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1.
Comparison of dynamic and step-and-shoot intensity-modulated radiation therapy planning and delivery. 总被引:1,自引:0,他引:1
Intensity-modulated radiation therapy (IMRT) is commonly delivered using the dynamic or segmental mode of multileaf collimators (DMLC or SMLC). Both methods are designed to deliver intensity-modulated beams as determined by inverse planning software. In this study, we have used the Helios IMRT planning system to generate ideal treatment plans for 10 cases of 2 common treatment sites (prostate and head and neck) and have investigated the actual treatment fluence distributions generated for each of the MLC leaf motion choices. The 2 dose delivery techniques were dosimetrically compared to each other and to the treatment plans. For each technique, point doses were measured in a water phantom using ionization chambers. Also for each technique, 2-dimensional dose distributions at a selected depth in a plastic phantom were obtained, using extended range film. The total delivery time and the number of monitor units (MU) delivered by each method were also compared. Our results indicate that the 2 delivery methods produce comparable results dosimetrically. For the cases reviewed, the delivery time was an average of 15% longer for SMLC deliveries, while the number of MUs (beam-on time) required by SMLC was an average of 15% fewer, than that for the DMLC. In the interest of simplicity, lower beam-on time, and potentially fewer mechanically-related problems, we think that the SMLC delivery technique may be the better choice when Helios is used for planning and Varian linear accelerators are used for delivery. 相似文献
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"Nonspecific" electrolytic lesions (with respect to subdivision) of the mouse inferior colliculus (IC) resulted in the attenuation of acoustic startle response (ASR) amplitudes on the 1st post-operative day, but ASR amplitudes increased to above baseline levels 1 week later. Lesions of the IC central nucleus (CN) also attenuated ASR amplitudes on the 1st postsurgery day, but startle amplitudes recovered to baseline levels 1 week after surgery. Lesions of the IC lateral nucleus (LN) or dorsal cortex (DC) resulted in elevation of startle amplitudes above baseline 7 days after surgery and produced enhanced ASR amplitudes to repeated stimuli. Fourteen days after the surgery, lesion effects on startle amplitudes remained the same as those on Day 7 for each lesion condition. The present findings implicate the ICLN and the ICDC as inhibitory modulators of the ASR, but indicate only a minor role for the ICCN. 相似文献
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Expression of the 5.1 H11 antigen, a fetal muscle surface antigen, in normal and neoplastic tissue 总被引:1,自引:0,他引:1
D R Strother D M Parham P J Houghton 《Archives of pathology & laboratory medicine》1990,114(6):593-596
The monoclonal antibody 5.1 H11 recognizes an antigen on human fetal muscle and on rhabdomyosarcoma cell lines and xenografts that has been shown to be homologous to the neural cell adhesion molecule. To evaluate its range of expression, we used immunoperoxidase staining of fresh frozen-tissue sections to determine monoclonal antibody 5.1 H11 reactivity in normal and neoplastic tissue. Among normal tissue specimens, intense antibody staining was seen in brain and peripheral nerve, and weaker staining in ganglionic elements of colon. In addition to 26 of 29 rhabdomyosarcoma specimens, 5.1 H11 antibody showed reactivity to 9 of 10 Wilms' tumors, 6 of 6 neural tumors, and 4 of 4 gliomas, and with single specimens of ectomesenchymoma, clear-cell sarcoma of kidney, undifferentiated sarcoma of liver, ovarian fibroma, and neurofibroma. We conclude that the monoclonal antibody 5.1 H11 recognizes an antigen present not only on fetal muscle but on normal brain and nerve as well. In addition to rhabdomyosarcoma, a variety of other tumors, most of which have been previously shown to express neural cell adhesion molecule, also appear to express the antigen recognized by 5.1 H11. Our results thus offer additional confirmatory evidence that an epitope of neural cell adhesion molecule is the antigen for 5.1 H11. 相似文献
6.
Methylation alterations of the MyoD1 upstream region are predictive of subclassification of human rhabdomyosarcomas.
