Does gantry rotation time influence accuracy of volume computed tomography dose index (CTDIvol) in modern CT?

PurposeThe purpose of this study was to develop a gantry overrun corrected CTDI_vol (cCTDI_vol) dosimetry and evaluate the differences between the displayed CTDI_vol (dCTDI_vol), measured CTDI_vol (mCTDI_vol), and the cCTDI_vol.Methods and materialsThe each 8 rotation times between 275 and 1000 ms of two CT scanners were investigated. Rotation time (T_rot) and the beam-on time (T_beam) in axial scanning were measured accurately to determine the gantry overrun time (T_over) as T_beam − T_rot. Subsequently, mCTDI_vol was measured by using a 100 mm ionization chamber and CTDI phantoms. Furthermore, we introduced a gantry overrun correction factor (C_o = T_rot/T_beam) to obtain cCTDI_vol. Upon completion of the data acquisition, the dCTDI_vol and mCTDI_vol were compared with the cCTDI_vol.ResultsThe discrepancies of T_rot were 0.2 ± 0.2 ms as compared to the preset rotation times, and T_over was machine-specific and almost constant (22.4 ± 0.5 ms or 45.1 ± 0.3 ms) irrespective of the preset rotation time. Both dCTDI_vol and mCTDI_vol were increasingly overestimated compared to cCTDI_vol as the faster the preset rotation time was selected (1.7–23.5%).ConclusionThe rotation time influences the accuracy of CTDI_vol in modern CT, and should be taken into consideration when assessing the radiation output in modern CT.     

Techniques for in utero,longitudinal MRI of fetal brain development in baboons at 3 T

Magnetic Resonance Imaging (MRI) is a promising tool for the noninvasive, longitudinal study of developing primate brains. We developed a protocol to scan pregnant baboons serially at 3 T for up to 3 h per session. This protocol includes procedures for animal preparation, anesthesia, MRI scanning, and post-scan animal care. We applied this protocol to scan 5 baboons multiple times across the latter 70% of gestation—from as early as 56 days post-conceptional age to as late as 185 days (term ～180 days). We successfully acquired high-resolution anatomical images and maps of relaxation times (T₁ and T₂) of the fetal brains at multiple time points across gestation. These images and maps demonstrated the convergence of gray and white matter contrast near term, and furthermore demonstrated that the convergence of contrast is a consequence of the continuous change in relaxation times during fetal brain development. We estimated the rates of decrease of T₁ and T₂ in white matter and gray matter, respectively. In addition, we measured the volumes of fetal brain at different gestational ages and calculated the growth rates of whole brain (0.91 ± 0.08 cm³/day) and cortical gray matter (0.40 ± 0.04 cm³/day). We also measured the mean diffusivity in white matter and deep gray matter using diffusion tensor imaging. In conclusion, in utero MRI of fetal baboon brains greatly enhances the use of nonhuman primate models to study fetal brain development longitudinally.     

Small field characterization of a Nanochamber prototype under flattening filter free photon beams

IntroductionNanochambers present some advantages in terms of energy independence and absolute dose measurement for small field dosimetry in the SBRT scenario. Characterization of a micro-chamber prototype was carried out both under flattened and flattening-filter-free (FFF) beams with particular focus on stem effect.MethodsThe study included characterization of leakage and stem effects, dose rate and dose per pulse dependence, measurement of profiles, and percentage depth doses (PDDs). Ion collection efficiency and polarity effects were measured and evaluated against field size and dose per pulse. The 6_MV, 6_MV_FFF and 10_MV FFF beams of a Varian EDGE were used. Output factors were measured for field sizes ranging from 0.8 × 0.8 cm² to 20 × 20 cm² and were compared with other detectors.ResultsThe 2 mm diameter of this chamber guarantees a high spatial resolution with low penumbra values. In orthogonal configuration a strong stem (and cable) effect was observed for small fields. Dose rate and dose per pulse dependence were <0.3% and 0.6% respectively for the whole range of considered values. The Nanochamber exhibits a field size (FS) dependence of the polarity correction >2%. The OF values were compared with other small field detectors showing a good agreement for field sizes >2 × 2 cm². The large field over-response was corrected applying k_pol(FS).ConclusionsNanochamber is an interesting option for small field measurements. The spherical shape of the active volume is an advantage in terms of reduced angular dependence. An interesting feature of the Nanochamber is its beam quality independence and, as a future development, the possibility to use it for small field absolute dosimetry.     

