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Biomedical subjects

J L Beach

Publications and source records attributed to J L Beach.

At least 19 recordsLinked to original sources
PubMed1997

A precision repeat localization head frame for fractionated stereotactic radiotherapy.

An immobilization device was constructed for Fractionated Stereotactic Radiotherapy (FSRT) based on registration of the teeth and facial bones in a single thermoplastic mask system, along with a custom hardened foam pillow for posterior head immobilization relative to the mask. The unit interfaces mechanically with all of our current radiosurgery equipment and can be used with any standard stereotactic planning system. After initial trials to design a reproducible radiographic localization test, we performed a series of daily AP and Lateral port films on 3 patients over five isocenters. Seventy-nine films were reviewed and the maximum deviation in anatomical projection in both sagittal and coronal planes was less than 2 mm, with over 60% of films showing no distinguishable deviations from initial port films. Ninety-three percent of the test films showed a repositioning accuracy of less than 1 mm for all tested structures. We have developed an accurate, non-invasive means of repeat head immobilization that, when properly constructed, can facilitate precise fractionated stereotactic radiation therapy with patient comfort, ease of construction and long term stability.

Humans↗
PubMed1991

A rapid-afterloading vaginal cylinder for 137Cs brachytherapy.

A small diameter, single-step afterloading vaginal cylinder has been developed for 137Cs brachytherapy of the vaginal cuff and walls. The Lucite cylinder has an interior slot of rectangular cross section running along its length and opening to the outside of the patient. A single rectangular Lucite insert, containing preselected sources, fits into the slot. Two short sources in the tip form a T with the sources along the vaginal canal and provide a high, uniform dose rate across the spherical tip of the applicator. A catalog of 30 precalculated loadings provides surface dose rates at the tip which vary from 140 to 230 cGy/hr for standard source strengths, as well as a variety of dose rate profiles along the vaginal wall. The applicator is tapered at the base for comfortable and secure placement, and the single-step insertion reduces both patient discomfort and personnel radiation exposure for this procedure.

Brachytherapy↗
PubMed1990

Boron neutron capture enhancement of 252Cf brachytherapy.

Dosimetric and radiobiological studies were undertaken to investigate the potential enhancement in dose, dose distribution and cell killing effectiveness of 252Cf brachytherapy achievable when boron-10 enriched compounds are incorporated into simulated 252Cf brain implants. Thermal neutron distributions in a human head phantom containing a 252Cf source were measured by gold foil activation and calculated using a 1-dimensional transport code. This information was then used to modify measured event size distributions for 252Cf neutrons to determine the corresponding increase in dose and dose equivalent throughout the phantom. The addition of subtoxic levels of boron-10 to a typical 252Cf implant was found to significantly enhance both the absorbed dose and the high LET event frequency at distances of 3 to 5 cm from individual sources. Some unexpected geometric considerations are discussed. Reduced survival of cultured Chinese hamster cells correlated with the predicted increase in absorbed dose from the capture events with a concentration of about 60 micrograms 10B per ml in the culture medium. It was found that boron increased alpha (the "single-hit" parameter of the linear quadratic survival model) by 32% and decreased beta (the "double-hit" parameter) by 8%. The alpha/beta ratio increased to 4.34 Gy in the presence of boron, from 3.03 Gy in its absence. This translated to an 8% reduction in californium dose needed to effect 10% cell survival. It is concluded that there is a sufficiently high thermal neutron fluence present during californium brachytherapy for boron neutron capture dose augmentation to be feasible.

Animals↗
PubMed1989

Killing of human lung cancer cells using a new [111In]bleomycin complex [111In]BLMC.

