Absorbed-Dose Specification in Nuclear Medicine: Abstract

Author(s):  
S. J. Adelstein ◽  
A. J. Green ◽  
R. W. Howell ◽  
J. L. Humm ◽  
P. K. Leichner ◽  
...  

A number of reasons have led to a reappraisal of dose specification for nuclear medicine. These include an appreciation of non-uniformities in the distribution of radioactivity in the body, at all levels, for even the most common diagnostic and therapeutic agents; an increasing need to deal with the complexities of varying dose rates; the imperative to provide individual rather than standardised dose estimates as targeted radionuclide therapy becomes more sophisticated; as well as improvements in technology. This Report deals first with biological considerations that inform the rational use of radionuclide dosimetry. Radiobiological factors in the selection of radionuclides and tumour and normal-tissue dose-responses are discussed. Then, the MIRD (medical internal radiation dose) approach to nuclear medical dosimetry, a robust method that has proven its clinical utility, is described. Following on is an elaboration of non-uniform distributions of radioactivity and of varying dose rates. Lastly, the Report deals with techniques and procedures for measuring time variant activity distributions, image fusion, patient specific dose computations, smallscale dosimetry, and the comparison of calculated and measured doses.

Author(s):  
An Aerts ◽  
Uta Eberlein ◽  
Sören Holm ◽  
Roland Hustinx ◽  
Mark Konijnenberg ◽  
...  

Executive SummaryWith an increasing variety of radiopharmaceuticals for diagnostic or therapeutic nuclear medicine as valuable diagnostic or treatment option, radiobiology plays an important role in supporting optimizations. This comprises particularly safety and efficacy of radionuclide therapies, specifically tailored to each patient. As absorbed dose rates and absorbed dose distributions in space and time are very different between external irradiation and systemic radionuclide exposure, distinct radiation-induced biological responses are expected in nuclear medicine, which need to be explored. This calls for a dedicated nuclear medicine radiobiology. Radiobiology findings and absorbed dose measurements will enable an improved estimation and prediction of efficacy and adverse effects. Moreover, a better understanding on the fundamental biological mechanisms underlying tumor and normal tissue responses will help to identify predictive and prognostic biomarkers as well as biomarkers for treatment follow-up. In addition, radiobiology can form the basis for the development of radiosensitizing strategies and radioprotectant agents. Thus, EANM believes that, beyond in vitro and preclinical evaluations, radiobiology will bring important added value to clinical studies and to clinical teams. Therefore, EANM strongly supports active collaboration between radiochemists, radiopharmacists, radiobiologists, medical physicists, and physicians to foster research toward precision nuclear medicine.


2020 ◽  
Vol 189 (1) ◽  
pp. 127-135
Author(s):  
Pradip Kumar ◽  
Sunil Dutt Sharma ◽  
Bhushan Dhabekar ◽  
Devesh Ramdhar Mishra ◽  
Narender Singh Rawat ◽  
...  

Abstract Circular discs of diameter 5 mm were made from three indigenously developed optically stimulated luminescent (OSL) phosphors for medical dosimetry. Dosimetric characteristics of these discs were evaluated for their use in machine and patient-specific dosimetry in radiotherapy. Uncertainty in dosimetric measurements using these discs was also estimated, and combined standard uncertainty in measurement of absorbed dose was found to be 3.34%. Characterisation studies indicate that OSL discs are suitable for dosimetric application in radiotherapy. These discs were also used for patient-specific dosimetry in conventional and conformal radiotherapy treatments (five different cases) vis-à-vis ionisation chamber and Gafchromic EBT3 film. Doses measured by OSL discs were found comparable to ionisation chamber and Gafchromic EBT3 film measured values and radiotherapy treatment planning system (TPS) calculated dose values in all the cases. The variation between TPS calculated dose values and OSL discs measured dose values was found within the measurement uncertainty.


Author(s):  
Mark Konijnenberg ◽  
Ken Herrmann ◽  
Carsten Kobe ◽  
Frederik Verburg ◽  
Cecilia Hindorf ◽  
...  

