Personnel exposure during gamma endovascular brachytherapy.

PURPOSE: The use of 192Ir brachytherapy for the treatment of in-stent restenosis of the coronary arteries has shown promising clinical results. This paper investigates the radiation exposure of catheterization laboratory staff associated with the performance of this procedure. METHODS AND MATERIALS: Cath lab staff were monitored using personal monitors (shielded against fluoroscopic x-rays) during the performance of eleven cases using nominal 10 GBq 192Ir sources. Staff positions in the lab were simultaneously tracked by video cameras. Direct measurements were also made using a survey meter. Treatments were administered in a conventional cardiac-catheterization-laboratory. RESULTS: The dosimeter readings were analyzed in combination with the radiation survey and time motion survey. Brachytherapy procedural times for the cardiologist, oncologist, physicist, and angiographic assistants were, respectively, 26 +/- 24, 401 +/- 132, 486 +/- 148, and 7 +/- 13 s per case (mean +/- standard deviation). Readings of the personnel monitors were low. Credible upper limits of the respective doses are estimated to be less than 10, 10, 7, and 5 microSv per procedure. Auxiliary shields reduced the dose to individuals located outside of the catheterization laboratory to less than 0.5 microSv per procedure. CONCLUSIONS: The average radiation dose received by laboratory personnel during a representative 192Ir endocoronary brachytherapy procedure is estimated to be less than 0.1% of the NCRP recommended annual radiation worker's Maximum Permissible Dose (1% of the general public's MPD). This level is justifiable as long as the use of 192Ir benefits patients by producing an improved clinical outcome relative to the use of a less penetrating radionuclide or the application of alternative therapies. Further optimization of the delivery procedure is expected to reduce staff dose.

Treatment of a large high-grade neurofibrosarcoma with concomitant vinblastine, doxorubicin, and radiotherapy.

A patient with neurofibromatosis developed a large inoperable malignant schwannoma on the posterior neck. The tumor underwent complete local regression following combined-modality treatment with radiotherapy, vinblastine, and doxorubicin. Vinblastine may be effective in combined-modality therapy.

Clinical features and treatment outcome of patients with epithelial carcinoma of the ovary metastatic to the central nervous system.

Involvement of the central nervous system with carcinoma of the ovary is being noted with increasing frequency. We report on six patients who presented with central nervous system metastases between 2-61 months after diagnosis. Five patients had elevated serum CA 125 values at the time of diagnosis of central nervous system disease and presenting symptoms, and findings on neurologic examination generally correlated with computed tomography-documented lesions. Eighty-three percent of our patients were symptomatically relieved with a course of 30 Gy given to the whole brain; however, there were no long-term survivors (range 2-24 months). Survival did not appear prolonged in the four patients who received systemic chemotherapy as well as whole-brain irradiation.

Activity of pp60c-src protein kinase in human breast cancer.

Because there is elevation of pp60c-src activity in breast carcinoma tissue, we analyzed primary breast cancer tissue samples from 30 women to determine whether pp60c-src activity correlated with specific clinical parameters. We found that tumors with a progesterone receptor had higher pp60c-src activity than tumors without such a receptor. But there was no association of pp60c-src activity with the presence of an estrogen receptor or of nodes, or with menopausal status or age. The function of pp60c-src in normal cells and in breast cancer is unknown, as is the significance of our finding of an association of elevated pp60c-src activity and the presence of progesterone receptors.

Combined chemotherapy and radiation therapy for advanced carcinoma of the cervix.

Ten patients with advanced squamous cell carcinoma of the uterine cervix received induction chemotherapy with cis-platinum, mitomycin-C, vincristine, and bleomycin (BOMP) over a 5 week period, followed by radiotherapy with concomitant weekly cisplatinum. Two patients were FIGO stage I-B barrel-shaped, five were stage II-B, and three were III-B. All patients responded to induction chemotherapy with five complete and five partial responses. At the completion of radiation therapy, nine patients had negative biopsies. One patient never reached a complete response and died of distant metastasis. Another underwent total exenteration for a central recurrence and was found to have microscopic paraaortic lymph node involvement. A third recurred in the parametrium. Two patients with barrel-shaped tumors underwent extrafascial hysterectomies; both had negative specimens and tolerated surgery well. Although follow-up is short, this new approach for advanced carcinoma of the cervix yielded excellent results and was well tolerated.

Transmission block to simplify combined pelvic and inguinal radiation therapy.

A homogeneous dose distribution of radiation to inguinal lymph nodes and deep pelvic structures can be achieved with use of a transmission block over the central portion of a large anterior pelvic-inguinal portal, together with a smaller posterior field. This relatively simple technique permits individualization of isodose distributions and eliminates the problems of matching abutting portals. Reproducibility of daily setup and optimization of machine utilization are both improved.

Antibody-mediated radiotherapy.

Antibodies that react with antigens on the surface of tumor cells but not normal cells have great potential for cancer detection and therapy. If radiolabeled without loss of immunologic specificity, such antibodies may be able to deliver cytoxic amounts of radiation. Target-cell specificity and a high extraction coefficient are necessary with any radionuclide in order to minimize normal tissue irradiation. Tumor-cell-retention time and the rate of catabolized radionuclide will also influence ultimate applicability. Among the unanswered questions for choosing a radionuclide is the choice of particle emitter. Although classic beta emitters have been used in a number of clinical situations, they have not had a major impact on disease outcome except in diseases of the thyroid. Unfortunately, Auger emitters such as iodine 125 are cytotoxic only when localized within close proximity to the genome. On the other hand, alpha emitters such as astatine 211 eliminate the need for subcellular sequestration but not cell-specific localization.