Additional services for the uranium enrichment cascade process, such as UF{sub 6} feed, sampling, and material storage are provided by several ancillary Uranium Material Handling (UMH) facilities at the PORTS site. These facilities include the X-343 Feed Vaporization and Sampling Facility, the X-744G Bulk Non-Uranium Enrichment Service Activity (UESA) Storage Building, the X-744H Waste Separation and Storage Facility, the X-344A Toll Enrichment Services Facility and the X-342A Feed Vaporization and Fluorine Generation Facility. As uranium operations are performed within these facilities, the potential for a criticality accident exists. In the event of a criticality accident within a process facility at PORTS, a Criticality Accident Alarm System (CAAS) is in place to detect the criticality accident and sound an alarm. In this report, an analysis was performed to provide verification that the existing CAAS at PORTS provides complete criticality accident coverage in the X-343, X-744G. X-744H. X-344A and X-342A facilities. The analysis has determined that all of the above-mentioned facilities have complete CAAS coverage.
Purpose: To demonstrate the ability to quickly generate an accurate collision avoidance map using multiple stereotactic cameras during simulation. Methods: Three Kinect stereotactic cameras were placed in the CT simulation room and optically calibrated to the DICOM isocenter. Immediately before scanning, the patient was optically imaged to generate a 3D polygon mesh, which was used to calculate the collision avoidance area using our previously developed framework. The mesh was visually compared to the CT scan body contour to ensure accurate coordinate alignment. To test the accuracy of the collision calculation, the patient and machine were physically maneuvered in the treatment room to calculated collision boundaries. Results: The optical scan and collision calculation took 38.0 seconds and 2.5 seconds to complete respectively. The collision prediction accuracy was determined using a receiver operating curve (ROC) analysis, where the true positive, true negative, false positive and false negative values were 837, 821, 43, and 79 points respectively. The ROC accuracy was 93.1% over the sampled collision space. Conclusion: We have demonstrated a framework which is fast and accurate for predicting collision avoidance for treatment which can be determined during the normal simulation process. Because of the speed, the system could be used to add a layer of safety with a negligible impact on the normal patient simulation experience. This information could be used during treatment planning to explore the feasible geometries when optimizing plans. Research supported by Varian Medical Systems
Metastases from tonsilar cancers are uncommon, usually found in the lung and less commonly in the bone, liver, and mediastinal sites. Only approximately 20% of patients die from distant metastasis. Central nervous system (CNS) metastases usually appear later in the course of the disease, with only 1% to 2% of patients developing metastasis involving the CNS in the course of their disease. Patients seen with symptomatic CNS lesions are rare.A case report is presented of a patient seen with signs and symptoms of CNS disease from an isolated CNS metastasis. The primary site was ultimately determined to be of tonsilar origin. The patient's treatment and outcome are discussed.Tonsilar cancers seen with signs and symptoms of CNS disease is a rare event. The benefit of aggressive treatment of isolated CNS metastasis from head and neck cancers will likely be gained from case reports because the incidence is quite low.
175 Background: To identify post-operative prostate cancer patients who are unlikely to achieve long-term biochemical control following salvage radiotherapy (SRT). We hypothesize that patients with node-positive disease, no nadir after radical prostatectomy (RP), or a high pre-radiotherapy (pre-RT) PSA levelwill have a low chance of benefitting from SRT. Methods: Ninety patients who received SRT following RP were retrospectively analyzed to determine factors associated with biochemical failure. Patients on continuous androgen deprivation therapy (ADT) were excluded from statistical analysis. Results: Median follow-up was 30 months (range 6-120). The overall projected 3-year bPFS was 70%. Factors significantly associated with biochemical failure on univariate analysis included Gleason score, positive seminal vesicle invasion, PSA doubling time of 6 months or less, and pre-RT PSA greater than 1.0 ng/mL. All patients with a pre-RT PSA greater than 3.0 ng/mL failed. Patients who did not reach an undetectable nadir following RP had 55% 3-year bPFS compared with 79% in those who did achieve an undetectable PSA (p=0.041). Multivariate analysis demonstrated that GS of 8 and pre-RT PSA were significant predictors. A separate analysis was performed on a subgroup of 8 patients with node-positive disease. Five patients failed at a median of 24 months (range 12-64). Of the remaining 3 patients, 2 had been maintained on long-term ADT, and 1 patient was 11 months out from treatment. Conclusions: Patients with node-positive disease are unlikely to achieve long-term biochemical control from SRT due to extra-prostatic disease spread. Although various factors may influence outcome, no other group demonstrated a very low chance of benefit. Patients with rising PSA benefit from early treatment before PSA rises above 1.0 ng/mL. [Table: see text]
