Direction Modulated Brachytherapy for Treatment of Cervical Cancer. II: Comparative Planning Study With Intracavitary and Intracavitary–Interstitial Techniques

Han, Dan; Safigholi, Habib; Soliman, A; Ravi, Ananth; Leung, Eric; Scanderbeg, Daniel J.; Liu, Zhaowei; Owrangi, Amir; Song, William Y.

doi:10.1016/j.ijrobp.2016.06.015

Cited by 37 publications

(54 citation statements)

References 35 publications

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“…All cases were then reoptimized for both Con.T&R and DMBT&R to receive the same CTV HR D 90 . In total, 108 individual plans (8 shields × 12 clinical cases) with DMBT&R and 12 respective individual Con.T&R plans were re‐optimized with an in‐house code based on gradient projection convex optimization algorithm. The optimization process was previously described in detail .…”

Section: Methodsmentioning

confidence: 99%

“…Such would be helpful especially when the CTV HR is irregular/bulky in shape and extends beyond upper vagina away from the reaches of the ovoids/ring. Recognizing this apparent lag in tandem technology, a novel six‐channel MR‐compatible intrauterine tandem applicator is designed around an isotropic 192 Ir source based on the concept of direction modulated brachytherapy (DMBT) . This design is able to create directional radiation dose profile via intelligently designed tungsten shield leading to enhanced dose sculpting capacity for each individual CTV HR through inverse optimization.…”

Section: Introductionmentioning

confidence: 99%

“…Recognizing this apparent lag in tandem technology, a novel six-channel MR-compatible intrauterine tandem applicator is designed around an isotropic 192 Ir source based on the concept of direction modulated brachytherapy (DMBT). [30][31][32] This design is able to create directional radiation dose profile via intelligently designed tungsten shield leading to enhanced dose sculpting capacity for each individual CTV HR through inverse optimization. In general, the quality of DMBT plans has outperformed plans with conventional T&R (Con.T&R) applicators.…”

Section: Introductionmentioning

confidence: 99%

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Direction modulated brachytherapy (DMBT) tandem applicator for cervical cancer treatment: Choosing the optimal shielding material

et al. 2018

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Direction modulated brachytherapy (DMBT) tandem applicator for cervical cancer treatment: Choosing the optimal shielding material

et al. 2018

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“…High-dose-rate (HDR) sources containing 153 Gd (9) or 192 Ir (10,11) with built-in shielding have been investigated, but current technology prohibits interstitial implantation due to the required shield thickness and resultant puncture diameter. A directional source is more readily achieved with a source having lower energy emissions and consequently a thinner shield.…”

Section: Introductionmentioning

confidence: 99%

A directional 103Pd brachytherapy device: Dosimetric characterization and practical aspects for clinical use

Rivard

2017

Brachytherapy

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PURPOSE A brachytherapy device has been developed with shielding to provide directional brachytherapy for preferentially irradiating malignancies while sparing healthy tissues. The CivaSheet is a flexible low-dose-rate brachytherapy device containing CivaDots with 103Pd shielded by a thin Au disk. This is the first report of a clinical dosimetric characterization of the CivaSheet device. METHODS AND MATERIALS Radiation dose distributions near a CivaDot were estimated using the MCNP6 radiation transport code. CivaSheet arrays were also modeled to evaluate the dose superposition principle for treatment planning. The resultant data were commissioned in a treatment planning system (VariSeed 9.0) and the accuracy of the dose superposition principle was evaluated for summing individual elements comprising a planar CivaSheet. RESULTS The dose-rate-constant (0.579 cGy/h/U) was lower than for 103Pd seeds due to Au L-shell x-rays increasing the air-kerma strength. Radial dose function values at 0.1, 0.5, 2, 5, and 10 cm were 1.884, 1.344, 0.558, 0.088, and 0.0046. The 2D anisotropy function exhibited dramatic reduction between the forward (0°) and rearward (180°) directions by a factor of 276 at r=0.1 cm, 24 at r=1 cm, and 5.3 at r=10 cm. This effect diminished due to increasingly scattered radiation. The largest gradient in the 2D anisotropy function was in contact with the device at 92° due to the Au disk shielding. TPS commissioning and dose superposition accuracies were typically within 2%. CONCLUSIONS Simulations of the CivaDot yielded comprehensive dosimetry parameters that were entered into a TPS and deemed acceptable for clinical use. Dosimetry measurements of the CivaSheet are also of interest to the brachytherapy community.

