Journal of Medical Physics
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NEWS
Year : 2022  |  Volume : 47  |  Issue : 3  |  Page : 311-314
 

News


Professor, Medical Physics Unit, IRCH, AIIMS, New Delhi, India

Date of Submission22-Sep-2022
Date of Decision26-Sep-2022
Date of Acceptance26-Sep-2022
Date of Web Publication8-Nov-2022

Correspondence Address:
Dr. Pratik Kumar
Medical Physics Unit, IRCH, AIIMS, New Delhi - 110 029
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jmp.jmp_89_22

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How to cite this article:
Kumar P. News. J Med Phys 2022;47:311-4

How to cite this URL:
Kumar P. News. J Med Phys [serial online] 2022 [cited 2022 Nov 29];47:311-4. Available from: https://www.jmp.org.in/text.asp?2022/47/3/311/360600



   International Atomic Energy Agency Issues Revised Quality Assurance Team in Radiation Oncology Guidelines Top


In 2007 International Atomic Energy Agency (IAEA) issued guidelines regarding the comprehensive external audit of radiotherapy (RT) establishment where cancer is treated by radiation entitled “Comprehensive Audits of Radiotherapy Practices: A tool for Quality Improvement.” The comprehensive quality audit which encompassed the organization, infrastructure, clinical practice, medical physics process, etc., was a comprehensive endeavor to evaluate the quality of all the components of the RT practice including professional competence. A multidisciplinary team comprising a radiation oncologist, a medical physicist, and a radiation therapist are required to carry out the audit. This team was called Quality Assurance Team in Radiation Oncology (QUATRO) and the guidelines for comprehensive audit are popularly called QUATRO Guidelines. However, since the publication of the first edition about 15 years back, the technology has changed and new modalities have been developed in radiation management. IAEA has revised and issued the second edition of this publication in September 2022 which incorporates the feedback of QUATRO audit teams and banks upon the experiences of the QUATRO auditors who have come across field realities while auditing the RT facilities across the globe.

The details may be accessed at:

https://www.iaea.org/publications/14754/comprehensive-audits-of-radiotherapy-practices-a-tool-for-quality-improvement

The free publication from IAEA may be downloaded from:

https://www-pub.iaea.org/MTCD/Publications/PDF/PUB1990_web.pdf


   Laser-based Proton Beam Got Tested in Animal Model Top


The scientists from Helmholtz-Zentrum Dresden-Rossendorf laboratory in Dresden, Germany, have successfully irradiated the animal with the protons accelerated by the laser for the first time. A proton beam created by laser is a novel concept and such a practical proton beam for preclinical irradiation may lead to optimal RT later. Such a laser proton system is likely to be compact as compared to the available proton accelerator facilities which need large particle accelerator and transport techniques. In laser proton, the high-power laser generates a strong but extremely short light pulse directed toward the thin plastic or metal foil. This intense laser flash knocks of hordes of electrons out of foil creating a strong electric field that can bundle protons into pulses and accelerate them to high energy. However, the scale of the phenomenon is very small and protons travel in terms of micrometers. Over one and half decades, scientists tried to understand the interaction of laser pulse with foil to ultimately create stable laser protons with sufficient energy. They found that in addition to other parameters, the shape of the laser flash was very important. It is to note that laser protons carry enormous intensity and hence deliver the required dose in a millionth of a second as compared to a few minutes as in presently functional proton accelerators. It is assumed that such FLASH-RT with the help of laser protons may spare the surrounding tissues.

The details may be accessed at:

https://www.news-medical.net/news/20220314/Irradiation-of-tumors-with-laser-protons-tested-for-the-first-time.aspx