Flattening filter-free (FFF) linear accelerators (linacs) are capable of delivering dose rates more than 4-times higher than conventional linacs during SBRT treatments, causing some to speculate whether the higher dose rate leads to increased toxicity owing to radiobiological dose rate effects. Despite wide clinical use of this emerging technology, clinical toxicity data for FFF SBRT are lacking. In this retrospective study, we report the acute and late toxicities observed in our lung radiosurgery experience using a FFF linac operating at 2400 MU/min.We reviewed all flattening filter-free (FFF) lung SBRT cases treated at our institution from August 2010 through July 2012. Patients were eligible for inclusion if they had at least one clinical assessment at least 30 days following SBRT. Pulmonary, cardiac, dermatologic, neurologic, and gastrointestinal treatment related toxicities were scored according to CTCAE version 4.0. Toxicity observed within 90 days of SBRT was categorized as acute, whereas toxicity observed more than 90 days from SBRT was categorized as late. Factors thought to influence risk of toxicity were examined to assess relationship to grade > =2 toxicity.Sixty-four patients with >30 day follow up were eligible for inclusion. All patients were treated using 10 MV unflattened photons beams with intensity modulated radiation therapy (IMRT) inverse planning. Median SBRT dose was 48 Gy in 4 fractions (range: 30-60 Gy in 3-5 fractions). Six patients (9%) experienced > = grade 2 acute pulmonary toxicity; no non-pulmonary acute toxicities were observed. In a subset of 49 patients with greater than 90 day follow up (median 11.5 months), 11 pulmonary and three nerve related grade > =2 late toxicities were recorded. Pulmonary toxicities comprised six grade 2, three grade 3, and one each grade 4 and 5 events. Nerve related events were rare and included two cases of grade 2 chest wall pain and one grade 3 brachial plexopathy which spontaneously resolved. No grade > =2 late gastrointestinal, skin, or cardiac toxicities were observed. Tumor size, biologically effective dose (BED10, assuming α/β of 10), and tumor location (central vs peripheral) were not significantly associated with grade > =2 toxicity.In this early clinical experience, lung SBRT using a FFF linac operating at 2400 MU/min yields minimal acute toxicity. Preliminary results of late treatment related toxicity suggest reasonable rates of grade > =2 toxicities. Further assessment of late effects and confirmation of the clinical efficacy of FFF SBRT is warranted.
Boron neutron capture therapy (BNCT) is an experimental radiation therapy that is being developed for the treatment of malignant tumors. One requirement for successful BNCT is that a sufficient amount of 10B concentrates in the tumor while clearing from normal tissues and blood. Many pharmaceuticals are currently being developed to selectively deliver 10B to a tumor. To evaluate the effectiveness of various 10B delivery agents, the concentrations of boron in blood, tumor, and normal tissues must be known. Using the solid-state nuclear track detector CR-39, a tissue assay technique has been developed to spatially determine 10B concentrations in tissue samples. The technique has been used to quantify 10B concentrations in tumor and normal tissue on lines across rat brain tissue sections. This was done by combining 10B concentrations measured on lines across the CR-39 with color digital images of the tissue section. Coupling the methodology that was developed for tissue samples with an existing analytical technique for blood-10B concentration measurements allows for complete evaluation of 10B distributions in blood, tumor, and normal tissues and should be useful in evaluating various 10B delivery agents for use in BNCT.
This report summarizes the results of an evaluation of Criticality Accident Alarm System (CAAS) coverage of the operating floors (first floors) of the X-333, X-330, and X-326 buildings. CAAS coverage of the process cell floors (second floors) has been evaluated in previous reports. Coverage of the roadways around the three processing buildings by the cell floor detectors in these buildings has also been verified in a previous report. In order to evaluate coverage, the facilities were modeled using the Monte Carlo N-Particle Transport Computer Code (MCNP). MCNP was then used to simulate criticality accidents at various locations throughout the operating floors of the buildings and the associated neutron flux at the current detector locations was calculated. The neutron flux was then converted to an absorbed dose rate (in tissue) and compared with the Portsmouth criticality accident alarm set-point of 5mrad/hr. The parameters defining the simulated criticality accidents have been calculated as ``the minimum accident of concern`` as defined in ANSI Standard ANS 8.3-1986. These calculations are documented in Portsmouth report number POEF-SH-31. The results of this evaluation indicate that the X-333 Operating Floor CAAS may not alarm in response to a minimum accident of concern. This is primarily because of shielding provided by the numerous concrete columns used to support the second floor of this building and the large distances between the CAAS detectors. Conversely, the results indicate that the X-326 and the X-330 CAAS systems would alarm in response to a minimum accident of concern occurring on the operating floors of these buildings. It should be noted that the cell floors in these two buildings are supported with steel I-beams instead of the concrete columns used in the X-333 building.
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