Page 213 - 2014 Printable Abstract Book
P. 213
purpose of feasibility study, an experiment was carried out which provided encouraging results which
prompted further work. The experimental setup and preliminary results will be presented.
(PS3-41) Commissioning of XRAD320 X-Ray irradiator for small animal studies. Abdul M. Kazi, PhD;
Wilfred Goetz, MS; Giovanni Lasio, PhD; Wei Lu, PhD; Mariana Guerrero, PhD; Karl Prado, PhD; Zeljko
Vujaskovic, MD; and Thomas MacVittie, PhD; University of Maryland School of Medicine, Baltimore, MD
It is common practice to use cabinet x-ray irradiators for radiobiological studies of small animals.
XRAD320 x-ray irradiators by Precision INC, is one of the available cabinet x-ray irradiators suitable for
this purpose. The relationship between survival vs delivered dose is the most significant Dose Response
Relationship (DRR) in radiobiological studies and the nature of this curve is very steep. The delivered
dose must be as accurate as possible since a 10% change in the dose specification may represent a 70-
80% change in survival. Commissioning of an x-ray irradiator for animal studies may be divided into two
significant steps; 1) Determination of the output (absolute dose rate) of the machine at a reference
point following a nationally recognized protocol such as Task Group 61 protocol of American Association
of Physicists in Medicine (AAPM TG61), and 2) Determination of dose rates at Animal Irradiation
Positions (AIP) in the irradiation setup for a specific animal study. Recently we commissioned an
XRAD320 irradiator for the studies of total-body irradiation (TBI), partial-body irradiation (PBI), and
whole thorax lung irradiation (WTLI) of mice. We found the ‘In-Air’ dose rate at reference point without
any backscatter to be 164.2 cGy/min. Since scatter from mice is substantially different from the notion
of backscatter used in TG61 protocol we followed TG61 protocol’s calibration method without the
backscatter. The scatter from mice was accounted for by using a polystyrene mouse phantom with a
custom made receptacle for our ion chamber to perform measurements at AIPs for a specific irradiation
platform. We found the dose rates at AIP to vary between 125.8 cGy /min and 94.9 cGy/min depending
on the specific geometry of the irradiation platform and the shielding used for TBI, PBI, and WTLI. This
project has been funded in whole or in part with Federal funds from the National Institute of Allergy and
Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under
Contract No. HHSN277201000046C.
(PS3-42) Analysis of targeted effects of ionizing radiations on 3D reconstructed human healthy cartilage
and chondrosarcoma. Dounia H. Hamdi, Pharm D.; François Chevalier, PhD; Jean-Louis Lefaix, PhD; and
Yannick Saintigny, PhD,CEA, Caen, France
Chondrosarcoma, second most common primary bone sarcoma, is resistant to chemotherapy and
conventional radiotherapy (X-rays). The sole alternative to mostly incapacitating surgery is
Hadrontherapy. Indeed, the benefit of better ballistic and high efficiency of hadrons (proton and carbon
ions) for cancer treatment was demonstrated since two decades. However, if the better ballistic of
protontherapy is already successfully used worldwide, hadrontherapy with carbon ions stay underused
and raise some concerns about likely sequelae for patients. Since one decade, 3D models are used in
radiobiology to approach tissue and tumor microenvironment. In fact, some recent studies have shown
that vascular damages could play an important role in tissue response to radiation exposure. Except for
cartilage, which is the only avascular tissue of human body, all 3D models available are developed without
vascular compartment and, per se, have key restraint in their use as relevant model for radiobiology. By
211 | P a g e
prompted further work. The experimental setup and preliminary results will be presented.
(PS3-41) Commissioning of XRAD320 X-Ray irradiator for small animal studies. Abdul M. Kazi, PhD;
Wilfred Goetz, MS; Giovanni Lasio, PhD; Wei Lu, PhD; Mariana Guerrero, PhD; Karl Prado, PhD; Zeljko
Vujaskovic, MD; and Thomas MacVittie, PhD; University of Maryland School of Medicine, Baltimore, MD
It is common practice to use cabinet x-ray irradiators for radiobiological studies of small animals.
XRAD320 x-ray irradiators by Precision INC, is one of the available cabinet x-ray irradiators suitable for
this purpose. The relationship between survival vs delivered dose is the most significant Dose Response
Relationship (DRR) in radiobiological studies and the nature of this curve is very steep. The delivered
dose must be as accurate as possible since a 10% change in the dose specification may represent a 70-
80% change in survival. Commissioning of an x-ray irradiator for animal studies may be divided into two
significant steps; 1) Determination of the output (absolute dose rate) of the machine at a reference
point following a nationally recognized protocol such as Task Group 61 protocol of American Association
of Physicists in Medicine (AAPM TG61), and 2) Determination of dose rates at Animal Irradiation
Positions (AIP) in the irradiation setup for a specific animal study. Recently we commissioned an
XRAD320 irradiator for the studies of total-body irradiation (TBI), partial-body irradiation (PBI), and
whole thorax lung irradiation (WTLI) of mice. We found the ‘In-Air’ dose rate at reference point without
any backscatter to be 164.2 cGy/min. Since scatter from mice is substantially different from the notion
of backscatter used in TG61 protocol we followed TG61 protocol’s calibration method without the
backscatter. The scatter from mice was accounted for by using a polystyrene mouse phantom with a
custom made receptacle for our ion chamber to perform measurements at AIPs for a specific irradiation
platform. We found the dose rates at AIP to vary between 125.8 cGy /min and 94.9 cGy/min depending
on the specific geometry of the irradiation platform and the shielding used for TBI, PBI, and WTLI. This
project has been funded in whole or in part with Federal funds from the National Institute of Allergy and
Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under
Contract No. HHSN277201000046C.
(PS3-42) Analysis of targeted effects of ionizing radiations on 3D reconstructed human healthy cartilage
and chondrosarcoma. Dounia H. Hamdi, Pharm D.; François Chevalier, PhD; Jean-Louis Lefaix, PhD; and
Yannick Saintigny, PhD,CEA, Caen, France
Chondrosarcoma, second most common primary bone sarcoma, is resistant to chemotherapy and
conventional radiotherapy (X-rays). The sole alternative to mostly incapacitating surgery is
Hadrontherapy. Indeed, the benefit of better ballistic and high efficiency of hadrons (proton and carbon
ions) for cancer treatment was demonstrated since two decades. However, if the better ballistic of
protontherapy is already successfully used worldwide, hadrontherapy with carbon ions stay underused
and raise some concerns about likely sequelae for patients. Since one decade, 3D models are used in
radiobiology to approach tissue and tumor microenvironment. In fact, some recent studies have shown
that vascular damages could play an important role in tissue response to radiation exposure. Except for
cartilage, which is the only avascular tissue of human body, all 3D models available are developed without
vascular compartment and, per se, have key restraint in their use as relevant model for radiobiology. By
211 | P a g e
