In-Room CT System for IGRT

2012 ◽  
pp. 45-60
Keyword(s):  
2007 ◽  
Vol 46 (01) ◽  
pp. 38-42 ◽  
Author(s):  
V. Schulz ◽  
I. Nickel ◽  
A. Nömayr ◽  
A. H. Vija ◽  
C. Hocke ◽  
...  

SummaryThe aim of this study was to determine the clinical relevance of compensating SPECT data for patient specific attenuation by the use of CT data simultaneously acquired with SPECT/CT when analyzing the skeletal uptake of polyphosphonates (DPD). Furthermore, the influence of misregistration between SPECT and CT data on uptake ratios was investigated. Methods: Thirty-six data sets from bone SPECTs performed on a hybrid SPECT/CT system were retrospectively analyzed. Using regions of interest (ROIs), raw counts were determined in the fifth lumbar vertebral body, its facet joints, both anterior iliacal spinae, and of the whole transversal slice. ROI measurements were performed in uncorrected (NAC) and attenuation-corrected (AC) images. Furthermore, the ROI measurements were also performed in AC scans in which SPECT and CT images had been misaligned by 1 cm in one dimension beforehand (ACX, ACY, ACZ). Results: After AC, DPD uptake ratios differed significantly from the NAC values in all regions studied ranging from 32% for the left facet joint to 39% for the vertebral body. AC using misaligned pairs of patient data sets led to a significant change of whole-slice uptake ratios whose differences ranged from 3,5 to 25%. For ACX, the average left-to-right ratio of the facet joints was by 8% and for the superior iliacal spines by 31% lower than the values determined for the matched images (p <0.05). Conclusions: AC significantly affects DPD uptake ratios. Furthermore, misalignment between SPECT and CT may introduce significant errors in quantification, potentially also affecting leftto- right ratios. Therefore, at clinical evaluation of attenuation- corrected scans special attention should be given to possible misalignments between SPECT and CT.


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Andrea Frezza ◽  
Corentin Desport ◽  
Carlos Uribe ◽  
Wei Zhao ◽  
Anna Celler ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Xin Wan ◽  
Ximing Liu ◽  
Jichen Miao ◽  
Peng Cong ◽  
Yuai Zhang ◽  
...  

Pebble dynamics is important for the safe operation of pebble-bed high temperature gas-cooled reactors and is a complicated problem of great concern. To investigate it more authentically, a computed tomography pebble flow detecting (CT-PFD) system has been constructed, in which a three-dimensional model is simulated according to the ratio of 1 : 5 with the core of HTR-PM. A multislice helical CT is utilized to acquire the reconstructed cross-sectional images of simulated pebbles, among which special tracer pebbles are designed to indicate pebble flow. Tracer pebbles can be recognized from many other background pebbles because of their heavy kernels that can be resolved in CT images. The detecting principle and design parameters of the system were demonstrated by a verification experiment on an existing CT system in this paper. Algorithms to automatically locate the three-dimensional coordinates of tracer pebbles and to rebuild the trajectory of each tracer pebble were presented and verified. The proposed pebble-detecting and tracking technique described in this paper will be implemented in the near future.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kyle S. Feldman ◽  
Eunwon Kim ◽  
Michael J. Czachowski ◽  
Yijen Wu ◽  
Cecilia W. Lo ◽  
...  

AbstractRespiratory mucociliary clearance (MCC) is a key defense mechanism that functions to entrap and transport inhaled pollutants, particulates, and pathogens away from the lungs. Previous work has identified a number of anesthetics to have cilia depressive effects in vitro. Wild-type C57BL/6 J mice received intra-tracheal installation of 99mTc-Sulfur colloid, and were imaged using a dual-modality SPECT/CT system at 0 and 6 h to measure baseline MCC (n = 8). Mice were challenged for one hour with inhalational 1.5% isoflurane, or intraperitoneal ketamine (100 mg/kg)/xylazine (20 mg/kg), ketamine (0.5 mg/kg)/dexmedetomidine (50 mg/kg), fentanyl (0.2 mg/kg)/1.5% isoflurane, propofol (120 mg/Kg), or fentanyl/midazolam/dexmedetomidine (0.025 mg/kg/2.5 mg/kg/0.25 mg/kg) prior to MCC assessment. The baseline MCC was 6.4%, and was significantly reduced to 3.7% (p = 0.04) and 3.0% (p = 0.01) by ketamine/xylazine and ketamine/dexmedetomidine challenge respectively. Importantly, combinations of drugs containing fentanyl, and propofol in isolation did not significantly depress MCC. Although no change in cilia length or percent ciliation was expected, we tried to correlate ex-vivo tracheal cilia ciliary beat frequency and cilia-generated flow velocities with MCC and found no correlation. Our results indicate that anesthetics containing ketamine (ketamine/xylazine and ketamine/dexmedetomidine) significantly depress MCC, while combinations containing fentanyl (fentanyl/isoflurane, fentanyl/midazolam/dexmedetomidine) and propofol do not. Our method for assessing MCC is reproducible and has utility for studying the effects of other drug combinations.


2020 ◽  
Vol 55 (4) ◽  
pp. 226-232
Author(s):  
Wei Zhou ◽  
Gregory J. Michalak ◽  
Jayse M. Weaver ◽  
Hao Gong ◽  
Lifeng Yu ◽  
...  

1986 ◽  
Vol 17 (7) ◽  
pp. 19-29
Author(s):  
Isao Horiba ◽  
Shigenobu Yanaka ◽  
Akira Iwata ◽  
Nobuo Suzumura

2009 ◽  
Vol 56 (5) ◽  
pp. 2714-2721 ◽  
Author(s):  
H. Muraishi ◽  
K. Nishimura ◽  
S. Abe ◽  
H. Satoh ◽  
S. Hara ◽  
...  

2014 ◽  
Vol 38 (3) ◽  
pp. 038201
Author(s):  
Shan-Wei Shen ◽  
Yan-Fang Wang ◽  
Hang Shu ◽  
Xiao Tang ◽  
Cun-Feng Wei ◽  
...  

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