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“…Intensity modulated brachytherapy (IMBT) is a novel brachytherapy technique which incorporates static or dynamic shields inside needles or applicators to direct the radiation toward the tumor and away from healthy tissues. [15][16][17] IMBT has been investigated for prostate, [18][19][20] cervical, [21][22][23][24][25][26] and rectal cancers. 27,28 In the case of prostate cancer, IMBT has the capability to reduce the dose delivered to nearby radiation sensitive healthy tissues, such as the urethra, or allow for dose escalation without an associated increase in urethral dose for monotherapy.…”

Section: Introductionmentioning

confidence: 99%

A novel ¹⁶⁹Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer

Famulari

Duclos²,

Enger

2019

Medical Physics

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Purpose Intensity modulated brachytherapy (IMBT) is a novel high dose rate brachytherapy (HDR BT) technique which incorporates static or dynamic shielding to increase tumor coverage and/or spare healthy tissues. The purpose of this study is to present a novel delivery system (AIM‐Brachy) design that can enable dynamic‐shield IMBT for prostate cancer. Methods The AIM‐Brachy system dynamically controls the rotation of platinum shields, placed within interstitial catheters, which partially collimate the radiation emitted from an 169Yb source. Conventional HDR BT (10 Ci 192Ir) and IMBT (18 Ci 169Yb) plans were generated for 12 patients using an in‐house column generation‐based optimizer, coupled to a Geant4‐based dose calculation engine, RapidBrachyMC. Treatment plans were normalized to match the same PTV D90 coverage as the clinical plan. Intershield attenuation effects were taken into account. A sensitivity analysis was performed to evaluate the dosimetric impact of systematic longitudinal source positioning errors (±1 mm, ±2 mm, and ±3 mm) and rotational errors (±5∘, ±10∘, and ±15∘) on clinically relevant parameters (PTV D90 and urethra D10). Results The platinum shield reduced the dose rate on the shielded side at 1 cm to 18.1% of the dose rate on the unshielded side. For equal PTV D90 coverage, the urethral D10 was reduced by 13.3% ± 4.7%, without change to other plan quality indices (PTV V100, V150, V200, bladder V75, rectum V75, HI, COIN). Delivery times for HDR BT and IMBT were 9.2 ± 1.6 min and 18.6 ± 4.0 min, respectively. In general, the PTV D90 was more sensitive to source positioning errors than rotational errors, while the urethral D10 was more sensitive to rotational errors than source positioning errors. For a typical range of positioning errors (±1 mm, ±5∘), the overall tolerance was <2%. Conclusions The AIM‐Brachy system was proposed to deliver dynamic‐shield IMBT for prostate cancer with the potential to create a low dose tunnel within the urethra. The urethra‐sparing properties are desirable to minimize the occurrence and severity of urethral strictures or, alternatively, to provide a method for dose escalation.

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Direction Modulated Brachytherapy for Treatment of Cervical Cancer. II: Comparative Planning Study With Intracavitary and Intracavitary–Interstitial Techniques

Cited by 37 publications

References 35 publications

Direction modulated brachytherapy (DMBT) tandem applicator for cervical cancer treatment: Choosing the optimal shielding material

Direction modulated brachytherapy (DMBT) tandem applicator for cervical cancer treatment: Choosing the optimal shielding material

A directional 103Pd brachytherapy device: Dosimetric characterization and practical aspects for clinical use

A novel ¹⁶⁹Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer

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Direction Modulated Brachytherapy for Treatment of Cervical Cancer. II: Comparative Planning Study With Intracavitary and Intracavitary–Interstitial Techniques

Cited by 37 publications

References 35 publications

Direction modulated brachytherapy (DMBT) tandem applicator for cervical cancer treatment: Choosing the optimal shielding material

Direction modulated brachytherapy (DMBT) tandem applicator for cervical cancer treatment: Choosing the optimal shielding material

A directional 103Pd brachytherapy device: Dosimetric characterization and practical aspects for clinical use

A novel 169Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer

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A novel ¹⁶⁹Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer