Chihray Liu - Independent Researcher (original) (raw)
Papers by Chihray Liu
Medical Physics, 2016
This paper explores the critical regionalism which could play a role in the continued development... more This paper explores the critical regionalism which could play a role in the continued development of global era Polish architecture, and the advancements achieved by those few contemporary Polish architects who have sought to combine modern tastes and techniques with culturally meaningful designs. The new culture of Poland is very much reflected in the design of many of its new buildings that have been completed since the political and economic changes in 1989. The architecture of Poland appears to have lurched from an inappropriate socialist modernism that was so horridly imposed during the communist era to an equally inappropriate post modernist hegemony in the new enterprise culture. In accordance with Poland, now is rejection of the centrally imposed system of building and architecture, and with the greater emphasis on individual initiative in the new culture, it seems a pity that the country should automatically adopt western modes of architectural expression. This paper suggests that with its newly founded freedom, Poland should be careful that it does not suffer a loss of identity and that, in its architecture, it should seek a way forward through a critical regionalism.
Evaluation of kV Cone-Beam CT Performance for Prostate IGRT: A Comparison of Automatic Grey-Value Alignment to Implanted Fiducial-Marker Alignment
American Journal of Clinical Oncology-cancer Clinical Trials, 2010
Cone-beam computed tomography (CBCT) is a new image-guided radiation therapy (IGRT) technique for... more Cone-beam computed tomography (CBCT) is a new image-guided radiation therapy (IGRT) technique for patient alignment in radiotherapy. The CBCT x-ray volume imaging system from Elekta allows for a variety of alignment methods. The aim of this study is to assess the accuracy of soft-tissue-based automatic alignment as compared with manual alignment using intraprostatic fiducials. All patients were treated on an Elekta Synergy S linear accelerator with kilovoltage CBCT. All alignments were performed using the x-ray volume imaging system and associated software. Automatic alignment with gray-value-based registration and manual alignment to fiducial markers were performed. Transitional corrections along each axis as well as 3-dimensional vectors were compared with evaluate the accuracy of gray-value-based registration compared with fiducials. The distribution of the 3-dimensional vectors between gray-value and fiducial registrations demonstrated notable differences. The mean summed vector was 0.75 cm, with a standard deviation (SD) of 0.52 cm and range from 0.04 to 2.06 cm. There was minimal difference along the lateral direction, with a mean ± SD of -0.02 cm ± 0.13 cm. However, there were large discrepancies along the superior-inferior and anterior-posterior direction alignments, with mean ± SD values of -0.55 ± 0.48 cm and -0.31 ± 0.43 cm, respectively. CBCT with soft-tissue-based automatic corrections is not an accurate alignment compared with manual alignment to fiducial markers for prostate IGRT. We have concluded that a daily manual alignment to fiducials is one of the most reliable methods to maintain accuracy in prostate IGRT.
The Extraction of True Profiles for TPS Commissioning and Its Impact on IMRT Patient-Specific QA
Medical physics, 2008
The aim of this work is to investigate the clinical impact of detector size effect on patient spe... more The aim of this work is to investigate the clinical impact of detector size effect on patient specific intensity-modulated radiation therapy (IMRT) quality assurance (QA). Two photon beam models, BM6 and BM4, were commissioned using photon beam profiles measured with a ...
Monitoring ABC-assisted deep inspiration breath hold for left-sided breast radiotherapy with an optical tracking system
Medical physics, 2015
Recent knowledge on the effects of cardiac toxicity warrants greater precision for left-sided bre... more Recent knowledge on the effects of cardiac toxicity warrants greater precision for left-sided breast radiotherapy. Different breath-hold (BH) maneuvers (abdominal vs thoracic breathing) can lead to chest wall positional variations, even though the patient's tidal volume remains consistent. This study aims to investigate the feasibility of using optical tracking for real-time quality control of active breathing coordinator (ABC)-assisted deep inspiration BH (DIBH). An in-house optical tracking system (OTS) was used to monitor ABC-assisted DIBH. The stability and localization accuracy of the OTS were assessed with a ball-bearing phantom. Seven patients with left-sided breast cancer were included. A free-breathing (FB) computed tomography (CT) scan and an ABC-assisted BH CT scan were acquired for each patient. The OTS tracked an infrared (IR) marker affixed over the patient's xiphoid process to measure the positional variation of each individual BH. Using the BH within which th...
