Health physics最新文献

{"title":"Investigation of the Effect of CT-Relative Electron Density Curves on Radiotherapy Dose Calculation.","authors":"Taylan Tuğrul","doi":"10.1097/HP.0000000000001990","DOIUrl":"https://doi.org/10.1097/HP.0000000000001990","url":null,"abstract":"<p><strong>Abstract: </strong>The computerized tomography scanners play a significant role in the radiotherapy treatment planning process. The electron density obtained from the CT-RED curve can be used to determine the structure of materials, and TPS calculates the dose based on the material's composition. Errors in this curve can lead to inaccuracies in dose estimation, particularly in heterogeneous tissues. In this study, the effect of variations in the CT-RED curve on the radiation dose calculated with different algorithms was also investigated. A virtual phantom was created by the TPS system for five different environments, including two low-density (HU:-750 and HU:-300) and two high-density (HU:750 and HU:300) materials. Four different erroneous CT-RED curves were created, representing -5%, -10%, +5%, and + 10% deviations from the original CT-RED curve. The positive deviations are more prominent in regions with low HU values. On the other hand, negative errors tend to be more noticeable in regions with higher HU values. This indicates that changes in dose discrepancies are not proportional to the variations in HU. Since the HU values are converted to RED by the TPS, inconsistencies in HU values ​​may lead to errors in the dose calculated by TPS. It is evident that errors in the CT-RED curve can affect the dose calculated by the TPS. However, it appears that this effect remains within acceptable limits. Given that different errors can combine to create significant differences, it is crucial not to overlook the importance of accurately transferring the CT-RED curve to the TPS.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144000561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pre-declaration Fetal Dose Assignment and Predictive Full term Fetal Dose at Medical Facilities.","authors":"James Kyle Underwood, Glenn M Sturchio","doi":"10.1097/HP.0000000000001914","DOIUrl":"10.1097/HP.0000000000001914","url":null,"abstract":"<p><strong>Abstract: </strong>Many medical facilities across the United States use ionizing-radiation-producing machines and radioactive materials for diagnostic and therapeutic purposes on a regular basis. While institutions are required to ensure full-term fetal doses are below the regulatory limit, clear guidance on how pre-declaration fetal doses should be estimated is not available. This paper provides a process that can be used to estimate the pre-declaration fetal dose and provides a predictive screening tool for licensees to use to recommend workload adjustments prior to actual fetal dosimetry results that could exceed the institutions derived investigation levels. The evaluation process presented herein serves as a guide for medical licensees when performing fetal dose evaluations for declared pregnant workers.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":" ","pages":"423-427"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142675651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study of Radium Content and Radon Exhalation Rates in Soil Samples from Abi-Adi Town, Ethiopia, Using LR-115 Type-II.","authors":"Nigus Alene Assefa, Yisak Arbese","doi":"10.1097/HP.0000000000001911","DOIUrl":"10.1097/HP.0000000000001911","url":null,"abstract":"<p><strong>Abstract: </strong>In the present study, we are presenting the results of radium content, radon concentration, and radon exhalation rates (both mass and area) for 32 soil samples collected from different locations of Abi-Adi Town, Ethiopia, by using the sealed can technique containing a LR-115 Type-II plastic detector. The values of radium content from soil samples were found to vary from 35.26 Bq kg -1 to 101.78 Bq kg -1 , with a mean value of 70.25 Bq kg -1 . The mass and area exhalation rates of radon were found to be from 2.72 × 10 -6 Bq kg -1 d -1 to 7.87 × 10 -6 Bq kg -1 d -1 and from 0.76 × 10 -4 Bq m -2 d -1 to 2.20 × 10 -4 Bq m -2 d -1 , with a mean value of 5.43 × 10 -6 Bq kg -1 d -1 and 1.52 × 10 -4 Bq m -2 d -1 , respectively. The outdoor and indoor annual effective dose equivalent varied from 0.24 mSv y -1 to 0.68 mSv y -1 and from 0.06 mSv y -1 to 0.17 mSv y -1 with a mean value of 0.37 mSv y -1 and 0.09 mSv y -1 , respectively. The working level varied from 2.50 mWL to 7.21 mWL with a mean value of 3.94 mWL. From the results of this study, we found that there was a positive correlation between radium content and radon exhalation rates in soil samples. The radium content values determined in soil samples are less than the permissible value of 370 Bq kg -1 recommended by Organization for Economic Cooperation and Developments as acceptable for safe use. Thus, results reveal that the area under investigation is safe as far as the health hazards of radon are concerned.