Individual fraction optimization vs. first fraction optimization for multichannel applicator vaginal cuff high-dose-rate brachytherapy

Symon, Zvi; Menhel, J.; Alezra, D.; Pfeffer, M. Raphael

doi:10.1016/j.brachy.2006.07.002

Cited by 15 publications

(10 citation statements)

References 17 publications

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“…Alternative approaches for a treatment individualized to the patient's anatomy are the use of ovoids for vaginas with ‘‘dog-ear’’ configuration, or a vaginal custom mold [ 10 , 11 ]. The use of anatomically conformal applicators, such as intra-vaginal balloon applicator or multi-channel applicator has been also suggested [ 12 , 13 ].…”

Section: Discussionmentioning

confidence: 99%

Assessment of air pockets in high-dose-rate vaginal cuff brachytherapy using cylindrical applicators

Hassouna¹,

Bahadur²,

Constantinescu³

2014

jcb

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PurposeTo retrospectively assess the incidence and magnitude of air pockets around vaginal cylinders and its impact on dose distribution in vaginal cuff image-guided high-dose-rate (HDR) brachytherapy.Material and methodsFifty endometrial carcinoma patients treated by postoperative HDR vaginal cuff brachytherapy were included in the study. The average age of patients was 58.3 ± 11.8 years (range: 31-87 years). Brachytherapy was performed using cylindrical applicators, and the dose prescribed to 0.5 cm from the applicator's surface, over a length of 5 cm from the applicator's tip. Computed tomography (CT) simulation was used for each brachytherapy fraction. The incidence, vaginal mucosa displacement, volume, and dosimetric effect of air pockets around the vaginal cylinder were evaluated.ResultsA total of 78 air pockets were found in 29/50 patients (58%) and 45/135 (33%) brachytherapy plans. They were located at the apex: 16/78 (20%) and lateral to the applicator: 62/78 (80%). The volume of air pockets ranged between 0.01 and 2.1 cm3 (mean: 0.15 cm3 ± 0.36 cm3), and the maximum displacement of vaginal mucosa from cylinder surface was between 0.1 and 1.09 cm (mean: 0.34 cm ± 0.2 cm). The dose reduction to the vaginal mucosa generated by the air pockets ranged from 0.5 to 66% (mean: 26.4% ± 13.9%).ConclusionsThe presence of air pockets around vaginal cylinder applicators is frequently noticed in post-operative vaginal cuff brachytherapy. The dose to the vaginal mucosa is reduced, as a result of displacement generated by air pockets. The effect on the clinical outcome of this dose reduction is yet to be determined.

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Section: Discussionmentioning

confidence: 99%

Assessment of air pockets in high-dose-rate vaginal cuff brachytherapy using cylindrical applicators

Hassouna¹,

Bahadur²,

Constantinescu³

2014

jcb

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“…Hoskins et al investigated the effect of the cylinder tilt on the sensitive structure volumes and suggested simulation of the applicator position before each fraction (6). Symon et al studied the effects of individualized fraction optimization vs. first fraction optimization for a multichannel vaginal cuff applicator and concluded that individualized fraction optimization was important to minimize doses to critical structures (7). One important limitation of that study, expressed by the authors, was that they did not study the vaginal surface dose.…”

Section: Introductionmentioning

confidence: 92%

Dosimetric Effects of Air Pockets Around High–Dose Rate Brachytherapy Vaginal Cylinders

Richardson

Palaniswaamy

Grigsby

2010

International Journal of Radiation Oncology*Biology*Physics

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“…Future work will be done to evaluate if there is a clinically significant benefit when CT images are acquired and a treatment plan is generated for each fraction. Symon et al ( 10 ) performed such an analysis and concluded that individual fraction optimization may be important to minimize doses to critical structures.…”

Section: Resultsmentioning

confidence: 99%

“…There is currently little guidance about the treatment planning methodology for the Miami applicator and there is limited published literature on this topic. ( 7 , 10 ) Our group developed a standardized procedure in order to achieve an appropriate plan in a timely manner, to reduce the risk of errors in treatment delivery and to increase patient safety. This methodology is presented here, along with the preliminary results obtained.…”

Section: Introductionmentioning

confidence: 99%

Treatment planning methodology for the Miami Multichannel Applicator following the American Brachytherapy Society recently published guidelines: the Lahey Clinic experience

Iftimia

Cirino

Mower

et al. 2013

J Applied Clin Med Phys

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The objective of this study was to develop a standardized procedure from simulation to treatment delivery for the multichannel Miami applicator, in order to increase planning consistency and reduce errors. A plan is generated prior to the 1st treatment using the CT images acquired with the applicator in place, and used for all 3 fractions. To confirm the application placement before each treatment fraction, an AP image is acquired and compared with the AP baseline image taken at simulation. A preplanning table is generated using the EBRT doses and is used to compute the maximum allowable D2cc for bladder, rectum, and sigmoid, and the mean allowable dose for the upper vaginal wall per HDR brachytherapy fraction. These data are used to establish the criteria for treatment planning dose optimization. A step‐by‐step treatment planning approach was developed to ensure appropriate coverage for the tumor (D90>100% prescribed dose of 700 cGy/fraction) and the uninvolved vaginal surface (dose for the entire treatment length > 600 cGy/fraction), while keeping the organs at risk below the tolerance doses. The equivalent dose 2 Gy (EQD2) tolerances for the critical structures are based on the American Brachytherapy Society (ABS) recently published guidelines. An independent second check is performed before the 1st treatment using an in‐house Excel spreadsheet. This methodology was successfully applied for our first few cases. For these patients: the cumulative tumor dose was 74–79 EQD2 Gy10 (ABS recommended range 70–85); tumor D90 was >100% of prescribed dose (range 101%–105%); cumulative D2cc for bladder, rectum, and sigmoid were lower than the tolerances of 90, 75, and 75 EQD2 Gy3, respectively; cumulative upper vaginal wall mean dose was below the tolerance of 120 EQD2 Gy3; the second check agreement was within 5%. By using a standardized procedure the planning consistency was increased and all dosimetric criteria were met.PACS numbers: 87.55‐x, 87.56 bg

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Individual fraction optimization vs. first fraction optimization for multichannel applicator vaginal cuff high-dose-rate brachytherapy

Cited by 15 publications

References 17 publications

Assessment of air pockets in high-dose-rate vaginal cuff brachytherapy using cylindrical applicators

Assessment of air pockets in high-dose-rate vaginal cuff brachytherapy using cylindrical applicators

Dosimetric Effects of Air Pockets Around High–Dose Rate Brachytherapy Vaginal Cylinders

Treatment planning methodology for the Miami Multichannel Applicator following the American Brachytherapy Society recently published guidelines: the Lahey Clinic experience

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