Biomedical subjects

K K Dass

Publications and source records attributed to K K Dass.

10 recordsLinked to original sources

PubMed1994

Endobronchial radiation therapy with or without neodymium yttrium aluminum garnet laser resection for managing malignant airway obstruction.

BACKGROUND: Previous reports have shown low-dose-rate (LDR) afterloading Ir-192 endobronchial radiation therapy (EnBRT) to effectively palliate symptoms in patients with malignant airway obstruction. The authors retrospectively assessed the consequences of LDR EnBRT with or without neodymium yttrium aluminum garnet (Nd:YAG) laser resection in 37 patients. METHODS: Between February 1986 and June 1991, 37 patients with malignant airway obstruction were treated with LDR EnBRT at The Cleveland Clinic Foundation. Inclusion criteria for LDR EnBRT with or without Nd:YAG laser resection were patients with recurrent, symptomatic endobronchial lesions treated previously with external beam irradiation. Of the 37 patients, 21 patients with endobronchial lesions underwent Nd:YAG laser resection; 16 patients with mainly extrinsic lesions received EnBRT only. Before EnBRT, selected patients (7 of 16 in the nonlaser-treatment group and 14 of 21 in the laser-treatment group) received additional external beam treatments of 2000 cGy/10 fractions. The LDR afterloading Ir-192 technique was used to deliver approximately 30 Gy to a 1.0-cm radius target. RESULTS: All patients had one or more of the following symptoms: 1) dyspnea, 2) fever, 3) cough, and 4) hemoptysis. Good-to-excellent symptom relief was apparent in 16 of 21 (76.2%) laser-treated patients and in 12 of 16 (75%) nonlaser-treated patients. Follow-up bronchoscopy in 28 patients revealed tumor regression in 22 (79%). Median survival time was 16.3 weeks in the laser group and 11.7 weeks in the nonlaser group (P = 0.36). Longer median survival times were noted in laser-treated (22.8 weeks) and nonlaser-treated (16.4 weeks) patients receiving additional external beam treatments. Exsanguination occurred in 7 of 21 (33.3%) laser-treated patients and in 4 of 16 (25%) nonlaser-treated patients. The only factor affecting the exsanguination rate was implant location: 6 of 11 (54.5%) patients had lesions in the right or left upper lobe. CONCLUSIONS: EnBRT alone or with Nd:YAG laser resection provided good-to-excellent symptom palliation in these patients although a high rate of exsanguination occurred in both groups.

Adult↗

PubMed1994

Uniform irradiation of the craniospinal axis with a penumbra modifier and an asymmetric collimator.

PURPOSE: A technique is described that uses an independent, asymmetric collimator and a penumbra modifier to uniformly administer radiation over the craniospinal axis. METHOD AND MATERIALS: An isocenter is used at the junction of the cranial and the upper spinal fields. These fields are defined by a single isocenter at spinal cord depth and an independent, asymmetric collimator. From the isocenter, the cranial and upper spinal fields are extended 1 cm inferiorly and superiorly, respectively. A modifier provides a 2-cm wide penumbra at the central axis of the beam (overlapping region) and is attached to a wedge tray in an accessory slot. This modifier allows the fields to be matched so a uniform dose is delivered over the isocenter and junction. Dose distribution was measured with an anthropomorphic head-and-neck wax phantom that included the seventh cervical vertebrae. A film was placed in a coronal cut at the spinal cord level. RESULTS: The administered dose varied less than 10% through the craniospinal axis. Reproducibility with portal films has been very good. Advantages include dose homogeneity, easy reproducibility, and decreased setup time. CONCLUSION: This single-field isocentric technique allows more uniform irradiation of the craniospinal axis than do previously described techniques.

Head and Neck Neoplasms↗

PubMed1993

Malignant mixed mullerian tumors of the ovary. An analysis of two long-term survivors.

Long-term survival following the diagnosis of ovarian malignant mixed mullerian tumor (MMMT) is unusual. This report analyzes two such long-term survivors. One patient presented with a FIGO Stage III, homologous MMMT treated initially with a combination of surgery and chemotherapy. Residual disease, present at the time of initial operation, responded to the chemotherapy; however, the tumor recurred 2 1/2 years postoperatively. This recurrence responded to a combination of surgery and chemotherapy, including continuous adjuvant chemotherapy. This patient is alive, on maintenance chemotherapy, and without evidence of disease, approximately 7 years after the recurrence and 9 years after the initial presentation. The other patient presented with a FIGO Stage III heterologous MMMT treated initially with combined surgery and chemotherapy. Residual disease was present at the time of initial operation. Persistent pelvic disease led to exploratory laparotomy, excision of an 8-cm diameter pelvic mass, and postoperative radiation therapy. The tumor recurred in the left supraclavicular lymph nodes 2 years later (3 years after the initial presentation). This recurrence responded to radiation therapy. This patient was last seen 2 years later (5 years after the initial presentation). At that time, she was without evidence of recurrence. She died 7 1/2 years after her initial presentation. These two patients represent examples of the unusual occurrence of patients with advanced-stage ovarian MMMT experiencing long-term survival following surgical and adjuvant therapy.

Aged↗

PubMed1975