Purpose: To develop and evaluate a modified anthropomorphic head phantom for evaluation of stereotactic radiosurgery (SRS) dose planning and delivery. Methods: A phantom was constructed from a water ...equivalent, plastic, head‐shaped shell. The original phantom design, with only a spherical target, was modified to include a nonspherical target (pituitary) and an adjacent organ at risk (OAR) (optic chiasm), within 2 mm, simulating the anatomy encountered when treating acromegaly. The target and OAR spatial proximity provided a more realistic treatment planning and dose delivery exercise. A separate dosimetry insert contained two TLD for absolute dosimetry and radiochromic film, in the sagittal and coronal planes, for relative dosimetry. The prescription was 25Gy to 90% of the GTV with >= 10% of the OAR volume receiving >= 8Gy. The modified phantom was used to test the rigor of the treatment planning process, dosimeter reproducibility, and measured dose delivery agreement with calculated doses using a Gamma Knife, CyberKnife, and linear accelerator based radiosurgery systems. Results: TLD results from multiple irradiations using either a CyberKnife or Gamma Knife agreed with the calculated target dose to within 4.7% with a maximum coefficient of variation of+/−2.0%. Gamma analysis in the coronal and sagittal film planes showed an average passing rate of 99.3% and 99.5% using +/−5%/3mm criteria, respectively. A treatment plan for linac delivery was developed meeting the prescription guidelines. Dosimeter reproducibility and dose delivery agreement for the linac is expected to have results similar to the results observed with the CyberKnife and Gamma Knife. Conclusions: A modified anatomically realistic SRS phantom was developed that provided a realistic clinical planning and delivery challenge that can be used to credential institutions wanting to participate in NCI funded clinical trials. Work supported by PHS CA010953, CA081647, CA21661 awarded by NCI. DHHS
LoTSS jellyfish galaxies Roberts, I. D.; van Weeren, R. J.; Timmerman, R. ...
Astronomy and astrophysics (Berlin),
02/2022, Letnik:
658
Journal Article
Recenzirano
Odprti dostop
In this paper we report the first identification of jellyfish galaxies in the Perseus cluster (Abell 426). We identified four jellyfish galaxies (LEDA 2191078, MCG +07-07-070, UGC 2654, UGC 2665) ...within the central 2° ×2° (2.6 Mpc × 2.6 Mpc) of Perseus based on the presence of one-sided radio continuum tails that were detected at 144 MHz by the LOw Frequency ARray (LOFAR). The observed radio tails, as well as the orientation of morphological features in the rest-frame optical, are consistent with these four galaxies being impacted by ram pressure stripping as they orbit through the Perseus intracluster medium. By combining the LOFAR imaging at 144 MHz with 344 MHz imaging from the
Karl G. Jansky
Very Large Array, we derived spectral indices for the disks and the stripped tails of these jellyfish galaxies. We show that the spectral indices over the galaxy disks are quite flat, while the indices of the stripped tails are substantially steeper. We also identified a number of compact H
α
+ N
II
sources with narrowband imaging from the
Isaac Newton
Telescope. These sources are brighter along the leading side of the galaxy (i.e., opposite to the direction of the stripped tail), which is consistent with ram pressure induced star formation. Lastly, consistent with previous works in other clusters, we find that these jellyfish galaxies show enhanced radio luminosities for their observed star formation rates. Given the small distance to the Perseus cluster (
D
∼ 70 Mpc, 1″ ≃ 340 pc), these galaxies are excellent candidates for multiwavelength follow-up observations to probe the impact of ram pressure stripping on galaxy star formation at subkiloparsec scales.
Objective: To investigate the long-term (2-15 years) functional outcome of children and young adults who received an early intensive neurorehabilitation programme (EINP) after a prolonged period of ...unconsciousness due to severe brain injury; to differentiate between traumatic brain injury (TBI) and non-traumatic brain injury (nTBI); and to compare the results on two different outcome scales: the Disability Rating Scale (DRS) and the Glasgow Outcome Scale Extended (GOSE).
Subjects: One hundred and forty-five patients, who were admitted to EINP between December 1987 and January 2001.
Outcome measures: The Post-Acute Level of Consciousness scale (PALOC-s), the DRS, including categorized scores (DRScat), and the GOSE.
Results: The long-term functional level of 90 patients could be determined, of whom 25 were deceased. The mean DRS-score of the surviving patients was 6.8 (SD = 6.6); the mean score on the GOSE was 4.5 (SD = 1.7). There was a significant difference in the outcome amongst traumatic and non-traumatic patients (t(88) = 4.21; p < 0.01). The correlation between the DRS and the GOSE was high (Spearman rho = 0.85; p < 0.01), as well as the correlation between the categorized scores of the DRS and the GOSE (Spearman rho = 0.81; p < 0.01). The distribution of outcome scores on the DRScat is more diverse than on the GOSE. Especially item 7 of the DRS, measuring functional independence, showed considerable variance in discriminating between different outcome levels.
Conclusions: More patients with TBI than expected reached a (semi-) independent level of functioning, indicating a possible effect of EINP. Patients suffering from nTBI did not demonstrate these outcome levels. Only a few patients stayed in a vegetative state for more than a couple of years. In this cohort of severe brain-injured young people, the DRS offered the best investigative possibilities for long-term level of functioning.
