Comparison of the Homogeneity of Breast Dose Distributions With and Without the Medial Wedge

Ikner, Cynthia; Russo, R; Podgorsak, Matthew B.; Proulx, Gary M.; Lee, R.Jeffrey

doi:10.1016/s0958-3947(98)00009-0

Cited by 9 publications

(6 citation statements)

References 13 publications

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“…The change in utilization of fixed and dynamic wedges may be a response to the guidelines, which advocate the use of a dynamic medial wedge. Studies suggest the dose to the contralateral breast is increased by the use of a fixed medial wedge as opposed to a dynamic wedge, although the effect varies considerably from department to department 8–11 . It is possible that those continuing to use a fixed wedge have data from their own equipment demonstrating an insignificant contribution to contralateral breast dose.…”

Section: Discussionmentioning

confidence: 99%

Changes in practice of breast cancer radiotherapy 1998–2002: An Australasian survey

Drummond

Power²,

Evans³

et al. 2005

Australasian Radiology

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In order to assess the impact on radiation oncology practice of the publication of evidence-based guidelines for technical aspects of therapeutic radiation for breast cancer, the Radiation Oncology Expert Advisory Group of the National Breast Cancer Centre conducted two postal surveys of radiation oncologists practising in Australia and New Zealand. Results from a survey conducted in 1998, prior to distribution of the guidelines, have been published previously. This article reports on results from a survey undertaken in 2002 and contains data from 102 respondents who manage women with breast cancer. The results show several important changes in practice since 1998, including increased use of CT scanning in breast cancer treatment planning and increased use of immobilization devices for patient treatment. There is also evidence of increased attention to technical aspects of treatment planning that reduce the potential risk of treatment toxicity. The influence of the guidelines, the wider availability of modern equipment and results from landmark clinical trials on change in radiation therapy practice is discussed.

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Section: Discussionmentioning

confidence: 99%

Changes in practice of breast cancer radiotherapy 1998–2002: An Australasian survey

Drummond

Power²,

Evans³

et al. 2005

Australasian Radiology

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“…The increase in heterogeneity with large breasted women has previously been described. [29][30][31] The effects of the different respiratory motions ͑no breathing, shallow breathing, normal breathing, and heavy breath-ing͒ on the CTV DVHs are shown in Fig. 7.…”

Section: A Evaluation Of the Effects Of Varying Respiratory Motion Omentioning

confidence: 99%

“…1 Methods that explicitly account for respirationinduced intrafraction motion include active breathing control, 4,5 voluntary breath-hold, 6 deep inspiration breath-hold, 7-10 respiratory gated techniques, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and 4D or tumor-tracking techniques. 26 -28 Because dose heterogeneity is an important factor determining cosmesis in breast therapy, [29][30][31] the use of intensity modulated radiation therapy ͑IMRT͒ for breast treatment can be effective in attaining the desired homogeneity for the planning target volume ͑PTV͒, 2,3 while minimizing the dose to heart and ipsilateral lung. Many patients have been treated with breast IMRT, and, in some institutions, breast IMRT is common practice, at least for early stage breast cancer.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the effect of intrafraction motion during breast IMRT planning and dose delivery

et al. 2003

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Respiratory motion during intensity modulated radiation therapy (IMRT) causes two types of problems. First, the clinical target volume (CTV) to planning target volume (PTV) margin needed to account for respiratory motion means that the lung and heart dose is higher than would occur in the absence of such motion. Second, because respiratory motion is not synchronized with multileaf collimator (MLC) motion, the delivered dose is not the same as the planned dose. The aims of this work were to evaluate these problems to determine (a) the effects of respiratory motion and setup error during breast IMRT treatment planning, (b) the effects of the interplay between respiratory motion and multileaf collimator (MLC) motion during breast IMRT delivery, and (c) the potential benefits of breast IMRT using breath-hold, respiratory gated, and 4D techniques. Seven early stage breast cancer patient data sets were planned for IMRT delivered with a dynamic MLC (DMLC). For each patient case, eight IMRT plans with varying respiratory motion magnitudes and setup errors (and hence CTV to PTV margins) were created. The effects of respiratory motion and setup error on the treatment plan were determined by comparing the eight dose distributions. For each fraction of these plans, the effect of the interplay between respiratory motion and MLC motion during IMRT delivery was simulated by superimposing the respiratory trace on the planned DMLC leaf motion, facilitating comparisons between the planned and expected dose distributions. When considering respiratory motion in the CTV-PTV expansion during breast IMRT planning, our results show that PTV dose heterogeneity increases with respiratory motion. Lung and heart doses also increase with respiratory motion. Due to the interplay between respiratory motion and MLC motion during IMRT delivery, the planned and expected dose distributions differ. This difference increases with respiratory motion. The expected dose varies from fraction to fraction. However, for the seven patients studied and respiratory trace used, for no breathing, shallow breathing, and normal breathing, there were no statistically significant differences between the planned and expected dose distributions. Thus, for breast IMRT, intrafraction motion degrades treatment plans predominantly by the necessary addition of a larger CTV to PTV margin than would be required in the absence of such motion. This motion can be limited by breath-hold, respiratory gated, or 4D techniques.

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“…If the isocenter has been moved anteriorly, then the gantry angle is changed so that the lateral tangent beam edge aligns with the line drawn by the physician. A 45° wedge is added to the lateral tangent beam, and, if needed, a 15° to 30° wedge may later be added to the medial tangent beam to improve dose homogeneity 13 . The physician draws the blocks for both the medial and lateral tangent fields so that the treatment portals follow the outlined breast parenchyma (Fig.…”

Section: Virtual Simulation/planningmentioning

confidence: 99%

On the use of virtual simulation in radiotherapy of the intact breast

Steeves

Paliwal

2000

J Applied Clin Med Phys

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In this paper a method of breast cancer treatment planning using virtual simulation implemented at the Department of Human Oncology at the University of Wisconsin is described. All patients in this procedure are placed in a custom vacuum mold in treatment position with both arms up to avoid collision with the CT scanner aperture. For all patients a CT scan of 5‐mm‐slice thickness is acquired. The ipsilateral and contralateral breast, the ipsilateral lung and the heart are delineated and a three‐dimensional plan is generated that tries to minimize the dose to the ipsilateral lung and heart while ensuring adequate coverage of the affected breast. Digitally reconstructed radiographs are used to verify the patient setup on the treatment machine. © 2000 American College of Medical Physics. PACS number(s): 87.53.–j

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Comparison of the Homogeneity of Breast Dose Distributions With and Without the Medial Wedge

Cited by 9 publications

References 13 publications

Changes in practice of breast cancer radiotherapy 1998–2002: An Australasian survey

Changes in practice of breast cancer radiotherapy 1998–2002: An Australasian survey

Quantifying the effect of intrafraction motion during breast IMRT planning and dose delivery

On the use of virtual simulation in radiotherapy of the intact breast

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