Executive Summary The EC Directive 2013/59/Euratom states in article 56 that exposures of target volumes in nuclear medicine treatments shall be individually planned and their delivery appropriately verified. The Directive also mentions that medical physics experts should always be appropriately involved in those treatments. Although it is obvious that, in nuclear medicine practice, every nuclear medicine physician and physicist should follow national rules and legislation, the EANM considered it necessary to provide guidance on how to interpret the Directive statements for nuclear medicine treatments. For this purpose, the EANM proposes to distinguish three levels in compliance to the optimization principle in the directive, inspired by the indication of levels in prescribing, recording and reporting of absorbed doses after radiotherapy defined by the International Commission on Radiation Units and Measurements (ICRU): Most nuclear medicine treatments currently applied in Europe are standardized. The minimum requirement for those treatments is ICRU level 1 (“activity-based prescription and patient-averaged dosimetry”), which is defined by administering the activity within 10% of the intended activity, typically according to the package insert or to the respective EANM guidelines, followed by verification of the therapy delivery, if applicable. Non-standardized treatments are essentially those in developmental phase or approved radiopharmaceuticals being used off-label with significantly (> 25% more than in the label) higher activities. These treatments should comply with ICRU level 2 (“activity-based prescription and patient-specific dosimetry”), which implies recording and reporting of the absorbed dose to organs at risk and optionally the absorbed dose to treatment regions. The EANM strongly encourages to foster research that eventually leads to treatment planning according to ICRU level 3 (“dosimetry-guided patient-specific prescription and verification”), whenever possible and relevant. Evidence for superiority of therapy prescription on basis of patient-specific dosimetry has not been obtained. However, the authors believe that a better understanding of therapy dosimetry, i.e. how much and where the energy is delivered, and radiobiology, i.e. radiation-related processes in tissues, are keys to the long-term improvement of our treatments.


2019 ◽  
Vol 21 (1) ◽  
pp. 26-30
Author(s):  
Abdus Sattar Mollah ◽  
Mohammad Ruhul Quddus ◽  
Sayeed Mohammad Iqubal

In nuclear medicine practices, internal radiation dosimetry offers methods for calculation of radiation absorbed dose and risks from radionuclides incorporated inside the body. To manually perform internal radiation dosimetry is time-consuming and errors can occur in each step leading to developing software tools to ease users. There are many software packages available; however, many of them have limited functions. Locally developed IRDE software has been used to calculate the absorbed dose per unit of radioactivity in the target organ. The dose calculation methodology in nuclear medicine practices is described in this study along with a preliminary result on dose calculation for Bangladeshi population due to ingestion of 131I radioisotope in nuclear medicine practices. IRDE is user-friendly, graphic user interface-based software. It can be performed all steps of internal dosimetry within single environment lead to reducing calculation time and reducing possibility of error. IRDE also provides fast and accurate results which may be useful for a routine work in nuclear medicine facilities. Bangladesh J. Nuclear Med. 21(1): 26-30, January 2018


2016 ◽  
Vol 17 (2) ◽  
pp. 134-137
Author(s):  
Kamila Afroj Quadir ◽  
Brian Zimmermann ◽  
Md Nahid Hossain ◽  
Md Nurul Islam ◽  
Ferdoushi Begum ◽  
...  

The accuracy of patient specific dosimetry is correlated with measured organ activity by gamma camera and SPECT system. The assessment of the radiation-absorbed dose by patients undergoing nuclear medicine investigation requires accurate measurement of organ activity, biokinetics data, as well as physical data. Activities were estimated by using Ba-133 phantom with both planar and SPECT systems. The objective of the study was to measure the activities of Ba-133 from gamma camera images using both planar and SPECT studies and compare the reference values with the dose calibrator values to quantify the actual activity with gamma camera. Four Ba-133 sources of different volume and activity 379, 950, 1219 and 1150 KBq are measured by using Veenstra Instrument VDC 404 Dose Calibrator. The second smallest source was used to determine the calibration factor. Acquisition, corrections, reconstruction, quantification and measuring activity from both planar and SPECT imaging were done with all Ba-133 sources in air. The activities of the Ba-133 sources were also measured using I-131 settings of the dose calibrator. The measurement of the second smallest source was used to obtain the calibration factor. This calibration factor was used to convert the planer and SPECT image count of all the sources into activities. In case of both planar and SPECT gamma camera, the measurements showed good correlations and all the values varied within ±15%. Planer and SPECT gamma camera image counts can be used to calculate activity in the organ. This information can play a very significant role in evaluating image based patient specific dosimetry in radionuclide therapy.Bangladesh J. Nuclear Med. 17(2): 134-137, July 2014