The ability of a [111In]bleomycin complex [( 111In]BLMC) to kill five cell lines of human lung cancer (small cell lung cancer) was investigated. Cells were exposed to either 0.9% NaCl, [111In]Cl3, BLM, [111In]BLMC, nonradioactive InCl3, or In-BLMC for 60 minutes, plated in soft agarose, and assessed for colony formation. [111In]BLMC (40-200 microCi carried by 15-25 micrograms BLM/ml) was more cytotoxic than BLM (15-25 micrograms BLM/ml) by a factor of 1.6-5.3 for five cell lines. The percent survival of N417 cells was 28.4 for [111In]BLMC (40 microCi/15 micrograms BLM/ml) and 54.3 for BLM (15 micrograms/ml); 1.9 for [111In]BLMC (200 microCi/25 micrograms BLM/ml), and 10.0 for BLM (25 micrograms/ml). 111InCl3 (200 microCi/ml) and nonradioactive InCl3 failed to inhibit colony formation. The new [111In]BLMC may be useful for therapy of some lung cancer patients.

Autoradiography↗
PubMed1988

Neutron interstitial brachytherapy for malignant gliomas: a pilot study.

Fifty-six patients with malignant glioma were treated with implantation of the neutron-emitting element californium-252 (252Cf) within 2 weeks after surgical debulking of the tumor. Implantation was performed using computerized tomography-guided placement of afterloading catheters, and the 252 Cf sources were removed after approximately 300 neutron rads were delivered. Patients then received 6000 to 7000 conventional photon rads by external beam. The total photon-equivalent dose to the tumor ranged from 8100 to 9100 rads. The median survival time was 10 months, with 18-and 24-month survival rates of 28% and 19%, respectively. The results of reoperation or autopsy showed that patients had recurrence of the tumor but that radiation necrosis was restricted to the area of the original tumor. Serious complications occurred in five patients (9%) and consisted of wound infections in three, cerebral edema in one, and radiation necrosis beyond the original tumor margin in one. Previous studies using external-beam neutron radiation have shown that neutrons are capable of totally eradicating malignant gliomas; however, in most cases, unacceptable widespread radiation necrosis has resulted. Neutron implants are a logical way to increase the dose to the tumor and decrease the dose to normal brain. Interstitial neutron radiation can be given safely with 252Cf, and the survival results achieved by radiation alone using relatively low doses of interstitial neutron radiation from 252Cf implants plus conventional photon radiation were equal to the results attained with any currently available conventional therapy.

Adult↗
PubMed1987

Treatment of stage IIIB cervical cancer with Californium-252 fast-neutron brachytherapy and external photon therapy.

From January 1977 to July 1984, 32 patients with Stage IIIB cervical cancer were treated at the University of Kentucky Medical Center by a combination of outpatient neutron brachytherapy and external pelvic radiation. These patients received 4500 to 5000 rad external photon therapy and two or three outpatient Californium-252 (252Cf) implants, plus sidewall boost irradiation. Treatment results were compared retrospectively to those obtained in a historical control group of patients with Stage IIIB cervical cancer treated with external radiation and conventional photon brachytherapy from 1972 to 1976. Local or regional tumor recurrence developed in 53% of patients treated with neutron therapy and an additional 9% experienced distant metastases. Thirty-eight percent of patients remain free of disease 12 to 96 months (mean, 51 months) after therapy. The 2-year and 5-year survival rates of patients treated with neutron therapy were 53% and 36%, which were not significantly different than those obtained with photon brachytherapy (2-year survival, 61%; 5-year survival, 34%). Complications of neutron therapy were minimal and included proctitis (19%) and vaginal stenosis (9%). There were no cases of enteric fistulae. Outpatient neutron brachytherapy was cost effective and was well tolerated by patients.

Adult↗
PubMed1987

Phase I-II clinical trial of Californium-252. Treatment of stage IB carcinoma of the cervix.

Intracavitary Californium-252 combined with whole-pelvis photon radiotherapy was tested as the sole form of treatment for 22 patients with Stage IB carcinoma of the cervix. Californium-252 (Cf) is a fast neutron-emitting radioisotope currently being tested in trials of neutron brachytherapy (NT). The outcomes of the treated group of patients were traced for local tumor control, survival, patterns of failure, and complications. The Cf intracavitary therapy combined with whole-pelvis photon radiotherapy resulted in 95% 2-year and 91% 5-year actuarial survival. There were 9% Grade II-III complications by the Stockholm scale and 4% local failures. These results were obtained in an early clinical trial with a group of largely poor-risk patients with tumors of mean diameter of 4.3 cm.