Electrodewatering is a technique in which pressure dewatering is combined with electrokinetic effects to realize an improved solid/liquid separation and hence increased filter cake dry matter ...contents. In order to be energy efficient, it is shown that sludge should be dewatered by pressure dewatering to a high extent prior to electric field application, and a sufficient contact time for the electric field must be guaranteed. In order to realize these goals, a bench- and pilot-scale diaphragm filter press suited for electrodewatering were constructed for treatment of sewage and other types of sludges. It was shown that electrodewatering of sludge is a feasible technique, especially for biological sludge types. Other types of sludge are less suited for electrodewatering because of the restricted improvements that can be realized in cake dry matter content and the high electric energy consumption. Furthermore, it was shown in pilot-scale tests that the use of a diaphragm filter press with electrodewatering facilities was very well suited to deliver dry filter cakes of sewage sludge at a moderate energy consumption. Depending on local market prices for investment, operating and sludge disposal costs, this technology may therefore lead to important savings in the sludge management process.
Purpose: To assess the precision of 4DCBCT in patient setup for stereotactic body radiation therapy of lung cancer. Methods and Materials: Eight cases of breathing motion patterns are imposed on ...phantom imitating the tumor motion in the lung. These simulated phantom motions are scanned by 4DCT. PTV volumes are defined from 4DCT images. At Elekta SynergyS, 3DCBCT images are acquired for phantom reproducing same motions at 4DCT. 3DCBCT data are transferred to XVI 1.51b and reconstructed into 4DCBCT. 4DCBCT images are imported into Pinnacle 8.1y. AVG and MIP images from 4DCBCT data are comparing with 4DCT. Matching are performed between AVG and MIP from 4DCBCT and 4DCT to set standards for accurate 4DCBCT derived irregularly target placement at treatment unit for case of irregular breathing motions for SBRT therapy of the lung. PTV location in laboratory frame of reference derived from known geometry of the phantom and known motion of the target is compared to PTV localization at same reference as derived from 4DCT and 4DCBCT. Results: Images from 4DCBCT for patient setup shows noticeable difference with setup based on standard 3DCBCT. We found up to 5mm difference between 3DCBCT based setup and 4DCBCT setup in case when irregular breathing pattern with over 20 mm range. When comparing static marker location to the tumor location defined by phantom dimensions and phantom motion with respect to PTV location derived from 4DCBCT, we found the center of PTV dislocation relative to its true center up to 4mm. Dosimetric impact of this error will be reported. Conclusions: 4DCBCT is not likely to improve the accuracy of patient positioning relative to 3DCBCT unless considerably slower gantry rotation is used to increase sampling of images needed for 4D binning.
Purpose: The purpose of this study is to compare the different dosemetric characteristics of Linac‐based SBRT and that of Cyberknife for lung tumor treatment. Methods: Eight patients with lung tumors ...received Linac‐based SBRT were retrospectively included in this study. 60Gy photon dose delivered in 5 frictions was prescribed to each target. To minimize respiratory motion impact, Synchrony™ (AccurayInc., Sunnyvale, CA) and a 4D dose calculation program were used for Cyberknife and Linac‐based SBRT treatment planning respectively. Identical patients' image (50% phase image of 4DCT corresponding to the end of exhalation) and contour sets were used for dose calculation. The DVHs of PTV, GTV, and lung were studied. Results: Both modalities can provide satisfactory dose coverage to target tumor. The lung dose (2.1±0.8Gy to 1500cc and 4.3±2.1Gy to 1000cc) is well below institutional constrains. Lung dose of Cyberknife plans is more susceptible to the tumor location than that of Linac‐based SBRT plan. When tumor attaches to anterior chest wall, Cyberknife may deliver less dose to patient lung than Linac‐based SBRT. When the tumor becomes more posterior, lung dose of Cyberknife plan increases much more quickly than that of Linac‐based SBRT plan. Cyberknife may delivery higher dose to lung than Linac‐based SBRT when the tumor is located close to the posterior chest wall. The dose distribution of Cyberknife is more heterogeneous than Linac‐based SBRT in all cases. Conclusion: Both Linac‐based SBRT and Cyberknife can provide adequate dose coverage for target tumor while sparing normal tissue. Cyberknife may delivery less dose to lung than Linac‐based SBRT when the tumor is close to anterior chest wall but more dose to lung when tumor attached to posterior chest wall. This study may provide useful information to help radiation oncologist to choose SBRT modalities for lung tumor treatment.
Surgical resection is standard therapy for patients with stage I non-small cell lung cancer (NSCLC), however, many patients are medically inoperable. We set out to investigate a new therapy akin to ...brain radiosurgery called extracranial stereotactic radioablation (ESR) in a phase I trial.
Eligible patients included those with clinically staged T1 or T2 (tumor size, < or = 7 cm) N0M0 biopsy confirmed NSCLC. All patients had comorbid medical problems that precluded thoracotomy. The median age was 75 years, and the median Karnofsky performance status was 80. ESR was administered in three separate fractions over 2 weeks. Three to five patients were treated within each dose cohort starting at 800 cGy per fraction (total, 2,400 cGy) followed by successive dose escalations of 200 cGy per fraction (total increase per cohort, 600 cGy). Waiting periods occurred between dose cohorts to observe toxicity. Patients with T1 vs T2 tumors underwent separate independent dose escalations.
A total of 37 patients were enrolled since February 2000. One patient experienced grade 3 pneumonitis, and another patient had grade 3 hypoxia. For the entire population, there was no appreciable decline in cardiopulmonary function as measured by symptoms, physical examination, need for oxygen supplementation, pulmonary function testing, arterial blood gas determinations, or regular chest imaging. Both T-stage groups ultimately reached and tolerated 2,000 cGy per fraction for three fractions (total, 6,000 cGy). The maximum tolerated dose for this therapy in either T-stage group has yet to be reached. Tumors responded to treatment in 87% of patients (complete response, 27%). After a median follow-up period of 15.2 months, six patients experienced local failure, all of whom had received doses of < 1,800 cGy per fraction.
Very high radiation dose treatments were tolerated in this population of medically inoperable patients with stage I NSCLC using ESR techniques.
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