 ％ and 83.5 ％,respectively.The early complication rates for grades 1 and 2 radiation esophagitis were 76.9 ％ (20/26) and 23.1％ (6/26),respectively.The late complication rates for grades 0 and 1 (according to the RTOG/EORTC standard) were 84.6 ％ (22/26) and 15.4 ％ (4/26),respectively.Barium esophagography after treatments confirmed that the complete response rate was 100 ％.Twenty-two patients were confirmed by endoscopy to have either normal mucosa or inflammation change.Conclusion EBRT combined with 252Cf NBT is an effective and safe treatment for early stage esophageal squamous cell carcinoma.
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Objective To observe the efficacy and the toxicity of external irradiation combined with 252Cf brachytherapy on advanced cardiac carcinoma.Methods 48 patients with advanced cardiac carcinoma hospitalized during March 2007 to December 2010 were recruited,in which 39 cases were adenocarcinoma,5 patients were squamous carcinoma and 4 cases were signet-ring cell carcinoma.All cases had a Kamofsky above 80,no metastasis and received radiotherapy sequenced external and internal irradiation.The external irradiation was conducted under a 6MV X linear accelerator,and a dose of 38-45 Gy (2 Gy/22 f).The type ZH-1000 252Cf neutron breach-loading machine was used for brachytherapy with a dose of 12-16 Gy.Results Dysphagia cleared in all cases.The short-term efficacy (PR+CR) rate was 91.7 ％ (44/48).One and two year survival rate were,respectively,39.6 ％ and 6.3 ％.25 (52.1％) patients had gastrointestinal symptoms such as nausea,vomiting and impedance,and grade 1,2 neutropenia were occurred in 21 (43.8 ％) and 3 (6.3 ％) patients.Conclusion External irradiation combined with 252Cf brachytherapy is a safe,effective and tolerable treatment for advanced cardiac carcinoma.
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Five winter oilseed rape cultivars (Benefit, Californium, Cortes, Ladoga, Navajo) were subjected to 30 days of cold treatment (4 °C) to examine the effect of cold on acquired frost tolerance (FT), dehydrin (DHN) content, and photosynthesis-related parameters. The main aim of this study was to determine whether there are relationships between FT (expressed as LT50 values) and the other parameters measured in the cultivars. While the cultivar Benefit accumulated two types of DHNs (D45 and D35), the other cultivars accumulated three additional DHNs (D97, D47, and D37). The similar-sized DHNs (D45 and D47) were the most abundant; the others exhibited significantly lower accumulations. The highest correlations were detected between LT50 and DHN accumulation (r=-0.815), intrinsic water use efficiency (WUEi; r=-0.643), net photosynthetic rate (r=-0.628), stomatal conductance (r=0.511), and intracellular/intercellular CO2 concentration (r=0.505). Those cultivars that exhibited higher Pn rate in cold (and further a significant increase in WUEi) had higher levels of DHNs and also higher FT. No significant correlation was observed between LT50 and E, PRI, or NDVI. Overall, we have shown the selected physiological parameters to be able to distinguish different FT cultivars of winter oilseed rape.
Subject(s)
Adaptation, Physiological , Brassica napus/physiology , Freezing , Photosynthesis/physiology , Plant Proteins/metabolism , Seasons , Water/physiology , Acclimatization , Analysis of Variance , Principal Component AnalysisABSTRACT
Objective The results and side effects of nasopharyngeal carcinoma treated by combined external radiotherapy and Californium -252 neutron after loading intracavitary radiotherapy. Methods From November 2005 to March 2007, 30 nasopharyngeal carcinoma patients with staged T1 and T2 by 1992 Fuzhou staging system, were treated by external beam radiotherapy combined with Californium-252 neutron after loading intraeavitary radiotherapy. Results All patients were followed up for 2 years. 2 cases recurred in the nasopharynx. 4 cases developed distant metastases. 2 cases developed trismus. No perforations in hand and soft palate occurred. Conclusion External beam radiotherapy combined with Californian-252 neutron after loading intracavitary radiotherapy for nasopharyngeal carcinoma is indicated for boosting the dose to the nasopharyngeal cavity; reducing the dose for external irradiation. It can improve local control rate of nasopharyngeal carcinoma and reduce occur rate for the trismus.
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Radiotherapy is an important treatment on gynecological tumors,especially for brachyther- apy.~(137)Cs,~(192)Ir were usually used in the past,but the local control and survival rates were not increased obvi- ously.The machines,that was made in China,of ~(252)Cf neutrons brachytherapy were used already by many hos- pitals in our country and played a preponderant role more and more.It can increase the local control and sur- vival rates effectively on gynecological tumors.
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Objective To evaluate the treatment of advanced endometrial cancer with californium-252 brachytherapy. Methods 21 cases of endometrial cancers who had not received any treatment were diagnosed as in the stages Ⅰ～Ⅳ according to the criteria of FIGO. Treatment schedule included: 252Cf brachytherapy, 8～12Gy/fraction/week, the total dose of reference point A was 35～45 Gy and total dose of reference point F was 35～50Gy in three to four implant sessions. On the second day after 252Cf therapy, the whole pelvis was treated with 6MV X-ray external beam radiotherapy, 200 cGy per fraction, 4 times per week. The total dose of external beam radiotherapy was 45 to 50 Gy (the middle of pelvis was shielded with 4cm of lead), and the total treatment time was 5～6weeks. The recent therapeutic effect and complications were observed. Results The average time of complete tumor regression was 25 days, the local control rate was over 90%; the late radioactive complications of bladder and rectum was low during the 5-year follow-up period. Conclusions Combined californium-252 brachytherapy and high energy X-ray external beam radiotherapy may be safe and effective on advanced endometrial cancer.
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0.05],significantly higher than stage Ⅲ,Ⅳ[60%(6/10),50%(5/10);P
