comunitat-uji-handle:10234/9
comunitat-uji-handle2:10234/36080
comunitat-uji-handle3:10234/36082
comunitat-uji-handle4:
INVESTIGACION
Resum
Background:
Intraoperative electron radiotherapy (IOERT) is a highly selective radiotherapy technique which aims
to treat restricted anatomic volumes during oncological surgery and is now the subject of intense ... [+]
Background:
Intraoperative electron radiotherapy (IOERT) is a highly selective radiotherapy technique which aims
to treat restricted anatomic volumes during oncological surgery and is now the subject of intense re-evaluation. In
vivo dosimetry has been recommended for IOERT and has been identified as a risk-reduction intervention in the
context of an IOERT risk analysis. Despite reports of fruitful experiences, information about in vivo dosimetry in
intraoperative radiotherapy is somewhat scarce. Therefore, the aim of this paper is to report our experience in
developing a program of in vivo dosimetry for IOERT, from both multidisciplinary and practical approaches, in a
consistent patient series. We also report several current weaknesses.
Methods:
Reinforced TN-502RDM-H mobile metal oxide semico
nductor field effect tran
sistors (MOSFETs) and
Gafchromic MD-55-2 films were used as a redundant in vivo treatment verification system with an Elekta
Precise fixed linear accelerator for calibrations and tre
atments. In vivo dosimetry was performed in 45 patients
in cases involving primary tumors or relapses. The m
ost frequent primary tumors were breast (37 %) and
colorectal (29 %), and local recurrences among relapses was 83 %. We made 50 attempts to measure with
MOSFETs and 48 attempts to measure with films in th
e treatment zones. The surgical team placed both
detectors with supervision from the radiation oncologist and following their instructions.
Results:
The program was considered an overall success by the different professionals involved. The absorbed doses
measured with MOSFETs and films were 93.8 ± 6.7 % and 97.9 ± 9.0 % (mean ±
SD
) respectively using a scale in which
90 % is the prescribed dose and 100 % is the maximum absorbed dose delivered by the beam. However, in 10 % of
cases we experienced dosimetric problems due to detector misalignment, a situation which might be avoided with
additional checks. The useful MOSFET lifetime length and the film sterilization procedure should also be controlled.
Conclusions:
It is feasible to establish an in vivo dosimetry program for a wide set of locations treated with
IOERT using a multidisciplinary approach according to the skills of the professionals present and the detectors
used; oncological surgeons
’
commitment is key to success in this context. Films are more unstable and show
higher uncertainty than MOSFETs but are cheaper and
are useful and convenient if real-time treatment
monitoring is not necessary. [-]
Drets d'accés
info:eu-repo/semantics/openAccess