Improvement of dose distribution with irregular surface compensator in whole brain radiotherapy

AbstractPurposeThe aim of this study was to evaluate the dosimetric aspects of whole brain radiotherapy (WBRT) using an irregular surface compensator (ISC) in contrast to conventional radiotherapy techniques.MethodsTreatment plans were devised for 20 patients. The Eclipse treatment planning system (Varian Medical Systems) was used for dose calculation. For the ISC, a fluence editor application was used to extend the range of optimal fluence. The treatment plan with the ISC was compared with the conventional technique in terms of doses in the planning target volume (PTV), dose homogeneity index (DHI), three-dimensional (3D) maximum dose, eye and lens doses and monitor unit (MU) counts required for treatment.ResultsCompared with conventional WBRT, the ISC significantly reduced the DHI, 3D maximum dose and volumes receiving 105% of the prescription dose, in addition to reducing both eye and lens doses (p<0·05 for all comparisons). In contrast, MU counts were higher for the ISC technique than for conventional WBRT (828 versus 328, p<0·01).ConclusionThe ISC technique for WBRT considerably improved the dose homogeneity in the PTV. As patients who receive WBRT have improved survival, the long-term side effects of radiotherapy are highly important.

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Influence of Modulation Factor on Treatment Plan Quality and Irradiation Time in Hippocampus-Sparing Whole-Brain Radiotherapy Using Tomotherapy

Technology in Cancer Research & Treatment ◽

10.1177/15330338211045497 ◽

2021 ◽

Vol 20 ◽

pp. 153303382110454

Author(s):

Akihiko Ishibashi ◽

Hiromasa Kurosaki ◽

Kosei Miura ◽

Nobuko Utsumi ◽

Hideyuki Sakurai

Keyword(s):

Dose Distribution ◽

Irradiation Time ◽

Body Position ◽

Treatment Plan ◽

Volumetric Modulated Arc Therapy ◽

Whole Brain Radiotherapy ◽

Whole Brain ◽

Modulation Factor ◽

Brain Radiotherapy ◽

Computed Tomography Images

Objectives: Hippocampus-sparing whole-brain radiotherapy (HS-WBRT) using tomotherapy is known to provide a better dose distribution than volumetric-modulated arc therapy but requires an extended irradiation time. The present study aimed to investigate whether irradiation time can be shortened by reducing the modulation factor (MF) without losing the target dose distribution. Methods: Using six tilted computed tomography images in the head area, the planning target volume (PTV) and hippocampal doses, and the irradiation time was investigated with a jaw width of 1 cm, a pitch of 0.200, and the MF changed from 3.0 to 2.6, 2.2, 1.8, and 1.4. Results: No significant changes in the PTV or hippocampus were found with MF in the range from 3.0 to 1.8, but marked deterioration was found with that of 1.4. The irradiation time showed a linear relationship with the MF within the range from 3.0 to 1.8, with 1334, 1158, 986, and 817 s at modulation factors of 3.0, 2.6, 2.2, and 1.8, respectively. However, when the MF was 1.4, the irradiation time was 808 s. Conclusions: When HS-WBRT is performed with a tilted body position and a jaw width of 1 cm, with a MF of 1.8, a favorable balance between dose parameters and irradiation time is achieved, whereas with a MF of 1.4, the quality of the radiotherapy plan deteriorates, and the irradiation time is approximately the same as that with a MF of 1.8.

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Inclined head position improves dose distribution during hippocampal-sparing whole brain radiotherapy using VMAT

Strahlentherapie und Onkologie ◽

10.1007/s00066-016-0973-0 ◽

2016 ◽

Vol 192 (7) ◽

pp. 473-480 ◽

Cited By ~ 5

Author(s):

Kyung Su Kim ◽

Suk-Jin Seo ◽

Jaegi Lee ◽

Jin-Yong Seok ◽

Joo Wan Hong ◽

...

Keyword(s):

Dose Distribution ◽

Whole Brain Radiotherapy ◽

Head Position ◽

Whole Brain ◽

Brain Radiotherapy ◽

Hippocampal Sparing

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Adjuvant Whole-Brain Radiotherapy Versus Observation After Radiosurgery or Surgical Resection of One to Three Cerebral Metastases: Results of the EORTC 22952-26001 Study

Yearbook of Neurology and Neurosurgery ◽

10.1016/j.yneu.2012.05.030 ◽

2012 ◽

Vol 2012 ◽

pp. 89-90

Author(s):

J. Uhm

Keyword(s):

