Virtueller Bolus zur inversen Bestrahlungsplanung bei intensitätsmodulierter Radiotherapie des Mammakarzinoms im Rahmen der adjuvanten Therapie

Thilmann, Christoph; Grosser, Karl Heinz; Rhein, B.; Zabel, Angelika; Wannenmacher, M; Debus, Jürgen

doi:10.1007/s00066-002-0915-x

Cited by 16 publications

(3 citation statements)

References 24 publications

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“…In situations where the PTV extends up to or near the surface of the patient, the treatment planning system compensates by boosting beamlets tangential to the superficial region. When the patient is displaced from their planned position, notable regions of high dose are presented upon a small movement in the patient's position, even when the original plan shows good homogeneity 1 , 2 , 3 . Such an effect is distinct from other potential sources of increased superficial dose, such as the bolus effect of immobilization masks (4) .…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies 1 , 2 have suggested the use of a “pretend bolus” (PB), applied in treatment planning but not during the actual treatment, as a method to reduce surface dose and high‐dose regions. This method leads the planning system into believing that the optimized PTV is at a depth within the patient rather than at the skin surface, giving adequate buildup of material to account for the skin sparing effect.…”

Section: Introductionmentioning

confidence: 99%

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The optimization of superficial planning target volumes (PTVs) with helical tomotherapy

Ashburner

Tudor

2014

J Applied Clin Med Phys

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When the planning target volume (PTV), extends close to or beyond the skin, inverse‐planned intensity‐modulated radiotherapy can boost the fluence from tangential angles to superficial parts of the PTV due to the buildup effect. This can result in significant regions of high dose upon a small movement in the patient's position. We analyzed different methods of reducing this effect in the TomoTherapy planning system, including using pretend bolus, clipping the PTV back from the skin surface, and combinations of both. No alternative technique was seen to be unconditionally superior to a 5 mm planning bolus. A clip distance of 3 mm gave acceptable results, but consideration should be given to the reduction in minimum dose or increase in maximum dose seen in clip distances just 1 mm less or more, respectively, when treating head and neck cases in TomoTherapy.PACS numbers: 87.55.de, 87.55.dh

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The optimization of superficial planning target volumes (PTVs) with helical tomotherapy

Ashburner

Tudor

2014

J Applied Clin Med Phys

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“…Various tricks are used by treatment planners to avoid these problems. One method is the use of 'pretend bolus' as proposed by Thilmann et al (2002). This involves the adding of bolus in the planning process, which is not used for treatment.…”

Section: Introductionmentioning

confidence: 99%

The optimization of intensity modulated radiotherapy in cases where the planning target volume extends into the build-up region

et al. 2009

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A common clinical problem in IMRT, especially when treating head and neck cases, is that the clinical target volume (CTV) stops short of the skin surface, whilst the margin for geometric uncertainties may take the planning target volume (PTV) to the skin surface or beyond. In these cases, optimization leads to over-dosing of the skin, unless the planner resorts to procedural tricks to avoid this, such as the use of pretend bolus or reduction of the PTV followed by adding 'flash' after optimization. This paper describes a method of avoiding the need for these tricks by using a multiple-isocentre CTV-based objective function. This enables plans to be produced that will give good coverage of the CTV for all the geometrical uncertainties that would have been covered by the PTV without causing the problem of over-dosing the skin. Eight isocentre shifts, equally distributed on the surface of a sphere with a radius equal to the CTV-PTV margin, are shown to be adequate for the optimization process. The resulting fluence maps are much simpler than those resulting from PTV optimization and will therefore be simpler to deliver. The method also permits better sparing of organs at risk such as the spinal cord.

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Intensitätsmodulierte Strahlentherapie

Thilmann¹,

Oelfke

Strahlentherapie

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Virtueller Bolus zur inversen Bestrahlungsplanung bei intensitätsmodulierter Radiotherapie des Mammakarzinoms im Rahmen der adjuvanten Therapie

Cited by 16 publications

References 24 publications

The optimization of superficial planning target volumes (PTVs) with helical tomotherapy

The optimization of superficial planning target volumes (PTVs) with helical tomotherapy

The optimization of intensity modulated radiotherapy in cases where the planning target volume extends into the build-up region

Intensitätsmodulierte Strahlentherapie

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