Summary. Single photon emission computed tomography (SPECT) has been the cornerstone of nuclear medicine and today it is widely used to detect molecular changes in cardiovascular, neurological and oncological diseases. While SPECT has been available since the 1980s, advances in instrumentation hardware, software and the availability of new radiotracers that are creating a revival in SPECT imaging are reviewed in this paper.The biggest change in the last decade has been the fusion of CT with SPECT, which has improved attenuation correction and image quality. Advances in collimator design, replacement of sodium iodide crystals in the detectors with cadmium zinc telluride (CZT) detectors as well as advances in software and reconstruction algorithms have all helped to retain SPECT as a much needed and used technology.Today, a wide spectrum of radiotracers is available for use in cardiovascular, neurology and oncology applications. The development of several radiotracers for neurological disorders is briefly described in this review, including [123 I]FP-CIT (DaTSCAN™) available for Parkinson's disease. In cardiology, while technetium-99m labeled tetrofosmin and technetium-99m labeled sestamibi have been well known for myocardial perfusion imaging, we describe a recently completed multicenter clinical study on the use of [ 123 I]mIBG (AdreView™) for imaging in chronic heart failure patients. For oncology, while bone scanning has been prevalent, newer radiotracers that target cancer mechanisms are being developed. Technetium-99m labeled RGD peptides have been reported in the literature that can be used for imaging angiogenesis, while technetium-99m labeled duramycin has been used to image apoptosis.While PET/CT is considered to be the more advanced technology particularly for oncology applications, SPECT continues to be the modality of choice and the workhorse in many hospitals and nuclear medicine centers. The cost of SPECT instruments also makes them more attractive in developing countries where the cost of a scan is still prohibitive for many patients.

Summary. Single photon emission computed tomography (SPECT) has been the cornerstone of nuclear medicine and today it is widely used to detect molecular changes in cardiovascular, neurological and oncological diseases. While SPECT has been available since the 1980s, advances in instrumentation hardware, software and the availability of new radiotracers that are creating a revival in SPECT imaging are reviewed in this paper.The biggest change in the last decade has been the fusion of CT with SPECT, which has improved attenuation correction and image quality. Advances in collimator design, replacement of sodium iodide crystals in the detectors with cadmium zinc telluride (CZT) detectors as well as advances in software and reconstruction algorithms have all helped to retain SPECT as a much needed and used technology.Today, a wide spectrum of radiotracers is available for use in cardiovascular, neurology and oncology applications. The development of several radiotracers for neurological disorders is briefly described in this review, including [123 I]FP-CIT (DaTSCAN™) available for Parkinson's disease. In cardiology, while technetium-99m labeled tetrofosmin and technetium-99m labeled sestamibi have been well known for myocardial perfusion imaging, we describe a recently completed multicenter clinical study on the use of [ 123 I]mIBG (AdreView™) for imaging in chronic heart failure patients. For oncology, while bone scanning has been prevalent, newer radiotracers that target cancer mechanisms are being developed. Technetium-99m labeled RGD peptides have been reported in the literature that can be used for imaging angiogenesis, while technetium-99m labeled duramycin has been used to image apoptosis.While PET/CT is considered to be the more advanced technology particularly for oncology applications, SPECT continues to be the modality of choice and the workhorse in many hospitals and nuclear medicine centers. The cost of SPECT instruments also makes them more attractive in developing countries where the cost of a scan is still prohibitive for many patients.

Research in the eld of periodontology has observed a huge upheaval in the last two decades unveiling newer alterations in techniques, methodologies, and material science. The recent centre of attention in periodontal research is an evidence-based approach which offers a bridge from science to clinical practice. Research inculcates scientic and inductive thinking and it promotes the development of logical habits of thinking and organization. In terms of research methodology, the article aim to inform the reader on topics relating to randomized controlled trials in periodontal research, evidence-based dentistry, calibration of clinical examiners and statistics relevant to periodontal research.

Objective: The aim of this study was to assess the awareness, concern and practice on hazards of ionizing radiation and radiation protection among radiographers and technologists of Pokhara, Nepal and to evaluate the knowledge of radiation and its protection among them. Materials and Methods: A validated questionnaire was used to collect data from radiographers and Technologists. The survey included multiple choice questions (MCQs) related to demographic characteristics (age, gender), academic qualification, and knowledge of radiation and radiation protection. Obtained data were analyzed using Statistical Package for Social Science (SPSS) version 25 software and shown in frequency, percentages. Results: Among 103 participants, only 73.8% were NHPC registered and 46.7% had attended classes/seminar on the topic of radiation protection. Only 8.7% used dosimeters to measure the radiation dose. Among participants, 77.7% knew that annual whole-body dose for a radiation worker is 20 mSv and 87.4% knew that there should be distance of more than six feet from the X-ray tube while taking X-ray in the case of non-barrier protection. This study shows that the knowledge and the perceptions regarding radiation and its protection among the radiographers/technologist is just satisfactory and needs to be improved. Conclusion: Overall awareness and knowledge of radiation protection and radiological procedures of radiologic technologist were satisfactory. However, there were some question that they needed mandatory training and knowledge. Therefore, we recommend that further workshops, seminars, symposium, training courses and Continuing Medical Education (CME) programs are recommended on a regular basis in collaboration with ISSRT and other national and international organizations to raise the level of radiation awareness.

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