2021 ◽  
Vol 12 ◽  
Author(s):  
Martin Andersson ◽  
Sören Mattsson

Radioactive iodine is commonly used for the treatment of different thyroid conditions since the 1940s. The EANM has developed a standard pre-therapeutic procedure to estimate patient specific thyroid uptake at treatment of benign thyroid diseases. The procedure which models the time dependent fractional thyroid uptake is based on a two-compartment fitting system, one representing the thyroid and the other the blood. The absorbed dose is however only estimated for the thyroid and not for any other organ in the body. A more detailed biokinetic model for iodine is given by the ICRP and includes an iodide transport in the whole body. The ICRP model has 30 different compartments and 48 transfer coefficients to model the biokinetics of iodide and to model different transfer for inorganic iodide and organic iodine. The ICRP model is a recirculation iodine model, and the optimization is performed on the whole model and not exclusively on the thyroid as in the EANM procedure. Combining the EANM method and the ICRP model gives both patient specific estimations of thyroid uptake and retention and include most organs in the body. The new software gives both an improved patient specific dosimetry for the thyroid and an estimation of the absorbed dose to non-target organs and tissues like kidneys, urinary bladder, stomach wall, and uterus. Using the method described in this paper, the repercussions on the daily routines will be minimal.


EDUSAINS ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 166-175
Author(s):  
Gia Juniar Nur Wahidah ◽  
Sjaeful Anwar

Abstract This research aims to produce science teaching materials in junior level with Energy in The Body as the theme using Four Steps Teaching Material Development  (4STMD). The material is presented in an integrated way so that students can  think holistically and contextually. The method used in this study is Research and Development. In this R&D methods is used 4STMD. There are four steps done on the development of teaching materials, the selection step, structuring step, characterization, and didactic reduction. Selection step includes the selection of indicators in accordance with the demands of the curriculum which is then developed with the selection of concepts and values that are integrated with the concept of science. Structuring step includes make macro structures, concept maps, and multiple representations. Characterization's step includes preparation instruments, then  trial to students to identify difficult concepts. The last, didactic reduction was done by neglect and the annotations in the form of sketches.The test results readability aspect instructional materials lead to the conclusion that by determining the main idea, the legibility of teaching materials reached 67%, with moderate readability criteria. Test results of feasibility aspects based on the results of questionnaires to the 11 teachers lead to the conclusion that the overall, level of eligibility teaching materials reached 91% with the eligibility criteria well. Keywords: teaching materials; energy; 4STMD Abstrak Penelitian ini bertujuan untuk menghasilkan bahan ajar IPA SMP pada tema Energi dalam Tubuh menggunakan metode Four Steps Teaching Material Development (4STMD). Materi disajikan secara terpadu sehingga memacu siswa untuk berpikir secara holistik dan kontekstual. Metode penelitian yang digunakan pada penelitian ini adalah metode penelitian dan pengembangan. Dalam penelitian dan pengembangan yang ini, digunakan metode Four Steps Teaching Material Development (4STMD). Terdapat empat tahap yang dilakukan pada pengembangan bahan ajar, yakni tahap seleksi, strukturisasi, karakterisasi, dan reduksi didaktik. Tahap seleksi meliputi pemilihan indikator yang sesuai dengan tuntutan kurikulum yang kemudian dikembangkan dengan pemilihan konsep dan nilai yang diintegrasikan dengan konsep IPA. Tahap strukturisasi meliputi pembuatan struktur makro, peta konsep, dan multipel representasi dari materi. Tahap karakterisasi meliputi penyusunan instrumen karakterisasi, kemudian uji coba kepada siswa untuk mengidentifikasi konsep sulit. Tahap terakhir, yaitu reduksi didaktik konsep terhadap konsep sulit. Reduksi didaktik yang dilakukan berupa pengabaian dan penggunaan penjelasan berupa sketsa. Hasil uji aspek keterbacaan bahan ajar menghasilkan kesimpulan bahwa berdasarkan penentuan ide pokok, keterbacaan bahan ajar mencapai 67%, dengan kriteria keterbacaan tinggi. Hasil uji aspek kelayakan berdasarkan hasil angket terhadap 11 orang guru menghasilkan kesimpulan bahwa secara keseluruhan tingkat kelayakan bahan ajar mencapai 91% dengan kriteria kelayakan baik sekali. Kata Kunci: bahan ajar; energi; 4STMD  Permalink/DOI: http://dx.doi.org/10.15408/es.v8i2.2039  


