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Bry V, Landers A, Kim JN, Meyer J. Robustness Analysis of Reference Surfaces for Surface Guided Radiation Therapy of the Breast. Int J Radiat Oncol Biol Phys 2023; 117:e645-e646. [PMID: 37785919 DOI: 10.1016/j.ijrobp.2023.06.2061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Surface guided radiation therapy (SGRT) implements an optical imaging system in radiation therapy for positioning and motion management. This system projects visible light onto a patient and the reflected light is used to generate 3D positional information so that clinicians can accurately reproduce body positions. Patient setup shifts are calculated with six degrees of freedom by a registration algorithm comparing a reference surface (RS) of the patient to a live surface map of the patient on treatment day. SGRT has been an effective tool in daily localization for the treatment of breast cancer patients. It is common for patients to have multiple RS throughout the course of their treatment to account for anatomical variation between fractions. We sought to evaluate the robustness of reference surfaces and vendor specific algorithms used for SGRT. MATERIALS/METHODS At our institution, positional shift data for five patients treated for right-sided breast cancer were retrospectively analyzed. SGRT performance was compared between RS using bilateral breasts or a single ipsilateral breast. Shift parameters were calculated over the entire treatment course for all patients with a vendor supplied software tool that offers rigid and deformable registration algorithms. The deformable algorithm was used for treatment setups, with the treatment RS encompassing both breasts plus a margin. Two robustness tests were carried out: 1) a trimmed down RS encompassing just the ipsilateral breast and 2) a comparison of deformable vs rigid registration of the clinically used RS. After obtaining translational and angular shift data, the absolute mean differences between shifts were calculated to compare differences between RS size and algorithm performance. RESULTS On average, 1.4 new RS were created per patient guided by weekly radiographic imaging to adjust for anatomical changes. The absolute value of the average of the discrepancies between shifts using the clinical RS subtracted from the trimmed external (89 fractions) were <1mm and 1° and the maximum differences were: Lateral: 2.6mm, Longitudinal: 1.4mm, Vertical: 1.1mm, Yaw: 1.1°, Roll: 1.5°, Pitch: 1.7°. Discrepancies between tracking algorithms (83 fractions) were <1.5mm and 1° and the maximum differences were: Lateral: 3.4mm, Longitudinal: 3.5mm, Vertical: 2.0mm, Yaw: 2.4°, Roll: 2.7°, Pitch: 1.9°. CONCLUSION Clinically negligible mean discrepancies were observed for both robustness tests showing that neither the reference surface size nor the algorithms investigated caused systematic variations in the shifts for this group of patients. Maximum discrepancies of up to 3 mm and 3° were found between the algorithms, which indicate some variation, but within clinical tolerance. Overall, different selection of reference surfaces and algorithms had a minor effect on clinical shifts for SGRT of the breast.
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Affiliation(s)
- V Bry
- University of Washington, Seattle, WA
| | - A Landers
- University of Washington, Seattle, WA
| | - J N Kim
- Department of Radiation Oncology, University of Washington, Seattle, WA
| | - J Meyer
- Department of Radiation Oncology, University of Washington - Fred Hutchinson Cancer Center, Seattle, WA
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Talcott WJ, Ford EC, Gillespie EF, Wright JL, Lincoln H, Meyer J, Kim JN, Landers A, Moran MS, Hartvigson P, Kishore M, Burmeister JW, Pawlicki T, Evans SB. A Prospective, Multi-Institutional Study of Problematic Plan Detection during Physician Chart Rounds. Int J Radiat Oncol Biol Phys 2023; 117:e445. [PMID: 37785438 DOI: 10.1016/j.ijrobp.2023.06.1625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) We performed a multi-institutional prospective study to determine the detection rate of problematic treatment plans (PP) at physician chart rounds (CR), and to identify factors associated with PP detection. MATERIALS/METHODS Curative intent PPs with simulated errors (representative of the most common targets of peer review) were generated. Two breast specialists selected twenty appropriate plans for inclusion and assigned them American Association of Physicists in Medicine (AAPM) Task Group 100 severity and detectability scores. The PPs were blinded and embedded at weekly virtual CR at 2 institutions over 12 months. At site A, both breast and lung cases were reviewed by a mix of breast and lung specialists during CR, and at site B, only breast cases were presented and reviewed by breast specialists. At both sites, breast plans were reviewed via slice-by-slice review in the treatment planning system (TPS), and both used a color-coded tool from the TPS to assess adherence to planning directives. Both sites had systematic approaches