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B. Chen P. Dias J. J. Jenkins rd V. H. Savell D. M. Parham 《The American journal of pathology》1998,152(4):1071
MyoD1 expression is a distinguishing characteristic of rhabdomyosarcoma. In this study, distinct methylation alterations were identified in the 5'' flanking region of the MyoD1 gene from the two major subtypes, ie, alveolar and embryonal rhabdomyosarcoma. The MyoD1 methylation patterns of 26 rhabdomyosarcomas were compared with that of normal skeletal muscle and nonmuscle specimens by Southern blot analysis using methylation-sensitive restriction enzymes HhaI and HpaII. A 5-kb region immediately upstream of the MyoD1 coding sequence was found to be methylated in adult muscle and all nonmuscle tissues tested. The MyoD1 upstream region was unmethylated in the majority of the alveolar rhabdomyosarcomas (13 of 15, 87%) examined in this study. In contrast, 10 of 11 (91%) embryonal rhabdomyosarcomas showed a methylation pattern that was also observed in fetal muscle cells, in which the CpG sites in the MyoD1 upstream region were partially methylated. Our data suggest that the methylation status of the MyoD1 upstream CpG sites may be related to rhabdomyosarcoma tumorigenesis and may have valuable implications for its differential diagnosis. 相似文献
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In a retrospective study of 126 cases of infiltrating ductal adenocarcinoma of the breast the percentage area of sections of each neoplasm occupied by malignant cells was assessed by morphometry. The duration of postoperative survival was related to the area occupied by tumour cells within a neoplasm; the greater the tumour cell area to stroma the more prolonged the survival. This variable seemed to be independent of histological grade and was of greater prognostic importance than the diameter of the neoplasm. Furthermore, combination of percentage of tumour area with histological grade provided greater information on the survival characteristics of these patients. Extensive tumour necrosis was a particularly poor prognostic feature. 相似文献
9.
Typing for class I HLA polymorphism: past, present, and future. 总被引:2,自引:0,他引:2
P Parham 《European journal of immunogenetics》1992,19(5):347-359
10.
Nicole Schneider Charles Fisher Andrew Glennie Jennifer Urquhart John Street Marcel Dvorak Scott Paquette Raphaele Charest-Morin Tamir Ailon Neil Manson Ken Thomas Parham Rasoulinejad Raja Rampersaud Chris Bailey 《The spine journal》2021,21(5):821-828
BACKGROUND CONTEXTThe indication to perform a fusion and decompression surgery as opposed to decompression alone for lumbar degenerative spondylolisthesis (LDS) remains controversial. A variety of factors are considered when deciding on whether to fuse, including patient demographics, radiographic parameters, and symptom presentation. Likely surgeon preference has an important influence as well.PURPOSEThe aim of this study was to assess factors associated with the decision of a Canadian academic spine surgeon to perform a fusion for LDS.STUDY DESIGN/SETTINGThis study is a retrospective analysis of patients prospectively enrolled in a multicenter Canadian study that was designed to evaluate the assessment and surgical management of LDS.PATIENT SAMPLEInclusion criteria were patients with: radiographic evidence of LDS and neurogenic claudication or radicular pain, undergoing posterior decompression alone or posterior decompression and fusion, performed in one of seven, participating academic centers from 2015 to 2019.OUTCOME MEASURESPatient demographics, patient-rated outcome measures (Oswestry Disability Index [ODI], numberical rating scale back pain and leg pain, SF-12), and imaging parameters were recorded in the Canadian Spine Outcomes Research Network (CSORN) database. Surgeon factors were retrieved by survey of each participating surgeon and then linked to their specific patients within the database.METHODSUnivariate analysis was used to compare patient characteristics, imaging measures, and surgeon variables between those that had a fusion and those that had decompression alone. Multivariate backward logistic regression was used to identify the best combination of factors associated with the decision to perform a fusion.RESULTSThis study includes 241 consecutively enrolled patients receiving surgery from 11 surgeons at 7 sites. Patients that had a fusion were younger (65.3±8.3 vs. 68.6±9.7 years, p=.012), had worse ODI scores (45.9±14.7 vs. 40.2±13.5, p=.007), a smaller average disc height (6.1±2.7 vs. 8.0±7.3 mm, p=.005), were more likely to have grade II spondylolisthesis (31% vs. 14%, p=.008), facet distraction (34% vs. 60%, p=.034), and a nonlordotic disc angle (26% vs. 17%, p=.038). The rate of fusion varied by individual surgeon and practice location (p<.001, respectively). Surgeons that were fellowship trained in Canada more frequently fused than those who fellowship trained outside of Canada (76% vs. 57%, p=.027). Surgeons on salary fused more frequently than surgeons remunerated by fee-for-service (80% vs. 64%, p=.004). In the multivariate analysis the clinical factors associated with an increased odds of fusion were decreasing age, decreasing disc height, and increasing ODI score; the radiographic factors were grade II spondylolisthesis and neutral or kyphotic standing disc type; and the surgeon factors were fellowship location, renumeration type and practice region. The odds of having a fusion surgery was more than two times greater for patients with a grade II spondylolisthesis or neutral and/or kyphotic standing disc type (opposed to lordotic standing disc type). Patients whose surgeon completed their fellowship in Canada, or whose surgeon was salaried (opposed to fee-for-service), or whose surgeon practiced in western Canada had twice the odds of having fusion surgery.CONCLUSIONSThe decision to perform a fusion in addition to decompression for LDS is multifactorial. Although patient and radiographic parameters are important in the decision-making process, multiple surgeon factors are associated with the preference of a Canadian spine surgeon to perform a fusion for LDS. Future work is necessary to decrease treatment variability between surgeons and help facilitate the implementation of evidence-based decision making. 相似文献