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Biomedical subjects

B B Mittal

Publications and source records attributed to B B Mittal.

At least 37 records · Page 2Linked to original sources
PubMed1996

Hyperfractionated craniospinal radiation in medulloblastoma.

From 1986 to 1991, 13 patients at Northwestern Memorial Hospital were entered onto a pilot study designed to test the feasibility of treating children with medulloblastoma (11 patients) or primitive neuroectodermal tumors of the cerebral hemispheres (2 patients) with hyperfractionated craniospinal radiotherapy (HFxRT). Follow-up times ranged from 10 to 96 months with a median of 53 months. The patients were prospectively divided among three treatment arms depending on prior treatment history, if any, and degree of surgical resection. The 3 patients in group I had undergone gross total resection of the primary site, receiving 64.8 Gy to the primary site and 31.2 Gy directed to the craniospinal axis (CSA). Of these 3 patients, patient 1 had residual disease in the thoracic spine at T-10. The 8 patients in group II, who had gross residual disease remaining at the primary site, received 72 Gy to the primary site and 34 Gy to the CSA. Five of these eight patients in group II also received 8-in-1 chemotherapy. The 2 patients in group III had already failed chemotherapy and were then treated with 60 Gy to the primary site and 26 Gy to the CSA. Of the 11 patients in groups I and II, 7 of the 11 (64%) have never recurred. Two of the three group-I patients have not recurred, and 5 of the 7 group-II patients have not recurred. In addition, patient 7 (group II) remains alive after salvage with bone marrow transplant, following a local failure bordering the tentorium. Unfortunately, neither of the group-III patients could be salvaged with HFxRT. Acute/subacute toxicities included 7 cases of external auditory canal or skin desquamation, 2 cases of postradiation somnolence, and 1 case each of poor wound healing and neutropenia. Chronic toxicities included hypothyroidism in 2 patients and growth problems in 2 patients. Neuropsychologic complications affected only the 3 youngest patients in the study. Three patients developed neurologic sequelae attributed to radiation, including 1 with progressive urinary incontinence, 1 who developed a transient ischemic attack, and 1 who became progressively ataxic. Our research, although based on a small number of patients, suggests that hyperfractionated radiation therapy to craniospinal access is feasible and that the survival results are favorable. This treatment strategy should be further explored in a phase-III randomized trial.

Adolescent↗
PubMed1993

Malignant tumors invading chest wall: treatment with CT-directed implantation of radioactive seeds.

Computed tomography (CT) was used to direct permanent implantation of radioactive iodine-125 seeds in two patients with unresectable lung cancer and in one with recurrent breast cancer invading the chest wall. An average of 60 seeds were implanted, with a mean total radioactivity of 35.6 mCi (1,317 MBq). Tumor coverage was adequate and pain relief was good in all patients. One patient had histologically documented complete response and another had CT-documented partial response.

Aged↗
PubMed1993

Role of radiation therapy in the management of carcinoma in situ of the larynx.

Twenty-one patients with carcinoma in situ of the larynx were treated with definitive irradiation from 1959 to 1987. The in situ changes were limited to 1 vocal cord in 19 patients, and to both vocal cords in 1 patient. One patient demonstrated extensive in situ changes involving the vocal cords bilaterally, as well as the anterior commissure, with both supraglottic and infraglottic extension. The mean follow-up from completion of treatment was 6.2 years, with a median of 50 months. Definitive irradiation resulted in a local control rate of 95%. The patient with extraglottic spread of in situ changes experienced a local failure 7 months after completion of treatment and, despite surgical salvage, died of local recurrence. This patient represents the only recurrence in our series. Our data suggest that radiation therapy can provide excellent control in carcinoma in situ limited to the true vocal cord.

Adult↗
PubMed1992

Effects of hyperthermia and iodine-131-labeled anticarcinoembryonic antigen monoclonal antibody on human tumor xenografts in nude mice.

