Computed tomography-based treatment planning for high-dose-rate brachytherapy using the tandem and ring applicator: influence of applicator choice on organ dose and inter-fraction adaptive planning

Dumane, V.A.; Yuan, Yading; Sheu, R; Gupta, Vishal

doi:10.5114/jcb.2017.68519

Cited by 11 publications

(8 citation statements)

References 28 publications

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“…The evolution of 3D planning from 2D planning resulted in the advent of volume-based HDR-BT planning, where the dose can be prescribed to the HR-CTV delineated by CT and/or MRI scans with close monitoring of OAR doses [ 7 , 8 ]. Accurate target and OAR delineation led to T&R and T&O based dose optimization techniques to create conformal plans by altering dwell times and dwell positions [ 34 , 35 , 36 ]. Several studies have shown the benefits of image-guided volume-based brachytherapy planning in gynecological malignancies compared to Point A-based plans [ 20 , 21 , 22 , 23 , 24 , 25 ].…”

Section: Discussionmentioning

confidence: 99%

Dosimetric evaluation of Point A and volume-based high-dose-rate plans: a single institution study on adaptive brachytherapy planning for cervical cancer

Paul

Nalichowski

Abrams

et al. 2018

jcb

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PurposeExternal beam radiation therapy (EBRT) and brachytherapy (BT) with concurrent cisplatin is the standard of care for locally advanced cervical cancer. The applicability of image-guided adaptive volume-based high-dose-rate (HDR) intracavitary brachytherapy planning is an active area of investigation. In this study, we examined whether volume-based HDR-BT (HDRVOL) plans leads to more conformal plans compared to Point A (HDRPointA)-based plans.Material and methodsTwo hundred and forty HDRPointA plans from 48 cervical cancer patients treated with chemoradiotherapy were retrospectively collected. Point A plans were renormalized with respect to the high-risk clinical target volume (HR-CTV) for the HDRVOL plans. The doses to organs at risk (OAR; rectum, sigmoid, and bladder), and HR-CTV and the conformal index were compared between HDRPointA and HDRVOL plans.ResultsHDRVOL plans resulted in a 6-12% reduction in the total dose (EBRT + HDR-BT) to 0.1 cc, 1.0 cc, and 2.0 cc of the OAR as well as an 8-37% reduction in the dose to 2 cc of OAR per HDR-BT fraction compared to HDRPointA plans. Differences in the conformal indexes between the two groups of plans showed an 18-31% relative increase per HDR-BT fraction for HDRVOL plans. The D90 of the HR-CTV was reduced by 11% by HDRVOL planning and had a median dose of 86 Gy.ConclusionsOur study reports the relative improvement in OAR doses per HDR-BT fraction by HDRVOL planning compared to HDRPointA planning and demonstrates the dosimetric advantages of volume-based HDR-BT planning in creating more conformal plans.

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Section: Discussionmentioning

confidence: 99%

Dosimetric evaluation of Point A and volume-based high-dose-rate plans: a single institution study on adaptive brachytherapy planning for cervical cancer

Paul

Nalichowski

Abrams

et al. 2018

jcb

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“…The decision can be easily made after the image registration of two CT images. Alternative way to reduce the dose to the critical organ are to place vaginal packing and/or rectal paddle to increase the distance between the radioactive source and the OARs, or modify the applicator angle and ring diameter for the last treatment to reduce the doses to the OARs, as proposed by …”

Section: Discussionmentioning

confidence: 99%

“…The entire radiation treatment is typically delivered in 45 Gy for 25 fractions with EBRT followed by HDR in 4–6 fractions using the tandem and ring (T&R) or tandem and ovoid (T&O) applicators. Magnetic resonance imaging or computerized tomography (CT) are currently used in HDR treatment planning to define the applicator position and delineate the target and organs at risk (OARs).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of offline adaptive planning techniques in image‐guided brachytherapy of cervical cancer