Actuarial Analysis↗
PubMed1987

Specimen histology after one or two preoperative CF-252 implants for bulky stage IB cervical cancer.

Using hysterectomy specimens obtained 1 month after Cf-252 neutron brachytherapy plus fractionated radiotherapy, we determined the fraction of positive and negative specimens with neutron dose for bulky Stage IB cervical cancers. The specimens obtained and studied after an initial Cf-252 insertion when the sources were newer and less decayed were more frequently negative for histological evidence of cancer than after the sources had decayed and 2 insertions were needed. After two insertions to deliver a therapeutic dose preoperatively the specimens were more frequently positive. When a larger initial dose was delivered to the tumor a larger proportion of negative specimens was noted. The size of neutron dose fraction was important to local tumor clearance and to rendering the specimens negative as well as schedule in use.

Brachytherapy↗
PubMed1986

Phase II clinical trial using californium 252 fast neutron brachytherapy, external pelvic radiation, and extrafascial hysterectomy in the treatment of bulky, barrel-shaped stage IB cervical cancer.

From June 1977 to June 1983, 32 patients with bulky (greater than 4 cm diameter), barrel-shaped Stage IB cervical cancer were treated at the University of Kentucky Medical Center by a combination of outpatient neutron brachytherapy using californium 252 (252Cf) and external pelvic radiation followed by extrafascial hysterectomy. Nineteen patients had cervical tumors 4 to 6 cm in diameter, and 13 patients had lesions in excess of 6 cm in diameter. A dose of 4500 rad external photon therapy was given from a linear accelerator, and one or two 6-hour 252Cf implants were given during or immediately after external radiation. Extrafascial hysterectomy with bilateral salpingo-oophorectomy was performed 6 weeks after completion of radiation therapy. Complications during and after radiation were minimal and included vaginal stenosis (three) and proctitis (two). Tumor clearance in the hysterectomy specimen was complete in 23 patients (72%) and residual cervical tumor was present in 9 patients (28%). Two patients developed tumor recurrence and died of disease 15 and 27 months after therapy, respectively. Thirty patients remain free of disease 26 to 96 months (median, 52 months) after treatment, and none have been lost to follow-up. The actuarial survival of these patients is 97% at 2 years and 94% at 5 years. Intracavitary neutron therapy is well tolerated and is effective when combined with external radiation and hysterectomy in the treatment of bulky, barrel-shaped Stage IB cervical cancer.

Adult↗
PubMed1986

Cf-252 neutron brachytherapy of short duration for bulky neck tumors.

Cf-252 (Cf) neutron brachytherapy (NT) was tested for treatment of bulky neck tumor masses in 13 patients. Complete regression (CR) or partial regression (PR) was obtained in 100% and local control in 85%. Tumors cleared rapidly and completely after an implant therapy of 4-7 hrs. Short duration Cf-NT can produce rapid and complete clearance of bulky tumors. Efficacy was independent of the implant time duration and without unusual adverse side effects or complications. The median survival time (MST) of patients dying of their disease was 6.8 months and 48% of treated patients survived greater than 18 months despite their advanced diseased status.

Adenoma, Pleomorphic↗
PubMed1985

Neutron brachytherapy is better than conventional radiotherapy in advanced cervical cancer.

Californium-252 (252Cf), a fast-neutron emitting radioisotope, was used for neutron brachytherapy (NT) of 82 patients with advanced (stage III and IV) cervical cancer. The results were compared with caesium-137 brachytherapy; both isotopes were given in combination with high-dose fractionated pelvic radiotherapy. In patients with stage IIIB disease (ie, tumour to the pelvic side-wall), 252Cf intracavitary therapy resulted in 54% 5-year survival compared with 12% in the caesium group. To be effective, Cf-NT must be given before external beam (photon) therapy.

Actuarial Analysis↗
PubMed1985

Therapeutic dosimetry for Cf-252 neutron brachytherapy of pelvic cancer.

