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Title: Characterization of unconventional electron fields for the treatment of mycosis fungoides using the total skin irradiation technique

Abstract

Mycosis fungoides is a cutaneous lymphoma that accounts for 2–3% of all lymphomas. Several clinical studies have demonstrated the effectiveness of TSEBT (Total Skin Electron Beam Therapy) in patients with mycosis fungoides. It is important to develop this technique and make it available to a larger number of patients in Mexico. Because large fields for electron TSEBT are required in order to cover the entire body of the patient, beam characterization at conventional treatment distances is not sufficient and a calibration distance of 500cm or higher is required. Materials and methods: Calibration of radiochromic Gafchromic® EBT2 film (RCF) for electrons was performed in a solid water phantom (Scanditronix Wellhöfer) at a depth of 1.4cm and a Source Axis Distance (SAD) of 100cm. A polynomial fit was applied to the calibration curve, in order to obtain the equation relating dose response with optical density. The spatial distribution is obtained in terms of percentage of the dose, placing 3×3cm samples of RCF on the acrylic screen, which is placed in front of the patient in order to obtain maximum absorbed dose on the skin, covering an area of 200×100cm{sup 2}. The Percentage Depth Dose (PDD) curve was obtained placing RCF samples atmore » depths of 0, 1, 1.2, 1.4, 1.5, 2, 3, 4, 5, 6, 7, 8 and 9cm in the solid water phantom, irradiated with an ELEKTA SINERGY Linear Accelerator electron beam, with an energy of 6 MeV, at a Source Skin Distance (SSD) of 500cm, with 1000MU = 100Gy, with a cone of 40×40cm and gantry angle of 90°. The RCFs were scanned on a flatbed scanner (EPSON EXPRESSION 10000 XL) and the images were processed with the ImageJ program using a region of interest (ROI) of 1×1cm{sup 2}. Results: The relative spatial dose distribution and the percentage depth dose for a SSD of 500±0.5cm, over an area of 200×100cm{sup 2} was obtained, resulting to an effective maximum dose depth (Z{sub ref}) for electrons of 1.4±0.05cm. Using the same experimental data, horizontal and vertical beam profiles were also graphed, showing a horizontal symmetry of ±035%, horizontal flatness of ±3.62%, vertical symmetry of ±2.1% and vertical flatness of ±14.2%. Conclusions: The electron beam was characterized and the data obtained were useful to determine the spatial dose distribution to a SSD of 500±0.5cm, in an area of 200×100cm{sup 2}. Dose profiles were obtained both horizontally and vertically, thus allowing to assess electron beam symmetry and flatness. PDD analysis up to a depth of 9±0.05cm, has made possible to establish the depth of electron penetration, assuring an only skin irradiation treatment.« less

Authors:
;  [1];  [2];  [3]
  1. Medical Physics Graduate Programme, Universidad Autónoma del Estado de México, Facultad de Medicina, Paseo Tollocan esquina Jesús Carranza Colonia Moderna de la Cruz, C.P. 50180, Toluca, Estado de México (Mexico)
  2. The American British Cowdray Medical Center, Centro de Cáncer, Calle Sur 136, no. 116, Colonia las Américas, C.P. 01120, México, D.F. (Mexico)
  3. Hospital General de México Dr. Eduardo Liceaga, Dr. Balmis 148, Colonia Doctores, C.P. 06726, México, D.F. (Mexico)
Publication Date:
OSTI Identifier:
22390528
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1626; Journal Issue: 1; Conference: 13. Mexican Symposium on Medical Physics, Leon, Guanajuato (Mexico), 15-16 Mar 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ABSORBED RADIATION DOSES; BEAM PROFILES; CALIBRATION; DEPTH DOSE DISTRIBUTIONS; ELECTRON BEAMS; IMAGES; IRRADIATION; LYMPHOMAS; MEV RANGE; OPACITY; PATIENTS; PHANTOMS; RADIOTHERAPY; SKIN; SPATIAL DISTRIBUTION

