26
|
Wu JZ, Hsieh PY, McGuire AV, Schmidt DL, Wood LT, Shen Y, Chu WK. Anisotropic properties of the high-quality epitaxial YBa2Cu3O7- delta (110) thin film. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:12643-12646. [PMID: 9999439 DOI: 10.1103/physrevb.44.12643] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
27
|
Kumar PP, Patil AA, Leibrock LG, Chu WK, Syh J, McCaul GF, Reeves MA. Brachytherapy: a viable alternative in the management of basal meningiomas. Neurosurgery 1991; 29:676-80. [PMID: 1961396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Thirteen patients with intracranial meningiomas of the skull base were treated with one or more high-activity iodine-125 seeds. In 11 patients, the seeds were implanted stereotactically under local anesthesia. A minimum dose of 100 to 500 Gy was delivered to the tumor at a dose rate of 5 to 25 cGy/h. Indications for this procedure included recurrence after initial surgery or as the primary modality of treatment in patients who were not candidates for surgery. All 13 patients are alive at a median follow-up of 15 months. Nine of 11 patients (82%) without calcification in their meningiomas achieved complete response. The remaining 4 patients-2 with calcification and 2 without--achieved partial response. No early or late complications were observed. We conclude from our experience that both recurrent and primary meningiomas of the skull base can be treated effectively with permanent iodine-125 brachytherapy.
Collapse
|
28
|
Wu JZ, Ting CS, Chu WK, Yao XX. Proximity effect on the superconducting transition temperature of YBa2Cu3O7-x/PrBa2Cu3O7-x superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:411-414. [PMID: 9998264 DOI: 10.1103/physrevb.44.411] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
29
|
Chu WK, Allen WR, Picraux ST, Ellison JA. Planar channeling in superlattices. III. Potential and parameter dependence of catastrophic dechanneling. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:5923-5935. [PMID: 9994666 DOI: 10.1103/physrevb.42.5923] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
30
|
McConnell JR, Fleming WH, Chu WK, Hahn FJ, Sarafian LB, Hofschire PJ, Kugler JD. Magnetic resonance imaging of the brain in infants and children before and after cardiac surgery. A prospective study. AMERICAN JOURNAL OF DISEASES OF CHILDREN (1960) 1990; 144:374-8. [PMID: 2305749 DOI: 10.1001/archpedi.1990.02150270124041] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We assessed the morphologic findings of the brain prospectively before and after cardiac surgery using magnetic resonance imaging. There were 12 patients with acyanotic and 6 with cyanotic heart disease. There were 2 deaths, and 1 patient did not have to undergo postoperative magnetic resonance imaging. The study group consisted of 15 patients completing both the preoperative and postoperative magnetic resonance imagings. All patients in the study group underwent moderate hypothermic cardiopulmonary bypass using a nonpulsatile membrane oxygenator. The mean (+/- SD) cardiopulmonary bypass time was 100 +/- 55 minutes. Ten of the preoperative studies were interpreted as normal. One third (5 of 15) of the patients showed ventriculomegaly and dilatation of the subarachnoid spaces on preoperative magnetic resonance images. Measurements of the preoperative and postoperative magnetic resonance images showed a postoperative increase in the bicaudate and third ventricular diameters. Four patients in the study group developed postoperative subdural hematomas. The subdural hematomas were small and caused no demonstrable mass effect on magnetic resonance imaging. One patient had a preoperative white matter infarction. There was 1 patient with a postoperative infarction.
Collapse
|
31
|
Kaplan PA, Lieberman RP, Chu WK. Comparison of omnipaque with hypaque in temporomandibular arthrography. AJR Am J Roentgenol 1989; 153:1225-7. [PMID: 2816636 DOI: 10.2214/ajr.153.6.1225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Decreasing or alleviating pain experienced by some patients during or after temporomandibular arthrography would make this relatively inexpensive and highly accurate technique more attractive. This is particularly true for those patients without access to MR or those whose referring physicians prefer arthrography to other techniques for diagnosing internal derangements. Ionic and nonionic contrast agents were compared in a randomized, double-blind trial to determine if pain could be decreased by using a nonionic contrast material. Forty patients received either Omnipaque 300 (nonionic, iohexol) or Hypaque 60 (ionic, diatrizoate meglumine). Radiographs were assessed for diagnostic quality, and patients were asked to note their level of discomfort. No significant differences between the agents were detected. Maximal discomfort was noted at 24 hr. Discomfort was classified as none, mild, or moderate, with no patients describing marked discomfort. This study does not support the use of nonionic contrast agents over the less expensive ionic agents for decreasing pain or improving film quality in temporomandibular joint arthrography.