Surgical Resection ◽

Whole Brain Radiotherapy ◽

Cerebral Metastases ◽

Whole Brain ◽

Brain Radiotherapy

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Use of a Head-Tilting Baseplate During Tomotherapy to Shorten the Irradiation Time and Protect the Hippocampus and Lens in Hippocampal Sparing-Whole Brain Radiotherapy

Technology in Cancer Research & Treatment ◽

10.1177/1533033820986824 ◽

2021 ◽

Vol 20 ◽

pp. 153303382098682

Author(s):

Kosei Miura ◽

Hiromasa Kurosaki ◽

Nobuko Utsumi ◽

Hideyuki Sakurai

Keyword(s):

At Risk ◽

Planning Target Volume ◽

Irradiation Time ◽

Organs At Risk ◽

Absorbed Dose ◽

Whole Brain Radiotherapy ◽

Target Volume ◽

Whole Brain ◽

Brain Radiotherapy ◽

Hippocampal Sparing

Purpose: The aim of this study is to comparatively examine the possibility of reducing the exposure dose to organs at risk, such as the hippocampus and lens, and improving the dose distribution of the planned target volume with and without the use of a head-tilting base plate in hippocampal-sparing whole-brain radiotherapy using tomotherapy. Methods: Five paired images of planned head computed tomography without and with tilt were analyzed. The hippocampus and planning target volume were contoured according to the RTOG 0933 contouring atlas protocol. The hippocampal zone to be avoided was delineated using a 5-mm margin. The prescribed radiation dose was 30 Gy in 10 fractions. The absorbed dose to planning target volume dose, absorbed dose to the organ at risk, and irradiation time were evaluated. The paired t-test was used to analyze the differences between hippocampal-sparing whole-brain radiotherapy with head tilts and without head tilts. Results: Hippocampal-sparing whole-brain radiotherapy with tilt was not superior in planning target volume doses using the homogeneity index than that without tilt; however, it showed better values, and for Dmean and D2%, the values were closer to 30 Gy. Regarding the hippocampus, dose reduction with tilt was significantly greater at Dmax, Dmean, and Dmin, whereas regarding the lens, it was significantly greater at Dmax and Dmin. The irradiation time was also predominantly shorter. Conclusion: In our study, a tilted hippocampal-sparing whole-brain radiotherapy reduced the irradiation time by >10%. Therefore, our study indicated that hippocampal-sparing whole-brain radiotherapy with tomotherapy should be performed with a tilt. The head-tilting technique might be useful during hippocampal-sparing whole-brain radiotherapy. This method could decrease the radiation exposure time, while sparing healthy organs, including the hippocampus and lens.

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A Dutch phase III randomized multicenter trial: whole brain radiotherapy vs. stereotactic radiotherapy for 4-10 brain metastases

Neuro-Oncology Advances ◽

10.1093/noajnl/vdab021 ◽

2021 ◽

Author(s):

Dianne Hartgerink ◽

Anna Bruynzeel ◽

Danielle Eekers ◽

Ans Swinnen ◽

Coen Hurkmans ◽

...

Keyword(s):

Quality Of Life ◽

Side Effects ◽

Brain Metastases ◽

Survival Rates ◽

Whole Brain Radiotherapy ◽

Phase Iii ◽

Whole Brain ◽

Brain Radiotherapy ◽

One Year

Abstract Background The clinical value of whole brain radiotherapy (WBRT) for brain metastases (BM) is a matter of debate due to the significant side effects involved. Stereotactic radiosurgery (SRS) is an attractive alternative treatment option that may avoid these side effects and improve local tumor control. We initiated a randomized trial (NCT02353000) to investigate whether quality of life is better preserved after SRS compared with WBRT in patients with multiple brain metastases. Methods Patients with 4 to 10 BM were randomized between the standard arm WBRT (total dose 20 Gy in 5 fractions) or SRS (single fraction or 3 fractions). The primary endpoint was the difference in quality of life (QOL) at three months post-treatment. Results The study was prematurely closed due to poor accrual. A total of 29 patients (13%) were randomized, of which 15 patients have been treated with SRS and 14 patients with WBRT. The median number of lesions were 6 (range, 4-9) and the median total treatment volume was 13.0 cc 3 (range, 1.8-25.9 cc 3). QOL at three months decreased in the SRS group by 0.1 (SD=0.2), compared to 0.2 (SD=0.2) in the WBRT group (p=0.23). The actuarial one-year survival rates were 57% (SRS) and 31% (WBRT) (p=0.52). The actuarial one-year brain salvage-free survival rates were 50% (SRS) and 78% (WBRT) (p=0.22). Conclusion In patients with 4 to 10 BM, SRS alone resulted in one-year survival for 57% of patients while maintaining quality of life. Due to the premature closure of the trial, no statistically significant differences could be determined.

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