Modified electron beam output calibration based on IAEA Technical Report Series 398.

PURPOSE: The recently worldwide standard measurement of electron beam reference dosimetry include the International Atomic Energy Agency (IAEA) Technical Report Series (TRS)-398 and Association of Physicists in Medicine (AAPM) Task Group (TG)-51 protocols. Muir et al. have modified calibration methods for electron beam calibration based on AAPM TG-51. They found that the use of cylindrical chambers at low energy gave acceptable results. In this study, we propose and report a modified calibration for electron beam based on IAEA TRS-398, the standard reference dosimetry protocol worldwide. METHODS: This work was carried out with energies of 6, 8, 10, 12, and 15 MeV. The electron beam is generated from Elektra Synergy Platform and Versa HD linear accelerator. The charge readings were measured with PTW 30013, IBA CC13, Exradin A1Sl, and Exradin A11 chambers connected to the electrometer. The dose calculation uses an equation of modified calibration for electron beam using the updated k Q ${k_Q}$ factor in previous work. The absorbed dose to water for electron beam is expressed in dose per monitor unit (cGy/MU). Thus, we compared dose per monitor unit (D/MU) calculation using a modified calibration to TRS-398. RESULTS: In this work, we have succeeded in implementing the modified calibration of electron beam based on TRS-398 by applying a cylindrical chamber in all energy beams and using the updated k Q ${k_Q}$ factor. The ratio of the absorbed dose to water between original and modified calibration protocols of TRS-398 (Dw ) for the cylindrical chamber was 1.002 on the Elekta Synergy Platform and 1.000 on the Versa HD while for the parallel-plate chamber it was 1.013 on the Elekta Synergy Platform and 1.014 on the Versa HD. Based on these results, both the cylindrical and parallel-plate chambers are still within the tolerance limit allowed by the TRS-398 protocol, which is ±2%. Therefore, modified calibration based on TRS-398 gives acceptable results and is simpler to use clinically.

Practical application of international recommendations and safety standards in the systematic planning and implementation of remediation of sites or areas with residual radioactive material.

The IAEA fundamental safety objective is'to protect people and the environment from harmful effects of ionizing radiation'and this must be done 'without unduly limiting the operation of facilities or the conduct of activities that give rise to radiation risks', while ensuring that people and the environment, present and future are protected against radiation risks (IAEA 2006Fundamental Safety Principles, Safety FundamentalsNo. SF-1). In addition,'protective actions to reduce existing or unregulated radiation risks must be justified and optimized'(IAEA 2006Fundamental Safety Principles, Safety FundamentalsNo. SF-1). An international system of radiological protection can be applied such that processes, such as remediation, can be systematically undertaken to address the wide range of'existing exposure situations'present globally. In doing so, decisions made regarding actions undertaken can be demonstrated to be'justified'and'optimized'(i.e. balanced), such that the amount of effort should be commensurate with the risk (applying a'graded approach'). In addition, protection of people and the environment can be demonstrated by comparing the actual exposure to appropriate criteria over the lifetime of remediation. This paper provides an overview of the current IAEA safety standards on remediation of sites or areas contaminated with residual radioactive material within the international system of radiological protection and provides practical examples of their application through case studies considered in IAEA international model validation programs.

The need to update NCRP 151 data for 10 MV linear accelerator bunker shielding based on new measurements and Monte Carlo simulations.

Linear accelerator bunker shielding protocols such as NCRP 151 have previously been tested against a large sample of measured data from real bunkers and machines but differences in per-energy concrete penetration (TVLs) for 10 MV has not yet been resolved. These differences are likely due to historical beam data and can potentially result in over-exposure of radiation workers and the public. This study examines a cohort of clinical linac bunker survey measurements and compares them to popular shielding protocols. Differences were investigated using contemporary beam data for both Monte Carlo simulation and in analytical equations. For primary barriers, NCRP 151 underestimates the dose rate through concrete by on average a factor of 2 with secondary barriers and maze entrance doses having much better agreement. Use of contemporary beam data in Monte Carlo simulation and an analytical equation yielded TVL values much closer to the measured values compared to NCRP 151. The TVL data in NCRP 151 is outdated and needs to be updated based upon the energy spectra of modern linear accelerators. Until then, physicists should use the TVL values shown in this study instead.