to case presentation (without a checklist). Site A was usually prospective CR, while site B was exclusively prospective. The following CR elements were recorded: PP detection, time of detection, length of CR, total number of cases presented, plan elements displayed, number and roles of attendees, and detector's role. Analysis was performed using simple statistics with chi-square testing. RESULTS By PP error type classification, 55.0% pertained to "target volume delineation," 25% to "non-target volume delineation or normal tissue sparing," and 20.0% to "dose prescription or written directives." Detectability was rated ≤5 (<5% likelihood of going undetected) for 60% of PPs, and severity was rated ≥7 ("at least potentially serious toxicity or tumor underdose") for only 30% of PPs. CR lasted a median of 64 minutes at site A (IQR 55-82.5) and 70 minutes at site B (IQR 52.5-81.5). PPs were presented at a median of 34 minutes (IQR 22.5-43, site A) and 41.5 minutes (IQR 23.5-56, site B) after CR start. A median of 16 cases (IQR 13-19) at site A and 32 cases (IQR 25-34.5) at site B were presented per CR session, with a median of 1 PP (site A and B) presented per session (range 1-2). The median time spent per case was 4.0 minutes (Site A) and 2.2 minutes (Site B). The median number of attendings at CR was 4 for site A (range 2-6) and 6.5 for Site B (range 5-10). PP detection rate at site A was 20% (n = 4) and at site B was 70% (n = 14) (p = 0.001). Detections were made by an attending physician in 100% (site A, n = 4) and 92.9% (Site B, n = 13) of PP detections. There were no differences in detection rate by PP error type (p = 0.78), detectability (p = 0.60) or severity score (p = 0.68), or by time PP presented after CR start (p = 0.39). CONCLUSION The effectiveness of PP detection at chart rounds can vary greatly between institutions. The study suggests possible areas for improvement but further study is needed to determine best practices.
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Affiliation(s)
- W J Talcott
- Zucker School of Medicine at Hofstra/Northwell, Lake Success, NY
| | - E C Ford
- Department of Radiation Oncology, University of Washington - Fred Hutchinson Cancer Center, Seattle, WA
| | - E F Gillespie
- Department of Radiation Oncology, University of Washington, Seattle, WA
| | - J L Wright
- Johns Hopkins Medicine, Department of Radiation Oncology, Baltimore, MD
| | - H Lincoln
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT
| | - J Meyer
- Department of Radiation Oncology, University of Washington - Fred Hutchinson Cancer Center, Seattle, WA
| | - J N Kim
- Department of Radiation Oncology, University of Washington, Seattle, WA
| | - A Landers
- University of Washington, Seattle, WA
| | - M S Moran
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT
| | - P Hartvigson
- University of Washington, Department of Radiation Oncology, Seattle, WA
| | - M Kishore
- Department of Radiation Medicine, Oregon Health and Science University, Portland, OR
| | | | - T Pawlicki
- University of California, San Diego, La Jolla, CA
| | - S B Evans
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT
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Landers A. Palliative medicine trainees and their mandatory oncology module. Intern Med J 2010; 40:530-3. [DOI: 10.1111/j.1445-5994.2010.02264.x] [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: 11/29/2022]
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Abstract
CASE REPORT A 25-year-old patient with fever, dysphagia, and reduced general condition was referred to our department by his dentist after 1 week of antibiotic therapy. He presented with a painful palpable mass in the right lower jaw that had developed 2 weeks before. The orthopantomogram showed a caries and periapical lesion at the right lower wisdom tooth. During extraction of the tooth and putative intra- and extraoral abscess incision, no pus could be drained and the mass persisted. CT scans then revealed lobulated soft tissue masses on both sides of the neck with the main focus on the right side. In an additional operation with excision of the mass, Castleman's disease of the hyaline vascular type was diagnosed. HISTOPATHOLOGIC FINDINGS Staging could not detect further pathological findings and the patient's postoperative general condition improved continuously. The histological features of the hayline vascular type of Castleman's disease were characterized by multiple germinal centers surrounded by circumferentially arranged layers of small lymphocytes interconnected by a prominent vascular stroma with occasional plasma cells ("onion skin"). CONCLUSION Castleman's disease is a rare and yet poorly understood disease, characterized by inhomogeneous growth of lymphoid tissue. Mostly benign it remains a diagnostic challenge before histological investigation. In unclear submandibular swellings and neck lumps assumed to be an abscess, this rare differential diagnosis must be considered. Facing recurrence and potential for malignancy, follow-up of the patients over several years is necessary.
