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Zourari K, Zoros E, Kalaitzakis G, Boursianis T, Maris T, Pappas E. AN INNOVATIVE PHANTOM-BASED DOSIMETRY AUDIT METHODOLOGY FOCUSED ON INTRACRANIAL STEREOTACTIC RADIOSURGERY APPLICATIONS. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)03097-6] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Stasinou D, Platoni K, Papanikolaou N, Zoros E, Kalaitzakis G, Zourari K, Pappas E. Overall Accuracy of Single-Isocenter Multiple Metastases SRS Treatments over Time: Comparison of Two Commercially Available Methods. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.2171] [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: 10/31/2022]
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Saenz D, Bry V, Zourari K, Zoros E, Pappas E, Rasmussen K, Papanikolaou N. PO-1641: Role of surface imaging for verification of mono-isocentric multi-focal stereotactic radiosurgery. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)01659-5] [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: 10/22/2022]
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Pappas E, Kalaitzakis G, Boursianis T, Zoros E, Zourari K, Pappas EP, Makris D, Seimenis I, Efstathopoulos E, Maris TG. Dosimetric performance of the Elekta Unity MR-linac system: 2D and 3D dosimetry in anthropomorphic inhomogeneous geometry. ACTA ACUST UNITED AC 2019; 64:225009. [DOI: 10.1088/1361-6560/ab52ce] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Pappas E, Pappas E, Zourari K, Kalaitzakis G, Zoros E, Makris D, Boursianis T, Maris T. Overall Spatial Uncertainty in Single-Isocenter Multi-Focal SRS for Multiple Brain Metastases: End-to-End QA Results Related to 208 Targets. Int J Radiat Oncol Biol Phys 2019. [DOI: 10.1016/j.ijrobp.2019.06.813] [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: 11/26/2022]
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Makris DN, Pappas EP, Zoros E, Papanikolaou N, Saenz DL, Kalaitzakis G, Zourari K, Efstathopoulos E, Maris TG, Pappas E. Characterization of a novel 3D printed patient specific phantom for quality assurance in cranial stereotactic radiosurgery applications. Phys Med Biol 2019; 64:105009. [PMID: 30965289 DOI: 10.1088/1361-6560/ab1758] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In single-isocenter stereotactic radiosurgery/radiotherapy (SRS/SRT) intracranial applications, multiple targets are being treated concurrently, often involving non-coplanar arcs, small photon beams and steep dose gradients. In search for more rigorous quality assurance protocols, this work presents and evaluates a novel methodology for patient-specific pre-treatment plan verification, utilizing 3D printing technology. In a patient's planning CT scan, the external contour and bone structures were segmented and 3D-printed using high-density bone-mimicking material. The resulting head phantom was filled with water while a film dosimetry insert was incorporated. Patient and phantom CT image series were fused and inspected for anatomical coherence. HUs and corresponding densities were compared in several anatomical regions within the head. Furthermore, the level of patient-to-phantom dosimetric equivalence was evaluated both computationally and experimentally. A single-isocenter multi-focal SRS treatment plan was prepared, while dose distributions were calculated on both CT image series, using identical calculation parameters. Phantom- and patient-derived dose distributions were compared in terms of isolines, DVHs, dose-volume metrics and 3D gamma index (GI) analysis. The phantom was treated as if the real patient and film measurements were compared against the patient-derived calculated dose distribution. Visual inspection of the fused CT images suggests excellent geometric similarity between phantom and patient, also confirmed using similarity indices. HUs and densities agreed within one standard deviation except for the skin (modeled as 'bone') and sinuses (water-filled). GI comparison between the calculated distributions resulted in passing rates better than 97% (1%/1 mm). DVHs and dose-volume metrics were also in satisfying agreement. In addition to serving as a feasibility proof-of-concept, experimental absolute film dosimetry verified the computational study results. GI passing rates were above 90%. Results of this work suggest that employing the presented methodology, patient-equivalent phantoms (except for the skin and sinuses areas) can be produced, enabling literally patient-specific pre-treatment plan verification in intracranial applications.