Sensitivity of ACL volume and T21 relaxation time to magnetic resonance imaging scan conditions

Anterior cruciate ligament (ACL) volume and T₂¹ relaxation times from magnetic resonance (MR) images have been previously shown to predict the structural properties of healing ligaments. We investigated whether MR imaging scan resolution and condition (in vivo, in situ, or ex vivo) affected ACL volume and T₂¹ relaxation times in intact ligaments. ACLs of 14 pigs were imaged using a 3 T scanner and a six-channel flexcoil using at least two of four possible scan conditions: (1) in vivo moderate resolution (n = 14); (2) in vivo high resolution (n = 7); (3) in situ high resolution acquired within 60 minutes of euthanasia (n = 6); and (4) ex vivo high resolution following hind limb disarticulation and one freeze-thaw cycle (n = 7). T₂¹ relaxation times were mapped to the ACL voxels. The total ACL volume was then divided into four sub-volumes (Vol_1–4) based on predetermined increasing ranges of T₂¹ times. ACL T₂¹ statistics (first quartile, median, and standard deviation (SD)) were computed. Scan resolution had no effect on the total ACL volume, but Vol₁ and first quartile T₂¹ times decreased with high resolution and in situ/ex vivo scan conditions. The most dramatic differences in T₂¹ summary statistics were between in vivo moderate and ex vivo high resolution scan conditions that included a freeze-thaw cycle: ACL T₂¹ SD increased by over 50% in 9 animals, and more than 90% in 4 animals. Our results indicated that T₂¹-based prediction models to quantify in vivo structural properties of healing ligaments should be based on high resolution in vivo MR scan conditions.     

Role of “the frame cycle time” in portal dose imaging using an aS500-II EPID

IntroductionThis paper evaluates the role of an acquisition parameter, the frame cycle time “FCT”, in the performance of an aS500-II EPID.Materials and methodsThe work presented rests on the study of the Varian EPID aS500-II and the image acquisition system 3 (IAS3). We are interested in integrated acquisition using asynchronous mode. For better understanding the image acquisition operation, we investigated the influence of the “frame cycle time” on the speed of acquisition, the pixel value of the averaged gray-scale frame and the noise, using 6 and 15 MV X-ray beams and dose rates of 1–6 Gy/min on 2100 C/D Linacs.ResultsIn the integrated mode not synchronized to beam pulses, only one parameter the frame cycle time “FCT” influences the pixel value. The pixel value of the averaged gray-scale frame is proportional to this parameter. When the FCT <55 ms (speed of acquisition V_f/s > 18 frames/s), the speed of acquisition becomes unstable and leads to a fluctuation of the portal dose response. A timing instability and saturation are detected when the dose per frame exceeds 1.53 MU/frame. Rules were deduced to avoid saturation and to optimize this dosimetric mode.ConclusionThe choice of the acquisition parameter is essential for the accurate portal dose imaging.     

Dosimetric characterization of small fields using a plastic scintillator detector: A large multicenter study

PurposeIn modern radiation therapy accurate small fields dosimetry is a challenge and its standardization is fundamental to harmonize delivered dose in different institutions. This study presents a multicenter characterization of MLC-defined small field for Elekta and Varian linear accelerators. Measurements were performed using the Exradin W1 plastic scintillator detector.Materials and methodsThe project enrolled 24 Italian centers. Each center performed Tissue Phantom Ratio (TPR), in-plane and cross-plane dose profiles of 0.8 × 0.8 cm² field, and Output Factor (OF) measurements for square field sizes ranging from 0.8 to 10 cm. Set-up conditions were 10 cm depth in water phantom at SSD 90 cm. Measurements were performed using two twin Exradin W1 plastic scintillator detectors (PSD) correcting for the Cerenkov effect as proposed by the manufacturer.ResultsData analysis from 12 Varian and 12 Elekta centers was performed. Measurements of 7 centers were not included due to cable problems. TPR measurements showed standard deviations (SD) < 1%; SD < 0.4 mm for the profile penumbra was obtained, while FWHM measurements showed SD < 0.5 mm. OF measurements showed SD < 1.5% for field size greater than 2 × 2 cm². Median OFs values were in agreement with the recent bibliography.ConclusionsHigh degree of consistency was registered for all the considered parameters. This work confirmed the importance of multicenter dosimetric intercomparison. W1 PSD could be considered as a good candidate for small field measurements.     

