eXaSkin - High Density Bolus


A bolus material can be used to alter the depth of the maximum radiation dose (Dmax) during radiation therapy. It is a tissue-equivalent material, which means that it has similar properties to human tissue when it is irradiated.

During radiotherapy, the radiation dose usually “builds up” a couple of millimetres beneath the skin, instead of directly underneath it (the depth depends on the beam-energy). When treating conditions like skin cancer, you may want to alter the beam, so that the maximum dose can be located right underneath the skin, where it is most needed in this instance. The bolus material will serve as a “build-up material” and can help you to achieve just that.

The diagram below is an example for bolus use in Electron Beam Therapy. The orange region is the tumour, where you want the “build-up dose” to be deposited.

eXaSkin is the only High Density Bolus -HDB- on the market well suited for treating surface tumors using photons. With eXaSkin, it is possible to avoid the use of electron beams in treating superficial neoplastic lesions and the accurate photon beam therapy of the skin.

eXaSkin is presented in an easily manageable paste format, that hardens in less than two minutes and fully adapts to any skin shape. This is the time require to get a personalized bolus. eXaSkin allows a more precise delivery of the dose to the skin in any clinical situation, thus it is especially recommended for treating highly critical regions (scalp, neck, ear, nose or genitals, among others).

eXaSkin is also an universal system to achieve improved Head & Neck immobilization. It’s use as IMMOBILIZATION SUBMASK is compatible with any head and neck immobilization system or thermoplastic masks allowing the improvement of head and neck set-up and immobilization in radiotherapy treatments.  

With eXaSkin, it is possible to avoid the use of electron beams in treating skin neoplastic lesions. 

eXaskin features:

  • It fully adapts to any skin shape.
  • Avoid rebuild-up effect even in the presence of air gaps.
  • Eliminate build-up area with lower bolus thickness.
  • Bolus thickness is no longer an issue.
  • eXaSkin density, shape and thickness data are properly obtained by TPS from planning CT images.
  • Fixable to thermoplastic masks to improve set-up and reproducibility.
  • No shrinkage.


The analysis of comparative graphics of PDD curves with RC films for eXaSkin shows:

  • The complete elimination of "building-up" areas for 6 MV photon beams.
  • That eXaSkin is calculable in accordance with data calculated in TPS.

How to use

eXaSkin is presented in an easily manageable paste format, that fully adapts to any skin shape and hardens in less than two minutes. The use of eXaSkin can be easily integrated in current radiotherapy workflows, it does not require the acquisition of additional equipment’s, software’s or technical knowledge for its management. 


Work Flow:

  1. Prepare a layer of eXaSkin following the recommended procedure.
  2. Apply this layer over the area to be treated and, if required, place a thermoplastic mask over the layer.
  3. Wait until eXaSkin layer hardens (less than 2 minutes).
  4. Acquire CT images for normal simulation.
  5. Since eXaSkin can be calculated accurately, treatment planning is identical to any conventional photon beam application.

“It is possible to treat superficial tumors using photons and eXasKin”

"Improve H&N immobilization using eXaSkin as submask"


Downloads eXaSkin High Density Bolus Brochure: Download PDF (2.51 MB)