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Affiliation(s)
- D N Makris
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens 115 27, Greece
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Askounis P, Boziari A, Carinou E, Drikos G, Economides S, Hourdakis CJ, Housiadas C, Kalathaki M, Kamenopoulou V, Karabetsos E, Kehagia K, Kolovou M, Koukorava C, Lasithiotakis M, Makridakis T, Maltezos A, Mitrakos D, Nikolaki M, Nikolaou M, Nicolaou P, Petri A, Potiriadis C, Raftopoulos S, Simantirakis G, Tafili V, Veltsos C, Vogiatzi S, Xarchoulakos DC, Zourari K. A Holistic Approach to Assessment of Population Exposure to Radiation: Challenges and Initiatives of a Regulatory Authority. Health Phys 2018; 115:474-489. [PMID: 30148813 DOI: 10.1097/hp.0000000000000912] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A regulatory authority for radiation safety should continuously evaluate and improve the national safety framework, in line with current requirements and standards. In this context, the Greek Atomic Energy Commission initiated a series of concerted actions. The radiation dose to the population due to public and medical exposures was assessed. The assessment of dose due to public exposure was based on measurements of radon concentrations in dwellings, radionuclide concentrations in environmental samples, and air dose rates; the assessment of dose due to medical exposure was based on dose measurements for typical examinations or procedures and data on their frequency. The mean effective dose to a member of the population was found to be 4.5 mSv (1.8 mSv and 2.7 mSv from medical and public exposures, respectively). Regarding occupational exposure, aircrew dose assessment, eye lens monitoring, and the national dose registry were significantly improved. With respect to artificial tanning (sun beds), the ultraviolet radiation produced was assessed and the practices followed were observed. Results demonstrated exceedance of the 0.3 W m erythema effective irradiance limit set in European Union standards by 63.5% of the sun beds measured, along with general noncompliance with standards. An overarching activity was the upgrade of the Greek Atomic Energy Commission information system in order to collect and disseminate radiation data electronically, launch a networking strategy for interaction with stakeholders, and facilitate the process of regulatory control. In response to the above findings, regulatory actions have been initiated.
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Affiliation(s)
- P Askounis
- 1Greek Atomic Energy Commission (EEAE), PO Box 60092, Agia Paraskevi, 15310 Athens, Greece
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- Greek Atomic Energy Commission (EEAE), PO Box 60092, Agia Paraskevi, 15310 Athens, Greece
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Pantelis E, Moutsatsos A, Antypas C, Zoros E, Pantelakos P, Lekas L, Romanelli P, Zourari K, Hourdakis CJ. On the total system error of a robotic radiosurgery system: phantom measurements, clinical evaluation and long-term analysis. Phys Med Biol 2018; 63:165015. [PMID: 30033940 DOI: 10.1088/1361-6560/aad516] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The total system error (TSE) of a CyberKnife® system was measured using two phantom-based methods and one patient-based method. The standard radiochromic film (RCF) end-to-end (E2E) test using an anthropomorphic head and neck phantom and isocentric treatment delivery was used with the 6Dskull, Fiducial and Xsight® spine (XST) tracking methods. More than 200 RCF-based E2E results covering the period from installation in 2006 until 2017 were analyzed with respect to tracking method, system hardware and software versions, secondary collimation system, and years since installation. An independent polymer gel E2E method was also applied, involving a 3D printed head phantom and multiple spherical target volumes widely distributed within the brain. Finally, the TSE was assessed by comparing the delineated target in the planning computed tomography images of a patient treated for a thalamic functional target with the radiation-induced lesion defined on the six-month follow-up magnetic resonance (MR) images. Statistical analysis of the RCF-based TSE results showed mean ± standard deviation values of 0.40 ± 0.18 mm, 0.40 ± 0.19 mm, and 0.55 ± 0.20 mm for the 6Dskull, Fiducial, and XST tracking methods, respectively. Polymer gel TSE values smaller than 0.66 mm were found for seven targets distributed within the brain, showing that the targeting accuracy of the system is sustained even for targets situated up to 80 mm away from the center of the skull. An average clinical TSE value of 0.87 ± 0.25 mm was also measured using the FSE T2 and FLAIR post-treatment MR image data. Analysis of the long-term RCF-based E2E tests showed no changes of TSE over time. This study is the first to report long-term (>10 years) analysis of TSE, TSE measurement for targets positioned at large distances from the virtual machine isocenter, or a clinical assessment of TSE for the CyberKnife system. All of these measurements demonstrate TSE consistently < 1 mm.
