A dose homogeneity index for evaluating 192Ir interstitial breast implants

Wu, Andrew; Ulin, Kenneth; Sternick, Edward S.

doi:10.1118/1.596152

Cited by 135 publications

(43 citation statements)

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“…Sparing of the healthy tissues (skin, lung) was possible using the 3D CT-based planning (Figure 2). The dose homogeneity index was used to assess the implant quality [8]. Irradiation with fractionated brachytherapy was started between days 11 and 19 (median day 13) after surgery using the Iridium 192 HDR afterloading machine (GammaMedplus, Varian Medical Systems, USA).…”

Section: Figure 1amentioning

confidence: 99%

Perioperative interstitial CT-based brachytherapy boost in breast cancer patients with breast conservation after neoadjuvant chemotherapy

Doležel¹,

Šťastný²,

Odrážka³

et al. 2012

neo

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Intraoperative placement of catheters in the tumor bed during breast-conserving surgery (BCS) enables postponed targeted boost irradiation in high risk breast cancer patients. Twenty-three patients with high risk breast cancer underwent neoadjuvant chemotherapy and multifractionated perioperative brachytherapy as a boost to the tumor bed using threedimensional (3D) CT-based planning. Plastic catheters for brachytherapy were implanted during surgery and targeted irradiation was delivered in the course of 2-3 weeks. Acute and late toxicities were scored according to the RTOG Common Toxicity Criteria. Cosmetic outcomes were assessed using the Harvard criteria. No major perioperative complications were recorded. Circumscribed wound infection occurred in one patient (4.3%). Only 3 patients (13%) experienced acute skin toxicity Grade 1. We observed no teleangiectasias or pigmentations. The cosmetic outcome at last follow-up visit was rated as excellent/good, in 82.6%, fair, in 13% and poor in 4.4% of patients, respectively. There was no evidence of disease recurrence after median follow-up of 43. 4 months. Systematic integration of the perioperative fractionated 3D CT-based HDR brachytherapy as a boost for patients with breast cancer after BCS is feasible and seems safe. It might be beneficial especially for women with high risk of local recurrence.

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Section: Figure 1amentioning

confidence: 99%

Perioperative interstitial CT-based brachytherapy boost in breast cancer patients with breast conservation after neoadjuvant chemotherapy

Doležel¹,

Šťastný²,

Odrážka³

et al. 2012

neo

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“…HI ( 9 ) measures the fraction of target volume receiving dose in the interval of 1.0 to 1.5 times the reference dose.

HI = ({normalV}_{100} - {normalV}_{150}) / {normalV}_{tot}

…”

Section: Methodsmentioning

confidence: 99%

Dosimetric comparison of various optimization techniques for high dose rate brachytherapy of interstitial cervix implants

Shwetha

Ravikumar

Katke

et al. 2010

J Applied Clin Med Phys

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HDR brachytherapy treatment planning often involves optimization methods to calculate the dwell times and dwell positions of the radioactive source along specified afterloading catheters. The purpose of this study is to compare the dose distribution obtained with geometric optimization (GO) and volume optimization (VO) combined with isodose reshaping. This is a retrospective study of 10 cervix HDR interstitial brachytherapy implants planned using geometric optimization and treated with a dose of 6 Gy per fraction. Four treatment optimization plans were compared: geometric optimization (GO), volume optimization (VO), geometric optimization followed by isodose reshape (GO_IsoR), and volume optimization followed by isodose reshape (VO_IsoR). Dose volume histogram (DVH) was analyzed and the four plans were evaluated based on the dosimetric parameters: target coverage (normalV100), conformal index (COIN), homogeneity index (HI), dose nonuniformity ratio (DNR) and natural dose ratio (NDR). Good target coverage by the prescription dose was achieved with GO_IsoR (mean normalV100 of 88.11%), with 150% and 200% of the target volume receiving 32.0% and 10.4% of prescription dose, respectively. Slightly lower target coverage was achieved with VO_IsoR plans (mean normalV100 of 86.11%) with a significant reduction in the tumor volume receiving high dose (mean normalV150 of 28.29% and mean normalV200 of 7.3%). Conformity and homogeneity were good with VO_IsoR (mean COIN=0.75 and mean HI=0.58) as compared to the other optimization techniques. VO_IsoR plans are superior in sparing the normal structures while also providing better conformity and homogeneity to the target. Clinically acceptable plans can be obtained by isodose reshaping provided the isodose lines are dragged carefully.PACS number: 87.53 Bn

