PERFORMANCE OF BARC NEUTRON PERSONAL DOSEMETER IN EURADOS INTERCOMPARISON EXERCISE IC2017N - A LESSON LEARNT.

Bhabha Atomic Research Centre (BARC) conducts fast neutron personnel monitoring service to radiation workers involved in reactors, accelerators, spent fuel processing plants, oil-well industries, etc., using CR-39 detector based dosemeter. In this study, performance of the BARC fast neutron personnel dosemeter has been checked through EURADOS intercomparison exercise for simulated workplace neutron fields. The overall performance of the dosemeter in the lower dose equivalent (≤ 5 mSv) was found to be acceptable as per ISO-14146. The performance (ratio of estimated to reference dose equivalent) of the dosemeter in the higher dose equivalent (12 mSv) was found to be in the range of 0.48-0.44 and not satisfactory as per the ISO-14146 criteria for any dosimetry service. Based on this performance, a new imaging system was developed and performance of the dosemeters were improved and found to be acceptable (within ±20%) as per ISO.

Surface dose rate variations in planar and curved geometries of 106Ru/106Rh plaque sources for ocular tumors.

PURPOSE: Investigation of surface dose rate variation with respect to the source configuration of 106Ru/106Rh eye plaque. To explore an alternate way to determine activity of brachytherapy plaques. METHODS: The surface dose rates of 106Ru/106Rh plaque developed indigenously were measured by extrapolation chamber. To rule out possibility of any error in the activity distribution and quantity, same source was used in two different configurations namely planar and curved. EBT3 Gafchromic film was used for determination of uniformity in activity. Monte Carlo-based Codes EGSnrc and FLUKA were used to calculate dose rate in tissue, percentage depth dose and for determination of activity. Parameters and correction factors were estimated using simulations. RESULTS: The measured reference absorbed dose rates for planar and curved 106Ru/106Rh eye plaques are found to be 589 ± 29 mGy/h and 560 ± 28 mGy/h, respectively. The difference in the reference absorbed dose rate of curved eye plaque is about ~5% as compared to planar configuration. The FLUKA-calculated dose values are almost independent of cavity length of the extrapolation chamber for both eye plaques. The FLUKA-based dose rates per µCi 106Ru/106Rh are about 17.28 ± 0.08 mGy/h and 16.48 ± 0.06 mGy/h, respectively for planar and curved eye plaques which match well with the measurements. The calculated activities for planar and curved eye plaques are 34.08 µCi and 33.98 µCi, respectively. CONCLUSIONS: Surface dose rates for a prototype 106Ru/106Rh eye plaque with different configurations were estimated using simulations and measured experimentally. An alternate way to determine activity of beta-gamma brachytherapy plaque has been proposed.

The clinical course of actinic keratosis correlates with underlying molecular mechanisms.

BACKGROUND: Actinic keratoses (AKs) are common premalignant skin lesions triggered by excessive ultraviolet exposure. The majority of AKs regress or persist, but some progress to squamous cell carcinomas. Biomarkers associated with their persistence, progression and regression have not been characterized. OBJECTIVES: We performed skin biopsies in patients with extensive actinic damage to identify biomarkers that correlate with clinical progression and regression of AKs. METHODS: This was an observational study of a cohort of patients with extensive actinic damage. AKs were mapped on a clear plastic template in 26 patients at months 3, 6, 9 and 11. Biopsies were taken from randomly selected, predetermined AKs and were evaluated for p53, E-cadherin, Snail, Slug and Twist. The study is registered at Clinicaltrials.gov: NCT00027976. RESULTS: p53 exhibited greater expression in clinically apparent AKs (histological score 2·89 ± 1·45) than in regressed AKs (0·75 ± 0·96); P < 0·01. There was also significantly less membrane E-cadherin, the lack of which is a marker of epithelial-mesenchymal transition, in clinically apparent AKs (1·89 ± 1·81) than in sun-exposed skin (3·07 ± 1·75); P < 0·005. The E-cadherin transcription repressors Snail, Slug and Twist were increased in AKs compared with sun-exposed skin. A limitation of the study is that measurement of histological biomarkers was not a primary end point. In addition, patients were allowed to apply sunscreens. CONCLUSIONS: At the molecular level, loss of E-cadherin and an increase in p53 are linked to the dynamic interplay between the persistence, progression and regression of AKs. What's already known about this topic? Actinic keratoses (AKs) are common dysplastic epidermal lesions that result from chronic and excessive ultraviolet exposure. Biomarkers associated with progression and regression of AK have not been characterized. What does this study add? Decreased E-cadherin and increased p53, Snail, Slug and Twist (E-cadherin transcription factors) were associated with progression from AK to nonmelanoma skin cancer. What is the translational message? Strategies targeting these molecules may be effective in reversing rising skin cancer rates. E-cadherin, p53, Snail, Slug and Twist are potential biomarkers that may be used to assess the efficacy of existing chemopreventive agents.