Monte Carlo evaluation of particle interactions within the patient-dependent part of Elekta 6 MV photon beam applying IAEA phase space data.

BACKGROUND: This work aims to provide a simulated method to be used by designers of medical accelerators and in clinical centers to manage and minimize particles' interaction in the patient-dependent part of a 6 MV X-Ray Beam generated by the Elekta linear accelerator system, based on the latest GATE software version 9.0 Monte Carlo simulation, IAEA phase space data, and the last version of "Slurm" computing cluster. MATERIALS AND METHODS: The experimental results are obtained using the Elekta 6 MV accelerator. The simulation MC developed includes the majority of the patient-dependent segments, such as Multi-Leaf Collimator (MLC), Tongue and Groove T&G, Rounded leaf Part, including the Jaws (XY). This model is used, with a simulated Iba Blue Phantom 2 homogeneous water phantom with dimensions 480 × 480 × 410 mm3, positioned at a Source-to-Surface-Distance (SSD) of 100 cm, all of the interactions of the mega voltage 6 MV radiations in water are simulated. The IAEA phase space (PS) provided by the International Atomic Energy Agency database and cluster computing (Slurm HPC-MARWAN, CNRST, Morocco) are employed to reduce our simulation time. RESULTS: The results confirm that there are many interactions in all areas and the patient-dependent part's internal structures. Thus, electrons and positrons participation appear in the generated field previously designed to be an X-ray beam. Besides, to validate our implementation geometry, the PDD's and transverse profiles, at a depth ranging from 1.5 to 20 cm, for a field size of 10 × 10 cm2, the beam quality such as D 10%, d max (cm), d 80 (cm), TPR (20/10) , the two relative differences in dose were derived on σ i and σ i,max are calculated, respectively. Additionally, gamma index formalism for 2%/2 mm criteria is used. Once and for all, we typically take a good agreement between simulation MC GATE 9.0 and the experiment data with an error less than 2%/2 mm. CONCLUSIONS: In the field of X-ray photons, a significant contribution of electrons and positrons has been found. This contribution could be enough to be essential or affect the delivered dose. A good agreement of 98% between this new approach of simulation MC GATE 9.0 software based on IAEA phase space and experimental dose distributions is observed regarding the validation tests used in this task.

Evaluation of the PTW microDiamond in edge-on orientation for dosimetry in small fields.

PURPOSE: The PTW microDiamond has an enhanced spatial resolution when operated in an edge-on orientation but is not typically utilized in this orientation due to the specifications of the IAEA TRS-483 code of practice for small field dosimetry. In this work the suitability of an edge-on orientation and advantages over the recommended face-on orientation will be presented. METHODS: The PTW microDiamond in both orientations was compared on a Varian TrueBeam linac for: machine output factor (OF), percentage depth dose (PDD), and beam profile measurements from 10 × 10 cm2 to a 0.5 × 0.5 cm2 field size for 6X and 6FFF beam energies in a water tank. A quantification of the stem effect was performed in edge-on orientation along with tissue to phantom ratio (TPR) measurements. An extensive angular dependence study for the two orientations was also undertaken within two custom PMMA plastic cylindrical phantoms. RESULTS: The OF of the PTW microDiamond in both orientations agrees within 1% down to the 2 × 2 cm2 field size. The edge-on orientation overresponds in the build-up region but provides improved penumbra and has a maximum observed stem effect of 1%. In the edge-on orientation there is an angular independent response with a maximum of 2% variation down to a 2 × 2 cm2 field. The PTW microDiamond in edge-on orientation for TPR measurements agreed to the CC01 ionization chamber within 1% for all field sizes. CONCLUSIONS: The microDiamond was shown to be suitable for small field dosimetry when operated in edge-on orientation. When edge-on, a significantly reduced angular dependence is observed with no significant stem effect, making it a more versatile QA instrument for rotational delivery techniques.

Human bone and amniotic membrane banking in Bangladesh for grafting: the impact of the international atomic energy agency (IAEA) programme.

