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| 2. |
- Weiszflog, M., et al.
(författare)
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High-spin States in 89Mo
- 1993
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Ingår i: Conference Series. - 0951-3248. - 0750302623 ; 132, s. 631-633
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Konferensbidrag (refereegranskat)
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| 3. |
- Vatnitsky, S, et al.
(författare)
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Proton dosimetry intercomparison
- 1996
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Ingår i: Radiotherapy and Oncology. - 0167-8140 .- 1879-0887. ; 41:2, s. 169-77
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Methods for determining absorbed dose in clinical proton beams are based on dosimetry protocols provided by the AAPM and the ECHED. Both groups recommend the use of air-filled ionization chambers calibrated in terms of exposure or air kerma in a 60Co beam when a calorimeter or Faraday cup dosimeter is not available. The set of input data used in the AAPM and the ECHED protocols, especially proton stopping powers and w-value is different. In order to verify inter-institutional uniformity of proton beam calibration, the AAPM and the ECHED recommend periodic dosimetry intercomparisons. In this paper we report the results of an international proton dosimetry intercomparison which was held at Loma Linda University Medical Center. The goal of the intercomparison was two-fold: first, to estimate the consistency of absorbed dose delivered to patients among the participating facilities, and second, to evaluate the differences in absorbed dose determination due to differences in 60Co-based ionization chamber calibration protocols.MATERIALS AND METHODS: Thirteen institutions participated in an international proton dosimetry intercomparison. The measurements were performed in a 15-cm square field at a depth of 10 cm in both an unmodulated beam (nominal accelerator energy of 250 MeV) and a 6-cm modulated beam (nominal accelerator energy of 155 MeV), and also in a circular field of diameter 2.6 cm at a depth of 1.14 cm in a beam with 2.4 cm modulation (nominal accelerator energy of 100 MeV).RESULTS: The results of the intercomparison have shown that using ionization chambers with 60Co calibration factors traceable to standard laboratories, and institution-specific conversion factors and dose protocols, the absorbed dose specified to the patient would fall within 3% of the mean value. A single measurement using an ionization chamber with a proton chamber factor determined with a Faraday cup calibration differed from the mean by 8%.CONCLUSION: The adoption of a single ionization chamber dosimetry protocol and uniform conversion factors will establish agreement on proton absorbed dose to approximately 1.5%, consistent with that which has been observed in high-energy photon and electron dosimetry.
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| 4. |
- Schubart, R, et al.
(författare)
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In-beam spectroscopy and shell model structure of the neutron deficient In-103 and CD-100,CD-102
- 1995
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Ingår i: Physica Scripta. - : ROYAL SWEDISH ACAD SCIENCES. - 0031-8949 .- 1402-4896. ; T56, s. 311-315
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Tidskriftsartikel (refereegranskat)abstract
- The ?-decay of the neutron deficient nuclei 103In and 100,102Cd has been studied following the reactions 58Ni + 50Cr and 58Ni + 46,48Ti at 250 MeV and 230 MeV bombarding energy of the 58Ni beam, respectively. Evaporation neutrons and charged particles were measured in coincidence with prompt and delayed ?-rays with the multidetector array OSIRIS. To investigate the decay of the I? = 8+ isomers of 100,102Cd a recoil catcher setup inside OSIRIS was used. Six new ?-ray transitions of 100Cd and four of 102Cd with intensities of 1-10% of the main ?-ray cascades were found. Two new states of 100Cd were established and firm spin-parity assignments were made to all states below the isomer. These new states were identified as the 4+ and the 6+ members of the proton ?g9/2?2 multiplet. The experimental states of 103In and of 100,102Cd are compared to shell model predictions in the ?(p1/2, g9/2) v(d5/2, g7/2, s1/2, d3/2, h11/2) configuration space.
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| 5. |
- Vatnitsky, S, et al.
(författare)
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Proton dosimetry intercomparison based on the ICRU report 59 protocol
- 1999
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Ingår i: Radiotherapy and Oncology. - 0167-8140 .- 1879-0887. ; 51:3, s. 273-279
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE:A new protocol for calibration of proton beams was established by the ICRU in report 59 on proton dosimetry. In this paper we report the results of an international proton dosimetry intercomparison, which was held at Loma Linda University Medical Center. The goals of the intercomparison were, first, to estimate the level of consistency in absorbed dose delivered to patients if proton beams at various clinics were calibrated with the new ICRU protocol, and second, to evaluate the differences in absorbed dose determination due to differences in 60Co-based ionization chamber calibration factors.MATERIALS AND METHODS:Eleven institutions participated in the intercomparison. Measurements were performed in a polystyrene phantom at a depth of 10.27 cm water equivalent thickness in a 6-cm modulated proton beam with an accelerator energy of 155 MeV and an incident energy of approximately 135 MeV. Most participants used ionization chambers calibrated in terms of exposure or air kerma. Four ionization chambers had 60Co-based calibration in terms of absorbed dose-to-water. Two chambers were calibrated in a 60Co beam at the NIST both in terms of air kerma and absorbed dose-to-water to provide a comparison of ionization chambers with different calibrations.RESULTS:The intercomparison showed that use of the ICRU report 59 protocol would result in absorbed doses being delivered to patients at their participating institutions to within +/-0.9% (one standard deviation). The maximum difference between doses determined by the participants was found to be 2.9%. Differences between proton doses derived from the measurements with ionization chambers with N(K)-, or N(W) - calibration type depended on chamber type.CONCLUSIONS:Using ionization chambers with 60Co calibration factors traceable to standard laboratories and the ICRU report 59 protocol, a distribution of stated proton absorbed dose is achieved with a difference less than 3%. The ICRU protocol should be adopted for clinical proton beam calibration. A comparison of proton doses derived from measurements with different chambers indicates that the difference in results cannot be explained only by differences in 60Co calibration factors.
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