Rajender Kumar

Note: Tesla based pulse generator for electrical breakdown study of liquid dielectrics

In the process of studying charge holding capability and delay time for breakdown in liquids under nanosecond (ns) time scales, a Tesla based pulse generator has been developed. Pulse generator is a combination of Tesla transformer, pulse forming line, a fast closing switch, and test chamber. Use of Tesla transformer over conventional Marx generators makes the pulse generator very compact, cost effective, and requires less maintenance. The system has been designed and developed to deliver maximum output voltage of 300 kV and rise time of the order of tens of nanoseconds. The paper deals with the system design parameters, breakdown test procedure, and various experimental results. To validate the pulse generator performance, experimental results have been compared with PSPICE simulation software and are in good agreement with simulation results.

Sensitive Detection of a Small Parathyroid Adenoma Using Fluorocholine PET/CT: A Case Report

Primary hyperparathyroidism is caused by parathyroid adenoma in the majority of cases and diagnosis is usually made biochemically. Pre-surgical localization of parathyroid adenoma is essential to limit the extent of surgery and avoid missing them at ectopic sites. Anatomical and functional imaging are used for the localization, but may fail to identify the small and ectopic parathyroid adenoma. We present a case of small sized ectopic parathyroid adenoma at unusual location detected by F-18 fluorocholine (FCH) PET/CT, where other imaging modalities failed. The post-operative histopathology confirmed the diagnosis of ectopic parathyroid adenoma.

An Unusual And Intriguing Presentation Of Sydenham’s Chorea

A 26-year-old male born of a non-consanguineous marriage with normal birth and developmental history presented with abnormal movements for the last 15 years. He first noticed changes in his handwriting. The movements were jerky, non-stereotyped, and were associated with violent flinging movements. They were not preceded by any premonitory urge and were only partially suppressible. The movements gradually progressed to involve the face and neck, and, over the next 5 years, became generalized. His parents also complained of behavioral disturbances such as hyperactivity, aggressiveness, and obsessive-compulsive behavior. There was no history of cognitive decline, psychosis, seizures, or myoclonic jerks. Family history was non-contributory. There was no history of rheumatic fever, vasculitis, or exposure to toxins. The patient suffered frequent throat infections until the age of 5 years. He had been previously prescribed multiple medications, without significant improvement (tetrabenazine, haloperidol, valproate, clonazepam in various combinations). General physical examination was normal. He was alert, oriented to time, place, and person. Pertinent examination findings included unclear speech and generalized hypotonia. Deep tendon reflexes were 2+ with bilateral flexor plantar response and no cerebellar signs. The movement disorder is depicted in the Video 1. Work-up for his generalized chorea was undertaken. His C-reactive protein and antistreptolysin (ASO) titers were normal. Vasculitic markers Rheumatoid factor (RF/ ANA/dsDNA/C3/c-ANCA/p-ANCA/anti-Ro/La/anticardiolipin antibodies/APLA/LA), 24-hour urinary copper, ceruloplasmin levels, PBF for acanthocytes, TSH, anti-TPO antibodies, anti-TTG, alpha-fetoprotein, and vitamin E levels were all within normal limits. Antibody testing for paraneoplastic syndrome was negative. Previously performed normal investigations included tandem mass spectrometry for aminoacidopathies, urine for propionic aciduria, genetic testing for DYT1 mutation, and genetic testing for Huntington’s disease (CAG repeats25). Magnetic resonance imaging brain was normal. Fludeoxyglucose positron emission tomography (PET) brain revealed mild hypermetabolism in the bilateral caudate nuclei (Figure 1). Echocardiography revealed mild thickening of the mitral and aortic leaflets. In view of longstanding generalized chorea with the suggestion of mitral valve thickening on echocardiography and striatal hypermetabolism on the PET scan, the patient was diagnosed as a case of Sydenham’s chorea. Whole-exome sequencing did not reveal any pathogenic variation. Finally, antineuronal antibodies (Cunningham panel) were markedly elevated: dopamine D1, 16,000 (normal range 500–2000); lysoganglioside, 320 (normal range 80–320); tubulin, 4,000 (normal range 250–1,000), CaM kinase II, 120 (normal range 53–130). In view of these findings, the patient was started on methylprednisolone therapy and intravenous immunoglobulin. However, the patient showed only a marginal improvement in the severity of chorea. The hyperkinetic movements decreased in amplitude. His gait improved, and violent flinging movements of the arms also decreased in intensity. Presently, the patient is on periodic cycles of methylprednisolone and intravenous immunoglobulin Freely available online

Incremental Role of 18FDG PET/CT in Assessment of Testicular Viability

Testicular torsion is a common differential diagnosis of acute scrotal pain along with acute epididymo-orchitis, which may lead to testicular non-viability. Doppler ultrasound and testicular scintigraphy are two routinely used modalities for the assessment of testicular viability. However, in some cases, these investigations may prove inadequate in differentiating between the two entities with widely differing management. Here, we present a case of a 52-year-old male with questionable viability of testis, who was investigated initially using testicular scintigraphy and was further subjected to a regional 18F-FDG PET/CT scan, in view of inconclusive findings with the conventional modalities.

