A simple technique for craniospinal radiotherapy in the supine position

Parker, William; Freeman, Carolyn R.

doi:10.1016/j.radonc.2005.11.009

Cited by 84 publications

(50 citation statements)

References 14 publications

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“…A fixedbeam geometry was used, employing two bilateral halfbeam blocked cranial fields, collimated to match the divergence of the direct posterior spinal field. The details of the fixed geometry planning technique used in our study have been described previously [8]. Cranial bilateral beams and spinal fields were shaped based on the three-dimensional shape of both PTVs (PTV_brain and PTV_spine) using a Millennium MLC.…”

Section: Dcrt Planningmentioning

confidence: 99%

See 1 more Smart Citation

High-precision radiotherapy for craniospinal irradiation: evaluation of three-dimensional conformal radiotherapy, intensity-modulated radiation therapy and helical TomoTherapy

Sharma¹,

Gupta²,

Jalali³

et al. 2009

BJR

109

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ABSTRACT. This study aimed to establish the feasibility of intensity-modulated radiation therapy (IMRT) in craniospinal irradiation (CSI) using conventional linear accelerator (IMRT_LA) and compare it dosimetrically with helical TomoTherapy (IMRT_ Tomo) and three-dimensional conformal radiotherapy (3DCRT). CT datasets of four previously treated patients with medulloblastoma were used to generate 3DCRT, IMRT_ LA and IMRT_Tomo plans. A CSI dose of 35 Gy was prescribed to the planning target volume (PTV). IMRT_LA plans for tall patients were generated using an intensity feathering technique. All plans were compared dosimetrically using standardised parameters. The mean volume of each PTV receiving at least 95% of the prescribed dose (V 95% ) was .98% for all plans. All plans resulted in a comparable dose homogeneity index (DHI) for PTV_brain. For PTV_spine, IMRT_Tomo achieved the highest mean DHI of 0.96, compared with 0.91 for IMRT_LA and 0.84 for 3DCRT. The best dose conformity index was achieved by IMRT_Tomo for PTV_brain (0.96) and IMRT_LA for PTV_spine (0.83). The IMRT_Tomo plan was superior in terms of reduction of the maximum, mean and integral doses to almost all organs at risk (OARs). It also reduced the volume of each OAR irradiated to various dose levels, except for the lowest dose volume. The beam-on time was significantly longer in IMRT_Tomo. In conclusion, IMRT_Tomo for CSI is technically easier and potentially dosimetrically favourable compared with IMRT_LA and 3DCRT. IMRT for CSI can also be realised on a conventional linear accelerator even for spinal lengths exceeding maximum allowable field sizes. The longer beam-on time in IMRT_Tomo raises concerns about intrafraction motion and whole-body integral doses.

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Section: Dcrt Planningmentioning

confidence: 99%

“…Field shaping for CSI has evolved from traditional bony landmarks using two-dimensional (2D) planar radiographs to the more recent CT simulation techniques [7,8]. In most of these techniques, field shaping and matching of cranial and spinal fields are done geometrically with no attempt to compute the dose-volume data of the target and/or organs at risk (OARs).…”

mentioning

confidence: 99%

High-precision radiotherapy for craniospinal irradiation: evaluation of three-dimensional conformal radiotherapy, intensity-modulated radiation therapy and helical TomoTherapy

Sharma¹,

Gupta²,

Jalali³

et al. 2009

BJR

109

View full text Add to dashboard Cite

show abstract

“…Unfortunately, 3DCRT methods often result in dose inhomogeneity and inaccuracy at the field junction areas. A common solution to minimize the dose inhomogeneity is to use weekly interfractional manual shifts of the field junctions [1,2], but there are several disadvantages to this method. First, the high-dose gradients between the matched fields have the potential to create unintentional high and/or low doses in the spinal cord when even a small setup error is introduced [3].…”

Section: Introductionmentioning

confidence: 99%

Volumetric modulated arc therapy planning method for supine craniospinal irradiation