Collapse
|
32
|
Taylor TK, Chu WK, Teten S. Tracking radiation for quality's sake. ADMINISTRATIVE RADIOLOGY : AR 1989; 8:115-7. [PMID: 10296509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
|
33
|
Allen WR, Chu WK, Picraux ST, Biefeld RM, Ellison JA. Planar channeling in superlattices: Resonance channeling. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:3954-3958. [PMID: 9948729 DOI: 10.1103/physrevb.39.3954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
34
|
Picraux ST, Biefeld RM, Allen WR, Chu WK, Ellison JA. Planar channeling in superlattices. II. Catastrophic dechanneling. PHYSICAL REVIEW. B, CONDENSED MATTER 1988; 38:11086-11097. [PMID: 9945981 DOI: 10.1103/physrevb.38.11086] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
35
|
Hahn FJ, Chu WK, Coleman PE, Anderson JC, Dobry CA, Imray TJ, Hahn PY, Lee SH. Artifacts and diagnostic pitfalls on magnetic resonance imaging: a clinical review. Radiol Clin North Am 1988; 26:717-35. [PMID: 3380943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
High field MRI of the brain occasionally exhibits imaging artifacts; most artifacts are obvious and easily recognized, but some are subtle and mimic disease. A thorough understanding of brain MRI artifacts is important to avoid potential diagnostic pitfalls. Some imaging techniques or procedures could be utilized to remove or identify artifacts. These include additional projections, different pulse sequence, and 90 degree shift of phase-encoding gradient. The use of respiratory gating or cardiac gating may also improve image quality by reducing some of the motion-related artifacts.
Collapse
|
36
|
Ellison JA, Picraux ST, Allen WR, Chu WK. Planar channeling in superlattices: Theory. PHYSICAL REVIEW. B, CONDENSED MATTER 1988; 37:7290-7305. [PMID: 9944017 DOI: 10.1103/physrevb.37.7290] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
37
|
Taylor TK, Chu WK. Microcomputers in radiation oncology. ADMINISTRATIVE RADIOLOGY : AR 1987; 6:22-5. [PMID: 10284779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
|
38
|
Temme JB, Chu WK, Anderson JC. CT scanograms compared with conventional orthoroentgenograms in long bone measurement. Radiol Technol 1987; 59:65-8. [PMID: 3659341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In this article the standard orthoroentgenograph is compared with computed tomography (CT) scanography in determining bone length discrepancies. Dried femur bones are studied by both methods. The CT scanogram method is found to be more accurate than the orthoroentgenography method.
Collapse
|
39
|
Huurman WW, Jacobsen FS, Anderson JC, Chu WK. Limb-length discrepancy measured with computerized axial tomographic equipment. J Bone Joint Surg Am 1987; 69:699-705. [PMID: 3597470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A simple, rapid, and accurate method for measuring limb-length discrepancies with computerized axial tomographic equipment is described. With this method less irradiation is delivered and some of the errors of computation are eliminated, compared with conventional methods. The costs of the technique are comparable with those of scanograms. The method is particularly applicable in the patient who has contracture of a joint.
Collapse
|
40
|
Huurman WW, Jacobsen FS, Anderson JC, Chu WK. Limb-length discrepancy measured with computerized axial tomographic equipment. J Bone Joint Surg Am 1987. [DOI: 10.2106/00004623-198769050-00010] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
|
41
|
Chu WK, Sangster W. Potential impacts of MRI accidents. Radiol Technol 1986; 58:139-41. [PMID: 3786695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A minor accident occurred in our Magnetic Resonance imaging suite. It is minor, because no personal injury nor equipment damage resulted from it. However, this incident has prompted us to review and re-emphasize our safety precautions and to investigate means of insurance coverage for any potential effects that could result from such incidents.
Collapse
|
42
|
Kumar PP, Good RR, Skultety FM, Jones EO, Chu WK. Retreatment of recurrent cystic craniopharyngioma with chromic phosphorus P 32. J Natl Med Assoc 1986; 78:542-3, 547-9. [PMID: 3735454 PMCID: PMC2571306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A cystic craniopharyngioma in a two-year-old boy recurred six months after surgery and postoperative external-beam radiotherapy. Successful retreatment was accomplished with radioisotope injection of 0.5 mCi of chromic phosphorus P 32 into the intracranial cyst, which delivered approximately 300.00 Gy to the cyst wall. The patient's symptoms were relieved, and he is without evidence of disease or cystic fluid accumulation four years after intracavitary (32)P irradiation.