BACKGROUND: Many studies have demonstrated synergistic interaction between hyperthermia and radiation. This study was undertaken to determine whether hyperthermia could enhance the effect of radioimmunotherapy (RIT) in the treatment of human colon adenocarcinoma xenografts in nude mice. METHODS: The experiments were conducted in two parts. During the first part of the study, preliminary information was obtained regarding the effect of various temperatures (41 degrees C, 42 degrees C, and 43 degrees C for 45 minutes) and iodine-131-labeled anticarcinoembryonic antigen (CEA) monoclonal antibodies (RMoAb) with administered activity ranging from 130 +/- 19 microCi to 546 +/- 19 microCi on tumor regrowth delay (TRD) and volume doubling time. This information was used in Part 2 of the study, which included four groups of mice: (1) a control group, (2) a group treated with hyperthermia, (3) a group treated with RMoAb, and (4) a group treated with a combination of RMoAb and hyperthermia. RESULTS: Maximum and significantly increased TRD was observed in the group treated with RMoAb and hyperthermia (slope, 0.057) compared with the control group (slope, 0.322), the hyperthermia-treated group (slope, 0.302), and the group treated with RMoAb alone (slope, 0.098). The ratio of the slopes between the groups treated with RMoAb and those treated with RMoAb and hyperthermia was 1.72. No correlation was detected between the percent of antibody uptake in the tumor and tumor regression in the groups treated with heat and RMoAb and those treated with RMoAb alone. CONCLUSIONS: The results of these experiments show that hyperthermia increased the effectiveness of iodine-131-labeled anti-CEA monoclonal antibodies against human colon carcinoma xenografts in nude mice. This study offers a rationale for combining hyperthermia and low-dose radiation produced from RIT in clinical practice.

Adenocarcinoma↗
PubMed1992

Initial results for automated computational modeling of patient-specific electromagnetic hyperthermia.

Developments in finite-difference time-domain (FD-TD) computational modeling of Maxwell's equations, super-computer technology, and computed tomography (CT) imagery open the possibility of accurate numerical simulation of electromagnetic (EM) wave interactions with specific, complex, biological tissue structures. One application of this technology is in the area of treatment planning for EM hyperthermia. In this paper, we report the first highly automated CT image segmentation and interpolation scheme applied to model patient-specific EM hyperthermia. This novel system is based on sophisticated tools from the artificial intelligence, computer vision, and computer graphics disciplines. It permits CT-based patient-specific hyperthermia models to be constructed without tedious manual contouring on digitizing pads or CRT screens. The system permits in principle near real-time assistance in hyperthermia treatment planning. We apply this system to interpret actual patient CT data, reconstructing a 3-D model of the human thigh from a collection of 29 serial CT images at 10 mm intervals. Then, using FD-TD, we obtain 2-D and 3-D models of EM hyperthermia of this thigh due to a waveguide applicator. We find that different results are obtained from the 2-D and 3-D models, and conclude that full 3-D tissue models are required for future clinical usage.

Computer Simulation↗
PubMed1992

Results of radiation therapy in early glottic carcinoma: multivariate analysis of prognostic and radiation therapy variables.

A detailed retrospective analysis was performed with 103 patients who had T1 carcinoma of the glottic larynx and underwent radiation therapy between 1960 and 1987. Prognostic and radiation therapy variables were analyzed including sex; age; staging procedures; mucosal extent; histologic grading of tumor; field size; use of wedges; treatment of alternate fields versus both fields every day; nominal standard dose; time, dose, and fraction; dose per fraction; total radiation dose per fraction; total radiation doses; and the impact of cord stripping. Initial local control was 89%, and ultimate control after surgical salvage was 97%, with a 5- and 10-year adjusted survival of 98%. Univariate analysis indicated that larger field size (P = .04), histologic grade (P = .02), and treatment strategy (P = .08) were of some value in predicting recurrence. Multivariate analysis indicated that field size (P = .03) was the only significant variable in predicting local recurrence. These data confirm that radiation is highly effective in the treatment of early laryngeal cancer.

Adult↗
PubMed1992

Radiotherapy of lymphoproliferative diseases of the orbit. Surveillance of 65 cases.