Citation Formats

González, M. A. Pagnan, E-mail: miguelangel.pagnan@hotmail.com, Mitsoura, E., E-mail: meleni@uaemex.mx, Oviedo, J.O. Hernández, and Vázquez, D. R. Ruesga, E-mail: druesga@yahoo.com.mx. Characterization of unconventional electron fields for the treatment of mycosis fungoides using the total skin irradiation technique. United States: N. p., 2014. Web. doi:10.1063/1.4901368.
González, M. A. Pagnan, E-mail: miguelangel.pagnan@hotmail.com, Mitsoura, E., E-mail: meleni@uaemex.mx, Oviedo, J.O. Hernández, & Vázquez, D. R. Ruesga, E-mail: druesga@yahoo.com.mx. Characterization of unconventional electron fields for the treatment of mycosis fungoides using the total skin irradiation technique. United States. doi:10.1063/1.4901368.
González, M. A. Pagnan, E-mail: miguelangel.pagnan@hotmail.com, Mitsoura, E., E-mail: meleni@uaemex.mx, Oviedo, J.O. Hernández, and Vázquez, D. R. Ruesga, E-mail: druesga@yahoo.com.mx. 2014. "Characterization of unconventional electron fields for the treatment of mycosis fungoides using the total skin irradiation technique". United States. doi:10.1063/1.4901368.
@article{osti_22390528,
title = {Characterization of unconventional electron fields for the treatment of mycosis fungoides using the total skin irradiation technique},
author = {González, M. A. Pagnan, E-mail: miguelangel.pagnan@hotmail.com and Mitsoura, E., E-mail: meleni@uaemex.mx and Oviedo, J.O. Hernández and Vázquez, D. R. Ruesga, E-mail: druesga@yahoo.com.mx},
abstractNote = {Mycosis fungoides is a cutaneous lymphoma that accounts for 2–3% of all lymphomas. Several clinical studies have demonstrated the effectiveness of TSEBT (Total Skin Electron Beam Therapy) in patients with mycosis fungoides. It is important to develop this technique and make it available to a larger number of patients in Mexico. Because large fields for electron TSEBT are required in order to cover the entire body of the patient, beam characterization at conventional treatment distances is not sufficient and a calibration distance of 500cm or higher is required. Materials and methods: Calibration of radiochromic Gafchromic® EBT2 film (RCF) for electrons was performed in a solid water phantom (Scanditronix Wellhöfer) at a depth of 1.4cm and a Source Axis Distance (SAD) of 100cm. A polynomial fit was applied to the calibration curve, in order to obtain the equation relating dose response with optical density. The spatial distribution is obtained in terms of percentage of the dose, placing 3×3cm samples of RCF on the acrylic screen, which is placed in front of the patient in order to obtain maximum absorbed dose on the skin, covering an area of 200×100cm{sup 2}. The Percentage Depth Dose (PDD) curve was obtained placing RCF samples at depths of 0, 1, 1.2, 1.4, 1.5, 2, 3, 4, 5, 6, 7, 8 and 9cm in the solid water phantom, irradiated with an ELEKTA SINERGY Linear Accelerator electron beam, with an energy of 6 MeV, at a Source Skin Distance (SSD) of 500cm, with 1000MU = 100Gy, with a cone of 40×40cm and gantry angle of 90°. The RCFs were scanned on a flatbed scanner (EPSON EXPRESSION 10000 XL) and the images were processed with the ImageJ program using a region of interest (ROI) of 1×1cm{sup 2}. Results: The relative spatial dose distribution and the percentage depth dose for a SSD of 500±0.5cm, over an area of 200×100cm{sup 2} was obtained, resulting to an effective maximum dose depth (Z{sub ref}) for electrons of 1.4±0.05cm. Using the same experimental data, horizontal and vertical beam profiles were also graphed, showing a horizontal symmetry of ±035%, horizontal flatness of ±3.62%, vertical symmetry of ±2.1% and vertical flatness of ±14.2%. Conclusions: The electron beam was characterized and the data obtained were useful to determine the spatial dose distribution to a SSD of 500±0.5cm, in an area of 200×100cm{sup 2}. Dose profiles were obtained both horizontally and vertically, thus allowing to assess electron beam symmetry and flatness. PDD analysis up to a depth of 9±0.05cm, has made possible to establish the depth of electron penetration, assuring an only skin irradiation treatment.},
doi = {10.1063/1.4901368},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1626,
place = {United States},
year = 2014,
month =
}