Postoperative endometrial carcinoma treated with external beam irradiation plus vaginal-cuff brachytherapy. Is there a dose relationship with G2 vaginal complications?

AimTo analyse the possible relationship between the EQD2_(α/β=3Gy) at 2 cm³ of the vagina and late toxicity in vaginal-cuff-brachytherapy (VBT) after external-beam-irradiation (EBRT) for postoperative endometrial carcinoma (EC).Materials and methodsFrom 2014 to 2016, 62 postoperative EC patients were treated with EBRT + VBT. The median EBRT dose was 45 Gy (44 Gy–50.4 Gy). VBT involved a single 7 Gy dose. Toxicity was prospectively evaluated using the RTOG score for the rectum and bladder and the objective LENT-SOMA criteria for the vagina. EQD2_{(α/β = 3Gy)} at 2 cm³ of the most exposed part of the vagina was calculated by the sum of the EBRT + VBT dose. Statistics: Boxplot, Student’s t and Chi-square tests and ROC curves.ResultsMean follow-up: 39.2 months (15–68). Late toxicity: bladder:0 patient; rectum:2 patients-G1; Vagina: 26 patients-17G1, 9G2; median EQD2_(α/β=3Gy) at 2 cm³ in G0-G1 patients was 70.4 Gy(SD2.36), being 72.5 Gy(SD2.94) for G2p. The boxplot suggested a cut-point identifying the absence of G2: 100 % of G2p received >68 Gy, ROC curves showed an area under the curve of 0.72 (sensitivity of 1 and specificity of 0.15).ConclusionsDoses >68 Gy EQD2_(α/β=3Gy) at 2 cm³ to the most exposed area of the vagina were associated with late G2 vaginal toxicity in postoperative EC patients treated with EBRT + VBT suggesting a very good dose limit to eliminate the risk of G2 late toxicity. The specificity obtained indicates the need for prospective analyses.     

Optimization and evaluation of multiple gating beam delivery in a synchrotron-based proton beam scanning system using a real-time imaging technique

PurposeTo find the optimum parameter of a new beam control function installed in a synchrotron-based proton therapy system.MethodsA function enabling multiple gated irradiation in the flat top phase has been installed in a real-time-image gated proton beam therapy (RGPT) system. This function is realized by a waiting timer that monitors the elapsed time from the last gate-off signal in the flat top phase. The gated irradiation efficiency depends on the timer value, T_w. To find the optimum T_w value, gated irradiation efficiency was evaluated for each configurable T_w value. 271 gate signal data sets from 58 patients were used for the simulation.ResultsThe highest mean efficiency 0.52 was obtained in T_W = 0.2 s. The irradiation efficiency was approximately 21% higher than at T_W = 0 s, which corresponds to ordinary synchrotron operation. The irradiation efficiency was improved in 154 (57%) of the 271 cases. The irradiation efficiency was reduced in 117 cases because the T_W value was insufficient or the function introduced an unutilized wait time for the next gate-on signal in the flat top phase. In the actual treatment of a patient with a hepatic tumor at T_w = 0.2 s, 4.48 GyE irradiation was completed within 250 s. In contrast, the treatment time of ordinary synchrotron operation was estimated to be 420 s.ConclusionsThe results suggest that the multiple gated-irradiation function has potential to improve the gated irradiation efficiency and to reduce the treatment time.     

