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Abraham SA, Kearfott KJ. Residual Optically Stimulated Luminescent (OSL) Signals for Al2O3: C and a Readout System With Reproducible Partial Signal Clearance. HEALTH PHYSICS 2018; 115:561-568. [PMID: 29912009 DOI: 10.1097/hp.0000000000000853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Optically stimulated luminescent dosimeters are devices that, when stimulated with light, emit light in proportion to the integrated ionizing radiation dose. The stimulation of optically stimulated luminescent material results in the loss of a small fraction of signal stored within the dosimetric traps. Previous studies have investigated the signal loss due to readout stimulation and the optical annealing of optically stimulated luminescent dosimeters. This study builds on former research by examining the behavior of optically stimulated luminescent signals after annealing, exploring the functionality of a previously developed signal loss model, and comparing uncertainties for dosimeters reused with or without annealing. For a completely annealed dosimeter, the minimum signal level was 56 ± 8 counts, and readings followed a Gaussian distribution. For dosimeters above this signal level, the fractional signal loss due to the reading process has a linear relationship with the calculated signal. At low signal levels (below 20,000 counts) in this optically stimulated luminescent dosimeter system, calculated signal percent errors increase significantly but otherwise are on average 0.72 ± 0.27%, 0.40 ± 0.19%, 0.33 ± 0.12%, and 0.24 ± 0.07% for 30, 75, 150, and 300 readings, respectively. Theoretical calculations of uncertainties showed that annealing before reusing dosimeters allows for dose errors below 1% with as few as 30 readings. Reusing dosimeters multiple times increases the dose errors especially with low numbers of readouts, so theoretically around 300 readings would be necessary to achieve errors around 1% or below in most scenarios. Note that these dose errors do not include the error associated with the signal-to-dose conversion factor.
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Affiliation(s)
- Sara A Abraham
- 1Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109-2104
| | - Kimberlee J Kearfott
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109-2104
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Musa Y, Hashim S, Ghoshal S, Bradley D, Ahmad N, Karim M, Hashim A, Kadir A. General radiographic attributes of optically stimulated luminescence dosimeters: A basic insight. Radiat Phys Chem Oxf Engl 1993 2018. [DOI: 10.1016/j.radphyschem.2018.01.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hashim S, Musa Y, Ghoshal SK, Ahmad NE, Hashim IH, Yusop M, Bradley DA, Kadir ABA. Optically stimulated Al 2O 3:C luminescence dosimeters for teletherapy: H p(10) performance evaluation. Appl Radiat Isot 2018; 135:7-11. [PMID: 29353759 DOI: 10.1016/j.apradiso.2018.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 11/17/2022]
Abstract
The performance of optically stimulated luminescence dosimeters (OSLDs, Al2O3:C) was evaluated in terms of the operational quantity of HP(10) in Co-60 external beam teletherapy unit. The reproducibility, signal depletion, and dose linearity of each dosimeter was investigated. For ten repeated readouts, each dosimeter exposed to 50mSv was found to be reproducible below 1.9 ± 3% from the mean value, indicating good reader stability. Meanwhile, an average signal reduction of 0.5% per readout was found. The dose response revealed a good linearity within the dose range of 5-50mSv having nearly perfect regression line with R2 equals 0.9992. The accuracy of the measured doses were evaluated in terms of operational quantity HP(10), wherein the trumpet curve method was used respecting the 1990 International Commission on Radiological Protection (ICRP) standard. The accuracy of the overall measurements from all dosimeters was discerned to be within the trumpet curve and devoid of outlier. It is established that the achieved OSL Al2O3:C dosimeters are greatly reliable for equivalent dose assessment.
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Affiliation(s)
- S Hashim
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia; Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research (ISI-SIR), Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia.
