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via oxidative stress leading to overexpression of hypoxia inducible factor-1 (HIF-1). HIF-1 expression will
stimulate angiogenesis, epithelial mesenchymal transition (EMT), invasion/migration, and the
development of metastasis. 2) These effects will be abrogated by MnBuOE, an oxidative stress inhibitor.
Materials/Methods: Partial irradiation of 4T1 tumors grown in our dorsal window chamber model (X-ray,
300 micron beam; 0, 30, 50 Gy) was performed and tumor changes were assessed longitudinally with in
vivo hyperspectral imaging. 4T1 and 4T07 cells were irradiated in vitro (0, 2, 5, 10, 20Gy) and assessed for
EMT via immunofluorescence for biomarkers. Cells were analyzed in a transwell assay over 24 hours +/-
MnBuOE (1uM). Results: Partial tumor radiation initiated a robust angiogenic response, infiltration of
tumor cells along pre-existing vascular networks adjacent to the irradiated tumor, and migration of tumor
cells to distant unirradiated sites. Immunofluorescence for biomarkers revealed a dose-responsive EMT
in irradiated cells. MnBuOE reduced invasion in 4T07 cells by 2.58-fold. Conclusions: While the project is
ongoing, we have evidence that partial tumor radiation triggers aggressive tumor changes in vivo.
Radiation induces EMT in 4T1 and 4T07 cells in vitro and MnBuOE can reduce the invasion in 4T07 cells.
(PS3-30) Reusability of optically stimulated luminescent dosimeters (OSLD) in clinical dosimetry.Rafael
Khatchadourian; Yvan Zaccuri; Vincent Leduc; Malik Brunet-Benkhoucha; and Wieslaw Wierzbicki
Hopital Maisonneuve-Rosemont (HMR), Montreal, Canada
Optically stimulated luminescent dosimeters (OSLDs) consist of tiny disks of aluminum oxide
doped with carbon (Al2O3: C). The crystal can trap charge carriers when exposed to ionizing radiation and
energy released as luminescence after illumination of the OSLD is proportional to the dose received by
the crystal. NanoDot OSLDs manufactured by LANDAUER are commercialized as single use detectors with
an overall precision of ± 5 %. We studied the reusability of OSLDs 1) by comparing fluorescent and halogen
light sources for optimal signal annealing, 2) by investigating their behavior for different levels of
accumulated dose from 0 Gy to 700 Gy, and 3) by validating their use for the clinic through calibration
curves, control OSLDs, and temperature dependence measurements. Irradiations were done with a 16x16
field at SAD = 100 cm and a depth of 10 cm in solid water using 6 MV photons. Measurements pertaining
to temperature were made with a Cobalt-60 unit. The following observations are reported: 1) Exposure
of irradiated OSLDs to fluorescent lamps showed a 100x decrease in the signal after 3 hours. 2) Efficiency
of OSLD signal annealing after irradiation increases with absorbed cumulative dose. 3) Increase of post-
discharge background signal is linear with time and proportional to absorbed cumulative dose. 4) Post-
irradiation transient signal decay is less abrupt with increasing accumulated dose. 5) OSLD sensitivity
increases with absorbed cumulative dose but reaches a plateau beyond 530 Gy. 6) Luminescent signal
increases with OSLD temperature at readout time with a 30% variation between 6oC and 53oC. 7) There
is no temperature dependence between signal and OSLD temperature during irradiation. Calibration
curves were validated using three different curve fits (linear, bi-segment, and 2nd degree polynomial)
yielding results generally within 5% of expected values and an optimal fit corresponding to the bi-segment
model. The control OSLD method, although requiring a 3 day irradiation sequence, was more precise with
errors remaining within 3% of known values. In conclusion, multiple use of OSLD detectors is feasible and
is appropriate for clinical applications in a radiotherapy environment.
205 | P a g e
stimulate angiogenesis, epithelial mesenchymal transition (EMT), invasion/migration, and the
development of metastasis. 2) These effects will be abrogated by MnBuOE, an oxidative stress inhibitor.
Materials/Methods: Partial irradiation of 4T1 tumors grown in our dorsal window chamber model (X-ray,
300 micron beam; 0, 30, 50 Gy) was performed and tumor changes were assessed longitudinally with in
vivo hyperspectral imaging. 4T1 and 4T07 cells were irradiated in vitro (0, 2, 5, 10, 20Gy) and assessed for
EMT via immunofluorescence for biomarkers. Cells were analyzed in a transwell assay over 24 hours +/-
MnBuOE (1uM). Results: Partial tumor radiation initiated a robust angiogenic response, infiltration of
tumor cells along pre-existing vascular networks adjacent to the irradiated tumor, and migration of tumor
cells to distant unirradiated sites. Immunofluorescence for biomarkers revealed a dose-responsive EMT
in irradiated cells. MnBuOE reduced invasion in 4T07 cells by 2.58-fold. Conclusions: While the project is
ongoing, we have evidence that partial tumor radiation triggers aggressive tumor changes in vivo.
Radiation induces EMT in 4T1 and 4T07 cells in vitro and MnBuOE can reduce the invasion in 4T07 cells.
(PS3-30) Reusability of optically stimulated luminescent dosimeters (OSLD) in clinical dosimetry.Rafael
Khatchadourian; Yvan Zaccuri; Vincent Leduc; Malik Brunet-Benkhoucha; and Wieslaw Wierzbicki
Hopital Maisonneuve-Rosemont (HMR), Montreal, Canada
Optically stimulated luminescent dosimeters (OSLDs) consist of tiny disks of aluminum oxide
doped with carbon (Al2O3: C). The crystal can trap charge carriers when exposed to ionizing radiation and
energy released as luminescence after illumination of the OSLD is proportional to the dose received by
the crystal. NanoDot OSLDs manufactured by LANDAUER are commercialized as single use detectors with
an overall precision of ± 5 %. We studied the reusability of OSLDs 1) by comparing fluorescent and halogen
light sources for optimal signal annealing, 2) by investigating their behavior for different levels of
accumulated dose from 0 Gy to 700 Gy, and 3) by validating their use for the clinic through calibration
curves, control OSLDs, and temperature dependence measurements. Irradiations were done with a 16x16
field at SAD = 100 cm and a depth of 10 cm in solid water using 6 MV photons. Measurements pertaining
to temperature were made with a Cobalt-60 unit. The following observations are reported: 1) Exposure
of irradiated OSLDs to fluorescent lamps showed a 100x decrease in the signal after 3 hours. 2) Efficiency
of OSLD signal annealing after irradiation increases with absorbed cumulative dose. 3) Increase of post-
discharge background signal is linear with time and proportional to absorbed cumulative dose. 4) Post-
irradiation transient signal decay is less abrupt with increasing accumulated dose. 5) OSLD sensitivity
increases with absorbed cumulative dose but reaches a plateau beyond 530 Gy. 6) Luminescent signal
increases with OSLD temperature at readout time with a 30% variation between 6oC and 53oC. 7) There
is no temperature dependence between signal and OSLD temperature during irradiation. Calibration
curves were validated using three different curve fits (linear, bi-segment, and 2nd degree polynomial)
yielding results generally within 5% of expected values and an optimal fit corresponding to the bi-segment
model. The control OSLD method, although requiring a 3 day irradiation sequence, was more precise with
errors remaining within 3% of known values. In conclusion, multiple use of OSLD detectors is feasible and
is appropriate for clinical applications in a radiotherapy environment.
205 | P a g e
