An Endorectal Balloon Reduces Intrafraction Prostate Motion During Radiotherapy

Smeenk, Robert Jan; Louwe, R.; Langen, K; Shah, Amish P.; Kupelian, Patrick A.; Lin, Emile N.J.T. van; Kaanders, Johannes H.A.M.

doi:10.1016/j.ijrobp.2011.07.028

Cited by 83 publications

(76 citation statements)

References 27 publications

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“…Multiple centers have evaluated the use of endo-rectal balloons recently (15,16) with the results demonstrating the ability of this immobilization device to provide reproducible and effective immobilization of the prostate for treatment. The data produced by Wang et al (16) suggest that the use of an endo-rectal balloon can reduce the necessary symmetrical internal margin for prostate treatment by 40%.…”

Section: Target Motion Relative To Anatomy and Internal Immobilizationmentioning

confidence: 99%

Immobilization Considerations for Proton Radiation Therapy

Wroe

Bush

Slater

2014

Technol Cancer Res Treat

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Proton therapy is rapidly developing as a mainstream modality for external beam radiation therapy. This development is largely due to the ability of protons to deposit much of their energy in a region known as the Bragg peak, minimizing the number of treatment fields and hence integral dose delivered to the patient. Immobilization in radiation therapy is a key component in the treatment process allowing for precise delivery of dose to the target volume and this is certainly true in proton therapy. In proton therapy immobilization needs to not only immobilize the patient, placing them in a stable and reproducible position for each treatment, but its impact on the depth dose distribution and range uncertainty must also be considered.The impact of immobilization on range is not a primary factor in X-ray radiation therapy, but it is a governing factor in proton therapy. This contribution describes the immobilization considerations in proton therapy which have been developed at Loma Linda over twenty plus years of clinical operation as a hospital based proton center.

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Section: Target Motion Relative To Anatomy and Internal Immobilizationmentioning

confidence: 99%

Immobilization Considerations for Proton Radiation Therapy

Wroe

Bush

Slater

2014

Technol Cancer Res Treat

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“…Several studies7, 8 indicated that utilizing an endorectal balloon can effectively immobilize prostate and restrict rectal filling. The use of endorectal balloon, however, may introduce a large inter‐fraction prostate motion and deformation 4.…”

Section: Discussionmentioning

confidence: 99%

Volumetric‐based image guidance is superior to marker‐based alignments for stereotactic body radiotherapy of prostate cancer

Stephans

et al. 2018

J Applied Clin Med Phys

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PurposesThe aim of this study was to evaluate a dual marker‐based and soft‐tissue based image guidance for inter‐fractional corrections in stereotactic body radiotherapy (SBRT) of prostate cancer.Methods/MaterialsWe reviewed 18 patients treated with SBRT for prostate cancer. An endorectal balloon was inserted at simulation and each treatment. Planning margins were 3 mm/0 mm posteriorly. Prior to each treatment, a dual image guidance protocol was applied to align three makers using stereoscopic x ray images and then to the soft tissue using kilo‐voltage cone beam CT (kV‐CBCT). After treatment, prostate (CTV), rectal wall, and bladder were delineated on each kV‐CBCT, and delivered dose was recalculated. Dosimetric endpoints were analyzed, including V36.25 Gy for prostate, and D0.03 cc for bladder and rectal wall.ResultsFollowing initial marker alignment, additional translational shifts were applied to 22 of 84 fractions after kV‐CBCT. Among the 22 fractions, ten fractions exceeded 3 mm shifts in any direction, including one in the left‐right direction, four in the superior‐inferior direction, and five in the anterior‐posterior direction. With and without the additional kV‐CBCT shifts, the average V36.25 Gy of the prostate for the 22 fractions was 97.6 ± 2.6% with the kV x ray image alone, and was 98.1 ± 2.4% after applying the additional kV‐CBCT shifts. The improvement was borderline statistical significance using Wilcoxon signed‐rank test (P = 0.007). D0.03 cc was 45.8 ± 6.3 Gy vs. 45.1 ± 4.9 Gy for the rectal wall; and 49.5 ± 8.6 Gy vs. 49.3 ± 7.9 Gy for the bladder before and after applying kV‐CBCT shifts.ConclusionsMarker‐based alignment alone is not sufficient. Additional adjustments are needed for some patients based kV‐CBCT.

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“…There is therefore a question regarding how realistic the planned dose to the rectum is. Studies have shown that the use of an ERB during treatment is an effective method of stabilizing the rectum 29,30 and allows the dose to the rectum to be reduced (by pushing part of the rectum away from the high-dose region) with a corresponding decrease in observed late mucosal changes of the rectal wall. 21 Further work using the dose parametrization methods reported in the present study in conjunction with a means of stabilizing the rectum during treatment would be of interest.…”

Section: Discussionmentioning

confidence: 99%