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":" ","pages":"365-370"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143058875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the Effect of Adipose Tissue on Neutron Dose Evaluation for the Human Body Using Voxel Phantoms with Different Weight.","authors":"Xu Xu, Yong Yuan, Xiao-Min Zhang","doi":"10.1097/HP.0000000000001910","DOIUrl":"10.1097/HP.0000000000001910","url":null,"abstract":"<p><strong>Abstract: </strong>When human body is irradiated by neutrons, the adipose content has a significant impact on the neutron dose and induced 24Na activity. To investigate the effect of human adipose content on the conversion coefficients from 24Na activity to neutron dose, five male adult reference computational phantoms with weights ranging from 73.5 kg to 136.5 kg were used. The Monte Carlo N-particle (MCNP) code was used to calculate the neutron absorbed dose and the yield of induced 24Na in the phantoms irradiated by 252Cf neutrons and monoenergetic neutrons. The results showed that the difference in the conversion coefficients from 24Na activity to neutron absorbed dose among the five phantoms irradiated by 252Cf neutrons with anterior posterior (AP) geometry was ≤23.30%, and this difference was attributed mainly to the neutron absorbed dose, which increases with increasing adipose content. Considering the self-absorption of gamma rays in the human body, the counts of 24Na characteristic gamma rays measured directly by the radiation detector outside of the body have no significant trend varying with adipose content, and the difference in the conversion coefficients from the measured counts to neutron dose among the five phantoms irradiated by 252Cf neutrons with AP geometry was ≤5.25%.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":"128 5","pages":"356-364"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143718562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Atmospheric Conditions Leading to a Fumigation Event: Erratum.","authors":"Brian Viner, Steve Weinbeck, Christopher Sobecki","doi":"10.1097/HP.0000000000001979","DOIUrl":"10.1097/HP.0000000000001979","url":null,"abstract":"","PeriodicalId":12976,"journal":{"name":"Health physics","volume":"128 5","pages":"420"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143718462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gafchromic Films as a Complementary In-field Dosimetric Tool to Monitor Low Photon Radiation Doses (≤50 mSv).","authors":"Nicky Nivi, Helen Moise, Ana Pejović-Milić","doi":"10.1097/HP.0000000000001919","DOIUrl":"10.1097/HP.0000000000001919","url":null,"abstract":"<p><strong>Abstract: </strong>This study elucidated the radiation response characteristics of a Gafchromic radiochromic film subjected to low photon doses of ≤50 mSv, which corresponds to the annual whole body effective dose limit for radiation workers in Canada. Radiochromic films are investigated for possible use as a complementary tool for the Canadian Armed Forces that can be worn in addition to their existing personal dosimetry to quickly assess personal radiation dose received from radiological hazards without reliance on electronics. The films were exposed to varying photon energies emanating from x-ray generators and radioisotopes, specifically cesium-137, cobalt-60, and americium-241. The resultant radiation-induced film darkening was quantitatively assessed employing three analytical methodologies: net optical density analysis, UV/Visible spectroscopic analysis, and Fourier Transform Infrared spectroscopic analysis. Ideally, a film dosimeter necessitates a pronounced chromatic alteration and the capability to accurately quantify doses ≤50 mSv where net optical density analysis was identified as the optimal modality for interpreting the film darkening into a dose approximation. This new approach established a lower detection threshold of 7.6 mSv for the films when exposed to cesium-137 radiation. Notably, the film exhibited a linear dose response relationship in terms of net optical density; however, a photon energy-dependent variability was observed within the 0-100 mSv dose range. In conclusion, these Gafchromic radiochromic films present a promising candidate for military dosimetry applications. They offer a real-time, visual dose response that can be discerned by military personnel or analyzed using mobile spectroscopic instrumentation. Moreover, these films demonstrate proficiency in the accurate quantification of photon doses ≤50 mSv. Future investigations will evaluate the film's performance under heterogeneous and indeterminate radiation environments, as well as the impact of environmental conditions on the film's performance.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":" ","pages":"375-384"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142947843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peripheral Nerve Stimulation Thresholds Based on Waveform Shape and Implications for Guideline Limits.","authors":"Gregory B Gajda","doi":"10.1097/HP.0000000000001949","DOIUrl":"10.1097/HP.0000000000001949","url":null,"abstract":"<p><strong>Abstract: </strong>The objective of this paper is to derive basic restrictions for induced internal electric field and reference levels for external magnetic flux density for a class of periodic non-sinusoidal waveforms as multiples of the existing limits applicable to sinusoidal waveforms in current exposure standards. The Law of Electrostimulation and the Spatially Extended Nonlinear Node computational model were used to derive peripheral nerve stimulation thresholds of the internal electric field for both non-sinusoidal and sinusoidal waveforms. Threshold ratios (non-sinusoidal to sinusoidal) permitted basic restrictions and reference levels to be derived as multiples of the sinusoidal ones. Intercomparisons of threshold ratios from both models suggest that they are in agreement for flat-topped flux density waveforms with fast rise-times relative to the period but showed a discrepancy for the continuous sinusoid. Results from the computational model were used to establish the threshold ratios used in the conversion. Resulting non-sinusoidal basic restrictions and reference levels were found to have the same functional relationship with frequency as the sinusoidal ones, consisting of two ranges: a flat rheobase and a frequency-dependent (basic restriction) or inverse frequency-dependent (reference level) portion that intersects the rheobase at a transition frequency that is waveform-dependent. Above the transition frequency, the non-sinusoidal basic restriction was found to be inversely related to the flux density rise-time, resulting in an increased limit for fast-rising waveforms. The transition frequencies of fast-rising waveforms were found to be lowered relative to the sinusoidal one. Above the same transition frequency, the non-sinusoidal reference level is flat with frequency and was found to be approximately 79% lower than the sinusoidal one.