Characterization of 252Cf sources using high-resolution gamma spectroscopy.

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.

External beam radiation and high-dose-rate brachytherapy for elderly patients with gastroesophageal junction adenocarcinoma.

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.

Tagging fast neutrons from a 252Cf fission-fragment source.

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.

Californium-252 neutron brachytherapy combined with external pelvic radiotherapy plus concurrent chemotherapy for cervical cancer: a retrospective clinical study.

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.

Safety and outcome of external beam radiation and neutron brachytherapy in elderly patients with esophageal squamous cell cancer.

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.

Long-term results for Stage IIIB cervical cancer patients receiving external beam radiotherapy combined with either HDR (252)Cf or HDR (60)Co intracavitary brachytherapy.

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.

Californium-252 neutron brachytherapy combined with external beam radiotherapy for esophageal cancer: long-term treatment results.

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.

Clinical observation of external irradiation combined with 252Cf brachytherapy on advanced cardiac carcinoma / 肿瘤研究与临床

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.

A preliminary report of the treatment of endometrial cancer with californium-252 neutron intracavitary brachytherapy / 解放军医学杂志

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.