[en] The combinatorial approach for the discovery of new scintillating materials has been investigated using the wet-chemical (sol-gel) synthesis methods. Known scintillating compounds Lu₂SiO₅ (LSO) and (LuAl)O₃ (LAO) and solid solutions in the systems of Lu₂O₃-Y₂O₃--SiO₂ (CeO₂-doped) (LYSO) and Lu₂O₃ -Y₂O₃--Al₂O₃ (CeO₂-doped) (LYAO) were synthesized from sol-gel precursors. Sol-gel precursors were formulated from alkoxides and nitrates and acetates of the cations. Sol-gel solution precursors were formulated for the printing of microdot arrays of different compositions in the above oxide systems. Microdot arrays were successfully printed on C-cut and R-cut sapphire substrates using Biodot printer at Los Alamos National Laboratory (LANL). The microdot arrays were adherent and stable after heat-treating at 1665 C and had an average thickness of around 2 (micro)m. X-ray fluorescence elemental mapping showed the arrays to be of the correct chemical composition. Sintered microdots were found to be highly crystalline by microscopic observation and X-ray diffraction. Scintillation was not clearly detectable by visual observation under UV illumination and by video observation under the scanning electron beam of an SEM. The microdots were either poorly scintillating or not scintillating under the present synthesis and testing conditions. Further improvements in the synthesis and processing of the microdot arrays as well as extensive scintillation testing are needed

No abstract available

[en] The study aims to see the correlation between Standardized Uptake Value (Max) of prostatic lesions in relation with risk stratification of prostate cancers. Initial staging 68-Ga PSMA PET CT scans of 286 patients with prostate cancers (Low Risk- 11, Intermediate Risk- 63, High Risk- 212) were assessed. SUVmax values of the prostatic lesions were noted. Gleason’s score as per the respective histopathological reports available from Electronic Medical Records was recorded. Mean and median SUVmax values of respective categories were obtained. Kruskal Wallis test was applied to the given study data. The mean SUVmax in low risk / intermediate risk / high risk prostate cancers was found to be 15.07, 18.80 and 31.50 respectively. The median SUVmax across the categories was 8.78, 18.45 and 26.06 respectively. The median rank in low risk category was 69.09, in intermediate risk category was 104.95 and high risk category was 158.82. As per Kruskal Wallis test, difference between group SUVmax values across low / intermediate / high risk prostate cancer categories is statistically significant. A positive correlation was found between the SUVmax values of prostatic lesions and the risk category of the patient, a higher median SUVmax value being observed in high risk prostate cancers cases and a lower median SUVmax value being observed in low risk prostate cancer cases. The SUVmax value of prostatic primary lesion can be used as a predictive indicator of the risk category of the individual before a 12 core prostate biopsy. (author)

[en] With the increasing application of F-18-fluorodeoxyglucose (FDG) positron emission imaging, there has been an evolving appreciation for the range of normal variants and the realization that false- positives can lead to serious consequences. One of the most common causes of a false-positive study is the uptake of FDG in areas of brown adipose tissue. BAT is generally present in deep cervical regions, including the supraclavicular areas, the interscapular and paravertebral regions, and areas near large vessels. Areas of involvement are often spatially closely related to important lymph node groups in the neck, axilla, and upper mediastinum, making critical differentiation difficult. The uptake of 18F FDG in brown adipose tissue (BAT) limits the ability of a PET scan to detect the sites of viable disease. Many studies have been done after premedication with Diazepam (benzodiazepines) to reduce the uptake of FDG by brown fat. But they are of limited value. Thus, it would be ideal if a drug could completely reverse the brown fat uptake and thus aid in proper management of the patient. The aim of this study is to see if by giving a single dose of a beta-blocker such as 'Ciplar' (Propranolol) 40 mg, 30 minutes prior to the FDG injection will help in reduction of brown fat uptake of 18F-FDG or not. Materials and Methods: Patients who were referred for a PET scan, either for a pretreatment or a post treatment evaluation and who showed FDG uptake in brown adipose tissue (BAT) were taken up for this study. The total number of patients was 14. A repeat PET scan was done after a gap of at least 48 hrs after the first study. The patients were advised to keep themselves warm with adequate warm clothing on the day of the second study. 40 mg of 'Ciplar' (propranolol) was given orally 30 minutes prior to the 18F-FDG injection. A whole body PET scan was performed on a dedicated whole body PET scanner (ADVANCE, GE Medical Systems, Milwaukee, WI.), using attenuation correction with 68-Ge external pin sources. Results: All patients showed absence of uptake of FDG in BAT, post propranolol. Discussion: Intense FDG uptake in BAT can lead to false positive FDG PET findings. BAT is known to exhibit increased glucose uptake when the sympathetic nervous system is activated by cold stimulation. BAT has rich adrenergic innervation. BAT acts as a thermogenic organ by producing heat to maintain body temperature especially in young individuals. BAT requires glucose as a source of adenosine triphosphate (ATP). This ATP is required for fatty acid oxidation, which is the main mechanism for heat production. In this study, we demonstrated that the intense FDG uptake in BAT can be successfully eliminated by giving 40 mg of propranolol orally 30 minutes prior to the 18-F FDG injection. Propranolol is a non- selective beta-adrenergic receptor blocking agent. It has no other autonomic nervous system activity. It is rapidly and completely absorbed from the gastrointestinal tract and undergoes extensive first-pass elimination due to its high hepatic clearance. Conclusion: Propranolol reduces the uptake of 18F FDG in BAT and thus improves the accuracy of PET imaging. (author)

