Publications

PURPOSE

This study reports on prostate edema after prostate brachytherapy using Cesium-131 ((131)Cs) and describes our method to compensate.

METHODS AND MATERIALS

Thirty-one patients underwent brachytherapy using an afterloading technique. Volume measurements of the prostate were taken at various time intervals relative to the date of implant. Real-time operating room dosimetry was used for seed placement on the postneedle prostate volume. The prostate volumes at the various time points were used to determine the effect of prostate edema on dosimetry.

RESULTS

Increase in prostate volume occurred immediately after needle placement, as measured by both ultrasound (mean increase of 17.7% (0-75.0%) from 36.8 to 46.9 cc) and Day 0 CT (mean increase of 15.3% (0-54.8%) to 45.9 cc). Day 0 assessment of dosimetry revealed a median D(90) of 102.7% (86.7-133.4%), median V(100) of 91.8% (75.9-98.4%), median V(150) of 44.4% (23.8-81.3%), and median V(200) of 16.3% (7.8-36.9%). This edema dissipated over the next 4 weeks, with resultant changes in dosimetric parameters. By 4 weeks, prostate volume had returned to the preimplant volume (37.7 cc) with increased D(90) (118.2%), V(100) (95.6%), V(150) (63.9%), and V(200) (28.4%).

CONCLUSIONS

There is significant immediate edema with prostate brachytherapy. This affects the dosimetry of the implant substantially. Because of this edema, our planning for brachytherapy is done on the postneedle implant volume. Quality assurance studies should be done on the same day as the implant to avoid substantial overestimation of dosimetric parameters.

BACKGROUND

Fluorescent reporters are useful for assaying gene expression in living cells and for identifying and isolating pure cell populations from heterogeneous cultures, including embryonic stem (ES) cells. Multiple fluorophores and genetic selection markers exist; however, a system for creating reporter constructs that preserve the regulatory sequences near a gene's native ATG start site has not been widely available.

METHODOLOGY

Here, we describe a series of modular marker plasmids containing independent reporter, bacterial selection, and eukaryotic selection components, compatible with both Gateway recombination and lambda prophage bacterial artificial chromosome (BAC) recombineering techniques. A 2A self-cleaving peptide links the reporter to the native open reading frame. We use an emerald GFP marker cassette to create a human BAC reporter and ES cell reporter line for the early cardiac marker NKX2-5. NKX2-5 expression was detected in differentiating mouse ES cells and ES cell-derived mice.

CONCLUSIONS

Our results describe a NKX2-5 ES cell reporter line for studying early events in cardiomyocyte formation. The results also demonstrate that our modular marker plasmids could be used for generating reporters from unmodified BACs, potentially as part of an ES cell reporter library.

PURPOSE OF REVIEW

Evaluation and management of patients with pulmonary nodules continue to be a significant clinical challenge due to the possibility of malignancy.

RECENT FINDINGS

With advances in technology, several minimally invasive diagnostic options are available for diagnosis of peripheral pulmonary lesions. Development and refinement of minimally invasive sampling techniques will aid in clinical decision making, as well as help advance scientific understanding of lung cancer growth and metastasis.

SUMMARY

Although most surgical candidates should be referred promptly for resection, transthoracic or bronchoscopic biopsy may be particularly helpful when an infectious cause is suspected, when the patient is a marginal or poor candidate for surgery, or when a surgical candidate desires proof of malignancy before proceeding to surgery.Newer minimally invasive techniques should be rigorously evaluated for their role in the diagnostic algorithm of peripheral lung lesions.