Sixty-five patients with lymphoproliferative disease of the orbit were treated at the Joint Radiation Oncology Center of the University of Pittsburgh. An analysis of these patients was stratified by their initial tumor histopathology: benign lymphoid hyperplasia (BLH) in 28, malignant lymphoma (ML) in 20, and lymphoid infiltrate of indeterminate histology (IH) in 17. The median follow-up was 42 months. Radiation treatment was efficacious in all three groups of patients. The actuarial local recurrence-free survival rate is 84%. Treatment programs usually consisted of 20 to 30 Gy delivered in 10 to 15 fractions. ML patients had significantly lower overall and disease-specific survival rates than IH and BLH patient (p less than or equal to 0.02). BLH patients had a significantly lower local recurrence-free survival than patients with IH and BLH (p = 0.03). There was no significant difference between the three groups of patients with regard to the subsequent development of systemic lymphoma. There were no significant differences in local (16%) or systemic (36%) relapse between patients irradiated with less than 30 Gy or greater than or equal to 30 Gy. Cataracts were detected in 46% of the patients treated with anterior-posterior fields, but none were detected in those treated with other techniques. The results of this study emphasize the importance of long-term follow-up and careful treatment planning for patients with lymphoproliferative diseases of the orbit.

Adolescent↗
PubMed1991

Evaluation of an ingestible telemetric temperature sensor for deep hyperthermia applications.

We have investigated the potential of an ingestible thermometric system (ITS) for use with a deep heating system. The ingestible sensor contains a temperature-sensitive quartz crystal oscillator. The telemetered signal is inductively coupled by a radiofrequency coil system to an external receiver. The sensors, covered with a protective silicon coating, are 10 mm in diameter and 20 mm long and are energized by an internal silver-oxide battery. Experimental studies were carried out to investigate the accuracy of the system and the extent of reliable operation of these sensors in an electromagnetic environment. Different measurements were repeated for five sensors. Calibration accuracy was verified by comparison with a Bowman probe in the temperature range 30 degrees C to 55 degrees C. Linear regression analysis of individual pill readings indicated a correlation within +/- 0.4 degrees C at 95% prediction intervals in the clinical temperature range of 35 degrees C to 50 degrees C. Further work is required to improve this accuracy to meet the quality assurance guidelines of +/- 0.2 degrees C suggested by the Hyperthermia Physics Center. Response times were determined by the exponential fit of heat-up and cool-down curves for each pill. All curves had correlation coefficients greater than 0.98. Time (mean +/- SE) to achieve 90% response during heat-up was 115 +/- sec. Time to cool-down to 10% of initial temperature was 114 +/- 4 sec. The effect of the external antenna and sensor spacing and the angle of orientation of the sensor relative to the antenna plane were also studied. Electromagnetic interference effects were studied by placing the sensor with a Bowman probe in a cylindrical saline phantom for the tests in an annular phase array applicator. Different power levels at three frequencies--80, 100, and 120 MHz--were used. Accurate temperature readings could not be obtained when the electromagnetic power was on because of interference effects with the receiver. However, the temperatures read with the ITS immediately after the electromagnetic power was switched off correlated well with the Bowman probe readings across the power categories and the three frequencies used. The phantom was heated to steady state, with a Bowman probe placed at the central axis of the cylinder used as control. During the heat-up period and the steady state, the mean difference (+/- SE) between the ITS and Bowman probe was 0.12 degrees C (+/- 0.05 degrees C).(ABSTRACT TRUNCATED AT 400 WORDS)

Electromagnetic Fields↗
PubMed1991

Advanced techniques in radiation therapy for head and neck cancers.

This article focuses on a number of innovative radiotherapeutic methods to improve local and regional control with increased chances of preservation of normal function compared with the use of standard external beam irradiation alone in the management of selected head and neck cancers. Some of these radiotherapeutic techniques are well established (brachytherapy and neutron therapy in advanced salivary gland tumors); some have a large body of experience accumulated and are currently being investigated in phase III trials (thermoradiotherapy and altered fractionation); whereas the other techniques (intraoperative therapy, charged-particle therapy, and sterotactic radiosurgery) are highly experimental.

Brachytherapy↗
PubMed1990

Intraoperative radiation of canine carotid artery, internal jugular vein, and vagus nerve. Therapeutic applications in the management of advanced head and neck cancers.