The idea of establishing a human tissue bank in Bangladesh was started in 1985. However, in 2003, with the active cooperation of international atomic energy agency (IAEA) and Bangladesh Atomic Energy Commission, a tissue bank laboratory was upgraded as a unit for tissue banking and research. Due to increasing demand of allograft, this unit was transformed as an independent institute "Institute of Tissue Banking and Biomaterial Research (ITBBR)" in 2016. This is the only human tissue bank in Bangladesh, which processes human bone and amniotic membrane to provide safe and cost-effective allografts for transplantation. Importantly, banking of human cranial bone as autograft has also started at ITBBR. These processed grafts are sterilized using gamma radiation according to the IAEA Code of Practice for the radiation sterilization of tissues allografts. The amount of grafts produced by the ITBBR from 2007 to 2018 were 120,800 cc of bone chips, 45,420 cm2 of amniotic membranes, 277 vials of de-mineralized bone granules (DMB), 95 pieces of massive bones, and 134 pieces of cranial bones. Overall, 112,748 cc of bone chips, 40,339 cm2 of amniotic membranes, 174 vials of DMB, 44 pieces of massive bones, and 64 pieces of cranial bones were transplanted successfully. Nevertheless, to cope up with the modern advanced concepts of cell and tissue banking for therapeutic purpose, ITBBR is working to set up facilities for skin banking, stem cells banking including amniotic and cord blood derived stem cells and scaffold designing. To ensure the quality, safety, ethical and regulatory issues are sustainable in cell and tissue banking practices, ITBBR always works with the Government of Bangladesh for enhancing the national tissue transplantation programme within the contemporary facilities.

Tissue banking in Asia Pacific region: past, present and future.

Tissue banking in the Asia Pacific regions is driven by two main forces-firstly the International Atomic Energy Agency (IAEA) via Regional Co-operative Agreement projects and secondly by the Asia Pacific Association of Surgical Tissue Banking (APASTB). This overview is written in three sections: (1) History of tissue banking in individual country in the region. (2) History of APASTB. (3) History of IAEA programme in Asia Pacific region. The current status and future of the tissue banking programme in the region will be discussed.

Professor Glyn O. Phillip's legacy within the IAEA programme on radiation and tissue banking.

Professor Phillips began his involvement in the implementation of this important IAEA programme, insisting that there were advantages to be gained by using the ionizing radiation technique to sterilize human and animal tissues, based on the IAEA experience gained in the sterilization of medical products. The outcome of the implementation of the IAEA programme on radiation and tissue banking demonstrated that Professor Phillips was right in his opinion.

Application of gamma irradiation knowledge in tissue sterilisation: inactivation of malaria parasite.

Malaria is one of the exclusion criteria used in selecting tissue donors and the absence of this information can lead to rejection of tissues for transplant. The studies on the malaria parasite have been confined to low dose attenuation of parasites in blood for transfusion purposes. There is no published information relating to the inactivation of malaria parasites with irradiation for the sterilisation of tissues. A dose-surviving parasite population following radiation was replotted using D0 value from a published paper whereby D10 value of 41 Gy was obtained. Calculation of sterilisation dose for achieving SAL 10-6 of malaria parasites demonstrated the effectiveness of the sterilisation dose of 25 kGy being used in tissue banking.

Overview on radiation and tissue banking in Latin America.

The International Atomic Energy Agency (IAEA) played an important role in the establishment of new tissue banks and the improvement of already existing ones in Latin America. The Agency strongly supported, through regional, interregional and national technical cooperation projects, providing equipment, expert missions and training for the production and application of human tissues for transplantation. From 1999 to 2005 five regional courses were given in Buenos Aires under the modality of 1-year distance learning training courses and 1-week face to face courses. The courses were organized by the IAEA, through the National Atomic Energy Commission (CNEA) and the Faculty of Medicine of Buenos Aires University as Post Graduate Specialization Course. In 2005 the Latin American countries joined with Spain and Portugal, and created the Ibero American Network Council of Donation and Transplant (Red Consejo Iberoamericano de Donación y Trasplantes-RCIDT). The objective of this network is to cooperate among twenty-one Ibero American countries in organizational and legislative aspects, training of professionals, and ethical and social issues related to the donation and transplantation of organs, tissues and cells. The members of this Network work actively to harmonize the regulations and the control of donation and transplantation of human organs, tissues and cells. At present, in Latin America, more than 220 facilities of tissues banks are operating and tissue allografts are being produced by single and multi-tissue banks. The efforts made by the governments and professionals from the region allow the tissue banks to operate under quality systems and introduce new technologies.