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“…For the target volume, the dose coverage of %PTV_EVAL was calculated as the percentage volume of PTV_EVAL receiving the prescribed dose (V100%) after accounting for the trapped air gap on the surface of balloon, if present. ( 6 ) In addition, DHI ( 7 – 8 ) and COIN ( 7 , 9 – 10 ) values were evaluated over the PTV_EVAL volume. The DHI value was computed by

DHI = (V 100 [cc] - V 150 [cc]) / V 100 [cc]

.…”

Section: Methodsmentioning

confidence: 99%

Comparison of single and multiple dwell position methods in MammoSite high dose rate (HDR) brachytherapy planning

Kim

Trombetta

Miften

2010

J Applied Clin Med Phys

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The purpose of this study is to dosimetrically compare two plans generated using single dwell position method (SDPM) and multiple dwell position methods (MDPM) in MammoSite high dose rate (HDR) brachytherapy planning for 19 breast cancer patients. In computed tomography (CT) image‐based HDR planning, a surface optimization technique was used in both methods. Following dosimetric parameters were compared for fraction 1 plans: %PTV_EVAL (planning target volume for plan evaluation) coverage, dose homogeneity index (DHI), dose conformal index (COIN), maximum dose to skin and ipsilateral lung, and breast tissue volume receiving 150% (V150[cc]) and 200% (V200[cc]) of the prescribed dose. In addition, a plan was retrospectively generated for each fraction 2–10 to simulate the clinical situation where the fraction 1 plan was used for fractions 2–10 without modification. In order to create nine derived plans for each method and for each of the 19 patients, the catheter location and contours of target and critical structures were defined on the CT images acquired prior to each fraction 2–10, while using the same dwell‐time distribution as used for fraction 1 (original plan). Interfraction dose variations were evaluated for 19 patients by comparing the derived nine plans (each for fractions 2–10) with the original plan (fraction 1) using the same dosimetric parameters used for fraction 1 plan comparison. For the fraction 1 plan comparison, the MDPM resulted in slightly increased %PTV_EVAL coverage, COIN, V150[cc] and V200[cc] values by an average of 1.2%, 0.025, 0.5 cc and 0.7 cc, respectively, while slightly decreased DHI, maximum skin and ipsilateral lung dose by an average of 0.003, 3.2 cGy and 5.8 cGy, respectively. For the interfraction dose variation comparison, the SDPM resulted in slightly smaller variations in %PTV_EVAL coverage, DHI, maximum skin dose and V150[cc] values by an average of 0.4%, 0.0005, 0.5 cGy and 0.2 cc, respectively, while slightly higher average variations in COIN, maximum ipsilateral lung dose and V200[cc] values by 0.0028, 0.2 cGy and 0.2 cc, respectively. All differences were too small to be clinically significant. Compared to the MDPM, the SDPM combined with a surface optimization technique can generate a clinically comparable fraction 1 treatment plan with a similar interfraction dose variation if a single source is carefully positioned at the center of the balloon catheter.PACS number: 87.53.Jw

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A dose homogeneity index for evaluating ¹⁹²Ir interstitial breast implants

Cited by 135 publications

References 0 publications

Perioperative interstitial CT-based brachytherapy boost in breast cancer patients with breast conservation after neoadjuvant chemotherapy

Perioperative interstitial CT-based brachytherapy boost in breast cancer patients with breast conservation after neoadjuvant chemotherapy

Dosimetric comparison of various optimization techniques for high dose rate brachytherapy of interstitial cervix implants

Comparison of single and multiple dwell position methods in MammoSite high dose rate (HDR) brachytherapy planning

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