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Affiliation(s)
- E Pantelis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 11527 Athens, Greece. CyberKnife and TomoTherapy department, Iatropolis Clinic, 54-56 Ethnikis Antistaseos, 15231 Athens, Greece
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Zoros E, Pappas E, Zourari K, Pantelis E, Moutsatsos A, Kollias G, Hourdakis C, Karaiskos P. EP-1438: Experimental determination of correction factors for reference dosimetry in Gamma Knife Perfexion. Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)31873-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Pappas E, Zoros E, Zourari K, Hourdakis C, Papagiannis P, Karaiskos P, Pantelis E. PO-0774: Investigation of dose-rate dependence at an extensive range for PRESAGE radiochromic dosimeter. Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)31211-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [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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Pantelis E, Moutsatsos A, Zourari K, Kilby W, Antypas C, Papagiannis P, Karaiskos P, Georgiou E, Sakelliou L. On the implementation of a recently proposed dosimetric formalism to a robotic radiosurgery system. Med Phys 2016; 37:2369-79. [DOI: 10.1118/1.3404289] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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Zourari K, Fotina I, Pantelis E, Papagiannis P. On the dosimetric effect of heterogeneities and finite patient dimensions on 60Co HDR brachytherapy. Phys Med 2016. [DOI: 10.1016/j.ejmp.2016.07.701] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Pappas E, Karaiskos P, Zourari K, Peppa V, Papagiannis P. SU-F-BRA-11: An Experimental Commissioning Test of Brachytherapy MBDCA Dosimetry, Based On a Commercial Radiochromic Gel/optical CT System. Med Phys 2015. [DOI: 10.1118/1.4925222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Pappas E, Moutsatsos A, Zoros E, Peppa V, Zourari K, Karaiskos P, Papagiannis P. TH-AB-BRA-04: A Physical Phantom for Experimental Commissioning and Performance Testing of 192Ir MBDCAs. Med Phys 2015. [DOI: 10.1118/1.4926147] [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: 11/07/2022] Open
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Ma Y, Vijande J, Ballester F, Tedgren AC, Granero D, Haworth A, Mourtada F, Fonseca G, Zourari K, Papagiannis P, Rivard M, Siebert F, Sloboda R, Smith R, Thomson R, Verhaegen F, Beaulieu L. TH-AB-BRA-02: Generation of 3D Dosimetric Reference Datasets for Commissioning and Validation of 192Ir Brachytherapy Model-Based Dose Calculation Software. Med Phys 2015. [DOI: 10.1118/1.4926145] [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: 11/07/2022] Open
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Zourari K, Peppa V, Ballester F, Siebert FA, Papagiannis P. Brachytherapy structural shielding calculations using Monte Carlo generated, monoenergetic data. Med Phys 2014; 41:043901. [PMID: 24694161 DOI: 10.1118/1.4868456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To provide a method for calculating the transmission of any broad photon beam with a known energy spectrum in the range of 20-1090 keV, through concrete and lead, based on the superposition of corresponding monoenergetic data obtained from Monte Carlo simulation. METHODS MCNP5 was used to calculate broad photon beam transmission data through varying thickness of lead and concrete, for monoenergetic point sources of energy in the range pertinent to brachytherapy (20-1090 keV, in 10 keV intervals). The three parameter empirical model introduced by Archer et al. ["Diagnostic x-ray shielding design based on an empirical model of photon attenuation," Health Phys. 44, 507-517 (1983)] was used to describe the transmission curve for each of the 216 energy-material combinations. These three parameters, and hence the transmission curve, for any polyenergetic spectrum can then be obtained by superposition along the lines of Kharrati et al. ["Monte Carlo simulation of x-ray buildup factors of lead and its applications in shielding of diagnostic x-ray facilities," Med. Phys. 34, 1398-1404 (2007)]. A simple program, incorporating a graphical user interface, was developed to facilitate the superposition of monoenergetic data, the graphical and tabular display of broad photon beam transmission curves, and the calculation of material thickness required for a given transmission from these curves. RESULTS Polyenergetic broad photon beam transmission curves of this work, calculated from the superposition of monoenergetic data, are compared to corresponding results in the literature. A good agreement is observed with results in the literature obtained from Monte Carlo simulations for the photon spectra emitted from bare point sources of various radionuclides. Differences are observed with corresponding results in the literature for x-ray spectra at various tube potentials, mainly due to the different broad beam conditions or x-ray spectra assumed. CONCLUSIONS The data of this work allow for the accurate calculation of structural shielding thickness, taking into account the spectral variation with shield thickness, and broad beam conditions, in a realistic geometry. The simplicity of calculations also obviates the need for the use of crude transmission data estimates such as the half and tenth value layer indices. Although this study was primarily designed for brachytherapy, results might also be useful for radiology and nuclear medicine facility design, provided broad beam conditions apply.