  • Twelve consecutive patients with advanced stage mycosis fungoides (MF) were treated with combined total body X ray irradiation (TBI) and total skin electron beam radiotherapy (EBRT). Six had generalized plaque disease and dermatopathic nodes, three had tumor stage disease and node biopsy positive for mycosis fungoides, and three had erythroderma/Sezary syndrome. The treatment regimen consisted of split course total body X ray irradiation, given in twice weekly 15 cGy fractions to 75 cGy, then total skin electron beam radiation therapy given in once weekly 400 cGy fractions to a total dose of 2400 cGy. Underdosed areas and areas of greatestmore » initial involvement were boosted 400 cGy twice weekly for an additional 1200 cGy. This was followed by a second course of total body X ray irradiation, to a total dose of 150 cGy. The total skin electron beam radiotherapy technique is a modification of an established six position EBRT technique for mycosis fungoides. Measurements to characterize the beam with and without a lexan scattering plate, demonstrated that the combination of no-plate beams produced better dose uniformity with a much higher dose rate. This improved technique is particularly advantageous for elderly and/or frail patients. Nine (75%) of the 12 patients achieved complete response (CR). The other three had significant improvement with greater than 80% clearing of their disease and resolution of symptoms. All six patients with generalized plaque disease achieved complete response and remained free of disease from 2 to 16 months. Two of three node positive patients also achieved complete response; one, with massive biopsy-documented mycosis fungoides nodal disease and deep open tumors, remained relapse-free over 2 years. Only one of the three patients with erythroderma/Sezary syndrome achieved a complete response, which was short lived.« less
  • A technique using pendulum-arc rotation is presented for electron-beam treatment of generalized superficial malignancies. The technique consists of six arcing fields symmetrically dispersed around the body surface for circumferential coverage. The arc angle is selected to scan the height of the body fully. Beam uniformity within 10% over a height of 180 cm is achieved at a treatment distance of 385 cm. Randophantom dosimetry, using an 8 MeV electron beam degraded by 3/8 in. Plexiglas, indicates a surface dose uniformity within +- 7% over most of the body surface. Underdosages occur at regions obstructed by adjacent body parts.
  • Purpose: To determine the effect of low-dose (4 Gy) total skin electron beam therapy as a second-line treatment of Stage IB-II mycosis fungoides in a prospective, open-label study. Methods and Materials: Ten patients (6 men, 4 women, average age 68.7 years [range, 55-82 years]) with histopathologically confirmed mycosis fungoides T2-T4 N0-N1 M0 who did not achieve complete remission or relapsed within 4 months after treatment with psoralen plus ultraviolet-A were included. Treatment consisted of low-dose total skin electron beam therapy administered at a total skin dose of 4 Gy given in 4 fractions over 4 successive days. Results: Two patientsmore » had a complete clinical response but relapsed after 3.5 months. Six patients had partial clinical responses, with a mean duration of 2.0 months. One patient had no clinical response. Median time to relapse was 2.7 months. One patient died of unrelated causes and did not complete treatment. Acute side effects included desquamation, xerosis, and erythema of the skin. No severe side effects were observed. Conclusion: Low-dose total skin electron beam therapy can induce complete and partial responses in Stage IB-II mycosis fungoides; however, the duration of remission is short. Low-dose total skin electron beam therapy may find application in palliative treatment of mycosis fungoides because of limited toxicity and the possibility of repeating treatments for long-term disease control.« less
  • Purpose: Total skin electron beam therapy (TSEBT) is a highly effective treatment for mycosis fungoides (MF). The standard course consists of 30 to 36 Gy delivered over an 8- to 10-week period. This regimen is time intensive and associated with significant treatment-related toxicities including erythema, desquamation, anhydrosis, alopecia, and xerosis. The aim of this study was to identify a lower dose alternative while retaining a favorable efficacy profile. Methods and Materials: One hundred two MF patients were identified who had been treated with an initial course of low-dose TSEBT (5-<30 Gy) between 1958 and 1995. Patients had a T stagemore » classification of T2 (generalized patch/plaque, n = 51), T3 (tumor, n = 29), and T4 (erythrodermic, n = 22). Those with extracutaneous disease were excluded. Results: Overall response (OR) rates (>50% improvement) were 90% among patients with T2 to T4 disease receiving 5 to <10 Gy (n = 19). In comparison, OR rates between the 10 to <20 Gy and 20 to <30 Gy subgroups were 98% and 97%, respectively. There was no significant difference in median progression free survival (PFS) in T2 and T3 patients when stratified by dose group, and PFS in each was comparable to that of the standard dose. Conclusions: OR rates associated with low-dose TSEBT in the ranges of 10 to <20 Gy and 20 to <30 Gy are comparable to that of the standard dose ({>=} 30 Gy). Efficacy measures including OS, PFS, and RFS are also favorable. Given that the efficacy profile is similar between 10 and <20 Gy and 20 and <30 Gy, the utility of TSEBT within the lower dose range of 10 to <20 Gy merits further investigation, especially in the context of combined modality treatment.« less