Liu

Kinard

Mäurer

et al. 2018

J Applied Clin Med Phys

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Modern three‐dimensional image‐guided intracavitary high dose rate (HDR) brachytherapy is often used in combination with external beam radiotherapy (EBRT) to manage cervical cancer. Intrafraction motion of critical organs relative to the HDR applicator in the time between the planning CT and treatment delivery can cause marked deviations between the planned and delivered doses. This study examines offline adaptive planning techniques that may reduce intrafraction uncertainties by shortening the time between the planning CT and treatment delivery. Eight patients who received EBRT followed by HDR boosts were retrospectively reviewed. A CT scan was obtained for each insertion. Four strategies were simulated: (A) plans based on the current treatment day CT; (B) plans based on the first fraction CT; (C) plans based on the CT from the immediately preceding fraction; (D) plans based on the closest anatomically matched previous CT, using all prior plans as a library. Strategies B, C, and D allow plans to be created prior to the treatment day insertion, and then rapidly compared with the new CT. Equivalent doses in 2 Gy for combined EBRT and HDR were compared with online adaptive plans (strategy A) at D 90 and D 98 for the high‐risk CTV (HR‐CTV), and D 2 cc for the bladder, rectum, sigmoid, and bowel. Compared to strategy A, D 90 deviations for the HR‐CTV were −0.5 ± 2.8 Gy, −0.9 ± 1.0 Gy, and −0.7 ± 1.0 Gy for Strategies B, C, and D, respectively. D 2 cc changes for rectum were 2.7 ± 5.6 Gy, 0.6 ± 1.7 Gy, and 1.1 ± 2.4 Gy for Strategies B, C, and D. With the exception of one patient using strategy B, no notable variations for bladder, sigmoid, and bowel were found. Offline adaptive planning techniques can shorten time between CT and treatment delivery from hours to minutes, with minimal loss of dosimetric accuracy, greatly reducing the chance of intrafraction motion.

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“…Consequently, if such displacement occurs intra-fractionally, one should expect dose variation of similar magnitude as well as shown by some recent studies [ 15 , 16 ]. Some studies have looked into the geometric displacement, anatomic change, and other effect in each fraction of image-guided brachytherapy [ 17 , 18 , 19 , 20 , 21 ]. Monitoring of applicator motion relative to patient is therefore important in MR/CT-guided HDR brachytherapy.…”

Section: Purposementioning

confidence: 99%

Reduction of applicator displacement in MR/CT-guided cervical cancer HDR brachytherapy by the use of patient hover transport system

Andrew¹,

Kim²,

Ginader³

et al. 2018

jcb

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PurposeTo quantify the reduction of relative displacement between the implanted intracavitary applicator and the patient bony anatomy, due to the use of a hover transport system during the patient transports between the imaging table and the treatment table.Material and methodsThe displacement of the applicator inside the patient was measured by comparing the distance between the tip of the tandem and the pubic bone on X-ray radiography images taken before and after moving a patient to magnetic resonance/computed tomography imaging. Displacements were evaluated for 27 fractions of treatment using hover transport and 185 fractions of treatment using manual transport.ResultsThe use of hover transport system reduced the percentage of fractions with displacements greater than 5 mm from 22.7% to 7.4%. The reduction of applicator displacement using hover transport is statistically significant, compared to the manual transport method (p-value 0.0086; mean displacement 3.41 mm [95% CI: 2.96-3.97] for manual transport, and 2.27 mm [95% CI: 1.71-2.97] for hover transport fractions).ConclusionsThis study indicates that the hover transport system is effectively reducing displacement between tandem and patient bony anatomy during patient transports. The potential improvement in dosimetric accuracy due to this reduction warrants further study.

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Computed tomography-based treatment planning for high-dose-rate brachytherapy using the tandem and ring applicator: influence of applicator choice on organ dose and inter-fraction adaptive planning

Cited by 11 publications

References 28 publications

Dosimetric evaluation of Point A and volume-based high-dose-rate plans: a single institution study on adaptive brachytherapy planning for cervical cancer

Dosimetric evaluation of Point A and volume-based high-dose-rate plans: a single institution study on adaptive brachytherapy planning for cervical cancer

Evaluation of offline adaptive planning techniques in image‐guided brachytherapy of cervical cancer

Reduction of applicator displacement in MR/CT-guided cervical cancer HDR brachytherapy by the use of patient hover transport system

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