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Stalbaum T, Partain L, Weil MD, Kim J, Han JY, Plies MJ, Chen H, Ziskin V, Bazalova-Carter M, Song S, Rand R, Boyd D. Dosimetry of a novel converging X-ray source for kilovoltage radiotherapy. Med Phys 2021; 48:5947-5958. [PMID: 34390498 DOI: 10.1002/mp.15167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 07/26/2021] [Accepted: 08/04/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The objective of this work was to evaluate phantom dosimetry of a novel kilovoltage (kV) X-ray source, which employs a stationary tungsten anode and a linearly swept scanning electron beam. The source utilizes converging X-ray collimation along with orthogonal mechanical rotation to distribute surface flux over large area. In this study, this was investigated as a potential solution to fast-falloff limitations expected with kV radiotherapy. This was done with the aim of future clinical development of a lower cost radiotherapy alternative to megavoltage (MV) linac systems. METHODS Radiochromic film was employed for dosimetry on the kV X-ray source of the linear-converging radiotherapy system (LCRS). The source utilizes charge particle optics to magnetically deflect and focus an electron beam along a stationary, reflection tungsten target in an ultra-high-vacuum stainless-steel chamber. Resulting X-rays were collimated into converging beamlets that span a large planar angle and converge at the system isocenter. In this study, radiochromic film dosimetry was done at 140 and 145 kVp for a designated planning treatment volume (PTV) of 4 cm diameter. An acrylic phantom was employed for dose distribution measurements of stationary and rotational delivery. Film dosimetry was evaluated in planes parallel to the source X-ray window at various depths, as well as in the plane of gantry rotation. RESULTS At 140 and 145 kVp and using a collimated 4 cm square field at depth, lesion-to-skin dose ratio was shown to improve with additional beams from different relative source positions, where the different beams are focused at the same isocenter and do not overlap at the phantom surface. It was only possible to achieve a 1:1 Dmax -to-surface ratio with four delivery beams, but the ratio improved to 4:1 with 12 beams, focused at the same isocenter depth of 7.8 cm in an acrylic phantom. For the tests conducted, the following Dmax -to-surface ratios were obtained: 0.4:1 lesion-to-skin ratio for stationary delivery from one entry beam, 0.71:1 lesion-to-skin ratio was obtained for two beams, 1.07:1 ratio for four beams, and 4:1 for 12 beams. Dose-depth profiles were evaluated for stationary and rotational dosimetry. Additionally, rotational dosimetry was measured for a case more analogous to a clinical scenario, where the isocenter was located at an off-center simulated lesion. CONCLUSIONS The results demonstrate potential dose-depth improvements with kV arc therapy by distributing the surface flux with a wide converging beam along with perpendicular mechanical source rotation of the LCRS. The system delivered tolerable dose to a large surface area when a threshold of multiple, separated beams was reached. The radiochromic film data support the feasibility of the construct of the LCRS kV radiotherapy system design.
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Affiliation(s)
- Tyler Stalbaum
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | - Larry Partain
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | - Michael D Weil
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | - Joon Kim
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | - Jae Y Han
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | | | - Hong Chen
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | - Vitaliy Ziskin
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | | | - Samuel Song
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | - Roy Rand
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
| | - Douglas Boyd
- Imatrex Inc. and Precision RT Inc., Las Vegas, Nevada, USA
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Vining E, Duckwiler G, Udkoff R, Rand R, Lufkin R. Magnetic Resonance Imaging of the Thalamus following Cryothalamotomy for Parkinson's Disease and Dystonia. J Neuroimaging 2016. [DOI: 10.1111/jon199113146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Dercole F, Niklas K, Rand R. Self-thinning and community persistence in a simple size-structured dynamical model of plant growth. J Math Biol 2005; 51:333-54. [PMID: 15868195 DOI: 10.1007/s00285-005-0322-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 02/02/2005] [Indexed: 10/25/2022]
Abstract
This paper presents a size-structured dynamical model of plant growth. The model takes the form of a partial differential-integral equation and includes the effects of self- shading by leaves. Closed form solutions are presented for the equilibrium size density distribution. Analytic conditions are derived for community persistence, and the self-thinning exponent is obtained as a function of species characteristics and environmental conditions.
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Affiliation(s)
- F Dercole
- Department of Electronics and Information, Politecnico di Milano, Milano, Italy.
