High resolution (3 Tesla) MRI-guided conformal brachytherapy for cervical cancer: consequences of different high-risk CTV sizes

Anderson, James W.; Xia, Jie; Flynn, R; Modrick, Joseph M.; Bhatia, Sudershan K.; Jacobson, Geraldine M.; Kim, Yusung

doi:10.5114/jcb.2013.36180

Cited by 13 publications

(14 citation statements)

References 26 publications

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“…A T&O applicator was reconstructed (digitized) on T1‐weighted MR images 6. The details of the HDR workflow, imaging, and planning have been previously described 21, 22, 23, 24…”

Section: Methodsmentioning

confidence: 99%

“…The hybrid‐inverse optimization process21, 22, 25, 26 includes three main steps: (a) generate a conventional Point A plan, (b) set dose‐volume objective constraints for inverse optimization based upon the resulting DVH parameters, and (c) perform final dose shaping using graphical optimization based upon DVH parameters and isodose lines. As a last step, a physician reviews the isodose lines for each slice on coronal, sagittal, and axial views.…”

Section: Methodsmentioning

confidence: 99%

“…6 The details of the HDR workflow, imaging, and planning have been previously described. [21][22][23][24] An adaptive/conformal volume optimization HDR plan was retrospectively created for each clinical Point A plan through a hybrid-inverse optimization process that includes a combination of an inverse optimization and manual forward planning. The hybridinverse optimization process 21,22,25,26 5,7 and the ICRU Report #89.…”

Section: A | Ebrt and 3t Mri-guided Adaptive/conformal Volume Optimentioning

confidence: 99%

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Patient's specific integration of OAR doses (D2 cc) from EBRT and 3D image‐guided brachytherapy for cervical cancer

Gelover

Katherine

Mart

et al. 2018

J Applied Clin Med Phys

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The objective of this study was to assess the recommended DVH parameter (e.g., D2 cc) addition method used for combining EBRT and HDR plans, against a reference dataset generated from an EQD2‐based DVH addition method. A revised DVH parameter addition method using EBRT DVH parameters derived from each patient's plan was proposed and also compared with the reference dataset. Thirty‐one biopsy‐proven cervical cancer patients who received EBRT and HDR brachytherapy were retrospectively analyzed. A parametrial and/or paraaortic EBRT boost were clinically performed on 13 patients. Ten IMRT and 21 3DCRT plans were determined. Two different HDR techniques for each HDR plan were analyzed. Overall D2 cc and D0.1 cc OAR doses in EQD2 were statistically analyzed for three different DVH parameter addition methods: a currently recommended method, a proposed revised method, and a reference DVH addition method. The overall D2 ccEQD 2 values for all rectum, bladder, and sigmoid for a conformal, volume optimization HDR plan generated using the current DVH parameter addition method were significantly underestimated on average −5 to −8% when compared to the values obtained from the reference DVH addition technique (P < 0.01). The revised DVH parameter addition method did not present statistical differences with the reference technique (P > 0.099). When PM boosts were considered, there was an even greater average underestimation of −8~−10% for overall OAR doses of conformal HDR plans when using the current DVH parameter addition technique as compared to the revised DVH parameter addition. No statistically significant differences were found between the 3DCRT and IMRT techniques (P > 0.3148). It is recommended that the overall D2 cc EBRT doses are obtained from each patient's EBRT plan.

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“…A T&O applicator was reconstructed (digitized) on T1‐weighted MR images 6. The details of the HDR workflow, imaging, and planning have been previously described 21, 22, 23, 24…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: A | Ebrt and 3t Mri-guided Adaptive/conformal Volume Optimentioning

confidence: 99%

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Patient's specific integration of OAR doses (D2 cc) from EBRT and 3D image‐guided brachytherapy for cervical cancer

Gelover

Katherine

Mart

et al. 2018

J Applied Clin Med Phys

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“…Three Tesla (3T) MRI‐guided, titanium T&O HDR BT volume optimization planning is institutional standard care 23 , 24 , 25 , 26 . We validated the artifacts and distortions of titanium in the high 3T magnetic field (23) in order to use the 3T MRI as a single planning imaging modality for MRI‐guided GYN BT.…”

Section: Methodsmentioning

confidence: 99%

Commissioning of a 3D image‐based treatment planning system for high‐dose‐rate brachytherapy of cervical cancer

Kim

Modrick

Pennington

et al. 2016

J Applied Clin Med Phys

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The objective of this work is to present commissioning procedures to clinically implement a three‐dimensional (3D), image‐based, treatment‐planning system (TPS) for high‐dose‐rate (HDR) brachytherapy (BT) for gynecological (GYN) cancer. The physical dimensions of the GYN applicators and their values in the virtual applicator library were varied by 0.4 mm of their nominal values. Reconstruction uncertainties of the titanium tandem and ovoids (T&O) were less than 0.4 mm on CT phantom studies and on average between 0.8‐1.0 mm on MRI when compared with X‐rays. In‐house software, HDRCalculator, was developed to check HDR plan parameters such as independently verifying active tandem or cylinder probe length and ovoid or cylinder size, source calibration and treatment date, and differences between average Point A dose and prescription dose. Dose‐volume histograms were validated using another independent TPS. Comprehensive procedures to commission volume optimization algorithms and process in 3D image‐based planning were presented. For the difference between line and volume optimizations, the average absolute differences as a percentage were 1.4% for total reference air KERMA (TRAK) and 1.1% for Point A dose. Volume optimization consistency tests between versions resulted in average absolute differences in 0.2% for TRAK and 0.9 s (0.2%) for total treatment time. The data revealed that the optimizer should run for at least 1 min in order to avoid more than 0.6% dwell time changes. For clinical GYN T&O cases, three different volume optimization techniques (graphical optimization, pure inverse planning, and hybrid inverse optimization) were investigated by comparing them against a conventional Point A technique. End‐to‐end testing was performed using a T&O phantom to ensure no errors or inconsistencies occurred from imaging through to planning and delivery. The proposed commissioning procedures provide a clinically safe implementation technique for 3D image‐based TPS for HDR BT for GYN cancer.PACS number(s): 87.55.D‐

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“…This limits the deliverable radiation dose to cervical cancer tumors without exceeding the maximum allowable dose to the organs-at-risk (OARs) adjacent to the tumor. This is especially true in cases where the tumor is bulky (>40 cm 3 ), laterally extended, or nonsymmetric [2][3][4][5] where this can compromise treatment effectiveness if the high-risk clinical target volume (HR-CTV) is underdosed as a result.…”

Section: Introductionmentioning

confidence: 99%

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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High resolution (3 Tesla) MRI-guided conformal brachytherapy for cervical cancer: consequences of different high-risk CTV sizes

Cited by 13 publications

References 26 publications

Patient's specific integration of OAR doses (D2 cc) from EBRT and 3D image‐guided brachytherapy for cervical cancer

Patient's specific integration of OAR doses (D2 cc) from EBRT and 3D image‐guided brachytherapy for cervical cancer

Commissioning of a 3D image‐based treatment planning system for high‐dose‐rate brachytherapy of cervical cancer

Paddle‐based rotating‐shield brachytherapy

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