Collapse
|
43
|
Kumar PP, Good RR, Hodgson PE, Edney JA, Jones EO, Chu WK, McAnulty BE, Dunlap B, Rogers SS, McCaul GF. Intraoperative electron-beam facility at the University of Nebraska Medical Center. THE NEBRASKA MEDICAL JOURNAL 1986; 71:191-8. [PMID: 3724916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
44
|
Picraux ST, Allen WR, Biefeld RM, Ellison JA, Chu WK. Incident-angle dependence of catastrophic dechanneling for strained-layer superlattices. PHYSICAL REVIEW LETTERS 1985; 54:2355-2358. [PMID: 10031319 DOI: 10.1103/physrevlett.54.2355] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
45
|
Pan CK, Zheng DC, Finstad TG, Chu WK, Speriosu VS, Nicolet MA, Barrett JH. Structural study of GaSb/AlSb strained-layer superlattice. PHYSICAL REVIEW. B, CONDENSED MATTER 1985; 31:1270-1277. [PMID: 9935901 DOI: 10.1103/physrevb.31.1270] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
46
|
Hahn FJ, Chu WK, Cheung JY. CT measurements of cranial growth: alternative measurement method. AJNR Am J Neuroradiol 1985; 6:537-8. [PMID: 3927669 PMCID: PMC8335186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
47
|
Abstract
Newer CT scans have greatly enhanced oculometric research and made it possible to measure ocular dimensions. With these measurements, ocular volume can be more accurately estimated to understand its relationship with age and sex. One hundred CT orbit scans with presumed normal eyes were used for the data base. The mean values and normal variations of ocular volumes at various ages in both sexes are presented. Rapid growth of the eyeball was noted during the first 24 months of age. It reached its peak between the ages of 18 and 30 years of age, after which there was a reduction. Results may be of help in recognizing eye abnormalities such as microophthalmus and macrophthalmia.
Collapse
|
48
|
Chu WK, Dobry CA, Imasy TJ, Taylor TK. Comprehensive radiological equipment management program. JOURNAL OF CLINICAL ENGINEERING 1984; 9:281-9. [PMID: 10269779 DOI: 10.1097/00004669-198410000-00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The increasing cost and complexity of state-of-the-art radiological equipment, and the need for more comprehensive safety and performance assurance, have increased maintenance expenditures to a level where they have become one of the largest operating expenses of radiology departments. To cope with this ever increasing expenditure, a comprehensive in-house maintenance program was implemented in our institution. This program properly balanced the capability of the radiology department's in-house technical personnel with support provided by equipment manufacturers' service organizations. Quality assurance activities are also included as an integral part of the entire program. Since the implementation of the program, an average 40% reduction in the annual maintenance expenditure has been observed.
Collapse
|
49
|
Abstract
Growth patterns of the cranium measured directly as head circumference have been well documented. With the availability of computed tomography (CT), cranial dimensions can be obtained easily. The objective of this project was to establish the mean values and their normal variance of CT cranial area of subjects at different ages. Cranial areas and its long and short axes were measured on CT scans for 215 neurologic patients of a wide age range who presented no evidence of abnormal growth of head size. Growth patterns of the cranial area as well as the numeric product of its linear dimensions were determined via a curve fitting process. The patterns resemble that of the head circumference growth chart, with the most rapid growth observed in the first 12 months of age and reaching full size during adolescence. It is believed that the availability of such reference, in addition to the head circumference measurement, will be valuable to the CT reviewer in determining the growth status of head size.
Collapse
|
50
|
Hahn FJ, Chu WK, Torkelson RD. CT measurements of cranial growth: microcephaly. AJR Am J Roentgenol 1984; 142:1257-8. [PMID: 6609617 DOI: 10.2214/ajr.142.6.1257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Computed tomographic (CT) head scans were measured to determine the cranial dimensions of four children with microcephaly. These measurements were compared with cranial dimensions of normal children. CT proved to be useful in determining the developmental status of children with neurologic problems relative to their normal counterparts on the basis of cranial dimensions.
Collapse
|