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Allen F, Almasi G, Andreoni W, Beece D, Berne BJ, Bright A, Brunheroto J, Cascaval C, Castanos J, Coteus P, Crumley P, Curioni A, Denneau M, Donath W, Eleftheriou M, Flitch B, Fleischer B, Georgiou CJ, Germain R, Giampapa M, Gresh D, Gupta M, Haring R, Ho H, Hochschild P, Hummel S, Jonas T, Lieber D, Martyna G, Maturu K, Moreira J, Newns D, Newton M, Philhower R, Picunko T, Pitera J, Pitman M, Rand R, Royyuru A, Salapura V, Sanomiya A, Shah R, Sham Y, Singh S, Snir M, Suits F, Swetz R, Swope WC, Vishnumurthy N, Ward TJC, Warren H, Zhou R. Blue Gene: A vision for protein science using a petaflop supercomputer. ACTA ACUST UNITED AC 2001. [DOI: 10.1147/sj.402.0310] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Chi DD, Merchant RE, Rand R, Conrad AJ, Garrison D, Turner R, Morton DL, Hoon DS. Molecular detection of tumor-associated antigens shared by human cutaneous melanomas and gliomas. Am J Pathol 1997; 150:2143-52. [PMID: 9176405 PMCID: PMC1858329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Both melanocytes and glial cells are derived embryologically from the neural ectoderm. Their malignant transformed counterparts, melanoma and glioma cells, respectively, may share common antigens. Numerous tumor-associated antigens have been identified in melanomas but only a few a gliomas. Using an established reverse transcriptase polymerase chain reaction plus Southern blot assay, we compared the mRNA expression of melanoma-associated antigens (MAAs) of melanomas to brain tumors primarily derived from glial cells. The MAAs studied included tyrosinase (Tyr), tyrosinase-related protein-1 and -2 (TRP-1 and TRP-2), gp100, human melanoma antigen-encoding genes 1 and 3 (MAGE-1 and MAGE-3), and melanotransferrin (p97). Glioblastoma multiforme (n = 21), anaplastic astrocytoma (n = 3), ependymoma (n = 2), meningioma (n = 3), oligodendroglioma (n = 1), and melanoma (n = 12) tumor specimens were assayed for MAA mRNA expression. Glioblastoma multiforme, astrocytoma, and melanoma cell lines were also assayed. We observed that individual MAA mRNAs were expressed in these brain tumors and cell lines at varying frequencies. The melanogenesis-pathway-related MAAs Tyr, TRP-1, TRP-2, and gp100 mRNAs were also expressed at different levels in normal brain tissues but at a much lower frequency than in glioblastoma multiforme and melanoma. MAGE-1 and MAGE-3 mRNA were expressed in different types of tumor specimens and cell lines but never in normal brain tissue. Tumor antigen p97 was expressed in all types of tumors and also in normal brain tissues. These studies demonstrate that melanomas and primary brain tumors express common MAAs and could be exploited in patients with malignant glioma by active specific immunotherapy against these common MAAs.
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Affiliation(s)
- D D Chi
- National Genetics Institute, Los Angeles, California, USA
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Rand R. Comments on Proficiency Testing. Clin Chem 1992. [DOI: 10.1093/clinchem/38.10.2153a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Rand R. Comments on proficiency testing. Clin Chem 1992; 38:2153. [PMID: 1395014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Abstract
The magnetic resonance (MR) appearance of hemorrhagic acoustic neuromas has not previously been reported. Four patients with surgically proven acoustic neuromas containing spontaneous hemorrhage were preoperatively evaluated with MR imaging. All patients presented with new onset of symptoms and three had subarachnoid hemorrhage. Signal changes on T1- and T2-weighted spin echo sequences were characteristic for acute, subacute and chronic intraparenchymal hemorrhage. Recognition of hemorrhagic changes on MR is important since more rapid surgical intervention is required in this patient subgroup.
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Affiliation(s)
- E Spickler
- Department of Radiological Sciences, UCLA School of Medicine 90024
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Laub D, Horan RF, Yaffe H, Rand R, Baden HP. A child with hair loss. Pili torti, apparently unassociated with other abnormalities. Arch Dermatol 1987; 123:1071, 1074. [PMID: 3631987 DOI: 10.1001/archderm.123.8.1071a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstract
Eleven biopsy specimens (five papules and six dusky or crusted lesions) from four patients with pityriasis lichenoides et varioliformis acuta ( PLEVA ) were studied by direct immunofluorescence and immunoperoxidase technics. Slight vascular deposits of IgM and C3 were present in most lesions. Slight perivascular deposits of fibrin were observed in early lesions; more extensive perivascular and interstitial deposits of fibrin were detected in advanced lesions. Most of the infiltrating cells were T lymphocytes; cells with cytotoxic/suppressor phenotype (T8-positive) were generally more numerous than cells with helper/inducer phenotype (Leu-3a-positive, T4-positive). A marked increase in epidermal T8-positive cells over epidermal Leu-3a/T4-positive cells was found in late lesions. Moreover, a reduction of the ratio of circulating T4-positive to T8-positive cells was observed in most cases. The number of epidermal T6-positive (Langerhans/indeterminate) cells was decreased in the lower as compared with the upper stratum spinosum. About 5% of perivascular infiltrating cells were T6-positive. These results suggest that cell-mediated immune mechanisms are probably important in the pathogenesis of PLEVA .