252Cf (Cf) was used to treat tumors of the cervix and uterus with neutron brachytherapy (NT) in an ongoing clinical trial. Tandem and ovoids insertions were used and combinations of single and multiple applications along with high dose whole pelvic irradiation. Dosimetric analysis of treated cases for patterns of tissue dose were carried out. Tissue dose for Cf-NT was, in general, high for neutron components in the central pelvis only, and fell off rapidly with distance from the applicators. The majority and balance of therapeutic dose was contributed by low linear energy transfer (LET) high energy photon beam radiation to the whole pelvis. Comparison with fast neutron beam therapy (NBT) isodose curves showed that much more homogeneous neutron dose was delivered to the pelvic tumor and organs by NBT. Complication frequency has been reported to be higher for neutron beam therapy than for Cf-NT. It appears that the higher integral neutron biological dose to normal tissues for NBT compared to intracavitary Cf-NT probably contributed to the frequency of side effects.

Brachytherapy↗
PubMed1985

Study of acute 60Co, low dose rate CF-252 and CS-137 radiation on LSA ascites lymphoma in vivo.

Dose response curves were determined for the LSA lymphoma for acute 60Co, low dose rate Cs-137 and Cf-252 radiations using in vivo survival time bioassay. Mean survival times increased with dose with a prominent oxygen effect noted for acute 60Co and Cs-137. OER was lowest for Cf-252 where it was approximately 1.4. The RBEn for oxic LSA cells to Cf-252 neutrons was 3.1 for acute 60Co and 4.2 for Cs-137. It was larger for hypoxic tumor and RBE was 5.3 for 60Co and 5.8 for Cs-137. Survival curves based on survival data used a multitarget dose-response model for photon radiation and exponential dose-response for Cf-252 radiation. When LSA was irradiated in advanced tumor stages in vivo, Cf-252 was much more effective than acute 60Co or LDR Cs-137 for increasing survival time. Tumor response in vivo matched the in vitro irradiated tumor data. No schedule dependence was observed for mixing of 60Co and Cf-252 radiations.

Animals↗
PubMed1985

Clinical trial of 252Cf neutron brachytherapy vs. conventional radiotherapy for advanced cervical cancer.

252Cf, a neutron emitting radioactive transplutonium isotope, was tested for its efficacy against advanced bulky Stage III-IV cancers of the cervix in a clinical trial at the University of Kentucky Medical Center. Eighty-two patients were treated during 1976-1979 and followed for 5-year survival and tumor control. Three different treatment methods went on sequentially and concurrently, that is, (a) conventional whole pelvis photon with delayed 137Cs implants, (b) conventional photon therapy with delayed 252Cf implants, and (c) 252Cf implants ("early") preceding photon therapy. There were 12% 5-year survival for Stage IIIB cancers by conventional therapy, and 15% by delayed 252Cf implant therapy. For early 252Cf implant therapy there were 54% 5-year survivals with 4% complications and 65% 5-year local control, but distant metastases became a prominent delayed failure pattern.

Adult↗
PubMed1984

HeLa cell tumor response to 60Co, Cs-137, Cf-252 radiations and cisplatin chemotherapy in nude mice.

HeLa cells were implanted into athymic nude mice from tissue culture and solid tumors established (HeLa cell tumor or HCT). Large cell numbers of 1 X 10(7) were required to obtain consistent and progressive growth, and tumor growth followed a Gompertzian mode. Irradiation studies were carried out using acute Cobalt-60 (60Co), low-dose-rate (LDR) Cs-137 and LDR Cf-252. Cf-252, a neutron-emitting radioisotope, produced an immediate tumor shrinkage and regression response after a dose of 279 cGy. Acute 60Co or LDR Cs-137 irradiation with 1000 cGy had little effect on the HCT. After a dose of 2000 cGy of 60Co radiation tumor shrinkage followed a latent period of approximately 5 days. Cisplatin had no effect on the HCT in nude mice in stationary or late exponential growth.

Animals↗