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Affiliation(s)
- K Zourari
- Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 11527 Athens, Greece
| | - V Peppa
- Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 11527 Athens, Greece
| | - Facundo Ballester
- Department of Atomic, Molecular and Nuclear Physics, University of Valencia, Burjassot 46100, Spain
| | - Frank-André Siebert
- Clinic of Radiotherapy, University Hospital of Schleswig-Holstein, Campus Kiel 24105, Germany
| | - P Papagiannis
- Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 11527 Athens, Greece
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Zourari K, Peppa V, Herein A, Major T, Papagiannis P. A retrospective dosimetry comparison of TG43 and a commercially available MBDCA algorithm for an APBI brachytherapy patient cohort. Phys Med 2014. [DOI: 10.1016/j.ejmp.2014.07.308] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Zourari K, Pantelis E, Moutsatsos A, Sakelliou L, Georgiou E, Karaiskos P, Papagiannis P. Dosimetric accuracy of a deterministic radiation transport based (192)Ir brachytherapy treatment planning system. Part III. Comparison to Monte Carlo simulation in voxelized anatomical computational models. Med Phys 2013; 40:011712. [PMID: 23298082 DOI: 10.1118/1.4770275] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To compare TG43-based and Acuros deterministic radiation transport-based calculations of the BrachyVision treatment planning system (TPS) with corresponding Monte Carlo (MC) simulation results in heterogeneous patient geometries, in order to validate Acuros and quantify the accuracy improvement it marks relative to TG43. METHODS Dosimetric comparisons in the form of isodose lines, percentage dose difference maps, and dose volume histogram results were performed for two voxelized mathematical models resembling an esophageal and a breast brachytherapy patient, as well as an actual breast brachytherapy patient model. The mathematical models were converted to digital imaging and communications in medicine (DICOM) image series for input to the TPS. The MCNP5 v.1.40 general-purpose simulation code input files for each model were prepared using information derived from the corresponding DICOM RT exports from the TPS. RESULTS Comparisons of MC and TG43 results in all models showed significant differences, as reported previously in the literature and expected from the inability of the TG43 based algorithm to account for heterogeneities and model specific scatter conditions. A close agreement was observed between MC and Acuros results in all models except for a limited number of points that lay in the penumbra of perfectly shaped structures in the esophageal model, or at distances very close to the catheters in all models. CONCLUSIONS Acuros marks a significant dosimetry improvement relative to TG43. The assessment of the clinical significance of this accuracy improvement requires further work. Mathematical patient equivalent models and models prepared from actual patient CT series are useful complementary tools in the methodology outlined in this series of works for the benchmarking of any advanced dose calculation algorithm beyond TG43.
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Affiliation(s)
- K Zourari
- Medical School, University of Athens, Athens, Greece.