[en] Reduction and hydrofluorination are some of the most important stages in the production of nuclear grade green salt, UF₄, involving solid-gas reactions. They are difficult steps considering the process conditions and nature of materials to be handled (reduction involves cracked ammonia at 600 deg C which is highly explosive, handling of brown oxide which is radioactive and pyroforic; hydrofluorination involves highly toxic and corrosive hydrofluoric acid diluted with cracked ammonia at 450 deg C). In view of the above, emphasis has to be given for efficient leak tightness of the equipment being employed for this purpose such that atmospheric air should not leak into the equipment as well as process gases, radioactive powder should not leak out. Previous experience from other Department of Atomic Energy (DAE) units, indicated that the failure of dynamic seals is the nagging problem with consequent bearing on safety, availability and ease of maintenance. The attempt made in improving the design, showed promising results at Rare Materials Plant (RMP), Mysore is described. (author)

[en] Platelet monoamine oxidase is a mitochondrial enzyme taking part in the deamination reaction of total catecholamine. Recent studies of monoamine oxidase inhibitors have gained its importance in the control of variety of psychosomatic disorders like mental depression, arterial hypertension and anxiety neurosis. 30 apparently normal individuals and 42 diagnosed cases of essential hypertension were selected for the present study. The platelet monoamine oxidase activity was measured by using ¹⁴C-tryptamine bisuccinate. Comparatively low activity of platelet monoamine oxidase was noticed in hypertension cases than in the normal. After oral administration of an indigenous drug 'Geriforte' for three months, a significant rise in platelet monoamine oxidase activity was noticed in hypertension cases. It can be concluded that this indigenous formulation has the capacity to regulate the monoamine oxidase activity, as such, it may provide an alternative remedy in the management of psychosomatic disorders. (author). 11 refs