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Rand R, Sober AJ, Olmstead PM. Ketoconazole therapy and exfoliative erythroderma. Arch Dermatol 1983; 119:97-8. [PMID: 6297411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Rand R, Baden HP. Commentary: Darier-White disease. Arch Dermatol 1983; 119:81-3. [PMID: 6849569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Abstract
We report herein two cases of keratosis follicularis spinulosa decalvans (KFSD) and review the literature on this condition. The entity is one of a group of related disorders that shows keratosis pilaris with inflammation followed by atrophy. The clinical features and course of KFSD are characteristic. During infancy, keratosis pilaris begins on the face and, by childhood, progresses to involve the trunk and extremities. Sometime during childhood or up to the early teenage years, a cicatricial alopecia of the scalp and eyebrows develops and is the hallmark of this disorder. Hyperkeratosis of the palms and soles is a frequently associated finding and is usually manifested during adolescence. Other features occurring with this syndrome include atopy, photophobia, and corneal abnormalities. Sex-linked inheritance has been proposed by several authors.
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Kubilus J, Rand R, Baden HP. Effects of retinoic acid and other retinoids on the growth and differentiation of 3T3 supported human keratinocytes. In Vitro 1981; 17:786-95. [PMID: 6170570 DOI: 10.1007/bf02618445] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Using mitomycin C treated 3T3-Swiss fibroblasts as feeder cells, human keratinocytes derived from infant foreskins were subcultured in the presence of trans-retinoic acid (RA) and other retinoids. At 1 microgram/ml (3 x 10(-6) M) and higher RA concentrations plating efficiency was markedly reduced. Addition of retinoids to 1 microgram/ml after colonies were established produced no change in the rate of cell production, but caused differentiated cells to be sloughed earlier than in control cultures. Electron microscopy showed wider extra cellular spaces the contained numerous villi, increased numbers of microvilli at the surfaces of the outermost cells, and decreased number of cell layers all of which were consistent with the observed desquamatory effects of RA. Retinoic acid also extended the time during which cell population increased so that RA treated cultures produced more cells than control cultures over their respective lifetimes. Keratin polypeptides represented a smaller percentage of the total solubilizable protein and more keratin was present as acid soluble prekeratin in postconfluent RA treated cultures. This may be a consequence of early desquamation rather than a decrease in keratin synthesis. No unusual proteins were visible in RA treated cultures by simple sodium dodecylsulfate electrophoresis, nor was there increase in specific activities of three lysosomal enzymes.
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Mirra JM, Rand F, Rand R, Calcaterra T, Dawson E. Giant-cell tumor of the second cervical vertebra treated by cryosurgery and irradiation. Clin Orthop Relat Res 1981:228-33. [PMID: 7471562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A 17-year-old female presented with a large, destructive, giant-cell tumor of the second cervical vertebra. The lesion was obviously life-threatening. Owing to its proximity to the spinal cord and the danger of a pathologic fracture with cord transection and because of the effectiveness of cryosurgical methods in treating giant cell tumors of long bones, we decided to attempt local freezing of the lesion using a cryoprobe via a transoral approach. To further ensure tumor destruction, we followed cryosurgery with a course of radiotherapy (4600 rads). At this writing, 30 months later, healing has been excellent with no signs of recurrence, pain, tenderness or neurologic problems. To the best of our knowledge, this represents the first time a vertebral body bone tumor has been treated by cryosurgery.
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Jacques S, Shelden CH, McCann GD, Freshwater DB, Rand R. Computerized three-dimensional stereotaxic removal of small central nervous system lesions in patients. J Neurosurg 1980; 53:816-20. [PMID: 7003069 DOI: 10.3171/jns.1980.53.6.0816] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The authors describe the results of their recently reported computer-based stereotaxic surgical technique for the indentification, enhancement, three-dimensional reconstruction, localization, and removal of small central nervous system lesions. This technique has been applied to patients with various types of central nervous system pathology, and representative cases are reported.
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Rand R, Jenkins D. Serum seromucoid preinvasive and invasive cancer of the uterine cervix. Eur J Obstet Gynecol Reprod Biol 1978. [DOI: 10.1016/0028-2243(78)90072-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Abstract
Unexpected complications may follow therapeutic embolization, even though no apparent technical errors have occurred. This report includes four cases of facial palsy following middle meningeal artery embolization, one case of aspiration pneumonia following glomus tumor embolization, and a case of pulmonary embolization following embolization of a spinal arteriovenous malformation.
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Rains MD, Chaconas SJ, Caputo AA, Rand R. Stress analysis of plastic bracket configurations. J Clin Orthod 1977; 11:120-5. [PMID: 273605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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