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":" ","pages":"399-412"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11939105/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three Developments Related to ANSI/HPS Standard N13.56.","authors":"William Evans","doi":"10.1097/HP.0000000000001921","DOIUrl":"10.1097/HP.0000000000001921","url":null,"abstract":"<p><strong>Abstract: </strong>Three topics related to ANSI/HPS Standard N13.56, Sampling and Monitoring Releases of Airborne Radioactivity in the Workplace, are discussed. First, due to the omission of consideration of the activity's half-life in the standard's continuous particulate air monitor (CPAM) quantitative method, it is possible for concentration estimates produced by that calculation to be underestimated. Second, the concentration estimate found in air grab sampling, as discussed in the standard, is not, as claimed, an average unless the activity is \"long-lived\" (negligible decay during sampling). It is nonetheless possible for this calculation to produce a concentration estimate that is not significantly different from the average, depending on both the half-life of the activity and the sampling time. Third, the issue of when to change the filter for the CPAM method is addressed.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":" ","pages":"371-374"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142817852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Systematical Theoretical Study of the Nonpoint Source Effects in Nuclear Medicine Shielding Calculation.","authors":"Tianliang Gu","doi":"10.1097/HP.0000000000001930","DOIUrl":"10.1097/HP.0000000000001930","url":null,"abstract":"<p><strong>Abstract: </strong>The objective of this note was to systematically study the effects from nonpoint radiation sources on the nuclear medicine imaging room or uptake room shielding design. The dose from a nonpoint source to a location at a certain distance to the center of the source was calculated. A correction factor could be applied to the dose calculated using a point source model with the same distance to compensate the nonpoint source effects. The correction factor was a function only depending on the source relative dimension, the ratio of the source's geometric dimension to the distance. Theoretical and numerical calculation were performed to calculate the correction factor on a one-dimensional line source, two-dimensional circular disc source, three-dimensional sphere, and cylinder sources. Our study indicated that for large nuclear medicine imaging rooms, the point source model was a good approximation for shielding design. For a small uptake room, a nonpoint source correction may be considered to calculate the barrier thickness.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":"128 5","pages":"413-419"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143718658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of a Commercially Available Radiochromic Film for Use as a Complementary Dosimeter for Rapid In-field Low Photon Equivalent Radiation Dose (≤50 mSv) Monitoring.","authors":"Nicky Nivi, Helen Moise, Ana Pejović-Milić","doi":"10.1097/HP.0000000000001903","DOIUrl":"10.1097/HP.0000000000001903","url":null,"abstract":"<p><strong>Abstract: </strong>This work investigates the low photon radiation dose (≤50 mSv) response of commercially available radiochromic films as a potential field dosimeter that could be used by the Canadian Armed Forces to complement their existing personal radiation dosimeters. The films were exposed to various photon energies from x-ray devices and radioisotopes (cesium-137, cobalt-60, and americium-241), and their radiation signal was read using three methods: net optical density, UV/visible spectroscopy, and Fourier transform infrared spectroscopy. A complimentary film dosimeter for field usage should, for military use, display a visual color change and detect doses ≤50 mSv. Given the film's radiochromic properties, it was determined that the net optical density method was the most optimal read-out method, which ascertained a minimum detection dose limit of 4.5 mSv under exposure to a clinical orthovoltage operated at 100 kVp. The film presented an overall linear relationship between net optical density and radiation dose; however, they also portrayed a photon energy-dependent response between 0-100 mSv. Overall, the radiochromic films presented a real-time visual dose signal that could be interpreted rapidly in a mobile laboratory and possessed the ability to detect photon doses ≤50 mSv below the vendor's recommended limits, making it a suitable option as a complementary, disposable, military dosimetric tool. Future work includes the investigation of the film's response under multi- and unknown source environments and environmental-dependent factors such as UV/sunlight exposure and extreme temperatures.</p>","PeriodicalId":12976,"journal":{"name":"Health physics","volume":" ","pages":"345-355"},"PeriodicalIF":1.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142675650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}