Medical Physics, 2016
This paper explores the critical regionalism which could play a role in the continued development... more This paper explores the critical regionalism which could play a role in the continued development of global era Polish architecture, and the advancements achieved by those few contemporary Polish architects who have sought to combine modern tastes and techniques with culturally meaningful designs. The new culture of Poland is very much reflected in the design of many of its new buildings that have been completed since the political and economic changes in 1989. The architecture of Poland appears to have lurched from an inappropriate socialist modernism that was so horridly imposed during the communist era to an equally inappropriate post modernist hegemony in the new enterprise culture. In accordance with Poland, now is rejection of the centrally imposed system of building and architecture, and with the greater emphasis on individual initiative in the new culture, it seems a pity that the country should automatically adopt western modes of architectural expression. This paper suggests that with its newly founded freedom, Poland should be careful that it does not suffer a loss of identity and that, in its architecture, it should seek a way forward through a critical regionalism.
Evaluation of kV Cone-Beam CT Performance for Prostate IGRT: A Comparison of Automatic Grey-Value Alignment to Implanted Fiducial-Marker Alignment
American Journal of Clinical Oncology-cancer Clinical Trials, 2010
Cone-beam computed tomography (CBCT) is a new image-guided radiation therapy (IGRT) technique for... more Cone-beam computed tomography (CBCT) is a new image-guided radiation therapy (IGRT) technique for patient alignment in radiotherapy. The CBCT x-ray volume imaging system from Elekta allows for a variety of alignment methods. The aim of this study is to assess the accuracy of soft-tissue-based automatic alignment as compared with manual alignment using intraprostatic fiducials. All patients were treated on an Elekta Synergy S linear accelerator with kilovoltage CBCT. All alignments were performed using the x-ray volume imaging system and associated software. Automatic alignment with gray-value-based registration and manual alignment to fiducial markers were performed. Transitional corrections along each axis as well as 3-dimensional vectors were compared with evaluate the accuracy of gray-value-based registration compared with fiducials. The distribution of the 3-dimensional vectors between gray-value and fiducial registrations demonstrated notable differences. The mean summed vector was 0.75 cm, with a standard deviation (SD) of 0.52 cm and range from 0.04 to 2.06 cm. There was minimal difference along the lateral direction, with a mean ± SD of -0.02 cm ± 0.13 cm. However, there were large discrepancies along the superior-inferior and anterior-posterior direction alignments, with mean ± SD values of -0.55 ± 0.48 cm and -0.31 ± 0.43 cm, respectively. CBCT with soft-tissue-based automatic corrections is not an accurate alignment compared with manual alignment to fiducial markers for prostate IGRT. We have concluded that a daily manual alignment to fiducials is one of the most reliable methods to maintain accuracy in prostate IGRT.
The Extraction of True Profiles for TPS Commissioning and Its Impact on IMRT Patient-Specific QA
Medical physics, 2008
The aim of this work is to investigate the clinical impact of detector size effect on patient spe... more The aim of this work is to investigate the clinical impact of detector size effect on patient specific intensity-modulated radiation therapy (IMRT) quality assurance (QA). Two photon beam models, BM6 and BM4, were commissioned using photon beam profiles measured with a ...
Monitoring ABC-assisted deep inspiration breath hold for left-sided breast radiotherapy with an optical tracking system
Medical physics, 2015
Recent knowledge on the effects of cardiac toxicity warrants greater precision for left-sided bre... more Recent knowledge on the effects of cardiac toxicity warrants greater precision for left-sided breast radiotherapy. Different breath-hold (BH) maneuvers (abdominal vs thoracic breathing) can lead to chest wall positional variations, even though the patient's tidal volume remains consistent. This study aims to investigate the feasibility of using optical tracking for real-time quality control of active breathing coordinator (ABC)-assisted deep inspiration BH (DIBH). An in-house optical tracking system (OTS) was used to monitor ABC-assisted DIBH. The stability and localization accuracy of the OTS were assessed with a ball-bearing phantom. Seven patients with left-sided breast cancer were included. A free-breathing (FB) computed tomography (CT) scan and an ABC-assisted BH CT scan were acquired for each patient. The OTS tracked an infrared (IR) marker affixed over the patient's xiphoid process to measure the positional variation of each individual BH. Using the BH within which th...