Out-of-field doses for scanning proton radiotherapy of shallowly located paediatric tumours-a comparison of range shifter and 3D printed compensator

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F21%3A00539709" target="_blank" >RIV/61389005:_____/21:00539709 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1088/1361-6560/abcb1f" target="_blank" >https://doi.org/10.1088/1361-6560/abcb1f</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1361-6560/abcb1f" target="_blank" >10.1088/1361-6560/abcb1f</a>

Result language

angličtina

Original language name

Out-of-field doses for scanning proton radiotherapy of shallowly located paediatric tumours-a comparison of range shifter and 3D printed compensator

Original language description

The lowest possible energy of proton scanning beam in cyclotron proton therapy facilities is typically between 60 and 100 MeV. Treatment of superficial lesions requires a pre-absorber to deliver doses to shallower volumes. In most of the cases a range shifter (RS) is used, but as an alternative solution, a patient-specific 3D printed proton beam compensator (BC) can be applied. A BC enables further reduction of the air gap and consequently reduction of beam scattering. Such pre-absorbers are additional sources of secondary radiation. The aim of this work was the comparison of RS and BC with respect to out-of-field doses for a simulated treatment of superficial paediatric brain tumours. EURADOS WG9 performed comparative measurements of scattered radiation in the Proteus C-235 IBA facility (Cyclotron Centre Bronowice at the Institute of Nuclear Physics, CCB IFJ PAN, Krakow, Poland) using two anthropomorphic phantoms-5 and 10 yr old-for a superficial target in the brain. Both active detectors located inside the therapy room, and passive detectors placed inside the phantoms were used. Measurements were supplemented by Monte Carlo simulation of the radiation transport. For the applied 3D printed pre-absorbers, out-of-field doses from both secondary photons and neutrons were lower than for RS. Measurements with active environmental dosimeters at five positions inside the therapy room indicated that the RS/BC ratio of the out-of-field dose was also higher than one, with a maximum of 1.7. Photon dose inside phantoms leads to higher out-of-field doses for RS than BC to almost all organs with the highest RS/BC ratio 12.5 and 13.2 for breasts for 5 and 10 yr old phantoms, respectively. For organs closest to the isocentre such as the thyroid, neutron doses were lower for BC than RS due to neutrons moderation in the target volume, but for more distant organs like bladder-conversely-lower doses for RS than BC were observed. The use of 3D printed BC as the pre-absorber placed in the near vicinity of patient in the treatment of superficial tumours does not result in the increase of secondary radiation compared to the treatment with RS, placed far from the patient.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

30224 - Radiology, nuclear medicine and medical imaging

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physics in Medicine and Biology

ISSN

0031-9155

e-ISSN

1361-6560

Volume of the periodical

66

Issue of the periodical within the volume

3

Country of publishing house

GB - UNITED KINGDOM

Number of pages

17

Pages from-to

035012

UT code for WoS article

000611519200001

EID of the result in the Scopus database

2-s2.0-85101002831