The Effect of Oblique Electron Beams to the Surface Dose Under the Bolus

Demir, Bayram; Okutan, Murat; Aydın, Cevdet; Göksel, Evren Ozan; Bilge, Hatice

doi:10.1016/j.meddos.2008.12.001

Cited by 15 publications

(9 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In low energy electron beams for skin cancer treatment, the surface dose is quite lower than maximum dose and thus, a tissue equivalent material such as bolus is commonly used to increase skin dose and consequently, to achieve target coverage in the treating lesion. 6,7 For example, at 6 MeV electron energy, the surface dose, defined at 0•5-mm depth on the central axis, usually ranges between 70 and 80% of maximum dose for 10 × 10 cm 2 field size at 100 cm sourceto-surface distance (SSD). 2,[7][8][9] With 0•5 cm bolus, the surface dose can be increased by >10% for the same energy.…”

Section: Introductionmentioning

confidence: 99%

Practical lookup tables for ensuring target coverage in a clinical setup for skin cancer electron therapy

Lee

Kim

2017

J Radiother Pract

View full text Add to dashboard Cite

AimTo create practical lookup tables containing percent depth dose (PDD) and profile parameters of electron beams and to demonstrate clinical application of the lookup tables to skin cancer treatment to ensure target coverage in a clinical setup.Materials and methodsFor 6 and 9 MeV electron energies, PDDs and profiles at clinically relevant depths [i.e., R95 (distal depth of 95% maximum dose), R90, R85 and R80] were measured in water at 100 cm source-to-surface distance for an 10×10 cm2 open field and circular cutouts with diameters of 4, 5, 6, 7 and 8 cm. Then PDD parameters along with profile parameters such as width of isodose lines and penumbra at the clinically relevant depths were determined. Output factors for the cutouts were measured at dmax in water and solid water.ResultsWith PDD and profile parameters, dosimetry lookup tables were generated. Based upon the lookup tables, target coverage at prescribed depths was retrospectively reviewed for three skin cancer cases. The lookup tables suggested larger cutouts for adequate target coverage.FindingsDosimetry lookup tables for electron beam therapy should include profile parameters at clinically relevant depths and be provided to clinicians to ensure target coverage in a clinical setup.

show abstract

Section: Introductionmentioning

confidence: 99%

Practical lookup tables for ensuring target coverage in a clinical setup for skin cancer electron therapy

Lee

Kim

2017

J Radiother Pract

View full text Add to dashboard Cite

show abstract

“…All rights reserved. *Corresponding author: Tel: +82-41-530-1365 Fax: +82-41-530-3084, e-mail: jahn1365@gmail.com the head, neck, and skin to reduce the depth dose during electron-beam radiation treatment; moreover, a bolus is used in breast-cancer radiation therapy for patients who have undergone a mastectomy during photon treatment, whereby it is used to increase the surface dose and reduce the depth dose, akin to the functioning of a bolus during electron-beam treatment [7][8][9]. A bolus is therefore directly attached to the chest wall to increase the surface dose that is applied for the prevention of a local recurrence during radiation therapy, and it can be either attached to the entire chest wall or only to the vicinity of the surgical scars [10].…”

Section: Introductionmentioning

confidence: 99%

Chest-wall Surface Dose During Post-mastectomy Radiation Therapy, with and without Nonmagnetic Bolus: A Phantom Study

Choi¹,

Hong²,

Park³

et al. 2016

Journal of Magnetics

View full text Add to dashboard Cite

For mastectomy patients, sufficient doses of radiation should be delivered to the surface of the chest wall to prevent recurrence. A bolus is used to increase the surface dose on the chest wall, whereby the surface dose is confirmed with the use of a virtual bolus during the computerized treatment-planning process. The purpose of this study is an examination of the difference between the dose of the computerized treatment plan and the dose that is measured on the bolus. Part of the left breast of an Anderson Rando phantom was removed, followed by the attainment of computed tomography (CT) images that were used as the basis for computerized treatment plans that were established with no bolus, a 3 mm-thick bolus, a 5 mm-thick bolus, and a 10 mm-thick bolus. For the computerized treatment plan, a prescribed dose regimen was dispensed daily and planning target volume (PTV) coverage was applied according to the RTOG 1304 guidelines. Using each of the established computerized treatment plans, chest-wall doses of 5 points were measured; this chest-wall dose was used as the standard for the analysis of this study, while the level of significance was set at P < 0.05. The measurement of the chest-wall dose with no bolus is 1.6 % to 10.3 % higher, and the differences of the minimum average and the maximum average of the five measurement points are −13.8 and −1.9, respectively (P < 0.05); however, when the bolus was used, the dosage was measured as 3.7 % to 9.2 % lower, and the differences of the minimum average and the maximum average are 7.4 and 9.0, −1.2 and 17.4, and 8.1 and 19.8 for 3 mm, 5 mm, and 10 mm, respectively (P < 0.05). As the thickness of the bolus is increased, the differences of the average surface dose are further increased. There are a variety of factors that affect the surface dose on the chest wall during post-mastectomy radiation therapy, for which verification is required; in particular, a consideration of the appropriate thickness and the number of uses when a bolus is used, and which has the greatest effect on the surface dose on the chest wall, is considered necessary.

show abstract

“…Build-up bölgesi, sadece elektronların derinlikle artışından değil, aynı zamanda doku içine nüfuz ederken saçılmaya bağlı doğrultularda meydana gelen değişikliklerden de oluşur. [6][7][8] Elektron ışınlarıyla oluşan dozun, saçılan elektronlardan kaynaklandığı ve bu saçılmaların büyük ölçüde kolimatör dizaynına bağlı olduğu bilinmektedir. Aynı nominal enerjilerde çalışan farklı elektron kolimasyon sistemine sahip makinelerde bile yüzde derin doz ve doz verimi parametreleri gibi dozimetrik parametreler belirgin ölçüde farklı olabilmektedir.…”

unclassified

Virtual electron energies dosimetry of a medical linear accelerator

Okutan¹

2013

TJ Oncol

Self Cite

View full text Add to dashboard Cite

The aim of this study was to compare dosimetric characteristics of the virtual energies determined by the film dosimetry and treatment planning computer. METHODS GafChromic EBT films is placed perpendicular to solid water phantom irradiated with two different electron energies. Dosimetry of virtual energies were evaluated by PTW Mephysto mc 2 Verisoft software program. RESULTS The comparison of treatment planning computer and dosimetric data of the virtual energies showed that they were compatable with each other. CONCLUSION In conclusion; it is recommended that one should use the virtual energies after the determination of the dosimetric characteristics.

show abstract

The Effect of Oblique Electron Beams to the Surface Dose Under the Bolus

Cited by 15 publications

References 24 publications

Practical lookup tables for ensuring target coverage in a clinical setup for skin cancer electron therapy

Practical lookup tables for ensuring target coverage in a clinical setup for skin cancer electron therapy

Chest-wall Surface Dose During Post-mastectomy Radiation Therapy, with and without Nonmagnetic Bolus: A Phantom Study

Virtual electron energies dosimetry of a medical linear accelerator

Contact Info

Product

Resources

About