Combined molecular MRI and immuno-spin-trapping for in vivo detection of free radicals in orthotopic mouse GL261 gliomas

Free radicals play a major role in gliomas. By combining immuno-spin-trapping (IST) and molecular magnetic resonance imaging (mMRI), in vivo levels of free radicals were detected within mice bearing orthotopic GL261 gliomas. The nitrone spin trap DMPO (5,5-dimethyl pyrroline N-oxide) was administered prior to injection of an anti-DMPO probe (anti-DMPO antibody covalently bound to a bovine serum albumin (BSA)–Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)–biotin MRI contrast agent) to trap tumor-associated free radicals. mMRI detected the presence of anti-DMPO adducts by either a significant sustained increase (p < 0.001) in MR signal intensity or a significant decrease (p < 0.001) in T₁ relaxation, measured as %T₁ change. In vitro assessment of the anti-DMPO probe indicated a significant decrease (p < 0.0001) in T₁ relaxation in GL261 cells that were oxidatively stressed with hydrogen peroxide, compared to controls. The biotin moiety of the anti-DMPO probe was targeted with fluorescently-labeled streptavidin to locate the anti-DMPO probe in excised brain tissues. As a negative control a non-specific IgG antibody covalently bound to the albumin–Gd-DTPA–biotin construct was used. DMPO adducts were also confirmed in tumor tissue from animals administered DMPO, compared to non-tumor brain tissue. GL261 gliomas were found to have significantly increased malondialdehyde (MDA) protein adducts (p < 0.001) and 3-nitrotyrosine (3-NT) (p < 0.05) compared to normal mouse brain tissue, indicating increased oxidized lipids and proteins, respectively. Co-localization of the anti-DMPO probe with either 3-NT or 4-hydroxynonenal was also observed. This is the first report regarding the detection of in vivo levels of free radicals from a glioma model.     

Near real-time magnetic particle imaging for visual assessment of vascular stenosis in a phantom model

PurposeThis study aimed to investigate the potential of magnetic particle imaging (MPI) to quantify artificial stenoses in vessel phantoms in near real-time.MethodsCustom-made stenosis phantoms with different degrees of stenosis (0%, 25%, 50%, 75%, and 100%; length 40 mm, inner diameter 8 mm, Polyoxymethylene) were filled with diluted Ferucarbotran (superparamagnetic iron-oxide nanoparticle (SPION) tracer agent, 500 mmol (Fe)/l). A traveling wave MPI scanner (spatial resolution ~ 2 mm, gradient strength ~ 1.5 T/m, field of view: 65 mm length and 29 mm diameter, frequencies f₁ = 1050 Hz and f₂ = 12150 Hz) was used to acquire images of the phantoms (200 ms total acquisition time per image, 10 averages). Standardized grey scaling was used for comparability. All measured stenoses (n = 80) were graded manually using a dedicated software tool.ResultsMPI allowed for accurate visualization of stenoses at a frame rate of 5 frames per second. Less severe stenoses were detected more precisely than higher-grade stenoses and came with smaller standard deviations. In particular, the 0%, 25%, 50%, 75%, and 100% stenosis phantom were measured as 3.7 ± 2.7% (mean ± standard deviation), 18.6 ± 1.8%, 52.8 ± 3.7%, 77.8 ± 14.8% and 100 ± 0%. Geometrical distortions occurred around the center of the high-grade stenosis and led to higher standard deviations compared to lower grade stenoses. In the frame of this study the MPI signal depended linearly on the SPION concentration down to 0.05 mmol (Fe)/l.ConclusionNear real-time MPI accurately visualized and quantified different stenosis grades in vascular phantoms.     