As a step in the application of intraoperative radiotherapy (IORT) for treating advanced head and neck cancers, preliminary information was obtained on the radiation tolerance of the canine common carotid artery, internal jugular vein, and vagus nerve to a single, high-dose electron beam. Both sides of the neck of eight mongrel dogs were operated on to expose an 8-cm segment of common carotid artery, internal jugular vein, and vagus nerve. One side of the neck was irradiated, using escalating doses of 2500, 3500, 4500, and 5500 cGy. The contralateral side of the neck served as the unirradiated control. At 3 and 6 months after IORT, one dog at each dose level was killed. None of the dogs developed carotid bleeding at any time after IORT. Light microscopic investigations using hematoxylin-eosin staining on the common carotid artery and internal jugular vein showed no consistent changes that suggested radiation damage; however, the Masson trichrome stain and hydroxyproline concentration of irradiated common carotid artery indicated an increase in the collagen content of the tunica media. Marked changes in the irradiated vagus nerve were seen, indicating severe demyelination and loss of nerve fibers, which appeared to be radiation-dose dependent. Four patients with advanced recurrent head and neck cancer were treated with surgical resection and IORT without any acute or subacute complications. The role of IORT as a supplement to surgery, external beam irradiation, and chemotherapy in selected patients with advanced head and neck cancer needs further exploration.

Animals↗
PubMed1990

Simultaneous localized 915 MHz external and interstitial microwave hyperthermia to heat tumors greater than 3 cm in depth.

A technique for heating superficial lesions extending to a depth greater than 3 cm using 915 MHz electromagnetic energy is described. It is well established that with external microwave applicators operating at 915 MHz, it is only possible to heat adequately up to a maximum depth of 3 cm. However, it is demonstrated that by implanting additional layers of interstitial microwave antennas (1.5 cm spacing) at required depths greater than 3 cm, and by simultaneously exciting these applicators as well as an external applicator, it is possible to extend the depth of heating at this frequency. A large neck node was successfully heated when this combined technique was used. The details of the method and the equipment used are described. Specific Absorption Rate (SAR) values and temperature distributions obtained during the four treatments delivered to the patient are also presented. This technique can be used in situations where it is not possible to perform extensive interstitial implantation, and in institutions where hyperthermia equipment for heating deeper lesions is not available.

Aged↗
PubMed1989

The role of adjuvant irradiation following primary prostatectomy, based on histopathologic extent of tumor.

One hundred twenty-three patients who underwent primary prostatectomy at Northwestern Memorial Hospital during the-years 1976 to 1985 are reviewed. The patients were divided into three groups: Group 1 (50 patients) comprises patients with tumor well-contained within the prostate and without perineural, perivascular, or lymphatic (NVL) invasion; Group 2 (57 patients) comprises patients with more extensive tumor extending through or to the prostatic capsule, extending to or near the surgical margin, involving seminal vesicles, or having NVL invasion; Group 3 (16 patients) comprises those patients who received immediate postoperative irradiation. The actuarial 10-year local control rates of Group 1 (88%) and Group 3 (100%) were statistically superior to that of Group 2 (72%), p less than 0.05. The actuarial 10-year disease-free survival rate of Group 1 (72%) is statistically superior to that of Group 2 (56%), p less than 0.01; the difference in 10-year disease-free survival between Group 2 (56%) and Group 3 (64%) did not reach statistical significance. Ten-year actuarial survival statistics are 64%, 80%, and 76% for Groups 1, 2, and 3 respectively. There was no statistically significant difference in actuarial survival among any of the groups. Patients with tumor extending to or through the prostatic capsule, extending to or near the surgical margins, involving the seminal vesicles, or having NVL invasion all may benefit from adjuvant irradiation in the immediate perioperative period.

Aged↗
PubMed1989

Combined simultaneous cisplatin/fluorouracil chemotherapy and split course radiation in head and neck cancer.

