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

Safigholi, Habib; Han, Dan; Soliman, A; Song, William Y.

doi:10.1002/mp.13030

Cited by 17 publications

(16 citation statements)

References 53 publications

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“…1K). [27][28][29][30][31][32][33][34] As expected, static-shield IMBT methods did increase delivery times by 25%-319% relative to those of conventional BT plans. 21,25,28 However, these increases still yielded clinically feasible absolute delivery times of w20 minutes.…”

Section: Static-shielded Applicatorssupporting

confidence: 68%

“…Two studies for conceptual IMBT were reported with no specific applicator design. 81,82 Twenty-five studies were on clinically implemented IMBT techniques, 6,7,23,26,35,36,38-43,47-49,53,56,58,63,83-88 13 included a prototype of the applicator, 3,4,18,19,27,28,[31][32][33][34]66,73,78 and most of the other studies using simulated IMBT plans on real patients' simulation scans or dosimetric evaluations.…”

Section: Literature Searchmentioning

confidence: 99%

“…Grooved-shielding HDR applicators (Figs. 1K, L, and M), also known as direction-modulated brachytherapy (DirMBT) applicators, for rectal cancer, 25 breast cancer, 21 and cervical cancer, [27][28][29][30][31][32][33] have been introduced relatively recently, with the advance of dose optimization and heterogeneity-corrected dose-calculation technique. In this technique, a central tandem or cylinder with a high atomic number (Z) has "grooves" symmetrically placed around the periphery, into which sources can be translated.…”

Section: Static-shielded Applicatorsmentioning

confidence: 99%

“…"Static" IMBT approaches include those in which the shield does not move relative to the source or surrounding tissues during BT delivery, such as shielded applicators (eg, shielded cylinders, [3][4][5][6][7][8][9][10][11] shielded tandem and ovoids, [12][13][14][15][16][17][18][19][20] Strut-Adjusted Volume Implants [SAVI], 21 intracavitary mold applicators [ICMA], [22][23][24][25][26] direction-modulated brachytherapy [DirMBT], 21,25,[27][28][29][30][31][32][33][34] and cup or D-shaped applicators [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]…”

Section: Introductionmentioning

confidence: 99%

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Systematic Review of Intensity-Modulated Brachytherapy (IMBT): Static and Dynamic Techniques

Callaghan

Adams

Flynn

et al. 2019

International Journal of Radiation Oncology*Biology*Physics

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Purpose: To systematically review scientific literature on the use of intensity-modulated brachytherapy (IMBT), including static and dynamic shielding approaches, to enhance therapeutic ratio. Studies were evaluated for technique, disease site, dosimetry, applicators, dosimetric calculations, and planning algorithms. Comparisons with standard-of-care brachytherapy techniques, alternative IMBT methods, or both were performed for dose-to-target volumes, organs at risk (OARs), and treatment planning or delivery times. Methods and Materials: Inclusion criteria were any peer-reviewed journal articles on IMBT published from January 1, 1980, to January 1, 2019, on PubMed, Google Scholar, Cochrane Library, and EBSCO databases. Two independent investigators reviewed each article for inclusion and exclusion criteria and scope. Data collected on each study included technique, source or shield material, disease site, n of study (n Z number of simulated plans/treated patients), doseto-target/OARs, and planning or delivery times. This review adhered to the Preferred Reporting Items for Systemic reviews and Meta Analyses (PRISMA). Results: Database queries yielded 1734 results, which were reduced to 436 after exclusion criteria and 78 peer-reviewed journal articles after evaluation of scope. Studies per disease site were 31 for cervical; 16 for rectal; 10 for oculocutaneous; 7 for breast; 6 for prostate; and 8 for other, multiple, or no specific disease site. Eighteen studies demonstrated a significant decrease in dose to OARs (5.1%-68.2%), 11 improved treatment planning or delivery times (7.6%-99.7%), and 6 increased target coverage (18.6%-71.6%) relative to standard-of-care or alternative IMBT technique. IMBT consistently decreased dose to OAR compared with the standard of care at the cost of increased planning or delivery times. Innovations in dose calculation or planning algorithms and applicators were capable of ameliorating prolonged treatment intervals.

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Section: Static-shielded Applicatorssupporting

confidence: 68%

Section: Literature Searchmentioning

confidence: 99%

Section: Static-shielded Applicatorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Systematic Review of Intensity-Modulated Brachytherapy (IMBT): Static and Dynamic Techniques

Callaghan

Adams

Flynn

et al. 2019

International Journal of Radiation Oncology*Biology*Physics

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“…Despite the dosimetric advantages of IC/IS over IC, IC/IS is more challenging, 7 invasive, 8,9 and time‐consuming 3 to deliver than IC. Multiple intracavitary HDR‐BT approaches using partial source shielding within the tandem applicator have been proposed to reduce or eliminate the need for interstitial HDR‐BT in cervical cancer patients, including rotating shield brachytherapy (RSBT) 10–14 and direction‐modulated brachytherapy (DMBT) 15–21 . Rotating shield brachytherapy relies on rotational movement of high‐density shields to modulate dose rate and direct radiation away from organs‐at‐risk (OARs) and into the HR‐CTV, which can increase dose delivered to the HR‐CTV without violating OAR dose constraints.…”