Adsorption characteristics of sulfur powder by bamboo charcoal to restrain sulfur allergies

Exposures to particulate matter with a diameter of 2.5 μm or less (PM2.5) may influence the risk of birth defects and make you allergic, which causes serious harm to human health. Bamboo charcoal can adsorb harmful substances,that was of benefitto people’s health. In order to figure out the optimal adsorbtion condition and the intrinsic change of bamboo charcoal, five chemicals were adsorbed by bamboo charcoal and were analyzed by FT-IR. The optimal blast time was 80 min of Na₂SO₃, 100 min of Na₂S₂O₈, 20 min of Na₂SO₄, 120 min of Fe₂(SO₄)₃ and 60 min or 100 min of S. FT-IR spectra showed that bamboo charcoal had five characteristic peaks of SS stretch, H₂O stretch, OH stretch, CO stretch or CC stretch, and NO₂ stretch at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹, respectively. For Na₂SO₃, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 20 min. For Na₂S₂O₈, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. For Na₂SO₄, the peaks at 3850 cm⁻¹, 3740 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. For Fe₂(SO₄)₃, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 120 min. For S, the peaks at 3850 cm⁻¹ and 3740 cm⁻¹ achieved the maximum at 40 min, the peaks at 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. It proved that bamboo charcoal could remove sulfur powder from air to restrain sulfur allergies.     

EPID-based in vivo dosimetry for stereotactic body radiotherapy of non-small cell lung tumors: Initial clinical experience

PurposeEPID-based in vivo dosimetry (IVD) has been implemented for stereotactic body radiotherapy treatments of non-small cell lung cancer to check both isocenter dose and the treatment reproducibility comparing EPID portal images.Methods15 patients with lung tumors of small dimensions and treated with volumetric modulated arc therapy were enrolled for this initial experience. IVD tests supplied ratios R between in vivo reconstructed and planned isocenter doses. Moreover a γ-like analysis between daily EPID portal images and a reference one, in terms of percentage of points with γ-value smaller than 1, P_γ<1, and mean γ-values, γ_mean, using a local 3%–3 mm criteria, was adopted to check the treatment reproducibility. Tolerance levels of 5% for R ratio, P_γ<1 higher than 90% and γ_mean lower than 0.67 were adopted.ResultsA total of 160 EPID images, two images for each therapy session, were acquired during the treatment of the 15 patients. The overall mean of the R ratios was equal to 1.005 ± 0.014 (1 SD), with 96.9% of tests within ± 5%. The 2 D image γ-like analysis showed an overall γ_mean of 0.39 ± 0.12 with 96.1% of tests within the tolerance level, and an average P_γ<1 value equal to 96.4 ± 3.6% with 95.4% of tests with P_γ<1 > 90%. Paradigmatic discrepancies were observed in three patients: a set-up error and a patient morphological change were identified thanks to CBCT image analysis whereas the third discrepancy was not fully justified.ConclusionsThis procedure can provide improved patient safety as well as a first step to integrate IVD and CBCT dose recalculation.     

Comparaison entre OSEM-3D et rétroprojection filtrée pour les images traitées par SISCOM dans l’épilepsie temporale

IntroductionWhen ictal and interictal brain SPECT are reconstructed with filtered backprojection (FBP), the noise level of subtraction images is frequently high and requires the use of thresholding methods. The aim of this study was to compare the subtraction images for cerebral SPECT reconstructed either with FBP or with a 3D iterative reconstruction method (OSEM-3D).Material and methodsAfter optimisation of the reconstruction parameters on phantom, the subtraction SPECT images, which were obtained with FBP or with OSEM-3D and coregistered with MRI images, were analyzed in 15 patients with refractory temporal epilepsy.ResultsOn phantom and with the constrain of high enough spatial resolution (full width at half of maximum for a punctual source less than or equal to 11 mm) were reached using: (i) a Butterworth filter with a cut-off frequency of 0.4 Nyquist at order 6 for FBP and (ii) five iterations, 16 subsets and a 9 mm gaussian filter for OSEM-3D. On the subtraction images, which were obtained with these optimal parameters, the temporal foci from patients were smaller with OSEM-3D than with FBP (11 ± 6 cm³ versus 17 ± 10 cm³, P = 0.02), mean voxel activities were equivalent between the two methods within temporal foci (6.30 ± 3.13 counts versus 6.34 ± 4.93 counts) but these activities were dramatically reduced by OSEM-3D within background regions (0.02 ± 0.02 counts versus 0.19 ± 0.12 counts, P < 0.001).ConclusionFor the ictal–interictal subtraction SPECT images, which are obtained in patients with refractory temporal epilepsy, the use of an optimized OSEM-3D method leads to dramatically reduce the volume of temporal foci, as well as the background noise level, two properties that are likely to facilitate the detection and localisation of epilepsy foci.     