Novel use of 177Lu-DOTA-RGD2 in treatment of 68Ga-DOTA-RGD2-avid lesions in papillary thyroid cancer with TENIS

Thyroglobulin elevation with negative I scintigraphy (TENIS) in patients with differentiated thyroid carcinoma (DTC) poses a unique management challenge to the physician due to limited treatment modalities. Treatment with chemo-radiation, redifferentiation therapy, tyrosine kinase inhibitors and peptide receptor radionuclide therapy (PRRT) using somatostatin analogues have shown very insignificant clinical benefits with high incidence of adverse effects [1]. Arginylglycylaspartic acid (RGD) tripeptide sequence, having very high specificity towards αvβ3 integrin, is over-expressed on the tumor vasculature, including DTC and can be used as a theranostic agent [2–4]. We present a 54-year-old woman with papillary carcinoma thyroid who developed TENIS syndrome after receiving 500 GBq of I in cumulative doses. She experienced significant adverse effects with no clinical improvement on sorafenib therapy for 1 year and presented with severe pain and a palpable hard mass in the pre-sternal region. GaDOTA-RGD2 PET/CT was performed to evaluate disease extent and for pre-therapy assessment. The maximum intensity projection (MIP) image (a) and transaxial fused PET/CT images showed increased tracer uptake in the thyroid remnant [maximum standardized uptake value (SUVmax) = 4.7] with cervical lymph nodes (b), mediastinal lymph node (c; SUVmax = 8.4), lytic skeletal lesions with soft tissue component in the sternum (c; SUVmax = 7.8) and left iliac bone (d; SUVmax = 8.4) and multiple lung nodules (e). The patient received 5.5 GBq of Lu-DOTA-RGD2 with post-therapy whole-body images in anterior (f) and posterior (g) views revealing the overall distribution of LuDOTA-RGD2 and transaxial fused SPECT/CT images (h–k) showing tracer uptake at sites corresponding to Ga-DOTA-RGD2 -avid lesions. The patient was followed up at 4 months post-therapy, with significant pain relief and reduced pre-sternal swelling suggesting clinical benefit. Post-therapy follow-up Ga-DOTARGD2 PET/CT MIP image (l) and transaxial fused PET/CT images showed tracer uptake in the thyroid remnant (SUVmax = 3.0 vs. 4.7) with cervical lymph nodes (m), mediastinal lymph node (n; SUVmax = 7.7 vs. 8.4), lytic skeletal lesions with significant reduction in soft tissue component in the sternum (n; SUVmax = 6.6 vs. 7.8) and left iliac bone (o; SUVmax 8.1 vs. 8.4) and multiple lung nodules (p), suggesting response to therapy. To the best of our knowledge, this is the first reported theranostics using Ga-DOTA-RGD2 and Lu-DOTA-RGD2 and can be a stepping stone for future studies.

68Ga-labelled PSMA (prostate specific membrane antigen) expression in signet-ring cell gastric carcinoma

Despite the decrease in incidence of gastric carcinoma, the incidence of signet-ring cell gastric carcinoma (SRCG) has shown an increasing trend in the last 30 years [1]. Skeletal metastases from gastric cancer are very rare and seen in the later course of disease after excision of primary tumors [2]. Widespread bone metastasis at initial presentation is rare. A 65-year-old female presented with lower backache and loss of weight for one month (X-ray showed multiple lytic

Fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography masquerading as a case of sporadic malignant peripheral nerve sheath tumor of lower extremity presenting as massive lower limb edema

Malignant peripheral nerve sheath tumors (MPNSTs) are rare neuroectodermal tumors resulting from the malignant transformation of benign plexiform neurofibromas. The sporadic form of these tumors is rare than familial variants (seen in neurofibromatosis Type 1) and making the diagnosis difficult. We are presenting a case of 40–-year-old female with the complaint of progressive swelling of lower limb with initial suspicion of lymphedema and underwent lymphoscintigraphy, magnetic resonance imaging, and finally fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography scans were done to rule out mitotic etiology and extent of the disease. The patient underwent below-knee amputation, and histopathological examination confirmed the diagnosis of sporadic MPNST.

Primary adrenal T-cell lymphoma in a young adult presented with pseudo-hypopyon: a case report and literature review

Fig. 1. Microscopic findings, immunohistochemical staining, and whole-body fluorine-18-fluorodeoxyglucose positron emission tomography /computed tomography (F-FDG PET/CT) of primary adrenal T-cell lymphoma. (A) Aqueous humor aspiration showed infiltration of atypical lymphoid cells. (B) Bone marrow (BM) aspiration showed infiltration of atypical lymphoid cells with irregular nuclear membrane, coarse chromatin, basophilic cytoplasm and fine azurophilic granules