ABSTRACT
Objectives: The aim of this study is to address the limitation of combined intracavitary-interstitial (IC/IS) brachytherapy (BT) in locally advanced cervical cancer using standardized applicators and to determine the optimal dose distribution in patients with challenging tumors, innovative methods of customizing and optimizing the IS needle configuration for combined IC/IS BT are proposed and investigated. Materials and Methods: A software module that could customize the IS needle configuration and subsequently generate the digital model of guiding template for three-dimensional printing was developed and integrated into our in-house treatment planning system for BT. The inverse optimization method based on the technique of mixed-integer linear programming was introduced to determine the needle tracks out of a candidate pool and dwell times at corresponding locations to best meet dose objectives. A treatment planning study was conducted to evaluate the feasibility and performance of the proposed methods. Results: The workflow for combined IC/IS BT with customized and inverse optimized IS needle configuration was presented. Dosimetric results of the treatment planning study showed that sufficient target coverage could be obtained with the customized IS needle configuration for challenging cases. The proposed dose-based optimization method for IS needle configuration was feasible and effective. Improved target coverage and organ-at-risk sparing were achieved using the inverse planning method. Conclusions: Using the proposed methods of customizing and optimizing the IS needle configuration, the limitation in the standardized design of combined IC/IS applicators can be addressed, and sufficient target coverage is obtained in cervical cancer patients with unfavorable tumor topography and/or extra lateral expansion.
ABSTRACT
Objective@#To summarize the individual design of the perforator flap based on the descending branch of the lateral circumflex femoral artery and ecological protection of the flap.@*Methods@#From June 2013 to June 2017, 33 cases of extremities wound defects were repaired with the descending branch perforator flap of the lateral circumflex femoral artery. According to the chracteristics of extremity wound and the anatomy of the descending branch perforator of the lateral circum flex artery, a medial incision of the flap according to the demarcation line was performed. Through meticulous dissection, two perforator branches were found and traced on the surface of facia lata. The size of the kiss flap was adjusted according to the perforator caliber. The chimeric muscular flap was incised according to muscular penetration point of the perforator and the course of lateral fermoral nerve with cautious protection of muscular branch of femoral nerve. During the incision, fascia lata, nerves and muscles on donor site were protected to reduce the damage to donor site. Meanwhile, ecological structure on donor site was reconstructed. Our series include 22 males, 11 females. The average age ranged from 13 to 71 years (mean: 47years). There were 21 cases of wounds on dorsum manus and wrists and 12 cases of wounds on the dorsum pedis and lower limbs. The wound dimension ranged from 7 cm×8 cm to 13 cm×24 cm. The flap dimension ranged from 6 cm×7 cm to 8 cm×15 cm.There were 22 cases of KISS flaps and 11 cases of chimeric flaps. Wounds on all donor sites were primarily sutured. Course of the disease ranged from 1 week to 2 months.@*Results@#All flaps were harvested uneventfully and survived well. No vascular crisis occurred. Wounds on all donor sites were primarily sutured. Three to 24 (mean 18) months of follow-up was made on 28 cases. The color and texture of flaps was good. Appearance of the flaps was good. Protective sensation recovered. Only linear scar can be seen on donor sites. No muscular hernia and cinesipathy was noticed on donor sites.@*Conclusions@#The size of KISS flaps depends on the caliber of perforator branch estimated intraoperatively. Muscular part of the chimeric flaps was harvested according to the muscular entry points of perforators and the demand of recipient sites. The wound defects were reconstructed individually according to the peculiarity of the defects. Fascialate, nervus cutaneus and muscle was cautiously protected in the course of flap harvest. Ecological structure was reestablished after flap harvest to reduce complications.