Transrectal implantation and stability of gold markers in prostate bed for salvage radiotherapy of macroscopic recurrences

Background and purposeThe objective of the study was to verify the stability of gold markers in the prostatic bed (PB) during salvage radiotherapy.Material and methodsSeven patients, diagnosed with a macroscopic nodule visible on MRI, underwent targeted MRI-guided biopsies. Three gold markers were implanted into the PB close to the relapsing nodule for CT/MRI fusion. A dose of 60 Gy was delivered using IMRT to the PB followed by a dose escalation up to 72 Gy to the macroscopic nodule. Daily anterior and left-lateral kV-images were acquired for repositioning. The coordinates of the center of each marker were measured on the two kV-images. The distance variations (Dvar) of the markers in the first session and the subsequent ones were compared.ResultsNo marker was lost during treatment. The average distance between markers was 7.8 mm. The average Dvar was 0.8 mm, in absolute value. A total of 380/528 (72%) Dvar were ⩽1 mm. A Dvar greater than 2 mm was observed in 5.7% of measurements, with a maximum value of 4.8 mm.ConclusionsDespite the absence of the prostate, the implantation of gold markers in the PB remains feasible, with Dvar often less than 2 mm, and could be used to develop new approaches of salvage focal radiotherapy on the macroscopic relapse after prostatectomy.     

Implementation and evaluation of a transit dosimetry system for treatment verification

PurposeTo evaluate a formalism for transit dosimetry using a phantom study and prospectively evaluate the protocol on a patient population undergoing 3D conformal radiotherapy.MethodsAmorphous silicon EPIDs were calibrated for dose and used to acquire images of delivered fields. The measured EPID dose map was back-projected using the planning CT images to calculate dose at pre-specified points within the patient using commercially available software, EPIgray (DOSIsoft, France). This software compared computed back-projected dose with treatment planning system dose. A series of tests were performed on solid water phantoms (linearity, field size effects, off-axis effects). 37 patients were enrolled in the prospective study.ResultsThe EPID dose response was stable and linear with dose. For all tested field sizes the agreement was good between EPID-derived and treatment planning system dose in the central axis, with performance stability up to a measured depth of 18 cm (agreement within −0.5% at 10 cm depth on the central axis and within −1.4% at 2 cm off-axis). 126 transit images were analysed of 37 3D-conformal patients. Patient results demonstrated the potential of EPIgray with 91% of all delivered fields achieved the initial set tolerance level of Δ_D of 0 ± 5-cGy or %Δ_D of 0 ± 5%.ConclusionsThe in vivo dose verification method was simple to implement, with very few commissioning measurements needed. The system required no extra dose to the patient, and importantly was able to detect patient position errors that impacted on dose delivery in two of cases.     

Megavoltage 2D topographic imaging: An attractive alternative to megavoltage CT for the localization of breast cancer patients treated with TomoDirect

PurposeTo show the usefulness of topographic 2D megavoltage images (MV2D) for the localization of breast cancer patients treated with TomoDirect (TD), a radiotherapy treatment technique with fixed-angle beams performed on a TomoTherapy system.MethodsA method was developed to quickly localize breast cancer patients treated with TD by registering the MV2D images produced before a TD treatment with reference images reconstructed from a kilovoltage CT simulation scanner and by using the projection of the beam-eye-view TD treatment field. Dose and image quality measurements were performed to determine the optimal parameters for acquiring MV2D images. A TD treatment was simulated on a chest phantom equipped with a breast attachment. MVCT and MV2D images were performed for 7 different shifted positions of the phantom and registered by 10 different operators with the simulation kilovoltage CT images.ResultsCompared to MVCT, MV2D imaging reduces the dose by a factor of up to 45 and the acquisition time by a factor of up to 49. Comparing the registration shift values obtained for the phantom images obtained with MVCT in the coarse mode to those obtained with MV2D, the mean difference is 1.0 ± 1.1 mm, −1.1 mm ± 1.1, and −0.1 ± 2.2 mm, respectively, in the lateral, longitudinal, and vertical directions.ConclusionsWith dual advantages (very fast imaging and a potentially reduced dose to the heart and contralateral organs), MV2D topographic images may be an attractive alternative to MVCT for the localization of breast cancer patients treated with TomoDirect.     