Dosimetry of indigenously developed 177Lu patch source for surface brachytherapy-Experimental and Monte Carlo methods.

This paper describes the evaluation of dosimetry characteristics of an in-house developed 177Lu skin patch source for treatment of non-melanoma skin cancer. A 177Lu skin patch source based on Nafion-115 membrane backbone containing 3.46 ± 0.01 mCi of activity was used. Activity measurement of the patch source was based on gamma ray spectrometry using a HPGe detector. The efficiencies of the HPGe detector were fitted using an orthogonal polynomial function. The absorbed dose rate to water at 5 µm depth in water was determined using an extrapolation chamber, EBT3 Gafchromic film and compared with Monte Carlo methods. The correction factors such as Bragg-Gray stopping power ratio of water-to-air and chamber wall material being different from water, needed to be applied on measurements for establishing the dose rate at 5 µm depth, were calculated using the Monte Carlo method. Absorbed dose rate at 5 µm depth in water (surface dose rate) measured using an extrapolation chamber and EBT3 Gafchromic film were 9.9 ± 0.7 and 8.2 ± 0.1 Gy h-1 mCi-1 respectively for the source activity of 3.46 ± 0.01 mCi. The surface dose rate calculated using the Monte Carlo method was 8.7 ± 0.2 Gy h-1 mCi-1, which agrees reasonably well with measurement. The measured dose rate per mCi offers scope for ascertaining treatment time required to deliver the dose for propitious therapeutic outcome. Additionally, on-axis depth dose and lateral dose profiles at 5 µm and 1 mm depth in water phantom were also calculated using the Monte Carlo method.

DEVELOPMENT OF AN ALGORITHM TO ESTIMATE EYE LENS DOSE IN TERMS OF OPERATIONAL QUANTITY Hp(3) USING HEAD TLD BADGE.

In view of the recommendations of International Commission on Radiological Protection for reduction of the occupational annual dose limit for eye lens from 150 mSv to 20 mSv/y, questions have been raised on the adequacy of monitoring for the quantities Hp(10) and Hp(0.07). As an immediate requirement, in the present situation, where there is no exclusive eye lens dosemeter in India, the existing chest TLD badge was modified to be used as head badge (head dosemeter) by including a strap to enable wearing on the forehead. In order to estimate the eye lens dose in terms of the operational quantity Hp(3), the prevalent algorithm of chest badge was also modified. The modified algorithm was applied to estimate Hp(3) for dosemeters irradiated to various beta and photon radiations including mixtures. The Q values (estimated/delivered dose equivalent) were found to be within ±20% for most of the photon beams.

Measurements of background radiation levels around Indian station Bharati, during 33rd Indian Scientific Expedition to Antarctica.

A comprehensive measurement of radioactivity concentrations of the primordial radionuclides 238U, 232Th and 40K and their decay products in the soil samples collected from the sites of Indian research stations, Bharati and Maitri, at Antarctica was carried out using gamma spectrometric method. The activity concentrations in the soil samples of Bharati site were observed to be few times higher than of Maitri site. The major contributor to radioactivity content in the soil at Bharati site is 232Th radionuclide in higher concentration. The gamma radiation levels based on the measured radioactivity of soil samples were calculated using the equation given in UNSCEAR 2000. The calculated radiation levels were compared with the measured values and found to correlate reasonably well. The study could be useful for the scientists working at Antarctica especially those at Indian station to take decision to avoid areas with higher radioactivity before erecting any facility for long term experiment or use.

Study on the measurement of photo-neutron for15 MV photon beam from medical linear accelerator under different irradiation geometries using passive detectors.

