These findings indicate that breast stroma tissue outside the incident tumor can be quantified using signal enhancement ratio analysis on dynamic contrast-enhanced MRI. Stromal signal enhancement ratio is a potential indicator for response to treatment and for overall outcome in patients with breast cancer; however, these results should be validated in a prospective study.

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BackgroundTissue expanders are used in breast reconstruction after mastectomy to stretch the remaining tissue to create space for placement of permanent breast implants. The AeroForm™ Tissue Expander, developed by AirXpanders™ Inc., contains electronic components designed to activate the release of carbon dioxide from an internal reservoir to inflate the expander. Breast cancer patients who undergo mastectomy and tissue expander/implant-based breast reconstruction may require radiation therapy at doses up to 50–60 Gy while the expander is in place. The ionizing radiation used in postmastectomy radiation therapy interacts with electronic components in medical implants, which may cause degradation in performance above certain levels. Most commercial electronic components used in medical devices, such as complementary metal-oxide semiconductor or bipolar integrated circuits can withstand radiation levels in the 50 Gy range without any performance degradation. Beyond this level, the performance may still be sufficient to guarantee functionality, but this needs to be confirmed at the system and electronic circuit level. We assessed the impact of radiation levels up to 75 Gy on 32 AeroForm™ Tissue Expanders (AirXpanders, Inc., Palo Alto, CA USA) and on the associated internal printed circuit assemblies.FindingsThe electronics inside the AeroForm™ Tissue Expander implant continued to function properly after exposure to radiation levels up to 75 Gy, which is well above the maximum total dose level typically used in postmastectomy radiation therapy.ConclusionsStandard postmastectomy radiation therapy doses do not damage or affect the functionality of the AeroForm™ Tissue Expander.

Purpose This study aims to investigate a new planning method that avoids the match-line while maintaining larynx protection as in split field intensity-modulated radiation therapy (IMRT) and to evaluate the potential match-line dose variations with split IMRT. Methods/materials The new planning method, referred to as selective extended-field IMRT, selected anterior and anterior oblique fields to treat the entirety tumor volumes while restricting other IMRT fields from treating the tumor volumes below the larynx. Five patients with nasopharyngeal cancer, who underwent conventional extended-field IMRT, were replanned using the selective extended IMRT and split-field IMRT techniques. Results When treatment goals to the target volumes were met, selective extended-field IMRT resulted in an average mean larynx dose of 28.6±1.4 Gy, as compared with 41.9±10.6 and 29.3±5.6 Gy for extended-field and split-field IMRT, respectively. For other organs at risk, there were no significant dose differences (p>0.05) among three planning methods. Conclusions Selective extended-field IMRT achieves comparable tumor volume coverage as the conventional extendedfield IMRT and comparable larynx sparing as split-field IMRT while eliminating field matching.

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