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Papers by Thomas Maris
IEEE Transactions on Medical Imaging, 2010
In this paper, we present a new optical computed tomography (Optical-CT) scanner for the verifica... more In this paper, we present a new optical computed tomography (Optical-CT) scanner for the verification of the radiation dose schemes delivered in modern radiotherapy applications. The optical-CT scanner is capable of providing rapid relative 3-D dosimetry with high spatial resolution with the use of normoxic N-Vinylpyrrolidone based polymer gel dosimeter. The scanner employs a diffuse uncollimated light illumination beam, a computer controlled motorized rotation stage and a charge-coupled device (CCD) camera. Various test experiments were performed to determine the performance characteristics of the optical-CT apparatus. Attenuation coefficient () versus dose calibration data were generated from two calibration experiments using gel containers of two different diameters. All irradiations were performed using a 6 MV linear accelerator. A comparison of the reconstructed images between optical-CT scans using refractive index (RI) matching fluid and corresponding scans performed in free space was demonstrated. The dose readout of a test irradiation model was found to be in good agreement with independent readout performed by MR imaging. The findings presented in this study suggest that polymer dosimeters combined with the new optical-CT scanner constitute a potentially feasible method capable of measuring complex 3-D dose distributions with high resolution and in a wide dose range.
European Journal of Radiology, 2007
Osteonecrosis of the femoral head is a disabling clinical entity affecting young adults that usua... more Osteonecrosis of the femoral head is a disabling clinical entity affecting young adults that usually leads to destruction of the hip joint. A high index of suspicion is necessary for the diagnosis due to the insidious onset of the bone infarcts and the lack of specific clinical signs at the early stages. Many etiology-associated factors have been identified reducing thus the number of idiopathic cases. A number of joint salvaging treatment options are available if early diagnosis can be achieved. MR imaging has been proved to be a highly accurate method both for early diagnosis and for staging of the disease. Replacement of the hip joint is the last resort for pain relief and function, although non-desirable because of the young age of the affected population.
IEEE Transactions on Medical Imaging, 2010
In this paper, we present a new optical computed tomography (Optical-CT) scanner for the verifica... more In this paper, we present a new optical computed tomography (Optical-CT) scanner for the verification of the radiation dose schemes delivered in modern radiotherapy applications. The optical-CT scanner is capable of providing rapid relative 3-D dosimetry with high spatial resolution with the use of normoxic N-Vinylpyrrolidone based polymer gel dosimeter. The scanner employs a diffuse uncollimated light illumination beam, a computer controlled motorized rotation stage and a charge-coupled device (CCD) camera. Various test experiments were performed to determine the performance characteristics of the optical-CT apparatus. Attenuation coefficient () versus dose calibration data were generated from two calibration experiments using gel containers of two different diameters. All irradiations were performed using a 6 MV linear accelerator. A comparison of the reconstructed images between optical-CT scans using refractive index (RI) matching fluid and corresponding scans performed in free space was demonstrated. The dose readout of a test irradiation model was found to be in good agreement with independent readout performed by MR imaging. The findings presented in this study suggest that polymer dosimeters combined with the new optical-CT scanner constitute a potentially feasible method capable of measuring complex 3-D dose distributions with high resolution and in a wide dose range.
European Journal of Radiology, 2007
Osteonecrosis of the femoral head is a disabling clinical entity affecting young adults that usua... more Osteonecrosis of the femoral head is a disabling clinical entity affecting young adults that usually leads to destruction of the hip joint. A high index of suspicion is necessary for the diagnosis due to the insidious onset of the bone infarcts and the lack of specific clinical signs at the early stages. Many etiology-associated factors have been identified reducing thus the number of idiopathic cases. A number of joint salvaging treatment options are available if early diagnosis can be achieved. MR imaging has been proved to be a highly accurate method both for early diagnosis and for staging of the disease. Replacement of the hip joint is the last resort for pain relief and function, although non-desirable because of the young age of the affected population.