AIM OF STUDY: The photo-neutron dose equivalents of 15 MV Elekta precise accelerators were measured for different depths in phantom, for various field sizes, at different distances from the isocenter in the patient plane and for various wedged fields. MATERIALS AND METHODS: Fast and thermal neutrons are measured using passive detectors such as Columbia Resin-39 and pair of thermoluminescent dosimetry (TLD) 600 and TLD 700 detector from Elekta medical linear accelerator. RESULTS: It is found that fast photo-neutron dose rate decreases as the depth increases, with a maximum of 0.57 ± 0.08 mSv/Gy photon dose at surface and minimum of 0.09 ± 0.02 mSv/Gy photon dose at 15 cm depth of water equivalent phantom with 10 cm backscatter. Photo neutrons decreases from 1.28 ± 0.03 mSv/Gy to 0.063 ± 0.032 when measured at isocenter and at 100 cm far from the field edge along the longitudinal direction in the patient plane. Fast and thermal neutron doses increases from 0.65 ± 0.05 mSv/Gy to 1.08 ± 0.07 mSv/Gy as the field size increases; from 5 cm × 5 cm to 30 cm × 30 cm for fast neutrons. With increase in wedge field angle from 0° to 60°, it is observed that the fast neutron dose increases from 0.42 ± 0.03 mSv/Gy to 0.95 ± 0.05 mSv/Gy.s CONCLUSIONS: Measurements indicate the photo-neutrons at few field sizes are slightly higher than the International Electrotechnical Commission standard specifications. Photo-neutrons from Omni wedged fields are studied in details. These studies of the photo-neutron energy response will enlighten the neutron dose to radiation therapy patients and are expected to further improve radiation protection guidelines.

Determination of surface dose rate of indigenous (32)P patch brachytherapy source by experimental and Monte Carlo methods.

Isotope production and Application Division of Bhabha Atomic Research Center developed (32)P patch sources for treatment of superficial tumors. Surface dose rate of a newly developed (32)P patch source of nominal diameter 25 mm was measured experimentally using standard extrapolation ionization chamber and Gafchromic EBT film. Monte Carlo model of the (32)P patch source along with the extrapolation chamber was also developed to estimate the surface dose rates from these sources. The surface dose rates to tissue (cGy/min) measured using extrapolation chamber and radiochromic films are 82.03±4.18 (k=2) and 79.13±2.53 (k=2) respectively. The two values of the surface dose rates measured using the two independent experimental methods are in good agreement to each other within a variation of 3.5%. The surface dose rate to tissue (cGy/min) estimated using the MCNP Monte Carlo code works out to be 77.78±1.16 (k=2). The maximum deviation between the surface dose rates to tissue obtained by Monte Carlo and the extrapolation chamber method is 5.2% whereas the difference between the surface dose rates obtained by radiochromic film measurement and the Monte Carlo simulation is 1.7%. The three values of the surface dose rates of the (32)P patch source obtained by three independent methods are in good agreement to one another within the uncertainties associated with their measurements and calculation. This work has demonstrated that MCNP based electron transport simulations are accurate enough for determining the dosimetry parameters of the indigenously developed (32)P patch sources for contact brachytherapy applications.

Radiation safety aspects of the operation of first three synchrotron beam lines of Indus-2.

Five synchrotron radiation beam lines are commissioned and now under regular operation at the Synchrotron Radiation Source, Indus-2 at Raja Ramanna Centre For Advanced Technology (RRCAT), Indore, India. Nine beam lines are under trial operation, and six beam lines are in the installation stage. In the early phase of installation of beam lines on Indus-2, three bending magnet beam lines, Extended X-ray Absorption Fine Structure (EXAFS, BL-8), Energy Dispersive X-ray Diffraction (EDXRD, BL-11) and Angle Dispersive X-ray Diffraction (ADXRD, BL-12), were installed and commissioned, after approval from Atomic Energy Regulatory Board (AERB), India. These beam lines are pink (BL-8), white (BL-11) and monochromatic (BL-12), which are housed in specially designed shielded hutches. In order to ensure safety of users and other working personnel from ionizing radiations present in these beam lines, several safety systems are incorporated and safety procedures are followed. The paper describes the radiological safety aspects of the three beam lines during its initial commissioning trials and also the measurements on radiation levels carried out in and around the beam line hutches.

