Quality assurance for dynamic tumor tracking using the Vero4DRT system

Purpose: We perform quality assurance (QA) for indirect dynamic tumor tracking (DTT) using four-dimensional radiation therapy (the Vero4DRT™ system).Methods: A single photon beam was set with a 40 × 40 mm2 field size at a gantry angle of zero degrees and a low monitor unit setting of 200. Doses were measured using a 0.016 cm3 ionization chamber inserted in a phantom under stationary, DTT, and non-DTT conditions for sinusoidal (peak-to-peak) amplitude [A] and breathing period [T] (20 mm, 2 s; 20 mm, 4 s; and 40 mm, 4 s). The stationary condition was measured for comparison. Dose profiles were measured using Gafchromic EBT3 films in the phantom under the same conditions.Results: For chamber measurement, the relative doses were as follows: 0.99 with non-DTT and 1.00 with DTT at A = 20 mm and T = 2 s; 0.99 with non-DTT and 1.00 with DTT at A = 20 mm and T = 4 s; and 0.84 with non-DTT and 1.00 with DTT at A = 40 mm and T = 4 s. For film measurement, the spatial distances between the 90% dose of the dose profiles were as follows: 6.53 mm for non-DTT and 0.40 mm for DTT at A = 20 mm and T = 2 s; 6.33 mm for non-DTT and 0.15 mm for DTT at A = 20 mm and T = 4 s; and 10.61 mm for non-DTT and 0.17 mm with DTT at A = 40 mm and T = 4 s.Conclusion: Our results showed high dosimetric and geometric accuracy for DTT using four-dimensional modeling and marked reduction of the blurring effects on dose distribution. We recommend the use of a QA procedure for DTT performed using the Vero4DRT™ system

DLC Inner Wall Hybrid Coating of Narrow Tubes by the 2nd Harmonic ECR Micro Plasma

ナノダイナミクス国際シンポジウム 平成22年1月21日(木) 於長崎大学Nagasaki Symposium on Nano-Dynamics 2010 (NSND2010), January 21, 2010, Nagasaki University, Nagasaki, Japan, Invited Lectur

Effect of tumor amplitude and frequency on 4D modeling of Vero4DRT system

BackgroundAn important issue in indirect dynamic tumor tracking with the Vero4DRT system is the accuracy of the model predictions of the internal target position based on surrogate infrared (IR) marker measurement. We investigated the predictive uncertainty of 4D modeling using an external IR marker, focusing on the effect of the target and surrogate amplitudes and periods.MethodsA programmable respiratory motion table was used to simulate breathing induced organ motion. Sinusoidal motion sequences were produced by a dynamic phantom with different amplitudes and periods. To investigate the 4D modeling error, the following amplitudes (peak-to-peak: 10–40[[ce:hsp sp="0.25"/]]mm) and periods (2–8[[ce:hsp sp="0.25"/]]s) were considered. The 95th percentile 4D modeling error (4D-E95%) between the detected and predicted target position (μ[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]2SD) was calculated to investigate the 4D modeling error.Results4D-E95% was linearly related to the target motion amplitude with a coefficient of determination R2[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.99 and ranged from 0.21 to 0.88[[ce:hsp sp="0.25"/]]mm. The 4D modeling error ranged from 1.49 to 0.14[[ce:hsp sp="0.25"/]]mm and gradually decreased with increasing target motion period.ConclusionsWe analyzed the predictive error in 4D modeling and the error due to the amplitude and period of target. 4D modeling error substantially increased with increasing amplitude and decreasing period of the target motion

Quality assurance for dynamic tumor tracking using the Vero4DRT system

Purpose: We perform quality assurance (QA) for indirect dynamic tumor tracking (DTT) using four-dimensional radiation therapy (the Vero4DRT™ system).Methods: A single photon beam was set with a 40 × 40 mm2 field size at a gantry angle of zero degrees and a low monitor unit setting of 200. Doses were measured using a 0.016 cm3 ionization chamber inserted in a phantom under stationary, DTT, and non-DTT conditions for sinusoidal (peak-to-peak) amplitude [A] and breathing period [T] (20 mm, 2 s; 20 mm, 4 s; and 40 mm, 4 s). The stationary condition was measured for comparison. Dose profiles were measured using Gafchromic EBT3 films in the phantom under the same conditions.Results: For chamber measurement, the relative doses were as follows: 0.99 with non-DTT and 1.00 with DTT at A = 20 mm and T = 2 s; 0.99 with non-DTT and 1.00 with DTT at A = 20 mm and T = 4 s; and 0.84 with non-DTT and 1.00 with DTT at A = 40 mm and T = 4 s. For film measurement, the spatial distances between the 90% dose of the dose profiles were as follows: 6.53 mm for non-DTT and 0.40 mm for DTT at A = 20 mm and T = 2 s; 6.33 mm for non-DTT and 0.15 mm for DTT at A = 20 mm and T = 4 s; and 10.61 mm for non-DTT and 0.17 mm with DTT at A = 40 mm and T = 4 s.Conclusion: Our results showed high dosimetric and geometric accuracy for DTT using four-dimensional modeling and marked reduction of the blurring effects on dose distribution. We recommend the use of a QA procedure for DTT performed using the Vero4DRT™ system.</p