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Affiliation(s)
- F Hölzle
- Klinik für Mund-, Kiefer- und Plastische Gesichtschirurgie der Ruhr-Universität Bochum, Knappschaftskrankenhaus Bochum-Langendreer, 44892 Bochum.
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Schmidt-Böcking H, Schmidt L, Weber T, Mergel V, Jagutzki O, Czasch A, Hagmann S, Doerner R, Demkov Y, Jahnke T, Prior M, Cocke C, Osipov T, Landers A. Dynamics of multiple ionization of atoms and molecules by electron, photon, and ion impact—investigated by the COLTRIMS imaging method. Radiat Phys Chem Oxf Engl 1993 2004. [DOI: 10.1016/j.radphyschem.2004.04.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Weber T, Czasch AO, Jagutzki O, Müller AK, Mergel V, Kheifets A, Rotenberg E, Meigs G, Prior MH, Daveau S, Landers A, Cocke CL, Osipov T, Díez Muiño R, Schmidt-Böcking H, Dörner R. Complete photo-fragmentation of the deuterium molecule. Nature 2004; 431:437-40. [PMID: 15386008 DOI: 10.1038/nature02839] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Accepted: 07/13/2004] [Indexed: 11/09/2022]
Abstract
All properties of molecules--from binding and excitation energies to their geometry--are determined by the highly correlated initial-state wavefunction of the electrons and nuclei. Details of these correlations can be revealed by studying the break-up of these systems into their constituents. The fragmentation might be initiated by the absorption of a single photon, by collision with a charged particle or by exposure to a strong laser pulse: if the interaction causing the excitation is sufficiently understood, the fragmentation process can then be used as a tool to investigate the bound initial state. The interaction and resulting fragment motions therefore pose formidable challenges to quantum theory. Here we report the coincident measurement of the momenta of both nuclei and both electrons from the single-photon-induced fragmentation of the deuterium molecule. The results reveal that the correlated motion of the electrons is strongly dependent on the inter-nuclear separation in the molecular ground state at the instant of photon absorption.
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Affiliation(s)
- T Weber
- Institut für Kernphysik, Universität Frankfurt, D 60486 Frankfurt, Germany
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Osipov T, Cocke CL, Prior MH, Landers A, Weber T, Jagutzki O, Schmidt L, Schmidt-Böcking H, Dörner R. Photoelectron-photoion momentum spectroscopy as a clock for chemical rearrangements: isomerization of the di-cation of acetylene to the vinylidene configuration. Phys Rev Lett 2003; 90:233002. [PMID: 12857254 DOI: 10.1103/physrevlett.90.233002] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2002] [Indexed: 05/24/2023]
Abstract
We have used complete correlated momentum mapping of the photoelectron and heavy ion products from the dissociation of the di-cation of acetylene, induced by photoionizing the carbon K shell of one of the atoms, to map out the angular correlation between the electron and the axis of the target molecule. The (quasi-) symmetric decay is found to proceed through both acetylene and vinylidene configurations. By using the strongly peaked photoelectron emission to "start a clock," an upper limit of 60 fs is placed on the isomerization time from the acetylene to the vinylidene configuration.