The emergence and pitfalls of international tissue banking.

The rapid growth of tissue banking and associated international organisations following the fall of the Berlin wall in 1991 is described. This surge in collaboration led to a world-wide constructive movement to use and to produce human tissues. As the years progressed industrialisation, led by the USA, improved the quality of tissue allografts but led higher costs and consolidation within the developing industry. The growth of litigation more than kept pace with the industrial progress. One landmark case is described, the outcome of which could revolutionise the current practices now applied to eliminate possible viral contamination of implanted tissue grafts.

Comparison of AAPM Addendum to TG-51, IAEA TRS-398, and JSMP 12: Calibration of photon beams in water.

The American Association of Physicists in Medicine (AAPM) Working Group on TG-51 published an Addendum to the AAPM's TG-51 protocol (Addendum to TG-51) in 2014, and the Japan Society of Medical Physics (JSMP) published a new dosimetry protocol JSMP 12 in 2012. In this study, we compared the absorbed dose to water determined at the reference depth for high-energy photon beams following the recommendations given in AAPM TG-51 and the Addendum to TG-51, IAEA TRS-398, and JSMP 12. This study was performed using measurements with flattened photon beams with nominal energies of 6 and 10 MV. Three widely used ionization chambers with different compositions, Exradin A12, PTW 30013, and IBA FC65-P, were employed. Fully corrected charge readings obtained for the three chambers according to AAPM TG-51 and the Addendum to TG-51, which included the correction for the radiation beam profile (Prp ), showed variations of 0.2% and 0.3% at 6 and 10 MV, respectively, from the readings corresponding to IAEA TRS-398 and JSMP 12. The values for the beam quality conversion factor kQ obtained according to the three protocols agreed within 0.5%; the only exception was a 0.6% difference between the results obtained at 10 MV for Exradin A12 according to IAEA TRS-398 and AAPM TG-51 and the Addendum to TG-51. Consequently, the values for the absorbed dose to water obtained for the three protocols agreed within 0.4%; the only exception was a 0.6% difference between the values obtained at 10 MV for PTW 30013 according to AAPM TG-51 and the Addendum to TG-51, and JSMP 12. While the difference in the absorbed dose to water determined by the three protocols depends on the kQ and Prp values, the absorbed dose to water obtained according to the three protocols agrees within the relative uncertainties for the three protocols.

History and Organizations for Radiological Protection.

International Commission on Radiological Protection (ICRP), an independent international organization established in 1925, develops, maintains, and elaborates radiological protection standards, legislation, and guidelines. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) provides scientific evidence. World Health Organization (WHO) and International Atomic Energy Agency (IAEA) utilise the ICRP recommendations to implement radiation protection in practice. Finally, radiation protection agencies in each country adopt the policies, and adapt them to each situation. In Korea, Nuclear Safety and Security Commission is the governmental body for nuclear safety regulation and Korea Institute of Nuclear Safety is a public organization for technical support and R&D in nuclear safety and radiation protection.

Reaching environmental levels of 244Pu by accelerator mass spectrometry at the Centro Nacional de Aceleradores.

244Pu (T1/2 = 81 My) is the longest-lived, most minor, and the most understudied Pu isotope. The anthropogenic production of 244Pu is linked to nuclear detonations. Reported 244Pu/239Pu atom ratios in environmental samples range from below 10-6 to above 10-3. This work discusses the performance of the 1 MV Accelerator Mass Spectrometry system at the Centro Nacional de Aceleradores (CNA, Seville, Spain) to analyse 244Pu at environmental levels. The presence of 232Th traces in the Pu sample limits the sensitivity of the technique through the formation of the diatomic trication (232Th12C)3+, of mass 244 u, which must be suppressed by adjusting the stripper gas pressure. A244Pu background of 0.0075 fg (2 × 104 at) is demonstrated for samples that have undergone a chemical treatment. The reliability of the technique is proved through the analysis of three reference sediments provided by the International Atomic Energy Agency (IAEA-412, IAEA-465, IAEA-385). 244Pu results are complemented with 239Pu, 240Pu, 241Pu and 236U and their relative isotopic abundances are discussed.

