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Your search keyword '"Johansen, Jacob G."' showing total 12 results
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12 results on '"Johansen, Jacob G."'

4. Study of bound states in ¹⁰Be by one neutron removal reactions of ¹¹Be

Author

Johansen, Jacob G., Bildstein, V., Borge, M. J. G., Cubero, M., Diriken, J., Elseviers, J., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Gernhäuser, R., Jonson, B., Koldste, G. T., Konki, J., Kröll, T., Krücken, R., Mücher, D., Nilsson, T., Nowak, K., Pakarinen, J., Pesudo, V., Raabe, R., Riisager, K., Seidlitz, M., Tengblad, O., Törnqvist, H., Voulot, D., Warr, N., Wimmer, K., De Witte, H., Johansen, Jacob G., Bildstein, V., Borge, M. J. G., Cubero, M., Diriken, J., Elseviers, J., Fraile, L. M., Fynbo, H. O. U., Gaffney, L. P., Gernhäuser, R., Jonson, B., Koldste, G. T., Konki, J., Kröll, T., Krücken, R., Mücher, D., Nilsson, T., Nowak, K., Pakarinen, J., Pesudo, V., Raabe, R., Riisager, K., Seidlitz, M., Tengblad, O., Törnqvist, H., Voulot, D., Warr, N., Wimmer, K., and De Witte, H.

Abstract

The bound states of ¹⁰Be have been studied by removing single neutrons from ¹¹Be nuclei. A 2.8 MeV u⁻¹ beam of ¹¹Be was produced at ISOLDE, CERN and directed on to both proton and deuteron targets inducing one-neutron removal reactions. Charged particles were detected to identify the two reaction channels (d, t) and (p, d), and the individual states in ¹⁰Be were identified by gamma detection. All bound states but one were populated and identified in the (d, t) reaction. The combination of REX-ISOLDE and MINIBALL allowed for a clean separation of the high-lying states in ¹⁰Be. This is the first time these states have been separated in a reaction experiment. Differential cross sections have been calculated for all the reaction channels and compared to DWBA calculations. Spectroscopic factors are derived and compared to values from the litterature. While the overall agreement between the spectrocopic factors is poor, the ratio between the ground state and the first excited state is in agreement with the previous measured ones. Furthermore, a significant population of the 2⁺₂ state is observed, which which may indicate the presence of multi-step processes at our beam energy.

Published
2024

5. Spread-out Bragg peak FLASH: quantifying normal tissue toxicity in a murine model.

Author

Kristensen, Line, Poulsen, Per Rugaard, Kanouta, Eleni, Rohrer, Sky, Ankjærgaard, Christina, Andersen, Claus E., Johansen, Jacob G., Simeonov, Yuri, Weber, Uli, Grau, Cai, and Sørensen, Brita Singers

Subjects
RADIATION damage, RADIATION protection, PROTON beams, PROTON therapy, TISSUES
Abstract

Objective: A favorable effect of ultra-high dose rate (FLASH) radiation on normal tissue-sparing has been indicated in several preclinical studies. In these studies, the adverse effects of radiation damage were reduced without compromising tumor control. Most studies of proton FLASH investigate these effects within the entrance of a proton beam. However, the real advantage of proton therapy lies in the Spread-out Bragg Peak (SOBP), which allows for giving a high dose to a target with a limited dose to healthy tissue at the entrance of the beam. Therefore, a clinically relevant investigation of the FLASH effect would be of healthy tissues within a SOBP. Our study quantified the tissue-sparing effect of FLASH radiation on acute and late toxicity within an SOBP in a murine model. Material/Methods: Radiation-induced damage was assessed for acute and late toxicity in the same mice following irradiation with FLASH (Field dose rate of 60 Gy/s) or conventional (CONV, 0.34 Gy/s) dose rates. The right hindleg of unanesthetized female CDF1 mice was irradiated with single-fraction doses between 19.9-49.7 Gy for CONV and 30.4-65.9 Gy for FLASH with 5-8 mice per dose. The leg was placed in the middle of a 5 cm SOBP generated from a mono-energetic beam using a 2D range modulator. Acute skin toxicity quantified by hair loss, moist desquamation and toe separation was monitored daily within 29 days post-treatment. Late toxicity of fibrotic development measured by leg extendibility was monitored biweekly until 30 weeks post-treatment. Results: Comparison of acute skin toxicity following radiation indicated a tissuesparing effect of FLASH compared to conventional single-fraction radiation with a mean protection ratio of 1.40 (1.35-1.46). Fibrotic development similarly indicated normal tissue sparing with a 1.18 (1.17-1.18) protection ratio. The acute skin toxicity tissue sparing was similar to data from entrance-beam irradiations of Sørensen et al. (4). Conclusion: Full dose-response curves for acute and late toxicity after CONV and FLASH radiation were obtained. Radiation within the SOBP retains the normal-tissue-sparing effect of FLASH with a dose-modifying factor of 40% for acute skin damage and 18% for fibrotic development. [ABSTRACT FROM AUTHOR]

Published
2024
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6. 596: The utilisation of brachytherapy in Europe – A BrachyHERO survey.

Author

Johansen, Jacob G., Jürgenliemk-Schulz, Ina-Maria, Haddad, Hathal, Hannoun-Levi, Jean-Michel, Hellebust, Taran, Guix, Benjamin, Lössl, Kristina, Pieters, Bradley R., Rao, Christopher, Strnad, Vratislav, Sturdza, Alina E., Tagliaferri, Luca, Takácsi-Nagy, Zoltán, Villafranca, Elena, Wojcieszek, Piotr, Rembielak, Agata, and Niehoff, Peter

Subjects
*RADIOISOTOPE brachytherapy
Published
2024
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