| | - Y Musa
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia; Centre for Energy Research and Training, Ahmadu Bello University, Zaria. P.M.B, 1014 Samaru, Nigeria
| | - S K Ghoshal
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
| | - N E Ahmad
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
| | - I H Hashim
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
| | - M Yusop
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
| | - D A Bradley
- Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, United Kingdom; Institute for Healthcare Development, Sunway University, 46150 Petaling Jaya, Selangor, Malaysia
| | - A B A Kadir
- Secondary Standard Dosimetry Laboratory (SSDL), Malaysia Nuclear Agency, Bangi, 43000 Kajang, Malaysia
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Lai LH, Lo AY, Chuang KS, Lin HH, Liu YC, Liu PL, Lin JP. Optically stimulated luminescence radiation response of Au/Al2O3 phosphors. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2017.02.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abraham SA, Frank SJ, Kearfott KJ. An Efficient, Affordable Optically Stimulated Luminescent (OSL) Annealer. HEALTH PHYSICS 2017; 113:2-12. [PMID: 28542006 DOI: 10.1097/hp.0000000000000677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Optically stimulated luminescent (OSL) dosimeters are devices used for measuring doses of ionizing radiation. Signal is stored within an OSL material so that when stimulated with light, light of a specific wavelength is emitted in proportion to the integrated ionizing radiation dose. Each interrogation of the material results in the loss of a small fraction of signal, thus allowing multiple interrogations leading to more accurate measurements of dose. In order to reuse a dosimeter, the residual signals from prior doses must be taken into account and subtracted from current readings, adding uncertainty to any future measurements. To reduce these errors when they become large, it is desirable to completely clear the stored signal or anneal the dosimeter. Traditionally, heating the material has accomplished this. In a commercially available dosimeter badge system, the OSL material Al2O3:C is incorporated into a plastic slide that would melt at the necessary high temperatures, which can reach 900 °C, required for annealing. Fortunately, due to the material's high sensitivity to light, OSLs can be optically annealed instead. In order to do this, an affordable OSL dosimeter annealer was designed with inexpensive, exchangeable blue, green, and white high intensity light-emitting diodes (LEDs). Several dosimeters were repeatedly annealed for recorded intervals and then read out. A single dosimeter was partially annealed through repeated interrogations with the LED array from a commercial reader. The signal loss due to the exposure to each light was analyzed to determine the practicality and efficiency of each color. The rate and extent of signal loss was dependent not only on the spectrum of annealing light but on the initial signal levels as well. These findings suggest that blue LEDs are the most promising for effective and rapid clearing of the OSL material Al2O3:C.
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Affiliation(s)
- Sara A Abraham
- *University of Michigan, Department of Nuclear Engineering and Radiological Sciences, Ann Arbor, MI 48109-2104
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Abraham SA, Kearfott KJ, Jawad AH, Boria AJ, Buth TJ, Dawson AS, Eng SC, Frank SJ, Green CA, Jacobs ML, Liu K, Miklos JA, Nguyen H, Rafique M, Rucinski BD, Smith T, Tan Y. Design of Interrogation Protocols for Radiation Dose Measurements Using Optically-Stimulated Luminescent Dosimeters. HEALTH PHYSICS 2017; 112:237-245. [PMID: 28121723 DOI: 10.1097/hp.0000000000000628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Optically-stimulated luminescent dosimeters are capable of being interrogated multiple times post-irradiation. Each interrogation removes a fraction of the signal stored within the optically-stimulated luminescent dosimeter. This signal loss must be corrected to avoid systematic errors in estimating the average signal of a series of optically-stimulated luminescent dosimeter interrogations and requires a minimum number of consecutive readings to determine an average signal that is within a desired accuracy of the true signal with a desired statistical confidence. This paper establishes a technical basis for determining the required number of readings for a particular application of these dosimeters when using certain OSL dosimetry systems.
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Affiliation(s)
- Sara A Abraham
- *University of Michigan, Department of Nuclear Engineering and Radiological Sciences, Ann Arbor, MI 48109-2104; †Department of Physics, University of Azad Jammu and Kashmir, Muzaffarabad, Azad Kashmir 13100, Pakistan; ‡College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang, Hunan Province, China
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Milinchuk V, Klinshpont E, Belozerov V, Khavroshina I, Sadikov E. Тhe transformation of the oxide coatings of aluminum by imitation factors of nuclear power plants. NUCLEAR ENERGY AND TECHNOLOGY 2016. [DOI: 10.1016/j.nucet.2016.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Poudel S, Currier B, Medich DC. Variation in the calibrated response of LiF, Al2O3, and silicon dosimeters when used for in-phantom measurements of source photons with energies between 30 KeV AND 300 KeV. HEALTH PHYSICS 2015; 108:434-442. [PMID: 25706137 DOI: 10.1097/hp.0000000000000229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The MCNP5 radiation transport code was used to quantify changes in the absorbed dose conversion factor for LiF, Al2O3, and silicon-based electronic dosimeters calibrated in-air using standard techniques and summarily used to measure absorbed dose to water when placed in a water phantom. A mono-energetic photon source was modeled at energies between 30 keV and 300 keV for a point-source placed at the center of a water phantom, a point-source placed at the surface of the phantom, and for a 10-cm radial field geometry. Dosimetric calculations were obtained for water, LiF, Al2O3, and silicon at depths of 0.2 cm and 10 cm from the source. These results were achieved using the MCNP5 *FMESH photon energy-fluence tally, which was coupled with the appropriate DE/DF card for each dosimetric material studied to convert energy-fluence into the absorbed dose. The dosimeter's absorbed dose conversion factor was calculated as a ratio of the absorbed dose to water to that of the dosimeter measured at a specified phantom depth. The dosimeter's calibration value also was obtained. Based on these results, the absorbed dose conversion factor for a LiF dosimeter was found to deviate from its calibration value by up to 9%, an Al2O3 dosimeter by 43%, and a silicon dosimeter by 61%. These data therefore can be used to obtain LiF, Al2O3, and silicon dosimeter correction factors for mono-energetic and poly-energetic sources at measurement depths up to 10 cm under the irradiation geometries investigated herein.