Fifty-three patients with stage III (eight patients, 15%), stage IV (36 patients, 68%), or recurrent disease (nine patients, 17%) entered a study of simultaneous cisplatin, 60 mg/m2 day 1, fluorouracil (5-FU) infusion, 800 mg/m2 days 1 to 5, and radiation, 2 Gy days 1 to 5, every other week for a total of seven cycles (70 Gy in 13 weeks). Patient acceptance was high, with only two patients (4%) refusing to complete therapy. The median actual dose delivered was 88% of the planned dose for cisplatin, 78% for 5-FU, and 70 Gy for radiation. Weight loss of 10% or more and severe mucositis were the most common side effects (53% and 48% incidence, respectively). All patients were followed at least 1 year (median, 51 months). While the complete response rate (55%) seemed no better than that reported in other series, freedom of progression of regional disease (73%), and the survival of all patients (median, 37 months) were substantially improved. Only 33% of partial responders have failed regionally, while 15% of complete responders have failed regionally (P greater than .10), which indicates that clinical assessment of response was unreliable. Stage, the presence of N3 disease, and delivery of less than the median actual dose received of 5-FU (but not cisplatin) were significantly associated with failure. This regimen is feasible and tolerable in this difficult patient population. It generally requires no special forced feeding techniques. Survival results from this limited institution study appear better than those using sequential multimodality therapies. With such favorable regional control, this approach may offer an alternative in the future to radical surgery and radiation in resectable disease. More definitive evaluation seems warranted.

Actuarial Analysis↗
PubMed1988

Classical and anaplastic seminoma: difference in survival.

Classical and anaplastic seminoma are traditionally treated with radiation therapy and are said to have the same prognosis. A retrospective study was undertaken of 90 seminoma patients treated with radiation therapy between 1961 and 1985. The classical group consisted of 71 patients of whom 50 had stage I and 21 had stage II disease. The anaplastic group consisted of 19 patients of whom ten had stage I and nine had stage II disease. The median follow-up time was 64 months for the entire group. The 10-year relapse-free survival rate for the classical group was 94% and for the anaplastic group was 70% (P less than .05). For patients with classical stage I disease, the relapse-free actuarial survival rate was 98%; for patients with anaplastic stage I disease, it was 64% (P less than .02). For the classical stage II disease group, the relapse-free actuarial survival rate was 84% and for the anaplastic stage II disease group, 75% (P less than .70). Four patients in the classical group (6%) had relapses; of these, one patient had local recurrence of tumor, and three had distant metastases. In the anaplastic group, four patients (21%) had relapses; two patients had local recurrence of tumor, and two had distant metastases. Therefore the data suggest a difference in survival and relapse rates between classical and anaplastic seminoma.

Adolescent↗
PubMed1986

Radiation therapy for local-regional recurrent breast carcinoma.

One hundred seven women with recurrent breast carcinoma involving the chest wall and/or regional lymph node regions were treated with radiotherapy between 1970 and 1979. Local-regional tumor was the initial and only evidence of recurrent breast carcinoma in all cases. Forty-seven patients had their disease confined to the chest wall alone and sixty (56%) patients had chest wall involvement as some component of their local-regional recurrent disease. Within five years after the initial mastectomy, 80.5% of recurrences were manifested. All patients had radiotherapy to at least the site of involvement. Eighty-four patients (78.5%) had a complete response. The absolute 5-year survival of all patients following local-regional recurrence was 34.6%. Five year survival was 29% in those patients who had recurrence within 5 years of the original mastectomy. For those patients whose local-regional recurrence occurred after a 5-year disease-free interval, the subsequent 5-year survival was 57%. For patients with recurrence confined to the chest wall, subsequent 5-year survival was 48.9%. Patients who had supraclavicular involvement as part of their local-regional recurrence had only a 16.1% 5-year survival. The majority of patients developed distant metastasis. Twenty-two patients developed carcinoma of the contralateral breast following local-regional recurrence. Five year survival following local-regional recurrence was only 4.3% for patients whose initial treatment for their primary breast carcinoma was surgery and adjuvant chemotherapy. For those patients whose primary breast carcinoma was treated by surgery alone or surgery and post-operative radiotherapy, the 5-year survival following local-regional recurrence was over 40%.

Breast Neoplasms↗