Dosimetric impact of cylinder size in high‐dose rate vaginal cuff brachytherapy (VCBT) for primary endometrial cancer

Zhang, Hualin; Gopalakrishnan, Mahesh; Lee, Plato; Kang, Zhuang; Sathiaseelan, V.

doi:10.1120/jacmp.v17i5.6182

Cited by 8 publications

(6 citation statements)

References 14 publications

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“…A recently published modern series noted a significantly increased proportion of patients requiring smaller cylinders, with 194/381 (51%) fitted with cylinder sizes ≤2.5 cm; however, about a third of the patients in this study also received EBRT, and the main finding was that the addition of EBRT, low BMI, and low weight was associated with need for smaller cylinders [ 17 ]. Although prior studies have noted dosimetric disadvantages associated with smaller cylinder size [ 8 18 ], there are no prior studies to our knowledge which have examined the demographics and clinical outcomes of patients treated with small cylinders.…”

Section: Discussionmentioning

confidence: 99%

Impact of vaginal cylinder diameter on outcomes following brachytherapy for early stage endometrial cancer

et al. 2017

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ObjectiveTo examine the outcomes (tolerability, toxicity, and recurrence) of vaginal brachytherapy (VBT) among endometrial cancer (EC) patients treated with small cylinder size.MethodsPatients with EC who received adjuvant VBT between September 2011 and December 2015 were reviewed. Patients were fitted with the largest vaginal cylinder they could comfortably accommodate, from 2.0–3.0 cm diameter. Small cylinders were defined as size 2.3 cm or less. Patient, tumor, or treatment characteristics were correlated with need for small cylinders. Treatment tolerability, measures of gastrointestinal (GI), genitourinary (GU), and vaginal toxicity, and rates of recurrence were analyzed.ResultsThree hundred four patients were included. Small cylinders were used in 51 patients (17%). Normal body mass index (BMI; p<0.001), nulligravidity (p<0.001), and shorter vaginal length (p<0.001) were associated with small cylinder size. There was no acute or late grade 3 toxicity. Rates of acute (grade 1–2) GI, GU, or vaginal symptoms were low (10%, 11%, and 19%, respectively). Small cylinder size was associated with increased likelihood of reporting acute GI (p<0.05) but not GU or vaginal symptoms. Small cylinder size was associated with higher risk of grade 1–2 vaginal stenosis (odds ratio [OR]=4.7; 95% confidence interval [CI]=1.5–14.7; p=0.007). There was no association between cylinder size and recurrence rate (p=0.55).ConclusionVBT is generally very well tolerated, however, patients fitted with smaller cylinders (commonly nulligravid and low BMI) may have increased side effects. Further study to improve the dosimetry of VBT for patients requiring small cylinders may be worthwhile.

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Section: Discussionmentioning

confidence: 99%

Impact of vaginal cylinder diameter on outcomes following brachytherapy for early stage endometrial cancer

et al. 2017

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“…The treatment regimens were selected from the ABS (American Brachytherapy Society) recommendations, 17 their equivalency was evaluated in a recent study. 18 The evaluation target volume was a 0.5 cm ring surrounding the cylinder with different treatment lengths, named PTV_Eval. The rationale for using this target volume was based upon data, 19 that approximately 95% of vaginal lymphatic channels (a potential surrogate for cancer cell location) are located within a 0.3 cm depth from the vaginal surface and that the density of lymphatic channels decreases with the depth.…”

Section: Methodsmentioning

confidence: 99%

“…The planning method of this study was the same as that used in other studies. 6,18 By analyzing the dose volume histograms (DVH) of target, the mean doses (D-mean) and the doses covering 90% (D90), 10% (D10), and 5% (D5) of PTV_Eval of S-Cylinder HDR VCBT and M-Cylinder HDR VCBT plans were calculated and compared.…”

Section: S-hdr Vcbt Plansmentioning

confidence: 99%

Treating Cylindrically Populated Endometrial Cancers With High Dose Rate Vaginal Cuff Brachytherapy: Should We Use a MulTi-Channel or Single-Channel Cylinder?

