Measurement of skin and target dose in post-mastectomy radiotherapy using 4 and 6 MV photon beams

Fischbach, Melanie; Hälg, Roger A.; Hartmann, Matthias; Besserer, Jürgen; Gruber, Günther; Schneider, Uwe

doi:10.1186/1748-717x-8-270

Cited by 18 publications

(6 citation statements)

References 11 publications

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“…In the present study, the OSD values with phantom and patients (Group A; n = 28) were 82.9% and 79.2%, respectively, under the application of gel bolus for 60% of treatment fractions ( n = 15). This is in agreement with a mean surface dose of 81.6% measured with TLD on a RANDO phantom by Fischbach et al [ 30 ] The surface dose measured was in the range 77.8%–107.6% with a mean of 83.0% reported by other groups. [ 31 ]…”

Section: Discussionsupporting

confidence: 91%

Surface dose measurements in chest wall postmastectomy radiotherapy to achieve optimal dose delivery with 6 MV photon beam

Srinivas¹,

Lobo²,

Banerjee³

et al. 2021

J Med Phys

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Aim: A tissue-equivalent bolus of sufficient thickness is used to overcome build up effect to the chest wall region of postmastectomy radiotherapy (PMRT) patients with tangential technique till Radiation Therapy Oncology Group (RTOG) Grade 2 (dry desquamation) skin reaction is observed. The aim of this study is to optimize surface dose delivered to chest wall in three-dimensional radiotherapy using EBT3 film. Materials and Methods: Measurements were conducted with calibrated EBT3 films with thorax phantom under “open beam, Superflab gel (0.5 cm) and brass bolus conditions to check correlation against TPS planned doses. Eighty-two patients who received 50 Gy in 25# were randomly assigned to Group A (Superflab 0.5 cm gel bolus for first 15 fractions followed by no bolus in remaining 10 fractions), Group B or Group C (Superflab 0.5 cm gel or single layer brass bolus, respectively, till reaching RTOG Grade 2 skin toxicity). Results: Phantom measured and TPS calculated surface doses were within − 5.5%, 4.7%, and 8.6% under open beam, 0.5 cm gel, and single layer of brass bolus applications, respectively. The overall surface doses (OSD) were 80.1% ±2.9% ( n = 28), 92.6% ±4.6% ( n = 28), and 87.4% ±4.7% ( n = 26) in Group A, B, and C, respectively. At the end of treatment, 7 out of 28; 13 out of 28; and 9 out of 26 patients developed Grade 2 skin toxicity having the OSD value of 83.0% ±1.6% ( n = 7); 93.7% ±3.2% ( n = 13); and 89.9% ±5.6% ( n = 9) in Groups A, B, and C, respectively. At the 20 th –23 rd fraction, 2 out of 7; 6 out of 13; and 4 out of 9 patients in Groups A, B, and C developed a Grade 2 skin toxicity, while the remaining patients in each group developed at the end of treatment. Conclusions: Our objective to estimate the occurrence of optimal dose limit for bolus applications in PMRT could be achieved using clinical EBT3 film dosimetry. This study ensured correct dose to scar area to protect cosmetic effects. This may also serve as quality assurance on optimal dose delivery for expected local control in these patients.

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Section: Discussionsupporting

confidence: 91%

Surface dose measurements in chest wall postmastectomy radiotherapy to achieve optimal dose delivery with 6 MV photon beam

Srinivas¹,

Lobo²,

Banerjee³

et al. 2021

J Med Phys

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“…Different methodologies for skin dose measurement and detectors characterization have been reported in the literature: radiochromic films; thermoluminescent dosimeters (TLD), and other passive solid state dosimeters; diodes; metal oxide semiconductor field effect transistors (MOSFETs)‐based dosimeter, etc …”

Section: Introductionmentioning

confidence: 99%

Optimization of skin dose usingin‐vivoMOSFETdose measurements in bolus/non‐bolus fraction ratio: AVMATand a 3DCRTstudy

Dias

Pinto

Borges

et al. 2019

J Applied Clin Med Phys

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In‐phantom and in‐vivo three dimensional conformal radiation therapy (3DCRT) and volumetric modulated arc therapy (VMAT) skin doses, measured with and without bolus in a female anthropomorphic phantom RANDO and in patients, were compared against treatment planning system calculated values. A thorough characterization of the metal oxide semiconductor field effect transistor measurement system was performed prior to the measurements in phantoms and patients. Patients with clinical indication for postoperative external radiotherapy were selected. Skin dose showed higher values with 3DCRT technique compared with VMAT. The increase in skin dose due to the use of bolus was quantified. It was observed that, in the case of VMAT, the bolus effect on the skin dose was considerable when compared with 3DCRT. From the point of view of treatment time, bolus cost, and positioning reproducibility, the use of bolus in these situations can be optimized.

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“…They recommend using a 1 cm TE bolus 60% of the time. Fischbach et al (2013) used an anthropomorphic phantom with thermoluminescent dosimeters at depths of 1 and 3 mm. They considered a 5 mm TE bolus with 4 and 6 MV tangent beams.…”

Section: Introductionmentioning

confidence: 99%

Skin dose in chest wall radiotherapy with bolus: a Monte Carlo study

Oliver¹,

Monajemi²

2020

Phys. Med. Biol.

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Monte Carlo simulations are used to investigate skin dose resulting from chest wall radiotherapy with bolus. A simple model of a female thorax is developed, which includes a 2 mm-thick skin layer. Two representative 6 MV source models are considered: a tangents source model consisting of a parallel opposed pair of medial and lateral fields and subfields, and an arc source model. Tissue equivalent (TE) boluses (thicknesses of 3, 5 and 10 mm) and brass mesh bolus are considered. Skin dose distributions depend on incident photon obliquity: for tangents, radiation is incident more obliquely, resulting in longer path lengths through the bolus and higher skin dose compared to the arc source model in most cases. However, for thicker TE boluses, attenuation of oblique photons becomes apparent. Brass bolus and 3 mm TE bolus result in similar mean skin dose. This relatively simple computational model allows for consideration of different bolus thicknesses, materials and usage schedules based on desired skin dose and choice of either tangents or an arc beam technique. For example, using a 5 mm TE bolus every second treatment would result in mean skin doses of 89% and 85% for tangents and the arc source model, respectively. The hot spot metric D would be 103% and 99%, respectively.

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Measurement of skin and target dose in post-mastectomy radiotherapy using 4 and 6 MV photon beams

Cited by 18 publications

References 11 publications

Surface dose measurements in chest wall postmastectomy radiotherapy to achieve optimal dose delivery with 6 MV photon beam

Surface dose measurements in chest wall postmastectomy radiotherapy to achieve optimal dose delivery with 6 MV photon beam

Optimization of skin dose usingin‐vivoMOSFETdose measurements in bolus/non‐bolus fraction ratio: AVMATand a 3DCRTstudy

Skin dose in chest wall radiotherapy with bolus: a Monte Carlo study

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