Chen¹,

Chen²,

Atwood³

et al. 2012

J Radiat Oncol

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Background The purpose of this study is to propose a volumetric modulated arc therapy (VMAT) treatment planning technique for supine craniospinal irradiation (CSI) in order to improve dose conformity and homogeneity, as well as the reliability of the matching of abutting fields. Methods and materials CT datasets of a 9-year-old child and a 24-year-old adult treated with supine CSI were identified. The planning target volume (PTV) was contoured to include the whole contents of the brain and spinal canal with a uniform margin of 5 mm. RapidArc plans were generated with two partial arcs covering the brain and the superior portion of the spinal cord and a single partial arc covering the remaining inferior portion of the spinal cord. Conformity and heterogeneity indexes (CI and HI) and organs at risk (OAR) dose-volume histograms were evaluated. The effect of treatment inaccuracy was simulated with intentional patient shifts of ±3 mm. Results The CI for the pediatric and adult cases was 1.0 and 0.99, respectively, and the HI for the two cases was 12.7 and 11.8 %, respectively. The mean dose to the PTV was 102.5 and 102.1 %, respectively, while the mean doses to the OARs were all low. The simulated ±3-mm shift in patient position generated an error of less than ±10 % of the calculated dose in the spinal cord. Conclusions VMAT CSI was able to achieve highly conformal and homogeneous dose distributions, with minor doses to the surrounding normal tissues. Setup errors of ±3 mm were shown to have little effect on the intended dose distribution.

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“…CT simulation has drastically decreased the time required for simulation and increased the accuracy of coverage of the target volume. 4 Furthermore, the supine technique is better tolerated, more comfortable and more stable than the prone technique, which reduces the treatment time and improves the accuracy of treatment. 2,3 Not only involving immobilization in the supine position and CT simulation as the traditional techniques, 1-3 our approach also includes SAD irradiation and the combination of half-and full-beam irradiation which saves time and minimizes the risk of over-or underdosing at the junctions.…”

Section: Discussionmentioning

confidence: 99%

“…Several CSI techniques employing the supine position have been reported in recent years, [2][3][4][5][6] but numerous issues must be considered. One relates to SSD irradiation and the need for more parameters, another concerns limitations to the plan when the length of the spinal field exceeds the maximal length of the collimator jaw (40 cm) and a third involves couch rotation, which adds to the complexity of the treatment.…”

Section: Introductionmentioning

confidence: 99%

A novel supine isocentric approach for craniospinal irradiation and its clinical outcome

Cheng

Zeng

et al. 2016

BJR

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The authors Yi-Kan Cheng, Lei Zeng and Shu-Biao Ye contributed equally to this article.Objective: To report a novel approach for craniospinal irradiation (CSI) using a supine isocentric technique. Methods: Patients were treated in the supine position using CT simulation. Half-beam-blocked lateral cranial fields and superior spinal fields have the same isocentre, and their beam divergences match. Tangential irradiation provides a non-divergent junction for the other two fullbeam spinal fields. Shielding for cranial fields was generated, and dose distribution was calculated using a three-dimensional planning system. When sacral spinal fields were required, two lateral opposite fields were designed to protect the urogenital organs. All treatment portals were filmed once per week. Results: At a median follow-up of 49.8 months, 5 relapses and no cases of radiation myelitis developed in 26 consecutive patients. In the junctions of the brain-spine or spine-spine field, no failure occurred. Three failures occurred in the primary site alone, two in the spinal axis alone. Conclusion:The results of our study have shown that our novel approach for CSI was not associated with increased failures at the field junction and deaths. In addition, no radiation myelitis, pneumonia, severe damage to the heart and gastrointestinal tract, and second cancers occurred in our study. Advances in knowledge: This new approach is an optimal alternative in cancer centre without tomotherapy because of its convenience for immobilization, repeatability, optimal dose distribution and satisfactory clinical outcome.

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A simple technique for craniospinal radiotherapy in the supine position

Cited by 84 publications

References 14 publications

High-precision radiotherapy for craniospinal irradiation: evaluation of three-dimensional conformal radiotherapy, intensity-modulated radiation therapy and helical TomoTherapy

High-precision radiotherapy for craniospinal irradiation: evaluation of three-dimensional conformal radiotherapy, intensity-modulated radiation therapy and helical TomoTherapy

Volumetric modulated arc therapy planning method for supine craniospinal irradiation

A novel supine isocentric approach for craniospinal irradiation and its clinical outcome

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