To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This exploration is intended to analyse the dosimetric characteristics of proton beams of multiple energies using different snout sizes.
Materials and methods
A synchrotron was used for the extraction of eight proton beam energies (100–250 MeV). Dosimetric measurements were taken in a water phantom that was irradiated with a proton beam emanating from the gantry system at angles 0, 90, 180 and 270 degree using a large and a medium snout. The range of beam energies in the phantom, their corresponding centre modulation depth (CMD) and the width of spread out Bragg peak (SOBP) were measured by Markus chamber. Double scattering technique was employed for the creation of SOBPs.
The range of proton beams varied from 4·3 cm for 100 MeV beam to 28·5 cm for 250 MeV beam with the medium snout and from 4·3 cm for 100 MeV to 25 cm for 250 MeV beam with large snout in the water phantom. SOBP width showed a variation from 4 to 10 cm with medium and large snout. While determining the output with medium snout, the discrepancy of 1·1% was observed between the maximum and minimum mean values of output for all the given set of energies and angles. There occurred a difference of 0·9% between the maximum and minimum mean values of output with the large snout. Beam output at SOBP centre was 12% higher with large snout as compared to that with medium snout for all the given beam energies. Flatness and symmetry were found within ±2·5% tolerance limits with medium and large snouts.
Flatness and symmetry were found within explicit limits with both medium and large snouts. Large snout produced higher beam output than that of medium snout at the centre of SOBP. This exploration can be extended to the determination of beam output, flatness and symmetry with a small snout.
To determine the feasibility of an anthropomorphic breast polyurethane-based three-dimensional (3D) dosimeter with cavity to measure dose distributions and skin dose for a commercial strut-based applicator strut-adjusted volume implant (SAVI™) 6–1.
Materials and methods
An anthropomorphic breast 3D dosimeter was created with a cavity to accommodate the SAVI™ strut-based device. 2 Gy was prescribed to the breast dosimeter having D95 to planning target volume evaluation (PTV_EVAL) while limiting 125% of the prescribed dose to the skin. Independent dose distribution verification was performed with GAFCHROMIC® EBT2 film. The dose distribution from the 3D dosimeter was compared to the distributions from commercial brachytherapy treatment planning system (TPS) and film. Point skin doses, line profiles and dose–volume histogram (DVHs) for the skin and PTV_EVAL were compared.
The maximum difference in skin dose for TPS and the 3D dosimeter was 4% whereas 41% between the TPS and EBT2 film. The maximum dose difference for line profiles between TPS, 3D dosimeter, and film was 4·1%. DVHs of skin and PTV_EVAL for TPS and 3D dosimeter differed by a maximum of 4% at 5 mm depth and skin differed by a maximum 1·5% between TPS and 3D dosimeter. The criterion for gamma analysis comparison was 92·5% at ±5%±3 mm criterion. The TPS demonstrated at least ±5% comparability in predicting dose to the skin, PTV_EVAL and normal breast tissue.
3D anthropomorphic polyurethane dosimeter with cavity gives comparable results to the TPS dose predictions and GAFCHROMIC® EBT2 film results in the context of HDR brachytherapy.
Whole-breast external beam radiotherapy results in significant reduction in the risk for breast cancer-related death, but this may be offset by an increase in deaths from other causes and toxicity to surrounding organs. Partial breast irradiation techniques are approaches that treat only the lumpectomy area rather than the whole breast. Quality assurance in the radiation therapy treatment planning process is essential to ensure accurate dose delivery to the patient. For this purpose, this article compares the results from an anthropomorphic PRESAGE® dosimeter, radiation treatment planning system and from the GAFCHROMIC® EBT2 film.
Materials and methods
A breast dosimeter was created and a three-field partial plan was generated in the Pinnacle3 treatment planning system. Dose distribution comparisons were made between Pinnacle3 treatment planning system, GAFCHROMIC® EBT2 film and PRESAGE® dosimeter. Dose–volume histograms (DVHs), gamma maps and line profiles were used to evaluate the comparison.
DVHs of gross tumour volume, clinical tumour volume and planning tumour volume for the PRESAGE® dosimeter and Pinnacle3 treatment planning system shows that both measured and calculated statistics were in agreement, with a value of 97.8% of the prescribed dose. Gamma map comparisons showed that all three distributions passed 95% at the ±3%/±3 mm criteria. Comparisons of isodose line distribution between the PRESAGE® dosimeter, EBT2 film and planning system demonstrated agreement, with an average difference of 1.5%.
This work demonstrated the feasibility of PRESAGE® to function as an anthropomorphic phantom and laid the foundation for research studies in PRESAGE®/optical-computed tomography three-dimensional dosimetry with the most complex anthropomorphic phantoms.
Email your librarian or administrator to recommend adding this to your organisation's collection.