A new certified reference material IAEA-465 for radionuclides in Baltic Sea sediment.

Certified reference material (CRM) for natural (40K,210Pb,210Po,226Ra,228Ra,228Th,230Th,232Th,234U,235U, and238U) and anthropogenic (137Cs,239+240Pu, and241Am) radionuclides in marine sediment from the Baltic Sea (IAEA-465) has been developed. Information values are given for 238Pu,239Pu and240Pu. Altogether 27 laboratories participated in this exercise. Radiometric (alpha-spectrometry, gamma-spectrometry and beta counting, as well as mass spectrometry (ICP-MS and AMS) techniques were applied in measurements. The CRM is intended to be used for Quality Assurance/Quality Control of radionuclide analyses, for the development and validation of analytical methods, for the development of reference methods and for training purposes.

Multi-Organizational Insights Into Radiological Safety Standards in High-Dose Rate Brachytherapy.

The review provides an extensive study of regulations and recommendations set forth by organizations worldwide in the domain of high-dose rate (HDR) brachytherapy for the prevention and mitigation of radiation hazards. The relevant reports and publications by the International Commission on Radiological Protection (ICRP), International Atomic Energy Agency (IAEA), American Association of Physicists in Medicine (AAPM), United States (US) Nuclear Regulatory Commission (NRC), and Atomic Energy Regulatory Board (AERB) were accessed, and necessary information was compiled to clarify and understand concepts, similarities, and differences in safety standards concerning to the topic. The regulations and guidance are categorized under three major components of safety, namely layout, equipment, and source. Layout category accesses structure, design, layout, and survey. The equipment category summarizes the requirements of equipment, installation, commissioning, quality assurance (QA) and performance, safety precautions and preparedness, safety procedures, and instructions. The source category includes requirements for sealed source possession and use, calibration, categorization, certification, licensing, QA tests, and security. IAEA gives inclusive guidance on radiation protection and regulatory requirements, forming the basis of reference for other organizations worldwide. AERB regulates the radiation facilities in India; therefore, most set-ups follow their safety standards and instructions.

Strengthening education and training programmes for medical physics in Asia and the Pacific: the IAEA non-agreement technical cooperation (TC) regional RAS6088 project.

This article documents the work conducted in implementing the IAEA non-agreement TC regional RAS6088 project "Strengthening Education and Training Programmes for Medical Physics". Necessary information on the project was collected from the project counterparts via emails for a period of one month, starting from 21st September 2023, and verified at the Final Regional Coordination Meeting in Bangkok, Thailand from 30th October 2023 to 3rd November 2023. Sixty-three participants were trained in 5 Regional Training Courses (RTCs), with 48%, 32% and 20% in radiation therapy, diagnostic radiology, and nuclear medicine, respectively. One RTC was successfully organised to introduce molecular biology as an academic module to participants. Three participating Member States, namely United Arab Emirates (UAE), Nepal and Afghanistan have initiated processes to start the postgraduate master medical physics education programmes by coursework, adopting the IAEA TCS56 Guidelines. UAE has succeeded in completing the process while Nepal and Afghanistan have yet to initiate the programme. The postgraduate master medical physics programmes by coursework were strengthened in Indonesia, Jordan, Malaysia, Pakistan, Syria, and Thailand, along with the national registration of medical physicists. In particular, Thailand has revised 6 postgraduate master medical physics programmes by coursework during the tenure of this project. Home Based Assignment and RTCs have resulted in two publications. In conclusion, the RAS6088 project was found to have achieved its planned outcomes despite challenges faced due to the COVID-19 pandemic. It is proposed that a follow up project be implemented to increase the number of Member States who are better prepared to improve medical physics education and training in the region.

Assessment of four dose calculation algorithms using IAEA-TECDOC-1583 with medium dependency correction factor (Kmed) application.