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Affiliation(s)
- T Osipov
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS 66506, USA
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Nathoo N, Govender ST, Govender PV, Landers A, Dasi N, Corr P. Neuroendoscopy--report of initial experience. S Afr Med J 2001; 91:1046-7. [PMID: 11845601] [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: 02/23/2023] Open
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Landers A, Weber T, Ali I, Cassimi A, Hattass M, Jagutzki O, Nauert A, Osipov T, Staudte A, Prior MH, Schmidt-Böcking H, Cocke CL, Dörner R. Photoelectron diffraction mapping: molecules illuminated from within. Phys Rev Lett 2001; 87:013002. [PMID: 11461463 DOI: 10.1103/physrevlett.87.013002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2001] [Indexed: 05/23/2023]
Abstract
We demonstrate the use of a multiparticle coincidence technique to image the diffraction of an electron wave whose source is placed at a specific site in a free molecule. Core-level photoelectrons are used to illuminate the molecule from within. By measuring the vector momenta of two molecular fragments and the photoelectron, a richly structured electron diffraction pattern is obtained in a body-fixed frame of the randomly oriented molecule in the gas phase. We illustrate this technique for CO, creating a photoelectron from the C(1s) shell and scanning its energy from zero to 30 eV.
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Affiliation(s)
- A Landers
- Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008, USA.
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Affiliation(s)
- B Yung
- Department of Cystic Fibrosis, Royal Brompton Hospital, London, U.K
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Landers A, Murdoch IE, Birch J, Cousens SN, Babalola OE, Lawal B, Abiose A, Jones BR. Blue-yellow colour vision in an onchocercal area of northern Nigeria. Br J Ophthalmol 1998; 82:510-6. [PMID: 9713057 PMCID: PMC1722603 DOI: 10.1136/bjo.82.5.510] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIM To determine if the City University Tritan Test is a useful addition to visual function assessment in rural communities in northern Nigeria. METHODS The study was a cross sectional survey. The participants were 8394 people, aged 5 years and over, living in 37 rural communities, mesoendemic and nonendemic for onchocerciasis, in Kaduna State in northern Nigeria. The main outcome measures were the detection of a defect in blue-yellow colour vision by two criteria: (1) failure with the City University tritan screening plates; (2) failure with the City University grading plates to identify severe tritan defects. RESULTS 91% of those aged 10 years and above could perform the test. Below this age, there were difficulties in comprehension. The test showed good inter- and intraobserver agreement. After adjustment for confounders the odds of failing the screening plates were significantly increased in the presence of optic atrophy or glaucoma (3.55 (2.48-5.08) and 15.9 (4.22-60.2) respectively). There was a greater increase in the adjusted odds of failing the grading plates in the presence of optic atrophy or glaucoma (5.30 (2.97-9.45) and 8.87 (1.61-48.7) respectively). Cataract had a smaller effect on the screening plates, adjusted odds 1.63 (0.95-2.80). CONCLUSION Blue-yellow colour vision testing is a useful addition to visual function assessment in those aged 10 years and above in rural northern Nigeria, particularly in the detection of optic nerve disease.
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Affiliation(s)
- A Landers
- Kaduna-London Collaboration for Research on Onchocerciasis, Institute of Ophthalmology, London
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Davis P, Landers A, Gentry B, Montague J, Dancer J, Jackson J, Williams L. Speech and language characteristics of children with strokes due to sickle cell disease. Percept Mot Skills 1997; 85:809-10. [PMID: 9399283 DOI: 10.2466/pms.1997.85.3.809] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The receptive and expressive language skills of 10 children with strokes due to sickle cell disease were significantly poorer than those of their matched controls. The children with strokes had greatest difficulty in following oral directions and formulating sentences.
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Affiliation(s)
- P Davis
- University of Arkansas at Little Rock 72204, USA.
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Landers A, Belfer KF, Jenkins AD. Superglue lids: possibly non-accidental and a medico-legal problem. Eye (Lond) 1996; 10 ( Pt 3):402-3. [PMID: 8796172 DOI: 10.1038/eye.1996.83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Landers A, Billington B, Tapley J. Low vision. Br J Ophthalmol 1996; 80:380-1. [PMID: 8703898 PMCID: PMC505473 DOI: 10.1136/bjo.80.4.380-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Landers A. A DOG WHO CHANGED MY PRACTICE, FOR A WHILE. West J Med 1996. [DOI: 10.1136/bmj.312.7033.747] [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: 11/03/2022]
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Landers A. Ophthalmic services for children. Br J Ophthalmol 1995; 79:964. [PMID: 7488589 PMCID: PMC505302 DOI: 10.1136/bjo.79.10.964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Abstract
A new mechanical localizer for retinal detachment surgery has two modes of action. The localizer is positioned under visualization in the undepressed state to avoid engaging or marking sclera until the surgeon elects to depress the marking pick after optimum localization.
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