Dynamic modulated brachytherapy (DMBT) for rectal cancer

Webster, Matthew J.; Dević, Slobodan; Vuong, T.; Han, Dan; Park, Justin C.; Scanderbeg, Daniel J.; Lawson, Joshua D.; Song, Byung Cheol; Watkins, W. Tyler; Pawlicki, Todd; Song, William Y.

doi:10.1118/1.4769416

Cited by 44 publications

(57 citation statements)

References 40 publications

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“…Generally, the use of collimation increases the entrance air kerma rate [5] which is a very crucial consideration if there is to be any possibility of deducing the deterministic effects such as erythema and epilation. Additional studies are needed in this field.…”

Section: Letter To Editorsmentioning

confidence: 99%

Effect of Collimation on Radiation Exposure and Image Quality

Ghobadifar

Zarei

2013

Korean J Pain

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Section: Letter To Editorsmentioning

confidence: 99%

Effect of Collimation on Radiation Exposure and Image Quality

Ghobadifar

Zarei

2013

Korean J Pain

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“…Quantitative comparisons on HR-CTV D 90 were also performed for P-RSBT with different paddle sizes against S-RSBT and D-RSBT, while setting different delivery time budgets (10,15,20,25, and 30 min/fx).…”

Section: D Treatment Planningmentioning

confidence: 99%

“…It was also assumed for all patients that the same HDR-BT plan was delivered for all five treatment fractions, which is standard number of fractions at the authors' institution. The HR-CTV doses Gy fractions of EBRT (EQD2), 15 using α/ β values of 10 and 3 Gy, respectively. …”

Section: C Clinical Cases Treatment Goals and Plan Quality Metricsmentioning

confidence: 99%

“…Intensity-modulated brachytherapy techniques such as rotating-shield brachytherapy (RSBT) [11][12][13] and dynamic modulated brachytherapy (DMBT) [14][15][16] were introduced as a means of improving intracavitary brachytherapy dose distributions for rectal and cervical cancer. When used as proposed by the authors, RSBT works by using a shield that partially occludes an electronic brachytherapy (eBT) source (Xoft Axxent™, iCAD, Inc., Nashua, NH, USA), which rotates in a manner that directs radiation away from healthy sensitive tissues and into cancerous tissue.…”

Section: Introductionmentioning

confidence: 99%

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Paddle‐based rotating‐shield brachytherapy

et al. 2015

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Purpose: The authors present a novel paddle-based rotating-shield brachytherapy (P-RSBT) method, whose radiation-attenuating shields are formed with a multileaf collimator (MLC), consisting of retractable paddles, to achieve intensity modulation in high-dose-rate brachytherapy. Methods: Five cervical cancer patients using an intrauterine tandem applicator were considered to assess the potential benefit of the P-RSBT method. The P-RSBT source used was a 50 kV electronic brachytherapy source (Xoft Axxent™). The paddles can be retracted independently to form multiple emission windows around the source for radiation delivery. The MLC was assumed to be rotatable. P-RSBT treatment plans were generated using the asymmetric dose-volume optimization with smoothness control method [Liu et al., Med. Phys. 41(11), 111709 (11pp.) (2014)] with a delivery time constraint, different paddle sizes, and different rotation strides. The number of treatment fractions (fx) was assumed to be five. As brachytherapy is delivered as a boost for cervical cancer, the dose distribution for each case includes the dose from external beam radiotherapy as well, which is 45 Gy in 25 fx. The high-risk clinical target volume (HR-CTV) doses were escalated until the minimum dose to the hottest 2 cm 3 (D 2cm 3) of either the rectum, sigmoid colon, or bladder reached their tolerance doses of 75, 75, and 90 Gy 3 , respectively, expressed as equivalent doses in 2 Gy fractions (EQD2 with α/ β = 3 Gy). Results: P-RSBT outperformed the two other RSBT delivery techniques, single-shield RSBT (S-RSBT) and dynamic-shield RSBT (D-RSBT), with a properly selected paddle size. If the paddle size was angled at 60• , the average D 90 increases for the delivery plans by P-RSBT on the five cases, compared to S-RSBT, were 2.2, 8.3, 12.6, 11.9, and 9.1 Gy 10 , respectively, with delivery times of 10, 15, 20, 25, and 30 min/fx. The increases in HR-CTV D 90 , compared to D-RSBT, were 16.6, 12.9, 7.2, 3.7, and 1.7 Gy 10 , respectively. P-RSBT HR-CTV D 90 -values were insensitive to the paddle size for paddles angled at less than 60• . Increasing the paddle angle from 5• to 60• resulted in only a 0.6 Gy 10 decrease in HR-CTV D 90 on average for five cases when the delivery times were set to 15 min/fx. The HR-CTV D 90 decreased to 2.5 and 11.9 Gy 10 with paddle angles of 90• and 120• , respectively. Conclusions: P-RSBT produces treatment plans that are dosimetrically and temporally superior to those of S-RSBT and D-RSBT, although P-RSBT systems may be more mechanically challenging to develop than S-RSBT or D-RSBT. A P-RSBT implementation with 4-6 shield paddles would be sufficient to outperform S-RSBT and D-RSBT if delivery times are constrained to less than 15 min/fx.

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“…The intensity of radiation is modulated by the amount of time the shield is pointed in a given direction. RSBT [5,4,12] and other intensitymodulated brachytherapy techniques such as dynamic modulated brachytherapy (DMBT) [11,10,9] were further studied with the aim of improving intracavitary brachytherapy dose distributions for rectal and cervical cancer. We will first focus on a peculiar type of shield which have been briefly described in the patent [8] and studied in [3].…”

Section: Introductionmentioning

confidence: 99%

SOBRA - Shielding Optimization for BRAchytherapy

Blin

Gasparoux

Ordyniak

et al. 2016

Lecture Notes in Computer Science

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In this paper, we study a combinatorial problem which arises in the development of innovative treatment strategies and equipment using tunable shields in internal radiotherapy. From an algorithmic point of view, the problem is related to circular integer word decomposition into circular binary words under constraints. We consider several variants of the problem, depending on constraints and parameters and present polynomial time exact algorithms, polynomial time approximation algorithms and NP-hardness results.

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Dynamic modulated brachytherapy (DMBT) for rectal cancer

Cited by 44 publications

References 40 publications

Effect of Collimation on Radiation Exposure and Image Quality

Effect of Collimation on Radiation Exposure and Image Quality

Paddle‐based rotating‐shield brachytherapy

SOBRA - Shielding Optimization for BRAchytherapy

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