2008 ◽  
Vol 47 (06) ◽  
pp. 267-274 ◽  
Author(s):  
F. Boldt ◽  
C. Kobe ◽  
W. Eschner ◽  
H. Schicha ◽  
F. Sudbrock

Summary Aim: After application of radiopharmaceuticals the patient becomes a radioactive source which leads to radiation exposure in the proximity. The photon dose rates after administration of different radiopharmaceuticals used in diagnostic nuclear medicine were measured at several distances and different time intervals. These data are of importance for estimating the exposure of technologists and members of the public. Patients, method: In this study dose rates were measured for 67 patients after application of the following radiopharmaceuticals: 99mTc-HDP as well as 99mTcpertechnetate, 18F-fluorodeoxyglucose, 111In-Octreotid and Zevalin® and 123I-mIBG in addition to 123I-NaI. The dose rates were measured immediately following application at six different distances to the patient. After two hours the measurements were repeated and – whenever possible – after 24 hours and seven days. Results: Immediately following application the highest dose rates were below 1 mSv / h: with a maximum at 780 μSv/h for 18F (370 MBq), 250 μSv/h for 99mTc (700 MBq), 150 μSv/h for 111In (185 MBq) and 132 μSv/ h for 123I (370 MBq). At a distance of 0.5 m the values decrease significantly by an order of magnitude. Two hours after application the values are diminished to 1/3 (99mTc, 18F), to nearly ½ (123I) but remain in the same order of magnitude for the longer-lived 111In radiopharmaceuticals. Conclusion: For greater distances the doses remain below the limits outlined in the national legislation.


Author(s):  
Vikas V. Gaikwad ◽  
Abasaheb B. Patil ◽  
Madhuri V. Gaikwad

Scaffolds are used for drug delivery in tissue engineering as this system is a highly porous structure to allow tissue growth.  Although several tissues in the body can regenerate, other tissue such as heart muscles and nerves lack regeneration in adults. However, these can be regenerated by supplying the cells generated using tissue engineering from outside. For instance, in many heart diseases, there is need for heart valve transplantation and unfortunately, within 10 years of initial valve replacement, 50–60% of patients will experience prosthesis associated problems requiring reoperation. This could be avoided by transplantation of heart muscle cells that can regenerate. Delivery of these cells to the respective tissues is not an easy task and this could be done with the help of scaffolds. In situ gel forming scaffolds can also be used for the bone and cartilage regeneration. They can be injected anywhere and can take the shape of a tissue defect, avoiding the need for patient specific scaffold prefabrication and they also have other advantages. Scaffolds are prepared by biodegradable material that result in minimal immune and inflammatory response. Some of the very important issues regarding scaffolds as drug delivery systems is reviewed in this article.


2021 ◽  
pp. 105971232199468
Author(s):  
Paolo Pagliuca ◽  
Stefano Nolfi

We introduce a method that permits to co-evolve the body and the control properties of robots. It can be used to adapt the morphological traits of robots with a hand-designed morphological bauplan or to evolve the morphological bauplan as well. Our results indicate that robots with co-adapted body and control traits outperform robots with fixed hand-designed morphologies. Interestingly, the advantage is not due to the selection of better morphologies but rather to the mutual scaffolding process that results from the possibility to co-adapt the morphological traits to the control traits and vice versa. Our results also demonstrate that morphological variations do not necessarily have destructive effects on robots’ skills.


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