A randomized controlled phase II trial of a novel composition of paclitaxel embedded into neutral and cationic lipids targeting tumor endothelial cells in advanced triple-negative breast cancer (TNBC).

BACKGROUND: EndoTAG-1, composed of paclitaxel embedded in liposomal membranes targeting tumor endothelial cells, was evaluated for safety and efficacy in advanced triple-negative breast cancer (TNBC). PATIENTS AND METHODS: One hundred and forty patients were treated with weekly EndoTAG-1 (22 mg/m(2)) plus paclitaxel (70 mg/m(2)), twice weekly EndoTAG-1 (2× 44 mg/m(2)), or weekly paclitaxel (90 mg/m(2)) for greater than or equal to four cycles (3-week treatment + 1-week rest) or until progression/toxicity. Primary end point was progression-free survival (PFS) rate evaluated centrally after four cycles of therapy (week 16). The study was not powered for intergroup comparisons. RESULTS: The PFS rate at week 16 was 59.1% [one-sided 95% CI: 45.6, ∞] on combination treatment, 34.2% [21.6, ∞] on EndoTAG-1, and 48.0% [30.5, ∞] on paclitaxel. Median PFS reached 4.2, 3.4, and 3.7 months, respectively. After complete treatment (week 41 analysis), median overall survival (OS) was 13.0, 11.9, and 13.1 months for the modified Intention-to-Treat (ITT) population and 15.1, 12.5, and 8.9 months for the per-protocol population, respectively. The clinical benefit rate was 53%, 31%, and 36% for the treatment groups. Safety analysis revealed known toxicities of the drugs with slight increases of grade 3/4 neutropenia on combination therapy. CONCLUSION: Treatment of advanced TNBC with a combination of EndoTAG-1 and standard paclitaxel [Taxol® (Bristol-Myers Squibb GmbH), or equivalent generic formulation] was well tolerated and showed antitumor efficacy. The positive trend needs to be confirmed in a randomized phase III trial. STUDY REGISTRATION: European Clinical Trials Database: EudraCT number 2006-002221-23. ClinicalTrials.gov identifier: NCT00448305.

Response of ionization chamber based pocket dosimeter to beta radiation.

Quantitative estimate of the response of ionization chamber based pocket dosimeters (DRDs) to various beta sources was performed. It has been established that the ionization chamber based pocket dosimeters do not respond to beta particles having energy (Emax)<1 MeV and same was verified using (147)Pm, (85)Kr and (204)Tl beta sources. However, for beta particles having energy >1 MeV, the DRDs exhibit measureable response and the values are ~8%, ~14% and ~27% per mSv for natural uranium, (90)Sr/(90)Y and (106)Ru/(106)Rh beta sources respectively. As the energy of the beta particles increases, the response also increases. The response of DRDs to beta particles having energy>1 MeV arises due to the fact that the thickness of the chamber walls is less than the maximum range of beta particles. This may also be one of the reasons for disparity between doses measured with passive/legal dosimeters (TLDs) and DRDs in those situations in which radiation workers are exposed to mixed field of gamma photons and beta particles especially at uranium processing plants, nuclear (power and research) reactors, waste management facilities and fuel reprocessing plants etc. The paper provides the reason (technical) for disparity between the doses recorded by TLDs and DRDs in mixed field of photons and beta particles.

Is there a role for metronomic induction (and maintenance) therapy in elderly patients with acute myeloid leukemia? A literature review.

Acute myeloid leukemia (AML) in older adults differs biologically and clinically from that in younger patients and is characterized by adverse chromosomal abnormalities, stronger intrinsic resistance, and lower tolerance to chemotherapy. In patients over age 60 with AML, cure rates are under 10% despite intensive chemotherapy, and most of them die within a year of diagnosis. Over the last decade, metronomic chemotherapy has emerged as a potential strategy to control advanced/refractory cancer. Here, we report a case of a 68-year-old gentleman having AML with high-risk cytogenetic features, who achieved complete remission on our oral metronomic PrET (PrET: Prednisolone, etoposide, thioguanine) protocol on an outpatient basis. He was later treated with standard high-dose (HD) cytosine arabinoside (Ara-C) consolidation followed by maintenance with etoposide, thioguanine, and sodium valproate. Presently, the patient is nearly 35 months since diagnosis and 21 months off treatment. This case report and review highlights that the combination of oral low-intensity metronomic therapy, followed by standard HD consolidation therapy and metronomic maintenance therapy may be well tolerated by elderly patients especially with less proliferative, high (cytogenetic)-risk AML who are otherwise deemed to be unfit for intensive intravenous induction chemotherapy regimens. References for this review were identified through searches of Pubmed for recent publications on the subject as well as searches of the files of the authors themselves. The final list was generated on the basis of originality and relevance to this review.