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Peppa V, Zourari K, Pantelis E, Papagiannis P. PO-0970: Tissue segmentation significance for individualized 192Ir brachytherapy dosimetry. Radiother Oncol 2013. [DOI: 10.1016/s0167-8140(15)33276-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pantelis E, Moutsatsos A, Zourari K, Petrokokkinos L, Sakelliou L, Kilby W, Antypas C, Papagiannis P, Karaiskos P, Georgiou E, Seimenis I. On the output factor measurements of the CyberKnife iris collimator small fields: Experimental determination of the kQclin,Qmsrfclin,fmsr correction factors for microchamber and diode detectors. Med Phys 2012; 39:4875-85. [DOI: 10.1118/1.4736810] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Zourari K, Pantelis E, Sakelliou L, Georgiou E, Papagiannis P. PO-337 MAPPING OF RELATIVE DOSE RATE DISTRIBUTION UNCERTAINTY OWING TO SOURCE CONSTRUCTION. Radiother Oncol 2012. [DOI: 10.1016/s0167-8140(12)72303-4] [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: 11/25/2022]
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Zourari K, Pantelis E, Moutsatsos A, Roussou E, Georgiou E, Sakelliou L, Karaiskos P, Papagiannis P. 1087 poster A VIRTUAL PHANTOM/DICOM PROTOCOL – BASED QA PROCEDURE FOR CONTEMPORARY HDR 192IR BRACHYTHERAPY TPS. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)71209-9] [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: 11/17/2022]
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Zourari K, Ballester F, Baltas D, Papagiannis P, Pérez-Calatayud J, Venselaar J. 421 poster CALCULATION OF BRACHYTHERAPY BROAD BEAM TRANSMISSION FACTORS USING MC GENERATED MONOENERGETIC DATA*. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)70543-6] [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: 11/15/2022]
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Petrokokkinos L, Zourari K, Pantelis E, Moutsatsos A, Karaiskos P, Sakelliou L, Seimenis I, Georgiou E, Papagiannis P. Dosimetric accuracy of a deterministic radiation transport based I192r brachytherapy treatment planning system. Part II: Monte Carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator. Med Phys 2011; 38:1981-92. [DOI: 10.1118/1.3567507] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Perisinakis K, Manousaki E, Zourari K, Tsetis D, Tzedakis A, Papadakis A, Karantanas A, Damilakis J. Accuracy of multislice CT angiography for the assessment of in-stent restenoses in the iliac arteries at reduced dose: a phantom study. Br J Radiol 2011; 84:244-50. [PMID: 21325364 PMCID: PMC3473874 DOI: 10.1259/bjr/63029326] [Citation(s) in RCA: 2] [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] [Received: 09/04/2009] [Revised: 01/22/2010] [Accepted: 03/10/2010] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE We investigated the potential of low-dose CT angiography for accurate assessment of in-stent restenoses (ISRs) of the iliac artery. METHOD A Rando anthropomorphic phantom (Alderson Research Labs, Stanford, CA), custom-made wax simulating hyperplastic tissue and a nitinol stent were used to simulate a patient with clinically relevant iliac artery ISRs. The cylindrical lumen was filled with a solution of iodine contrast medium diluted in saline, representing a patient's blood during CT angiography. The phantom was subjected to standard- and low-dose angiographic exposures using a modern multidetector (MD) CT scanner. The percentage of ISR was determined using the profile along a line normal to the lumen axis on reconstructed images of 2 and 5 mm slice thickness. Percentage ISRs derived using the standard- and low-dose protocols were compared. In a preliminary study, seven patients with stents were subjected to standard- and low-dose MDCT angiography during follow-up. The resulting images were assessed and compared by two experienced radiologists. RESULTS The accuracy in measuring the percentage ISR was found to be better than 12% for all simulated stenoses. The differences between percentage ISRs measured on images obtained at 120 kVp/160 mAs and 80 kVp/80 mAs were below 6%. Patient image sets acquired using low-exposure factors were judged to be of satisfactory diagnostic quality. The assessment of ISR did not differ significantly between image sets acquired using the standard factors and those acquired using the low-exposure factors, although the mean reduction in patient effective dose was 48%. CONCLUSION A reduction in exposure factors during MDCT angiography of the iliac artery is possible without affecting the accuracy in the determination of ISRs.
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Affiliation(s)
- K Perisinakis
- Department of Medical Physics, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece.
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Zourari K, Pantelis E, Moutsatsos A, Petrokokkinos L, Karaiskos P, Sakelliou L, Georgiou E, Papagiannis P. Dosimetric accuracy of a deterministic radiation transport based I192r brachytherapy treatment planning system. Part I: Single sources and bounded homogeneous geometries. Med Phys 2010; 37:649-61. [DOI: 10.1118/1.3290630] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Moutsatsos A, Petrokokkinos L, Zourari K, Papagiannis P, Karaiskos P, Dardoufas K, Damilakis J, Seimenis I, Georgiou E. Gamma Knife relative dosimetry using VIP polymer gel and EBT radiochromic films. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/164/1/012053] [Citation(s) in RCA: 4] [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: 11/11/2022]
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