PURPOSE: This study discusses the measurement of dose in clinical commissioning tests described in IAEA-TECDOC-1583. It explores the application of Monte Carlo (MC) modelled medium dependency correction factors (Kmed) for accurate dose measurement in bone and lung materials using the CIRS phantom. METHODS: BEAMnrc codes simulate radiation sources and model radiation transport for 6 MV and 15 MV photon beams. CT images of the CIRS phantom are converted to an MC compatible phantom. The PTW 30013 farmer chamber measures doses within modeled CIRS phantom. Kmed are determined by averaging values from four central voxels within the sensitive volume of the farmer chamber. Kmed is calculated for Dm.m and Dw.w algorithm types in bone and lung media for both photon beams. RESULTS: Average modelled correction factors for Dm.m calculations using the farmer chamber are 0.976 (±0.1 %) for 6 MV and 0.979 (±0.1 %) for 15 MV in bone media. Correspondingly, correction factors for Dw.w calculations are 0.99 (±0.3 %) and 0.992 (±0.4 %), respectively. For lung media, average correction factors for Dm.m calculations are 1.02 (±0.3 %) for 6 MV and 1.022 (±0.4 %) for 15 MV. Correspondingly, correction factors for Dw.w calculations are 1.01 (±0.3 %) and 1.012 (±0.2 %), respectively. CONCLUSIONS: This study highlights the significant impact of applying Kmed on dose differences between measurement and calculation during the dose audit process.

Fabrication of biosensor for the assessment of radon and lead levels in the blood.

This study aimed to develop and test a biosensor for detecting radioactive radon gas and lead ions in blood samples collected from donors in Iraq. The biosensor was made up of aptamer, acetic acid, malachite green, and TRIS-HAC, and results were measured using a fluorescence spectrophotometer. This study found that 222Rn in the blood varied between individuals, with higher levels in males and smokers, and the highest concentration found in a male patient with cancer. The biosensor used to detect 222Rn in the blood was effective, sensitive, and low-cost, and the levels detected were within the limits set by the WHO. The study also looked at pb+2, a toxic metal, and found that levels were within permissible limits. The biosensor was also effective in detecting pb+2. The correlations between the variables are generally weak to moderate, and there are some negative relationships between humidity and other variables. There are also some strong positive relationships between temperature (Tin) and temperature (Tout). The results suggest that these variables are not strongly correlated with each other, which is an important finding for understanding their potential effects on health outcomes. However, further validation and testing may be necessary before its widespread use in clinical settings. This study highlights the importance of monitoring these substances in the blood, especially for individuals with occupational exposure to radiation. The biosensor was found to be sensitive, cost-effective, fast to manufacture, and efficient compared to other detection devices. Therefore, the study recommends the use of this biosensor for measuring radon and lead ions in blood samples. The biosensor used in this study could be a useful tool for such monitoring.

Toolkit implementation to exchange phase-space files between IAEA and MCNP6 monte Carlo code format.

PURPOSE: Some Monte Carlo simulation codes can read and write phase space files in IAEA format, which are used to characterize accelerators, brachytherapy seeds and other radiation sources. Moreover, as the format has been standardized, these files can be used with different simulation codes. However, MCNP6 has not still implemented this capability, which complicate the studies involving this kind of sources and the reproducibility of results among independent researchers. Therefore, the purpose of this work is to develop a tool to perform conversions between IAEA and MCNP6 phase space files formats, to be used for Monte Carlo simulations. MATERIALS AND METHODS: This paper presents a toolkit written in C language that uses the IAEA libraries to convert phase space files between IAEA and MCNP6 format and vice versa. To test the functionality of the provided tool, a set of verification tests has been carried out. In addition, a linear accelerator treatment has been simulated with the PENELOPE library using the PenEasy framework, which is already capable to read and write IAEA phase space files, and MCNP6 using the developed tools. RESULTS: Both codes show compatible depth dose curves and profiles in a water tank, demonstrating that the conversion tools work properly. Moreover, the phase space file formats have been converted from IAEA to MCNP6 format and back again to IAEA format, reproducing the very same results. CONCLUSION: The toolkit developed in this work offers MCNP6 scientific community an external and validated program able to convert phase space files in IAEA format to MCNP6 internal format and use them for Monte Carlo applications. Furthermore, the developed tools provide also the reverse conversion, which allow sharing MCNP6 results with users of other Monte Carlo codes. This capability in the MCNP6 ecosystem provides to the scientific community the ability not only to share radiation sources, but also to facilitate the reproducibility among different groups using different codes via the standard format specified by the IAEA.