[en] Aim: This study was undertaken to see whether FDG -PET is useful in discriminating benign and malignant solitary thyroid nodule (STN) and aid in preoperative evaluation, noninvasively. Materials and Methods: 89 patients with STN that were nonfunctioning or 'cold' on Pertechnetate/131-I scan were studied with 18F Fluorodeoxyglucose (FDG) - Positron Emission Tomography (PET) scanning. Results: They were graded as A-E for the type (depending on intensity) of uptake. Group A - Consisted of 23 patients with intense FDG uptake (grade III) in the STN. On histopathology 22 were carcinoma thyroid and 1 was Hurthle cell adenoma. Group B - consisted of 5 patients with intense uptake in the wall of the nodule. On surgery 4 were malignant and I was a benign thyroid cyst with granulomatous reaction and chronic inflammation rich in plasma cells. Group C - consisted of 9 patients with mild FDG uptake in the nodule. All were benign on histopathology and Fine Needle Aspiration Cytology (FNAC) correlation. Group D - 51 patients with no FDG uptake in the nodule. 50 were benign nodules and I was Papillary carcinoma. Group E - Had I patient with intense FDG uptake in both lobes with no FDG uptake in the nodule. FNAC from the nodule was benign and intense uptake in both lobes was due to thyroiditis confirmed by raised AntiMicrosomal Antibodies (AMA) titre. Discussion: The primary aim in the work up of thyroid nodules is to determine which nodules are benign and which harbor malignancy and need to undergo surgical resection. With the advent of FNA of thyroid nodules the percentage of patients undergoing surgical resection for asymptomatic benign nodules has decreased substantially. But the main problem lies in correctly differentiating benign follicular adenomas from follicular carcinoma by FNA. Therefore a non-invasive investigation, which could preoperatively distinguish benign and malignant lesions, would spare many patients from undergoing unnecessary surgical resection of benign lesions. It would also be helpful in patients who are at high-risk for surgical morbidity-as an unnecessary surgery can be avoided. PET differs from conventional imaging techniques like USG, CT, MRI in that they rely on morphological alterations for tumor detection. In contrast, PET is a functional imaging technique that relies on in vivo visualization of lesional glucose metabolism. The value of FDG- PET is already established in the follow- up of those thyroid cancers with elevated TG levels and negative radioiodine scans. This prospective study was undertaken to see the usefulness of PET in differentiation of benign and malignant thyroid nodules, preoperatively. In our study, 23 patients showed intense focal uptake in the solitary thyroid nodule. Out of these 23 patients, 22 were primary thyroid cancer and 1 was false positive. The histology of I was Hurthle cell adenoma. This finding is in concurrence with recent molecular studies that have shown Hurthle cell adenomas cluster with follicular and Hurthle cell cancers, rather than with benign follicular adenomas in hierarchical cluster analysis. According to this study Hurthle cell adenomas may in fact be pre malignant lesions. Grouping of hurthle cell adenoma with hurthle cell carcinoma supports this hypothesis. Thus hurthle cell adenoma showing intense FDG uptake with high SUV may point to a different biologic behavior of these masses. 5 patients showed intense uptake in the wall, consistent with focus of cancer in the wall in 4 patients and granulomatous reaction rich in plasma cells in 1. 9 patients with mild FDG uptake were colloid goiter in 1, follicular adenoma in I and Hashimoto's thyroiditis in 2. 52 patients showed photopenic defects. Out of these 52, 51 were benign and only one turned out to be papillary carcinoma. This was an isthmic nodule < 1 cm in size. Its small size was attributed to its false negativity. 1 of these 52, showed diffuse uptake of FDG in both lobes of thyroid, which was consistent with thyroiditis. The nodule was 'photopenic' and FNAC of the nodule was benign. Thus, intense foc al uptake, with a SUV of >3.5 in the thyroid gland suggested malignancy and minimal or no uptake of FDG was consistent with a benign lesions.There is a growing need for a non- invasive technique that can correctly segregate the patients into benign or malignant group in all 'cold' nodules. Clearly, a solitary nodule need undergo only a PET scan as a diagnostic modality. Only those showing either B or C type of uptake be sent for further tests like FNAC and ultrasound. Those with intense FDG uptake could be sent for surgery directly. This would narrow down the surgical referral and would be more cost effective than carrying out unnecessary surgery. Conclusion: FDG-PET can reliably distinguish the thyroid nodule into benign and malignant, when both visual interpretation and Standardized Uptake Values (SUVs) are taken into consideration. It has an important role in those nodules where the FNAC is indeterminate. In particular, FDG -PET thyroid scan plays an important in identifying malignancy in predominantly cystic lesions, which have been labeled as benign by other conventional modalities. Based on the FDG scan, after the analysis of the SUV, a patient can be directly sent for surgery or can be observed. (author)

[en] The local position invariance of a physical system is examined using a Rydberg atom and the universality of free fall is found to be invalid for a quantum system. A Rydberg atom is analysed in Newtonian gravity and curved space. The energy is found to vary as n² for very large values of the principal quantum number n. The change in energy is calculated using this formalism and compared to a similar calculation by Chiao. The value that we have got from our calculation is found to be 6 orders higher in magnitude than Chiao's value. These results can be of significance in gravitational redshift experiements proposed by Muller et al and Wolf et al

[en] With limited literature on the abilities of ⁶⁸Ga PSMA PET/CT as a treatment response assessment tool in patients with prostatic adenocarcinoma, we explore the patterns of disease response on this modality with respect to biochemical response based on S.PSA, after medical or surgical androgen deprivation therapy. This may lead to further understanding of the in vivo effect on PSMA expression and disease volume, which may enhance its value in routine clinical practice. Discordance between the volumetric response on PET/CT (using PSMA-TV) and biochemical response endorses a possibility of the true objective representation of the post therapy disease burden by ⁶⁸Ga PSMA PET/CT. Response to ADT differs lesion wise with primary disease showing persistence or progression in a strong majority of patients, whereas metastatic nodal and bony lesions show complete resolution in majority of the patients with the particular lesions respectively. Thus, post therapy PET/ CT response may be used as a guide to plan local therapy with curative intent, following ADT. It is particularly useful in cases with low pre-therapy serum PSA levels. (author)

[en] The existing beam Steerer magnet in K500 Superconducting Cyclotron (SCC) vertical injection beam line was designed for ±1.0 degree beam deflection both in horizontal and in vertical direction. The nominal operating current has been ± 3.0 A. However, during beam tuning it has been observed that coils got heated up with an increase in measured temperature of more than 110°C after few hours of operation and consequently the voltage across the coil gradually increases to the limiting rated voltage of power supply (20 V). This causes power supply to trip during beam tuning. The reason of coil heating-up is found to be due to poor heat transfer coefficient of still air cooling to coil surface. The possible solution of the heating-up issue is to use iron poles along with iron cylindrical return path (4 mm thickness) around the coil. Use of iron poles and return cylinder yoke around it reduces the operating current near to 1.5 A (instead of 3.0 A) to achieve the same performance of the coil. The paper describes the details of the correction made and subsequent results after the incorporation of iron poles. (author)