Lembit Sihver

Prof. Dr. Lembit Sihver

Department of Radiation Physics, Atominstitut, Technische Universität Wien, Stadionallee 2, 1020 Vienna, Austria

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 November 2023 in Journal of Nuclear Science and Technology
Verified
Journal Article
Open access
TSTatsuhiko Sato
Tatsuhiko Sato
YIYosuke Iwamoto
Yosuke Iwamoto
SHShintaro Hashimoto
Shintaro Hashimoto
TOTatsuhiko Ogawa
Tatsuhiko Ogawa
TFTakuya Furuta
Takuya Furuta
KNKoji Niita
Koji Niita

19 December 2017 in Cancers
Verified
Journal Article
Open access
PDF file
Ellas SpyratouEllas Spyratou
Ellas Spyratou
MMMersini Makropoulou
Mersini Makropoulou
Efstathios P. EfstathopoulosEfstathios P. Efstathopoulos
Efstathios P. Efstathopoulos
ALEXANDROS GEORGAKILASALEXANDROS GEORGAKILAS
ALEXANDROS GEORGAKILAS
Lembit SihverLembit Sihver
Lembit Sihver
Many tumor-targeted strategies have been used worldwide to limit the side effects and improve the effectiveness of therapies, such as chemotherapy, radiotherapy (RT), etc. Biophotonic therapy modalities comprise very promising alternative techniques for cancer treatment with minimal invasiveness and side-effects. These modalities use light e.g., laser irradiation in an extracorporeal or intravenous mode to activate photosensitizer agents with selectivity in the target tissue. Photothermal therapy (PTT) is a minimally invasive technique for cancer treatment which uses laser-activated photoabsorbers to convert photon energy into heat sufficient to induce cells destruction via apoptosis, necroptosis and/or necrosis. During the last decade, PTT has attracted an increased interest since the therapy can be combined with customized functionalized nanoparticles (NPs). Recent advances in nanotechnology have given rise to generation of various types of NPs, like gold NPs (AuNPs), designed to act both as radiosensitizers and photothermal sensitizing agents due to their unique optical and electrical properties i.e., functioning in dual mode. Functionalized AuNPS can be employed in combination with non-ionizing and ionizing radiation to significantly improve the efficacy of cancer treatment while at the same time sparing normal tissues. Here, we first provide an overview of the use of NPs for cancer therapy. Then we review many recent advances on the use of gold NPs in PTT, RT and PTT/RT based on different types of AuNPs, irradiation conditions and protocols. We refer to the interaction mechanisms of AuNPs with cancer cells via the effects of non-ionizing and ionizing radiations and we provide recent existing experimental data as a baseline for the design of optimized protocols in PTT, RT and PTT/RT combined treatment.

1 October 2021 in New Journal of Physics
Verified
Journal Article
Open access
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FLFrancesca Luoni
Francesca Luoni
FHFelix Horst
Felix Horst
CRC A Reidel
C A Reidel
AQAnastasiia Quarz
Anastasiia Quarz
LBLaura Bagnale
Laura Bagnale
Marco DuranteMarco Durante
Marco Durante

25 June 2021 in Cancers
Verified
Journal Article
Open access
PDF file
ITIoanna Tremi
Ioanna Tremi
Ellas SpyratouEllas Spyratou
Ellas Spyratou
MSMaria Souli
Maria Souli
Efstathios P. EfstathopoulosEfstathios P. Efstathopoulos
Efstathios P. Efstathopoulos
MMMersini Makropoulou
Mersini Makropoulou
Lembit SihverLembit Sihver
Lembit Sihver
Many different tumor-targeted strategies are under development worldwide to limit the side effects and improve the effectiveness of cancer therapies. One promising method is to enhance the radiosensitization of the cancer cells while reducing or maintaining the normal tissue complication probability during radiation therapy using metallic nanoparticles (NPs). Radiotherapy with MV photons is more commonly available and applied in cancer clinics than high LET particle radiotherapy, so the addition of high-Z NPs has the potential to further increase the efficacy of photon radiotherapy in terms of NP radiosensitization. Generally, when using X-rays, mainly the inner electron shells are ionized, which creates cascades of both low and high energy Auger electrons. When using high LET particles, mainly the outer shells are ionized, which give electrons with lower energies than when using X-rays. The amount of the produced low energy electrons is higher when exposing NPs to heavy charged particles than when exposing them to X-rays. Since ions traverse the material along tracks, and therefore give rise to a much more inhomogeneous dose distributions than X-rays, there might be a need to introduce a higher number of NPs when using ions compared to when using X-rays to create enough primary and secondary electrons to get the desired dose escalations. This raises the questions of toxicity. This paper provides a review of the fundamental processes controlling the outcome of metallic NP-boosted photon beam and ion beam radiation therapy and presents some experimental procedures to study the biological effects of NPs’ radiosensitization. The overview shows the need for more systematic studies of the behavior of NPs when exposed to different kinds of ionizing radiation before applying metallic-based NPs in clinical practice to improve the effect of IR therapy.

29 January 2009 in Physical Review C
Verified
Journal Article
Closed access
PDF file
DMDavide Mancusi
Davide Mancusi
KNKoji Niita
Koji Niita
TMTomoyuki Maruyama
Tomoyuki Maruyama
Lembit SihverLembit Sihver
Lembit Sihver
The JAERI quantum molecular dynamics (JQMD) model has been successfully used for a long time now to describe many different aspects of nuclear reactions in a unified way. In some cases, however, the JQMD model cannot produce consistent results: First, it lacks a fully relativistically covariant approach to the problem of molecular dynamics; second, the quantum-mechanical ground state of nuclei cannot be faithfully reproduced in a semiclassical framework. Therefore, we introduce R-JQMD, an improved version of JQMD that also features a new ground-state initialization algorithm for nuclei. We compare the structure of the two codes and discuss whether R-JQMD can be adjusted to improve JQMD's agreement with measured heavy-ion fragmentation cross sections.

25 May 2010 in Radiation and Environmental Biophysics
Verified
Journal Article
Closed access
PDF file
Lembit SihverLembit Sihver
Lembit Sihver
TST. Sato
T. Sato
MPM. Puchalska
M. Puchalska
GRG. Reitz
G. Reitz