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Affiliation(s)
- Sashi Poudel
- *Department of Physics, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609
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Presciutti SM, Karukanda T, Lee M. Management decisions for adolescent idiopathic scoliosis significantly affect patient radiation exposure. Spine J 2014; 14:1984-90. [PMID: 24333453 DOI: 10.1016/j.spinee.2013.11.055] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 10/09/2013] [Accepted: 11/26/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Adolescent idiopathic scoliosis (AIS) patients treated before the 1990s have a 1% to 2% increased lifetime risk of developing breast and thyroid cancer as a result of ionizing radiation from plain radiographs. Although present plain radiographic techniques have been able to reduce some of the radiation exposure, modern treatment algorithms for scoliosis often include computed tomography (CT) and intraoperative fluoroscopy. The exact magnitude of exposure to ionizing radiation in adolescents during modern scoliosis treatment is therefore unclear. PURPOSE To determine the difference in radiation exposures in patients undergoing various forms of treatment for AIS. STUDY DESIGN Retrospective cohort. PATIENT SAMPLE Patients aged 9 to 18 years with a diagnosis of AIS, followed and/or treated with nonoperative or operative management for a minimum of 2 years. OUTCOME MEASURES Number of radiographs and total radiation exposure calculated. METHODS The charts and radiographs of patients managed for AIS at a single institution between September 2007 and January 2012 were reviewed. Patients were divided into three groups: operative group, braced group, and observation group. Patient demographics, Cobb angles, and curve types were recorded. The number of radiographs per year that each patient received and the total radiation dose were recorded. The plain radiographic radiation exposure was then combined with the direct exposure recording from ancillary tests, such as fluoroscopy and CT, and a radiation exposure rate was calculated (mrad/y). A single-factor analysis of variance (α=0.01) with a Tukey honest significant difference post hoc analysis was used to test significance between groups. RESULTS Two hundred sixty-seven patients were evaluated: 86 operative, 80 brace, and 101 observation. All groups had similar demographics and curve type distribution. The mean initial Cobb angle at presentation was significantly different between the groups: operative (57°±11°), brace (24°±7.9°), and observation (18°±9.4°) (p<.01). There was a significant difference among the groups in terms of the mean number of radiographs received per year; operative group, 12.2 (95% confidence interval [CI]: 10.8-13.5; p<.001); braced group, 5.7 (95% CI: 5.2-6.2; p<.001), and observed group, 3.5 (95% CI: 3.160-3.864; p<.001). The operative group received 1,400 mrad per year (95% CI: 1,350-1,844; p<.001), braced group received 700 mrad per year (95% CI: 598-716; p<.001), and observed group received 400 mrad per year (95% CI: 363-444; p<.001). Importantly, 78% of radiation in the operative group was attributable to the operative fluoroscopy exposure. CONCLUSIONS Significant differences exist in the total radiation exposure in scoliosis patients with different treatment regimens, with operative patients receiving approximately 8 to 14 times more radiation than braced patients or those undergoing observation alone, respectively. Operative patients also receive more than twice the radiation per year than braced or observed patients. Almost 78% of the annual radiation exposure for operative patients occurs intraoperatively. Because children are notably more sensitive to the carcinogenic effects of ionizing radiation, judicious use of present imaging methods and a search for newer imaging methods with limited ionizing radiation should be undertaken.
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Affiliation(s)
- Steven M Presciutti
- Department of Orthopaedic Surgery, University of Connecticut Health Center, 263 Farmington Ave., MARB Building, 4th floor, Farmington, CT 06030, USA.
| | - Teja Karukanda
- Department of Orthopaedic Surgery, University of Connecticut Health Center, 263 Farmington Ave., MARB Building, 4th floor, Farmington, CT 06030, USA
| | - Mark Lee
- Department of Orthopaedics, Connecticut Children's Medical Center, 285 Washington St, Hartford, CT 06106, USA
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Lehmann J, Dunn L, Lye JE, Kenny JW, Alves ADC, Cole A, Asena A, Kron T, Williams IM. Angular dependence of the response of the nanoDot OSLD system for measurements at depth in clinical megavoltage beams. Med Phys 2014; 41:061712. [DOI: 10.1118/1.4875698] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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