Section: Introductionmentioning

confidence: 99%

Needle‐free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the ¹⁶⁹Yb Isotope

et al. 2020

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Purpose: To assess the capability of an intracavitary 169 Yb-based helical multishield rotating shield brachytherapy (RSBT) delivery system to treat cervical cancer. The proposed RSBT delivery system contains a pair of 1.25 mm thick platinum partial shields with 45°and 180°emission angles, which travel in a helical pattern within the applicator. Methods: A helically threaded tandem applicator with a 45°tandem curvature containing a helically threaded catheter was designed. A 0.6 mm diameter 169 Yb source with a length of 10.5 mm was simulated. A 37-patient treatment planning study, based on Monte Carlo dose calculations using MCNP5, was conducted with high-risk clinical target volumes (HR-CTVs) of 41.2-192.8 cm 3 (average AE standard deviation of 79.9 AE 35.8 cm 3 ). All patients were assumed to receive 25 fractions of 1.8 Gy of external beam radiation therapy (EBRT) before receiving 5 fractions of high-dose-rate brachytherapy (HDR-BT). For each patient, 192 Ir-based intracavitary (IC) HDR- BT, 192 Ir-based intracavitary/interstitial (IC/IS) HDR-BT using a hybrid applicator with eight IS needles, and 169 Yb-based RSBT plans were generated. Results: For the IC, IC/IS, and RSBT treatment plans, 38%, 84%, and 86% of the plans, respectively, met the planning goal of an HR-CTV D 90 (minimum dose to hottest 90%) of 85 Gy EQD2 (a/ b = 10 Gy). Median (25th percentile, 75th percentile) treatment times for IC, IC/IS, and RSBT were 11.71 (6.62, 15.40) min, 68.00 (45.02, 80.02) min, and 25.30 (13.87, 35.39) min, respectively. 192 Ir activities ranging from 159.1-370 GBq (4.3-10 Ci) and 169 Yb activities ranging from 429.2-999 GBq (11.6-27 Ci) were used, which correspond to the same clinical ranges of dose rates at 1 cm off-source-axis in water. Extra needle insertion and planning time beyond that needed for intracavitary-only approaches was accounted for in the IC/IS treatment time calculations. Conclusion: 169 Yb-based RSBT for cervical cancer met the HR-CTV D 90 goal of 85 Gy in a greater percentage of the patients considered than IC/IS (86% vs 84%, respectively) and can reduce overall treatment time relative to IC/IS. 169 Yb-based RSBT could be used to replace IC/IS in instances where IC/IS treatment is not available, especially in instances when HR-CTV volumes are ≥30 cm 3 .

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A novel minimally invasive dynamic‐shield, intensity‐modulated brachytherapy system for the treatment of cervical cancer

et al. 2020

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Purpose To present a novel, MRI‐compatible dynamicshield intensity modulated brachytherapy (IMBT) applicator and delivery system using 192Ir, 75Se, and 169Yb radioisotopes for the treatment of locally advanced cervical cancer. Needle‐free IMBT is a promising technique for improving target coverage and organs at risk (OAR) sparing. Methods and materials The IMBT delivery system dynamically controls the rotation of a novel tungsten shield placed inside an MRI‐compatible, 6‐mm wide intrauterine tandem. Using 36 cervical cancer cases, conventional intracavitary brachytherapy (IC‐BT) and intracavitary/interstitial brachytherapy (IC/IS‐BT) (10Ci 192Ir) plans were compared to IMBT (10Ci 192Ir; 11.5Ci 75Se; 44Ci 169Yb). All plans were generated using the Geant4‐based Monte Carlo dose calculation engine, RapidBrachyMC. Treatment plans were optimized then normalized to the same high‐risk clinical target volume (HR‐CTV) D90 and the D2cc for bladder, rectum, and sigmoid in the research brachytherapy planning system, RapidBrachyMCTPS. Plans were renormalized until either of the three OAR reached dose limits to calculate the maximum achievable HR‐CTV D90 and D98. Results Compared to IC‐BT, IMBT with either of the three radionuclides significantly improves the HR‐CTV D90 and D98 by up to 5.2% ± 0.3% (P < 0.001) and 6.7% ± 0.5% (P < 0.001), respectively, with the largest dosimetric enhancement when using 169Yb followed by 75Se and then 192Ir. Similarly, D2cc for all OAR improved with IMBT by up to 7.7% ± 0.6% (P < 0.001). For IC/IS‐BT cases, needle‐free IMBT achieved clinically acceptable plans with 169Yb‐based IMBT further improving HR‐CTV D98 by 1.5% ± 0.2% (P = 0.034) and decreasing sigmoid D2cc by 1.9% ± 0.4% (P = 0.048). Delivery times for IMBT are increased by a factor of 1.7, 3.3, and 2.3 for 192Ir, 75Se, and 169Yb, respectively, relative to conventional 192Ir BT. Conclusions Dynamic shield IMBT provides a promising alternative to conventional IC‐ and IC/IS‐BT techniques with significant dosimetric enhancements and even greater improvements with intermediate energy radionuclides. The ability to deliver a highly conformal, OAR‐sparing dose without IS needles provides a simplified method for improving the therapeutic ratio less invasively and in a less resource intensive manner.

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

Cited by 17 publications

References 53 publications

Systematic Review of Intensity-Modulated Brachytherapy (IMBT): Static and Dynamic Techniques

Systematic Review of Intensity-Modulated Brachytherapy (IMBT): Static and Dynamic Techniques

Needle‐free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the ¹⁶⁹Yb Isotope

A novel minimally invasive dynamic‐shield, intensity‐modulated brachytherapy system for the treatment of cervical cancer

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

Cited by 17 publications

References 53 publications

Systematic Review of Intensity-Modulated Brachytherapy (IMBT): Static and Dynamic Techniques

Systematic Review of Intensity-Modulated Brachytherapy (IMBT): Static and Dynamic Techniques

Needle‐free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the 169Yb Isotope

A novel minimally invasive dynamic‐shield, intensity‐modulated brachytherapy system for the treatment of cervical cancer

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Needle‐free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the ¹⁶⁹Yb Isotope