Zhang¹,

Lim²,

Kang³

et al. 2023

Preprint

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Purpose: The purpose of this study was to evaluate the dosimetric impact of multiple channels compared to a single channel in high dose rate (HDR) vaginal cuff brachytherapy (VCBT). Methods and materials: Sample plans of HDR VCBT from both single and multiple channel cylinders at 2.5, 3.0 and 3.5 cm in diameter were created and analyzed. The doses were prescribed either at the 0.5 cm depth with 5.5 Gy for 4 fractions or at the cylinder surface with 8.8 Gy for 4 frac¬tions, in various treatment lengths ranging from 3 to 8 cm. A 0.5 cm ring target volume called PTV_Eval was contoured for each plan and served as the target volume for dosimetric evaluation. Mean doses and the doses covering 90% (D90), 10% (D10), and 5% (D5) of PTV_Eval were calculated and compared. The same treatment lengths, same prescription regimens, same target volume contouring and same plan evaluation methods were repeated for the similar size single channel and multiple channel cylinders. Results: The mean doses of both regimens with the multi-channel cases (6.3 to 7.1 Gy) were comparable to single channel ones (6.4 and 7.5 Gy). The ranges of D90, D10 and D5 were from 3.654 to 5.04 Gy, 8.44 to 10.08 Gy and 8.84 to 10.86 Gy in the multi-channel cases, but from 5.36 to 5.76 Gy, 7.40 to 9.97 Gy and 8.16 to 11.93 Gy in the single channel cases, respectively. Conclusion: The single channel and multiple-channel cylinder deliver a similar mean dose, but with marked heterogeneity in D90, D5 and D10 for the same prescription dose and target volume. Multi-channel cylinders adequately cover the target volume, but given the heterogeneity, increased treatment time and cost are best suited for asymmetric target volumes.

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“…If the diameter of selected applicator does not fit the vagina wall, it might move between acquiring the planning images and treatment, which increase uncertainty of delivering the dose to patient. Also, if the diameter of selected applicator fit the vagina wall too tightly, it may cause a discomfort for patients [ 10 , 11 , 12 ]. The diameter of cylinder is important to correspond to the applicator inside the vagina wall.…”

Section: Purposementioning

confidence: 99%

Manufacturing and evaluation of multi-channel cylinder applicator with 3D printing technology

Mohammadi¹,

Siavashpour²,

Aghdam³

et al. 2021

jcb

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Purpose: This study was designed to assess dosimetric characteristics of 3D-printed personalized multi-channel cylinder applicator (MCCA). Material and methods: UnionTech RS Pro 600 (UnionTech, Inc., Shanghai, China) 3D printer was used for manufacturing MCCA. The geometry of MCCA was designed with Fusion 360 v.2.0.5827 (Autodesk, Inc.) software. The designed file was exported to Meshmixer v.3.5 (Autodesk, Inc.) to create three-dimensional model in stereolithography (STL) file format, which is the common file format for inputting data to 3D printers. We used high-temp resin, FLHTAM02 model (Formlabs Inc., MA, USA), as material in 3D printing process. This resin model has good resistance to high temperature and compatibility with various solvents. We created a simple cubic shape phantom for dosimetric evaluation of the applicator with Gafchromic EBT3 films. Also, Monte Carlo method was applied to simulate MCCA in the same configuration as in experimental test. Results: The mean ± standard deviation (SD) difference between measured and calculated doses in treatment planning system (TPS) for all control points was 0.0860 ±0.0393 Gy, corresponding to 4.01 ±1.21%. The mean ±SD difference between doses calculated by Monte Carlo simulation and TPS for all control points was 0.0996 ±0.0471 Gy, corresponding to 4.58 ±1.05%. The mean ±SD of dose difference between film measurement and Monte Carlo simulation for all control points was 0.0136 ±0.0200 Gy, corresponding to 0.60 ±0.69%. P-value for dose difference between film measurement and TPS, Monte Carlo and TPS, and film measurement and Monte Carlo were 0.7, 0.66, and 0.95, respectively. Conclusions: Dosimetric results and mechanical accuracy of MCCA show that high-temp resin with SLA 3D printing technique can be used for producing patient-specific MCCA in brachytherapy.

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Dosimetric impact of cylinder size in high‐dose rate vaginal cuff brachytherapy (VCBT) for primary endometrial cancer

Cited by 8 publications

References 14 publications

Impact of vaginal cylinder diameter on outcomes following brachytherapy for early stage endometrial cancer

Impact of vaginal cylinder diameter on outcomes following brachytherapy for early stage endometrial cancer

Treating Cylindrically Populated Endometrial Cancers With High Dose Rate Vaginal Cuff Brachytherapy: Should We Use a MulTi-Channel or Single-Channel Cylinder?

Manufacturing and evaluation of multi-channel cylinder applicator with 3D printing technology

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