Acute changes in knee cartilage transverse relaxation time after running and bicycling

PurposeTo compare the acute effect of running and bicycling of an equivalent cumulative load on knee cartilage composition and morphometry in healthy young men. A secondary analysis investigated the relationship between activity history and the change in cartilage composition after activity.MethodsIn fifteen men (25.8±4.2 years), the vertical ground reaction force was measured to determine the cumulative load exposure of a 15-min run. The vertical pedal reaction force was recorded during bicycling to define the bicycling duration of an equivalent cumulative load. On separate visits that were spaced on average 17 days apart, participants completed these running and bicycling bouts. Mean cartilage transverse relaxation times (T₂) were determined for cartilage on the tibia and weight-bearing femur before and after each exercise. T₂ was measured using a multi-echo spin-echo sequence and 3T MRI. Cartilage of the weight bearing femur and tibia was segmented using a highly-automated segmentation algorithm. Activity history was captured using the International Physical Activity Questionnaire.ResultsThe response of T₂ to bicycling and running was different (p=0.019; mean T₂: pre-running=34.27 ms, pre-bicycling=32.93 ms, post-running=31.82 ms, post-bicycling=32.36 ms). While bicycling produced no change (−1.7%, p=0.300), running shortened T₂ (−7.1%, p<0.001). Greater activity history predicted smaller changes in tibial, but not femoral, T₂.ConclusionsChanges in knee cartilage vary based on activity type, independent of total load exposure, in healthy young men. Smaller changes in T₂ were observed after bicycling relative to running. Activity history was inversely related to tibial T₂, suggesting cartilage conditioning.     

Characteristics of activated carbon remove sulfur particles against smog

Sulfur particles, which could cause diseases, were the main powder of smog. And activated carbon had the very adsorption characteristics. Therefore, five sulfur particles were adsorbed by activated carbon and were analyzed by FT-IR. The optimal adsorption time were 120 min of Na₂SO₃, 120 min of Na₂S₂O₈, 120 min of Na₂SO₄, 120 min of Fe₂(SO₄)₃ and 120 min of S. FT-IR spectra showed that activated carbon had the eight characteristic absorption of SS stretch, H₂O stretch, OH stretch, CH stretch, conjugated CO stretch or CC stretch, CH₂ bend, CO stretch and acetylenic CH bend vibrations at 3850 cm^–1, 3740 cm^–1, 3430 cm^–1, 2920 cm^–1, 1630 cm^–1, 1390 cm^–1, 1110 cm^–1 and 600 cm^–1, respectively. For Na₂SO₃, the peaks at 2920 cm^–1, 1630 cm^–1, 1390 cm^–1 and 1110 cm^–1 achieved the maximum at 20 min. For Na₂S₂O₈, the peaks at 3850 cm^–1, 3740 cm^–1 and 2920 cm^–1 achieved the maximum at 60 min. The peaks at 1390 cm^–1, 1110 cm^–1 and 600 cm^–1 achieved the maximum at 40 min. For Na₂SO₄, the peaks at 3430 cm^–1, 2920 cm^–1, 1630 cm^–1, 1390 cm^–1, 1110 cm^–1 and 600 cm^–1 achieved the maximum at 60 min. For Fe₂(SO₄)₃, the peaks at 1390 cm^–1, 1110 cm^–1 and 600 cm^–1 achieved the maximum at 20 min. For S, the peaks at 1630 cm^–1, 1390 cm^–1 and 600 cm^–1 achieved the maximum at 120 min. It provided that activated carbon could remove sulfur particles from smog air to restrain many anaphylactic diseases.     

