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Wyszukujesz frazę "Malicki, J" wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Effect of scattered radiation in the total body irradiation technique: evaluation of the spoiler and wall dose component in the depthdose distribution
Autorzy:
Piotrowski, T.
Adamska, K.
Malicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/147640.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
total body irradiation (TBI)
scattered radiation
leukaemia
Opis:
To determine the additional dose in layers of the body close to the skin during total body irradiation (TBI), due to radiation scattered off the treatment room walls and behind plexiglass spoilers applied to improve dose uniformity within the irradiated body. Large-field 6, 15 and 25 MV photon beams were generated by a Saturn 43 medical accelerator. A solid 30 ´ 30 ´ 30 cm3 PMMA (polymethylmethacrylate) phantom was used to represent radiation scattered from the body of the patient. Dose distributions were measured by a Farmer ionization chamber. The dose component arising from the spoiler was measured 5 mm below the phantom surface, over distances of 5-100 cm between the spoiler and the phantom surface. To measure the contribution of backscattered radiation from the walls, a small lead block was placed between the source and detector. Measurements were carried out in air with the PMMA phantom removed, to eliminate radiation backscattered from the phantom. As measured behind the spoiler, attenuation of the primary photon beam by the spoiler itself was by 8, 5 and 3% for 6, 15 and 25 MV beams, respectively. The highest dose contribution from the spoiler arose at 10 cm separation between the phantom surface and the spoiler. Assessed at a depth of 5 mm in the phantom, at spoiler-phantom separation of 10 cm, relative to case without spoiler and with wall backscatter subtracted, the dose enhancement due to the spoiler was by 8, 13 and 20% at beam energies 6, 15 and 25 MV, respectively. In these measurements, the distance between the source and the phantom surface was 300 cm and that between the source and the spoiler - 290 cm. The dose contributions due to radiation backscattered from the walls, relative to the case without any wall backscatter, estimated over the distal side of the phantom at a distance of 20 cm between the wall and that side of the phantom, were 5, 6 and 8% at beam energies 6, 15 and 25 MV, respectively. The use of a spoiler enhanced the dose in regions close to the phantom surface, compensating for the dose decrease over that area due to build-up effect. Radiation backscattered from the wall enhanced the dose in regions close to the phantom surface facing the wall.
Źródło:
Nukleonika; 2007, 52, 4; 153-158
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of doses from photon beam irradiation and scattered neutrons in an anthropomorphic phantom model of prostate cancer: a comparison between 3DCRT, IMRT and tomotherapy
Autorzy:
Kowalik, A.
Jackowiak, W.
Malicki, J.
Skórska, M.
Adamczyk, M.
Konstanty, E.
Piotrowski, T.
Polaczek-Grelik, K.
Powiązania:
https://bibliotekanauki.pl/articles/146348.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
3DCRT
IMRT
low doses
neutron doses
thermoluminescent detectors (TLD)
tomotherapy
Opis:
The rapid development of new radiotherapy technologies, such as intensity modulated radiotherapy (IMRT) or tomotherapy, has resulted in the capacity to deliver a more homogenous dose in the target. However, the higher doses associated with these techniques are a reason for concern because they may increase the dose outside the target. In the present study, we compared 3DCRT, IMRT and tomotherapy to assess the doses to organs at risk (OARs) resulting from photon beam irradiation and scattered neutrons. Material and methods. The doses to OARs outside the target were measured in an anthropomorphic Alderson phantom using thermoluminescence detectors (TLD 100) 6Li (7.5%) and 7Li (92.5%). The neutron fluence rate [cm–2·s–1] at chosen points inside the phantom was measured with gold foils (0.5 cm diameter, mean surface density of 0.108 g/cm3). Results. The doses [Gy] delivered to the OARs for 3DCRT, IMRT and tomotherapy respectively, were as follows: thyroid gland (0.62 ± 0.001 vs. 2.88 ± 0.004 vs. 0.58 ± 0.003); lung (0.99 ± 0.003 vs. 4.78 ± 0.006 vs. 0.67 ± 0.003); bladder (80.61 ± 0.054 vs. 53.75 ± 0.070 vs. 34.71 ± 0.059); and testes (4.38 ± 0.017 vs. 6.48 ± 0.013 vs. 4.39 ± 0.020). The neutron dose from 20 MV X-ray beam accounted for 0.5% of the therapeutic dose prescribed in the PTV. The further from the field edge the higher the contribution of this secondary radiation dose (from 8% to ~45%). Conclusion. For tomotherapy, all OARs outside the therapeutic field are well-spared. In contrast, IMRT achieved better sparing than 3DCRT only in the bladder. The photoneutron dose from the use of high-energy X-ray beam constituted a notable portion (0.5%) of the therapeutic dose prescribed to the PTV.
Źródło:
Nukleonika; 2017, 62, 1; 29-35
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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