Single agent weekly paclitaxel as neoadjuvant chemotherapy in locally advanced breast cancer: a feasibility study.

AIM: To study the toxicity profile and response rates of weekly paclitaxel given as neoadjuvant chemotherapy (NACT) in patients with locally advanced breast cancer. MATERIALS AND METHODS: The study was planned as a single arm, prospective phase II study. Twenty-six patients with locally advanced breast cancer were enrolled in the study from December 2006 to October 2007. These patients underwent NACT with weekly paclitaxel at 100 mg/m(2) for 8 consecutive weeks followed by surgery. This was followed by anthracycline-based chemotherapy for three to four cycles followed by radiation. The patients received standard adjuvant hormonal therapy. The patients were carefully monitored for side-effects using common toxicity criteria. The clinical and pathological response rates were documented. The response rates were descriptively stated. RESULTS: The median age of the patients was 52 years (30-67 years) and the median tumour size was 7 cm (2.5-15 cm). Of the 208 planned weekly cycles, 207 could be given. The rates of grade 3-4 neutropenia, thrombocytopenia and neuropathy were 4, 12 and 4%, respectively. A complete clinical response was observed in 10 patients (38.5%) and a completed pathological response, defined as the absence of invasive cancer from the breast and axillary nodes, was seen in 11.5% of patients. Breast-conserving surgery was possible in 23% of patients. CONCLUSION: The regimen of weekly single agent paclitaxel is feasible in patients with locally advanced breast cancer with acceptable toxicity. It resulted in a pathological response rate that was comparable with other regimens in this group of advanced stage patients. Considering the efficacy and low toxicity of this regimen, it is worth exploring in larger studies.

Study on the response of thermoluminescent dosemeters to synchrotron radiation: experimental method and Monte Carlo calculations.

In the present study, the energy dependence of response of some popular thermoluminescent dosemeters (TLDs) have been investigated such as LiF:Mg,Ti, LiF:Mg,Cu,P and CaSO(4):Dy to synchrotron radiation in the energy range of 10-34 keV. The study utilised experimental, Monte Carlo and analytical methods. The Monte Carlo calculations were based on the EGSnrc and FLUKA codes. The calculated energy response of all the TLDs using the EGSnrc and FLUKA codes shows excellent agreement with each other. The analytically calculated response shows good agreement with the Monte Carlo calculated response in the low-energy region. In the case of CaSO(4):Dy, the Monte Carlo-calculated energy response is smaller by a factor of 3 at all energies in comparison with the experimental response when polytetrafluoroethylene (PTFE) (75 % by wt) is included in the Monte Carlo calculations. When PTFE is ignored in the Monte Carlo calculations, the difference between the calculated and experimental response decreases (both responses are comparable >25 keV). For the LiF-based TLDs, the Monte Carlo-based response shows reasonable agreement with the experimental response.

CD26 expression in donor stem cell harvest and its correlation with engraftment in human haematopoietic stem cell transplantation: potential predictor of early engraftment.

BACKGROUND: The efficiency of haematopoietic stem and progenitor cells (HSPCs) is important when donor cell numbers are limiting. Stable white blood cell (WBC) and platelet engraftment is crucial for the outcome of haematopoietic stem cell transplantation (HSCT). DESIGN: This article evaluates CD26/dipeptidyl peptidase-IV expression on mobilised peripheral blood stem cell (PBSC) harvest of donors and its correlation with engraftment in HSCT. We have analysed CD26 expression on cells in various gates, that is, lymphocytes, monocytes, neutrophils and all populations using flow cytometry tool. RESULTS: Ours is the first study on human mobilised PBSC harvest from cancer patients or allogeneic related donors (n = 28) to demonstrate that increased CD26 expression leads to early engraftment in transplanted cancer patients. Correlation of CD26 expression with WBC engraftment was statistically significant (lymphocyte gate: P < 0.00001; monocyte gate: P < 0.00001; neutrophil gate: P < 0.00001; all populations: P < 0.00001). CD34 expression is a known predictor of engraftment. Nevertheless, there was no correlation between CD34 and CD26 expression in these cases. CONCLUSIONS: This study has given important leads indicating that CD26 expression may be an independent predictor of engraftment. Further study with large number of patients as well as study on circulatory CD26 may add valuable information towards improving current knowledge on CD26.