Quality assurance for dynamic tumor tracking using the Vero4DRT system

<p>Purpose: We perform quality assurance (QA) for indirect dynamic tumor tracking (DTT) using four-dimensional radiation therapy (the Vero4DRT™ system).</p><p>Methods: A single photon beam was set with a 40 × 40 mm² field size at a gantry angle of zero degrees and a low monitor unit setting of 200. Doses were measured using a 0.016 cm³ ionization chamber inserted in a phantom under stationary, DTT, and non-DTT conditions for sinusoidal (peak-to-peak) amplitude [<em>A</em>] and breathing period [<em>T</em>] (20 mm, 2 s; 20 mm, 4 s; and 40 mm, 4 s). The stationary condition was measured for comparison. Dose profiles were measured using Gafchromic EBT3 films in the phantom under the same conditions.</p><p>Results: For chamber measurement, the relative doses were as follows: 0.99 with non-DTT and 1.00 with DTT at <em>A</em> = 20 mm and <em>T</em> = 2 s; 0.99 with non-DTT and 1.00 with DTT at <em>A</em> = 20 mm and <em>T</em> = 4 s; and 0.84 with non-DTT and 1.00 with DTT at <em>A</em> = 40 mm and <em>T </em>= 4 s. For film measurement, the spatial distances between the 90% dose of the dose profiles were as follows: 6.53 mm for non-DTT and 0.40 mm for DTT at <em>A</em> = 20 mm and <em>T</em> = 2 s; 6.33 mm for non-DTT and 0.15 mm for DTT at <em>A</em> = 20 mm and <em>T</em> = 4 s; and 10.61 mm for non-DTT and 0.17 mm with DTT at <em>A</em> = 40 mm and <em>T</em> = 4 s.</p><p>Conclusion: Our results showed high dosimetric and geometric accuracy for DTT using four-dimensional modeling and marked reduction of the blurring effects on dose distribution. We recommend the use of a QA procedure for DTT performed using the Vero4DRT™ system.</p

PACAP Enhances Axon Outgrowth in Cultured Hippocampal Neurons to a Comparable Extent as BDNF

<div><p>Pituitary adenylate cyclase-activating polypeptide (PACAP) exerts neurotrophic activities including modulation of synaptic plasticity and memory, hippocampal neurogenesis, and neuroprotection, most of which are shared with brain-derived neurotrophic factor (BDNF). Therefore, the aim of this study was to compare morphological effects of PACAP and BDNF on primary cultured hippocampal neurons. At days <i>in vitro</i> (DIV) 3, PACAP increased neurite length and number to similar levels by BDNF, but vasoactive intestinal polypeptide showed much lower effects. In addition, PACAP increased axon, but not dendrite, length, and soma size at DIV 3 similarly to BDNF. The PACAP antagonist PACAP6–38 completely blocked the PACAP-induced increase in axon, but not dendrite, length. Interestingly, the BDNF-induced increase in axon length was also inhibited by PACAP6–38, suggesting a mechanism involving PACAP signaling. K252a, a TrkB receptor inhibitor, inhibited axon outgrowth induced by PACAP and BDNF without affecting dendrite length. These results indicate that in primary cultured hippocampal neurons, PACAP shows morphological actions via its cognate receptor PAC₁, stimulating neurite length and number, and soma size to a comparable extent as BDNF, and that the increase in total neurite length is ascribed to axon outgrowth.</p></div

PACAP and BDNF comparably increase axon, but not dendrite, length.

<p>Primary hippocampal neurons were cultured with 10 nM PACAP or 2 nM BDNF for 1 to 3 DIV and double-immunostained for pNF and MAP2. (A) Representative pNF- (red) and MAP2- (green) immunostained images of neurons. (B, C) Time-dependent effects of PACAP (closed circles), BDNF (closed triangles), and vehicle (open circles) on axon (B) and dendrite (C) length. Values represent mean ± SEM of 60 neurons from three independent experiments. **<i>P</i> < 0.01, two-way ANOVA followed by Tukey-Kramer test. Scale bar, 20 μm.</p

The effect of TrkB receptor inhibitor K252a on neurite outgrowth.

<p>Primary hippocampal neurons were cultured with 10 nM PACAP or 2 nM BDNF in the presence or absence of 200 nM K252a for 3 DIV and double-immunostained for pNF and MAP2. Representative pNF- (red) and MAP2- (green) immunostained images of neurons (A), axon length (B), and dendrite length (C) were shown. Values represent mean ± SEM of 60 neurons from three independent experiments. **<i>P</i> < 0.01 vs. control, ^##<i>P</i> < 0.01 vs. without K252a, two-way ANOVA followed by Tukey-Kramer test. Scale bar, 20 μm.</p

Comparable effects of PACAP and BDNF treatment on total neurite length in cultured hippocampal neurons at DIV 3.

<p>Primary hippocampal neurons were cultured with PACAP or BDNF for 2 to 3 DIV and immunostained for MAP2. (A) Representative MAP2-immunostained images of neurons at DIV 3. (B) Total neurite length of cultured hippocampal neurons treated with 10 nM PACAP and/or 2 nM BDNF. (C-E) Dose-dependent effects of PACAP (circles) and VIP (triangles) on total neurite length (C), and number of total (D) and primary (E) neurites. Values represent mean ± SEM of 69–75 neurons from three independent experiments. ^$$<i>P</i> < 0.01 vs. control, one-way ANOVA followed by Tukey-Kramer test; **<i>P</i> < 0.01 vs. control, ^##<i>P</i> < 0.01 vs. identical VIP dose, two-way ANOVA followed by Tukey-Kramer test. Scale bar, 20 μm.</p