   Piezoelectric Fiber Leads to Acoustic Clothes Top


Researchers at Massachusetts Institute of Technology, USA, have developed piezoelectric fiber which may enable the fabric to detect sound and sense mechanical vibration created by sound and convert them into an electrical signal. Such clothes may spur a range of medical and communication devices since such fabric may translate the pressure wave of sound reaching to it into mechanical vibration. It is just like our eardrum membrane works and converts the sound waves (pressure waves) to mechanical vibrations. Mechanical vibrations are carried to our cochlea which converts them into an electrical signal. Ultimately, our nervous system picks up these electrical signals. The researchers incorporated a piezoelectric polymer with piezoelectric barium titanate nanoparticles. The composite was heated and drawn into long fiber. Cycles of electric charges were applied to such fiber which developed aligned electric dipoles. The article published by the researchers in “Nature” states that drawing fiber produced voids around the barium titanate nanoparticles which increased the piezoelectric charge coefficient with respect to the same polymer without nanoparticles. Such piezoelectric fiber was able to generate a voltage in response to the acoustic sound waves. Researchers mounted the fiber on a membrane of Mylar (a polyester film) and the fiber generated an electrical signal which was two orders higher due to the strong coupling between the fiber and the vibrating membrane. Sound records from low volume (like a quiet library) to the volume of heavy traffic showed the production of output voltage in the fabric linearly with the volume of sound. The researchers incorporated one single piezoelectric fiber in a shirt made of cotton and Twaron (a stiffer fiber) at the chest area and the garment could measure the wearer's heartbeat and could discern different heart sounds as well. Other potential applications could be monitoring the breathing and the fetal heartbeat. The garment with two piezoelectric fibers may indicate the direction of the source of the sound. Such fabric may produce sound as well when an electrical signal is applied. Acoustic garments may help people with problems of hearing. However, the researchers are working on suitable wearable electronics which inevitably accompany with such wearable devices.

Details may be accessed at:

https://physicsworld.com/a/acoustic-clothing-can-hear-your-heart-beat


   The World Health Organization Incorporates Ethics into Radiological Imaging Top


The World Health Organization (WHO) has issued a policy brief regarding ethics and medical radiological imaging. The brief emphasizes integrating ethics into the existing framework of medical procedures in general, and medical radiological imaging, in particular, to save the patients from the risk rendered by such radiation. The WHO brief puts the patients at the center of health care and requires the delivery of radiation investigation in an ethical way. The greatly increased number of radiation imaging has prompted the WHO to make explicit reference to ethics. The brief stresses that all patients have a right to ethical healthcare which includes being informed and involved in the decision regarding diagnosis and treatment along with the appropriate and timely and safe services. Only necessary examinations should be performed. The brief wants to raise awareness among the clinicians who request radiological imaging investigations and also among the personnel who deliver such imaging services on a day-to-day basis. The WHO wishes to empower the scores of patients who undergo such radiation investigations and their families and make it the focus area of the patient-centric approach (where patients' interest is paramount) and thus bringing a cultural change in medical imaging.

The details may be accessed at

https://www.who.int/news-room/feature-stories/detail/ensuring-radiological-imaging-is-ethically-provided--new-who-policy-brief


   Novel Detector and Technique for Multiradionuclide In vivo Imaging Top


Researchers from the National Cancer Center, Japan, have developed a high-sensitivity cadmium telluride-based detector (IPMU imager) for multiradionuclide in vivo imaging. Multiradionuclide in vivo imaging needs high spatial resolution as well as good energy resolution to resolve the potential overlaps among multiple radiotracers. In vivo imaging is widely used in medicine, pharmaceutical applications, and biology, especially with multiple fluorescent tracers used simultaneously. It helps in visualizing the distribution of numerous molecules in the visible range. However, due to scattering and attenuation of visible light, the image reconstruction and quantification of florescent dyes become difficult. Therefore, the gamma-emitting radionuclide may be used for in vivo imaging by employing single-photon emission computed tomography (SPECT) and positron emission tomography (PET) to image radiotracers deep inside the body. However, similar or even overlapping energy ranges (or emission lines) among the radionuclides warrants newer hardware and techniques to improve the resolution. The researchers at the National Cancer Center collaborated with the Institute of Space and Astronautical Science and Riken (Institute of Physical and Chemical Research), Japan, to develop a cadmium telluride detector which is originally developed for hard X-ray and gamma-ray space observations. Although the IPMU imager has high spatial and energy resolution, it could not eliminate all noise arising from the similar emission lines of the multiple radionuclides. The researchers employed the spectral analysis method used in X-ray astronomy which involves fitting the observed spectra to a model of radionuclide emission lines in specific energy bands. The intensity ratio between the radionuclide helps in detecting and eliminating the contamination. The researchers verified this method by experimenting with the radionuclide solution of iodine-125 (I-125) and indium-111 (In-111). They used a pure I-125 sample and a mixture of I-125 and In-111 where the same activity of I-125 was mixed with In-111. The newly adopted analysis method separated the spectra from the individual radionuclide in the mixture and the background. The signal intensity of I-125 image from the pure I-125 sample and in the mixture was the same indicating the quantitative ability of the process to remove the background effectively. For measurement of spatial resolution, researchers used a phantom with various-sized holes filled with the solution of I-111 and I-125 (or Tc-99 m) and reconstructed the images in various energy bands (like 21-25, 26-29, and 135-143 keV). The spatial resolution came out to be about 300 μm which is similar to that of a state-of-art small-animal SPECT. Researchers also used an IPMU imager for in vivo experiments in mice for visualizing thyroid and lymph nodes in mandible and parotid using I-125, In-111, and Tc-99 m, respectively. The raw images had noise and ghosting due to these three radionuclides. The fitting technique detected unwanted radiation sources and produced separate images of each radioactivity. The researchers further plan to use the image and the technique developed so in visualizing the targeted radionuclide therapy drugs in vivo (accumulation of drugs in cancer cells).