Cytomegalovirus oesophagitis in a patient with Non-Hodgkin's lymphoma.

Cytomegalovirus (CMV) infection is frequent in immunocompromised patients, especially in AIDS, organ transplantation and rarely in Hodgkin's disease and Non-Hodgkin's lymphoma (NHL). We present a case of NHL with CMV oesophagitis, which has rarely been documented in literature. Apart from fungal and herpes simplex infections, as the common differential diagnosis for oesophagitis in patients of lymphoma, CMV should be considered an important etiologic agent. Early diagnosis and prompt treatment of CMV oesophagitis with gancyclovir can avert significant morbidity and avoid unacceptable treatment delays.

Fludarabine in lymphoproliferative malignancies: a single-centre experience.

BACKGROUND: Fludarabine has been reported to be an effective drug for the treatment of chronic lymphocytic leukaemia (CLL) and indolent lymphomas. However, its safety and efficacy in Indian patients has not been studied. We retrospectively analysed our experience with fludarabine in low grade lymphomas and CLL. METHODS: The records of all patients with low grade lymphoma or CLL who received fludarabine between April 1999 and November 2006 were analysed. Response evaluation was done as per the National Cancer Institute-Working Group guidelines for CLL and International Workshop criteria for non-Hodgkin lymphomas, respectively, in those patients who received at least 3 cycles of fludarabine. Toxicity was graded as per the common terminology criteria for adverse events, version 3.0. Median event-free survival was obtained using Kaplan-Meier survival analysis. RESULTS: Forty-seven patients were included in the study and 189 cycles were administered (median: 4 cycles per patient). Sixteen patients had a treatment delay, 14 due to myelosuppression. Twenty-five patients had low grade lymphoma and 22 had CLL. The response was evaluable in 22 patients with low grade lymphoma and 20 with CLL. The overall response rate for CLL was 100% in those treated upfront (n=9) and 55% in those with relapsed disease (n=11). The overall response rate for low grade lymphoma was 88% (63% complete remission) in untreated patients and 79% (43% complete remission) in those with relapsed disease. Common adverse events were myelosuppression and infection. Two patients died of sepsis and 4 due to disease progression on treatment. Median event-free survival for patients treated upfront with fludarabine was 31.4 months. CONCLUSION: In our patient population, response to fludarabine is similar to that in the published literature. Our patients had a higher frequency of haematological toxicity.

The effect of short-term intensive chemotherapy on reactivation of tuberculosis.

BACKGROUND: Various malignancies and cytotoxic chemotherapy have been proposed to increase the risk of reactivation of tuberculosis. Available literature to support this observation is still conflicting. There is scarcity of data from countries with rampant tubercular infection, such as India, in this regard. DESIGN AND METHODS: In the present retrospective analysis, patients with high-grade non-Hodgkin's lymphoma with past history of tuberculosis and have had adequate antitubercular therapy were identified from a Lymphoma Group study. These patients were followed up during cytotoxic chemotherapy and later to assess the risk of reactivation. RESULTS: A cohort of eight patients with past history of tuberculosis was selected from 141 patients of high-grade non-Hodgkin's lymphoma. The median age was 33.5 years (range, 24-53 years). Median duration between completion of antitubercular treatment and diagnosis of lymphoma was 5 years (range, 1.5-10 years). All patients received cyclical cytotoxic chemotherapy. The median duration of follow up after completion of chemotherapy was 5 years (range, 10 months to 5 years). None of these patients developed reactivation of tuberculosis. CONCLUSION: Cyclical chemotherapy for non-Hodgkin's lymphoma does not lead to reactivation of tuberculosis.