Page 316 - 2014 Printable Abstract Book
P. 316
biomarkers in patients suffering from radiation proctitis consecutive to complications of abdomino-pelvic
radiotherapy. In addition, we evaluated the relationship between circulating MPs and endothelium-
dependent responses. Flow cytometry analysis of platelet-free plasma from a cohort of 217 patients
overexposed to irradiation indicated that circulating levels of Annexin V+ MPs displayed a 3-fold increase
in grade 3 patients (SOMALENT scale) as compared to patients with grade 0, 1 and 2. Moreover, platelet-
derived CD41+ MPs constituted the major sub-population compared to leukocyte, monocyte, endothelial
and red blood cells in all groups. Using a clotting assay, we measured the procoagulant activity of MPs
and we found that thrombin generation velocity tended to decrease in grade 3 patients compared to other
groups. Finally, MPs from grade 3 patients did not affect endothelium activation in comparison to the
other grades. Our data demonstrate that high level of circulating MPs is correlated to the grade 3 patients
with radiation proctitis. These results suggest that detection of circulating MPs may be valuable for the
prognostic of radiotherapy complications. Eventually, this study could contribute to propose a new anti-
MPs therapeutic approach for the treatment of radiation-induced pelvic disease.
(PS5-51) Using 18F-FDG-PET for the assessment of gastrointestinal damage from radiation exposure.
3
2
2
1
Tien Tang ; David Rendon ; Caterina Kaffes ; Solmaz Afshar ; Omaima Sabek ; and M. Waleed Gaber
2
3
1
2
Rice University, Houston, TX ; Baylor College of Medicine, Houston, TX ; and Houston Methodist Hospital,
Houston, TX
3
Purpose: In the event of a nuclear accident or attack many will be exposed to harmful radiation
with the potential for mass causality. A lethal dose of radiation can cause massive cell death where the
extent of this damage is dependent on the dose, area exposed and exposure time. In the event of a
nuclear incident it would be necessary to find a fast and reliable way to triage patients who have been
exposed and provide proper treatment. In this study we propose the use of positron emission
tomography (PET) with fluorodeoxyglucose (FDG) imaging as a diagnostic tool to quickly diagnose
18
victims in the gastrointestinal syndrome dose range and track their recovery. F-FDG-PET imaging has
the capability to detect inflammation through the energy metabolism of inflammatory particles
attracted to site of damage. Methods: Wistar rats (n=23) were irradiated with a 7.5 Gy dose with the
following shielding scheme: whole body (WB) irradiated, with their upper half shielded (UHS), 2 legs
shielded (2LS), or cranial shielded. An additional group was used as control. The animals were imaged
18
using F-FDG-PET at different time points post radiation (5, 11, 35 days). The mean standard uptake
value (SUV) was examined by creating a region of interest of the intestinal area and compared across
experimental groups. Each group was imaged until the animal fully recovered as indicated by the SUV
18
and general health. Results: Using F-FDG-PET we found that irradiated animals had a higher SUV (p <
0.05) when compared to control (SUV=1.92±0.36) up to 11 days post irradiation. This imaging method
was also sensitive enough to differentiate between UHS (SUV=4±0.4) and WB (SUV=2.88±0.5) with p <
0.05 at 5 days post. Tracking recovery showed an increase in SUV that returned to control level and
therefore was an indication of full recovery after 35 days post. Shielded animals made a full recovery
18
while those fully exposed did not. Conclusion: Results show that F-FDG-PET is an imaging technique
that is sensitive enough to not only detect gastrointestinal damage, but also differentiate between
18
partial versus whole body exposure. This makes F-FDG-PET a valuable tool in triaging patients and in
18
following them over time. With many medical facilities having the capability to perform F-FDG-PET
imaging, clinicians now have a new tool to assess patients and track recovery.
314 | P a g e
radiotherapy. In addition, we evaluated the relationship between circulating MPs and endothelium-
dependent responses. Flow cytometry analysis of platelet-free plasma from a cohort of 217 patients
overexposed to irradiation indicated that circulating levels of Annexin V+ MPs displayed a 3-fold increase
in grade 3 patients (SOMALENT scale) as compared to patients with grade 0, 1 and 2. Moreover, platelet-
derived CD41+ MPs constituted the major sub-population compared to leukocyte, monocyte, endothelial
and red blood cells in all groups. Using a clotting assay, we measured the procoagulant activity of MPs
and we found that thrombin generation velocity tended to decrease in grade 3 patients compared to other
groups. Finally, MPs from grade 3 patients did not affect endothelium activation in comparison to the
other grades. Our data demonstrate that high level of circulating MPs is correlated to the grade 3 patients
with radiation proctitis. These results suggest that detection of circulating MPs may be valuable for the
prognostic of radiotherapy complications. Eventually, this study could contribute to propose a new anti-
MPs therapeutic approach for the treatment of radiation-induced pelvic disease.
(PS5-51) Using 18F-FDG-PET for the assessment of gastrointestinal damage from radiation exposure.
3
2
2
1
Tien Tang ; David Rendon ; Caterina Kaffes ; Solmaz Afshar ; Omaima Sabek ; and M. Waleed Gaber
2
3
1
2
Rice University, Houston, TX ; Baylor College of Medicine, Houston, TX ; and Houston Methodist Hospital,
Houston, TX
3
Purpose: In the event of a nuclear accident or attack many will be exposed to harmful radiation
with the potential for mass causality. A lethal dose of radiation can cause massive cell death where the
extent of this damage is dependent on the dose, area exposed and exposure time. In the event of a
nuclear incident it would be necessary to find a fast and reliable way to triage patients who have been
exposed and provide proper treatment. In this study we propose the use of positron emission
tomography (PET) with fluorodeoxyglucose (FDG) imaging as a diagnostic tool to quickly diagnose
18
victims in the gastrointestinal syndrome dose range and track their recovery. F-FDG-PET imaging has
the capability to detect inflammation through the energy metabolism of inflammatory particles
attracted to site of damage. Methods: Wistar rats (n=23) were irradiated with a 7.5 Gy dose with the
following shielding scheme: whole body (WB) irradiated, with their upper half shielded (UHS), 2 legs
shielded (2LS), or cranial shielded. An additional group was used as control. The animals were imaged
18
using F-FDG-PET at different time points post radiation (5, 11, 35 days). The mean standard uptake
value (SUV) was examined by creating a region of interest of the intestinal area and compared across
experimental groups. Each group was imaged until the animal fully recovered as indicated by the SUV
18
and general health. Results: Using F-FDG-PET we found that irradiated animals had a higher SUV (p <
0.05) when compared to control (SUV=1.92±0.36) up to 11 days post irradiation. This imaging method
was also sensitive enough to differentiate between UHS (SUV=4±0.4) and WB (SUV=2.88±0.5) with p <
0.05 at 5 days post. Tracking recovery showed an increase in SUV that returned to control level and
therefore was an indication of full recovery after 35 days post. Shielded animals made a full recovery
18
while those fully exposed did not. Conclusion: Results show that F-FDG-PET is an imaging technique
that is sensitive enough to not only detect gastrointestinal damage, but also differentiate between
18
partial versus whole body exposure. This makes F-FDG-PET a valuable tool in triaging patients and in
18
following them over time. With many medical facilities having the capability to perform F-FDG-PET
imaging, clinicians now have a new tool to assess patients and track recovery.
314 | P a g e