The details may be accessed at:

https://physicsworld. com/a/researchers-exploit-astronomy-technology-for-biomedical-imaging


   International Atomic Energy Agency Publishes Safety Report on Radiation Protection of Dental Radiology Top


IAEA has published a safety report for the radiation investigations carried out in dentistry. The Safety Report Series No. 108 entitled “Radiation Protection in Dental Radiology” has been published in May 2022 and has been endorsed by FDI World Dental Federation (Fédération Dentaire Internationale in French), Image Gently Alliance, International Association of Dentomaxillofacial Radiology, and International Organization of Medical Physics. Dentists treat dental cavities, place dental crowns, implants or braces, extract teeth, and many more procedures that need frequent X-ray imaging to know the extent of the pathology, anatomy, the fitting of external support, diagnose the disease, and plan the intervention and management of the conditions. Dental radiological investigations are one of the most common radiological investigations in the patient although the amount of radiation used in individual dental imaging is limited to the equivalent of the natural background radiation of a few days. In the year 2020, dental X-rays constituted 26% of all global diagnostic radiological examinations keeping this in mind IAEA has issued this specific and detailed guideline on the best practices for dental X-ray imaging. The guideline is meant for dental professionals, radiation protection experts, regulators, manufacturers of dental X-ray units, etc. The high volume of dental radiological investigations warrants that radiological examinations should be appropriately selected and optimized, and the latest standard as well as good practices should be followed so that patients and practitioners are exposed to minimum radiation. Lately, 3D dental imaging obtained by cone-beam computed tomography (CBCT) is catching the fascination of dentists. CBCT scanner rotates around the head of the patient taking a series of X-ray images whose combination renders 3D structures of the jaws and teeth. Such 3D images help in planning implants, measuring bone dimensions, assessing tumors, and treating injuries in a better way. However, CBCT imaging investigation imparts 10-20 times the radiation dose as compared to a single dental X-ray image. Another concern is the young patients (and children) who make the bulk of the workload of dental patients. As children are more sensitive to radiation IAEA guidelines emphasize that the justification and optimization of pediatric dental imaging must receive our adequate attention.

The details may be accessed at:

https://www.iaea.org/newscenter/news/iaea-helps-protect-patients-and-staff-in-dentistry

The book may be downloaded free at:

https://www-pub.iaea.org/MTCD/Publications/PDF/PUB1972_Web.pdf


   Magnetic Resonance Imaging Sequences and Modeling for Brain Inflammation Top


Researchers from the Institute of Neurosciences, a joint center of the Spanish Superior Research Council and Miguel Hernandez University, Spain, have developed magnetic resonance (MR) data acquisition sequences and mathematical models to detect inflammation in astrocytes and microglia, the two brain cell types associated with neural inflammation using diffusion-weighted MR imaging (DW-MRI). Chronic inflammation of the brain is linked with common degenerative brain diseases such as Alzheimer's and Parkinson's as evidence indicate that neuroinflammation may have complicity with the progression of such diseases. In general, PET is used to monitor neuroinflammation. Researchers concentrated to adapt and design advanced DW-MRI sequences in the combination of mathematical modeling as noninvasive and nonionizing radiation investigation to monitor the inflammation of the brain's gray matter. Most of the previous researchers focused on the brain's white matter and axons. Researchers from the institute of neurosciences tested their models on rats by inducing inflammation and were able to detect microglia and astrocyte activation in gray matter. They used the technique on six human volunteers as well. They hope that the work would lead to the better characterization of brain microstructures and the management of other diseases associated with glial inflammation.