Adsorption characteristics of sulfur solution by acticarbon against drinking-water toxicosis

Sulfur and ammonia nitrogen are rich nutrient pollutants, after entering water can cause algal blooms, cause eutrophication of water body, the spread of them will not only pollute the environment, destroy the ecological balance, but also harm human health through food chain channels, especially drinking-water toxicosis. Acticarbon can adsorb harmful substances, it was beneficial for people’s health. In order to figure out the optimal adsorption condition and the intrinsic change of acticarbon, five chemicals were adsorbed by acticarbon and analyzed by FT-IR. The optimal adsorption condition of Fe₂(SO₄)₃, Na₂SO₄, Na₂S₂O₈, S and Na₂SO₃ was 9 g/1000 g at 80 min, 21 g/1000 g at 20 min, 15g/1000 g at 20 min, 21 g/1000 g at 60 min and 21 g/1000 g at 100 min, respectively. FT-IR spectra showed that acticarbon had eight characteristic peaks, such as S-S stretch, H₂O stretch, OH stretch, CH stretch, CO or CC stretch, CH₂ bend, CH were at 3850 cm⁻¹, 3740 cm⁻¹, 3435 cm⁻¹, 2925 cm⁻¹, 1630 cm⁻¹, 1390 cm⁻¹, 1115 cm⁻¹, 600 cm⁻¹, respectively. For FT-IR spectra of Fe₂(SO₄)₃, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 2925 cm⁻¹ achieved the maximum with 9 g/1000 g at 20 min. For Na₂SO₄, the peaks at 2925 cm⁻¹, 1630 cm⁻¹, 1390 cm⁻¹, 1115 cm⁻¹, 600 cm⁻¹ achieved the maximum with 21 g/1000 g at 120 min. For ones of Na₂S₂O₈, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 1390 cm⁻¹, 1115 cm⁻¹, 600 cm⁻¹, achieved the maximum with 2 g/1000 g at 80 min. For ones of S, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 2925 cm⁻¹ achieved the maximum with 19 g/1000 g at 100 min, the peaks at 1390 cm⁻¹, 1115 cm⁻¹, 600 cm⁻¹ achieved the maximum with 19 g/1000 g at 20 min. For FT-IR spectra of Na₂SO₃, the peaks at 1630 cm⁻¹, 1390 cm⁻¹, 1115 cm⁻¹, 600 cm⁻¹ achieved the maximum with 2 g/1000 g at 100 min. It provided that acticarbon could adsorb and desulphurize from sulfur solution against drinking-water toxicosis.     

Respiratory motion of adrenal gland metastases: Analyses using four-dimensional computed tomography images

PurposeTo evaluate the respiratory motion of adrenal gland metastases in three-dimensional directions using four-dimensional computed tomography (4DCT) images.MethodsFrom January 2013 to May 2016, 12 patients with adrenal gland metastases were included in this study. They all underwent 4DCT scans to assess respiratory motion of adrenal gland metastases in free breathing state. The 4DCT images were sorted into 10 image series according to the respiratory phase from the end inspiration to the end expiration, and then transferred to FocalSim workstation. All gross tumor volumes (GTVs) of adrenal gland metastases were drawn by a single physician and confirmed by a second. Relative coordinates of adrenal gland metastases were automatically generated to calculate adrenal gland metastases motion in different axial directions.ResultsThe average respiratory motion of adrenal gland metastases in left-right (LR), cranial-caudal (CC), anterior-posterior (AP), 3-dimensional (3D) vector directions was 3.4 ± 2.2 mm, 9.5 ± 5.5 mm, 3.8 ± 2.0 mm and 11.3 ± 5.3 mm, respectively. The ratios were 58.6% ± 11.4% and 63.2% ± 12.5% when the volumes of GTV_In0% and GTV _In100% were compared with volume of IGTV_10phase. The volume ratio of IGTV_10phase to GTV_3D was 1.73 ± 0.48.ConclusionsAdrenal gland metastasis is a respiration-induced moving target, and an internal target volume boundary should be provided when designing the treatment plan. The CC motion of adrenal gland metastasis is predominant and >5 mm, thus motion management strategies are recommended for patients undergoing external radiotherapy for adrenal gland metastasis.