The use of magnetic field effects on photosensitizer luminescence as a novel probe for optical monitoring of oxygen in photodynamic therapy

Mermut, Ozzy; Diamond, Kevin R.; Cormier, J-F.; Gallant, Peter; N, Hô; Leclair, S.; Marois, J-S.; Noiseux, Isabelle; Jf, Morin; Patterson, Michael S.; Ml, Vernon

doi:10.1088/0031-9155/54/1/001

Cited by 18 publications

(22 citation statements)

References 59 publications

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“…Depending on the field of view and object size, reconstructed images can exhibit streaking and cupping artefacts, resulting in CT number inaccuracy [11]. In this study, measurements were not affected by these artefacts due to imaging parameters and phantom size.…”

Section: Resultsmentioning

confidence: 76%

Optimal slice thickness for cone-beam CT with on-board imager

Seet¹,

Barghi²,

Yartsev³

et al. 2010

Biomed. Imaging Interv. J.

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Purpose:To find the optimal slice thickness (Δτ) setting for patient registration with kilovoltage cone-beam CT (kVCBCT) on the Varian On Board Imager (OBI) system by investigating the relationship of slice thickness to automatic registration accuracy and contrast-to-noise ratio.Materials and method:Automatic registration was performed on kVCBCT studies of the head and pelvis of a RANDO anthropomorphic phantom. Images were reconstructed with 1.0 ≤ Δτ (mm) ≤ 5.0 at 1.0 mm increments. The phantoms were offset by a known amount, and the suggested shifts were compared to the known shifts by calculating the residual error. A uniform cylindrical phantom with cylindrical inserts of various known CT numbers was scanned with kVCBCT at 1.0 ≤ Δτ (mm) ≤ 5.0 at increments of 0.5 mm. The contrast-to-noise ratios for the inserts were measured at each Δτ.Results:For the planning CT slice thickness used in this study, there was no significant difference in residual error below a threshold equal to the planning CT slice thickness. For Δτ > 3.0 mm, residual error increased for both the head and pelvis phantom studies. The contrast-to-noise ratio is proportional to slice thickness until Δτ = 2.5 mm. Beyond this point, the contrast-to-noise ratio was not affected by Δτ.Conclusion:Automatic registration accuracy is greatest when 1.0 ≤ Δτ (mm) ≤ 3.0 is used. Contrast-to-noise ratio is optimal for the 2.5 ≤ Δτ (mm) ≤ 5.0 range. Therefore 2.5 ≤ Δτ (mm) ≤ 3.0 is recommended for kVCBCT patient registration where the planning CT is 3.0 mm.

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Section: Resultsmentioning

confidence: 76%

Optimal slice thickness for cone-beam CT with on-board imager

Seet¹,

Barghi²,

Yartsev³

et al. 2010

Biomed. Imaging Interv. J.

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“…For comparison, we also tested against a clinical spatiotemporal processing method [22]. In this method, the different gates were first reconstructed by using the filtered backprojection (FBP) method, then processed spatially with a Butterworth filter of order 2.4 and cutoff frequency of 0.2 cycles/voxel, and further processed with a temporal filter with impulse response 1/4, 2/4, 1/4.…”

Section: Resultsmentioning

confidence: 99%

Tomographic Reconstruction of Gated Data Acquisition Using DFT Basis Functions

Niu

Yang

2011

IEEE Trans. on Image Process.

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In image reconstruction gated acquisition is often used in order to deal with blur caused by organ motion in the resulting images. However, this is achieved almost inevitably at the expense of reduced signal-to-noise ratio in the acquired data. In this work, we propose a reconstruction procedure for gated images based upon use of discrete Fourier transform (DFT) basis functions, wherein the temporal activity at each spatial location is regulated by a Fourier representation. The gated images are then reconstructed through determination of the coefficients of the Fourier representation. We demonstrate this approach in the context of single photon emission computed tomography (SPECT) for cardiac imaging, which is often hampered by the increased noise due to gating and other degrading factors. We explore two different reconstruction algorithms, one is a penalized least-square approach and the other is a maximum a posteriori approach. In our experiments, we conducted a quantitative evaluation of the proposed approach using Monte Carlo simulated SPECT imaging. The results demonstrate that use of DFT-basis functions in gated imaging can improve the accuracy of the reconstruction. As a preliminary demonstration, we also tested this approach on a set of clinical acquisition.

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“…最新研究还利用超声回波中的非线性谐波成分对组织温度进行实时无创测温 . Mara-ghechi等人 [74] [75,76] , 同时不符合无创或微创治疗的原则; 通过荧光或磷光探测氧的方法, 由于荧光信号在传导过程中很不稳定, 因此对信号传输和探测的要求很高 [77] ; 基于磁共振技术的氧测量方式则存在设备复杂、成本过高的缺点 [77] . 在PDT中, ROS的探测大多采用间接方法, 通过加入ROS探针并监测其浓度变化可间接获得ROS浓度 [78] , 该方法在非均 [81] .…”

Section: 活体无创测温方面具有局限性而剪切波动态法则能够实现体内监测但对于深层组织的成像也具有unclassified