The details may be accessed at:

https://physicsworld.com/a/researchers-produce-first-in-vivo-images-of-brain-inflammation-using-mri


   Diamond Detector-based Dosimeter for FLASH Radiotherapy Top


Researchers at Tor Vergata University of Rome, Italy, have developed a diamond-based Schottky diode detector for FLASH-RT which is an interesting and still developing field of RT for cancer. In FLASH-RT, the targets are irradiated with an ultra-high dose rate (UH-DR) than that in conventional RT and are supposed to be causing a reduction in radiation-induced toxicities in surrounding normal tissues while retaining the equivalent tumor response. As the dose rate is very high, the treatment time is much less and also it is touted to be one-time therapy instead of conventionally fractionated RT. However, the obvious excitement for FLASH-RT has to solve some riddles before it becomes reality and one of them is its accurate dosimetry. The currently used ionization chamber and solid-state detectors are not suitable for UH-DR due to recombination, saturation, and nonlinearity in response. Passive dosimeters such as alanine and radiochromic film work but it is not real time and hence cannot be used for in vivo dosimetry and also for Quality Assurance (QA) work. In fact, the currently developed diamond detector called FLASH diamond (fD) may be one of the first real-time detectors suitable for UH-DR and ultrahigh-dose-per-pulse (UH-DPP) irradiation. The fD detector showed a linear response to DPP up to 26 Gy/pulse, an instantaneous dose rate of about 5 MGy/s, and an average dose rate of about 1 kGy/s. Dosimetric studies of fD were conducted for Co-60 irradiation, UH-DPP electron beams, and conventional electron beams. The experiments yielded the sensitivity of 0.309 ± 0.005, 0.305 ± 0.002, and 0.306 ± 0.005 nC/Gy, respectively, which showed close agreement to the response of fD for the above three irradiation conditions. Its response in the UH-DPP range was found to be linear till the investigated dose of 11.9 Gy. fD detector showed good agreement with commercially available detectors in conventional irradiation (microDiamond, Advanced Markus ionization chamber, silicon diode detector, and EBT-XD GafChromic film) in terms of PDD, beam profile, and output factors. fD also showed good agreement with EBT-XD film in UH-DPP radiation. The researchers also used fD detector for commissioning the Electron FLASH LINAC (7 and 9 MeV pulsed electron beam) with the capability to produce conventional and UH-DPP irradiation and hope it to be a viable dosimetric tool for FLASH-RT.

Details may be accessed at:

https://physicsworld.com/a/diamond-dosimeter-lines-up-for-flash-radiotherapy/?notification = onesignal


   International Commission on Radiological Protection Makes its Publication on Large Nuclear Accidents Free to Access Amid Concern about Military Activity in Ukraine Top


On August 23, 2022, the International Commission on Radiological Protection (ICRP) in partnership with SAGE Publishing, UK, has made ICRP Publication 146 entitled “Radiological Protection of People and the Environment in the Event of a Large Nuclear Accidents” free to access for all. The backdrop for such a decision is the significant concern raised about the military actions around the Zaporizhzhia power plant and the possibility of similar situations around other nuclear power plants in Ukraine. The ICRP site states that although Publication 146 does not cover the possible radioactive release due to military action, the principles and guidance provided may come in handy to the planners in case of any unfortunate event. Publication 146 provides a framework for the protection of people and the environment in case of a large nuclear accident. The publication makes distinctions between the early, intermediate, and long-term phases of the situation. In the early phase of an accident, urgent protective action has to be taken, often with little information available. In emergency and existing exposure situations, mitigation of radiological consequences is achieved using fundamental principles of justification of decision and optimization of protection. Publication 146 draws from the experience of the Chernobyl and Fukushima accidents.

The announcement of ICRP regarding making its Publication 146 free access may be seen at:

https://www.icrp.org/publication.asp?id=ICRP%20Publication%20146

The free copy of the Publication 146 of ICRP may be downloaded from:

https://journals.sagepub.com/doi/pdf/10.1177/ANIB_49_4




 

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