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Biomedical subjects

B C Wen

Publications and source records attributed to B C Wen.

51 records · Page 3Linked to original sources
PubMed1989

Alopecia associated with unexpected leakage from electron cone.

Excessive irradiation due to unexpected leakage was found on a patient receiving electron beam therapy. The cause of this leakage was analyzed and the amount of leakage was measured for different electron beam energies. The highest leakage occurred with a 6 x 6 cm cone using a 12 MeV electron beam. The leakage dose measured along the side of the cone could be as great as 40%. Until the cones are modified or redesigned, it is advised that all patient setups be carefully reviewed to assure that no significant patient areas are in the side scatter region.

Alopecia↗
PubMed1989

Adult acute lymphoblastic leukemia: results of the Iowa HOP-L protocol.

Fifty-nine consecutive previously untreated adult patients with acute lymphoblastic leukemia (ALL) were entered onto a prospective single-arm trial of doxorubicin, vincristine, prednisone, and asparaginase (HOP-L) induction therapy followed by CNS prophylaxis and 3 years of maintenance therapy. Consolidation therapy was not administered. The study population included a large number of older (greater than 50 years) patients. Seventy-five percent of patients achieved complete remission. With a median follow-up of 6 years, the median duration of complete remission is greater than 4 years, with 53% of patients expected to remain in remission at both 3 and 5 years. Overall, median survival duration is 27.9 months, with 45% and 35% of all patients expected to survive 3 and 5 years, respectively. Multivariate analysis identified patients with T-cell disease and mediastinal masses (P less than .001) and those with low values of lactic dehydrogenase (LDH) (P = .057) as being at greatest risk of relapse. Therapy was well tolerated by patients under age 35, but older patients suffered appreciable mortality. We conclude that this treatment program is effective therapy for adult ALL, yielding a large proportion of durable remissions despite the exclusion of consolidation therapy.

Adolescent↗
PubMed1989

Low rejection rate when using unrelated or haploidentical donors for children with leukemia undergoing marrow transplantation.

Thirty-nine children with leukemia were entered into a bone marrow transplantation study comparing the use of unrelated donors who were HLA-Dr identical and matched at least with three of the four HLA-A or B loci, with haploidentical related donors. Although marrows were prepared by T lymphocyte depletion in vitro, the rejection rate of marrow in these patients was only 13% (5/39). Four patients had early rejections, and three of these four had autologous recovery immediately without evidence of leukemic recurrence. The fifth had a delayed rejection occurring approximately 2 1/2 months after transplant. These results were achievable by an ablative regimen incorporating increased immunosuppression. Although the small sample size does not yet permit evaluation of outcome comparing one donor type versus another, the early findings document a high rate of successful engraftment.

Adolescent↗
PubMed1988

Primary malignant lymphoma of the mandible.

From 1945 through 1985, 32 cases of primary lymphoma of bone were treated at the University of Iowa Hospitals and Clinics. Sixteen cases (50%) demonstrated the lesion in the long tubular bones with a predilection for the lower and upper extremities. The frequently involved flat bones (six cases) were the bones of the pelvis. There were only three cases (9%) where the mandible was the primary site. In this report, the literature is reviewed and three cases with primary lymphoma of the mandible are presented.

Adolescent↗
PubMed1988

Chemodectoma of the temporal bone: a comparison of surgical and radiotherapeutic results.

Between January 1950 and December 1981, 32 patients with chemodectomas of the temporal bone were treated at the University of Iowa Hospitals and Clinics. Thirteen patients were treated with surgery alone, 15 with radiation therapy alone, one with preoperative radiation therapy and surgery, and three with surgery and postoperative radiation therapy. In general, the patients treated with radiotherapy alone or combined therapy (radiotherapy group) had more advanced tumors than those treated with surgery alone (surgery group). For the surgery group, the initial local control rate was 46% and the ultimate local control rate 84% following salvage with additional surgery, 31% developed complications, and 78% survived 10 years. For the radiotherapy group, 84% had local tumor control, 11% developed complications, and 77% survived 10 years. These results demonstrate that radiation therapy is an effective treatment modality for chemodectomas of the temporal bone.

Adult↗
PubMed1988

Allogeneic marrow grafting with partially mismatched, unrelated marrow donors.

Forty patients with advanced hematologic malignancies or severe aplastic anemia received marrow grafts from partially mismatched, unrelated marrow donors. All patients were administered conventional prophylaxis for acute graft-v-host disease (GVHD) consisting of methotrexate and low-dose glucocorticoids. All but two patients who survived at least 30 days showed durable engraftment. Six patients survive 17+ to 36+ months following transplantation. Severe acute GVHD was seen in 47% of the patients; however, no direct correlation between GVHD and the degree of mismatching could be determined. Fatal infections were seen in 29 patients, and in the majority the infection occurred after the granulocyte count had risen to greater than 500 cells/microL. We conclude that the problems encountered in this pilot study can potentially be solved, and that further studies with this type of marrow grafting are warranted.

Adolescent↗
PubMed1987

Uterine sarcoma: a retrospective study.

From 1965 to 1982, 86 analyzable patients with uterine sarcoma were treated. Nineteen patients (22%) presented with advanced disease. For the patients with curable diseases (67 patients), the disease-free survivals with a median follow-up of 4.5 years are 40% (surgery only), 53% (surgery + chemotherapy), 46% (surgery + radiation +/- chemotherapy). The local failure rates are 43%: 32%: 33%, respectively. There is no statistical significance. The most important prognostic factor is the clinical extent of the tumor. The role of radiation therapy and chemotherapy will be discussed.

Adult↗
PubMed1987

Chemotherapy in patients who fail radiotherapy for diffuse aggressive non-Hodgkin's lymphoma.

Twenty patients with diffuse aggressive non-Hodgkin's lymphoma were treated primarily with radiotherapy for localized disease and had subsequent disease progression. All 20 patients then received an adriamycin based, combination chemotherapy regimen, but only seven patients (35%) achieved a complete remission, and only four patients (20%) currently remain in remission. When 15 patients treated with the CHOP regimen were compared to 62 patients treated with CHOP during the same time period but who did not have preceding radiotherapy, patients with previous radiotherapy had a lower complete remission rate (i.e. 66% versus 33%) and a slightly lower 5-year survival rate (i.e. 41% versus 20%). Thus, unlike patients with Hodgkin's disease, patients with diffuse aggressive non-Hodgkin's lymphomas who fail radiotherapy for localized disease might not have an especially good outlook with subsequent chemotherapy.

Adult↗
PubMed1987

Inoperable adenocarcinoma of endometrium: radiation therapy.

Between 1960 and 1979, 41 patients with adenocarcinoma of the endometrium who were poor surgical risks were treated with radiation therapy at the University of Iowa. Local tumor control was achieved in 78% of the patients, 5% manifested complications, and 46% survived 5 years ("uncorrected" 5-year survival rate). Intercurrent disease was the major cause of death (54%), and intrauterine recurrence (22%) was the most frequent recurrence. Intraperitoneal spread (12%) occurred as commonly as hematogenous metastases (12%). Three of nine local failures occurred after 5 years. Local control rates correlated well with clinical stage, and the survival rates correlated well with the stage and grade of the tumor. Local tumor control was achieved in 95% of patients who received greater than 7,000 mg-h intracavitary radium, compared with 63% of patients treated with less than 7,000 mg-h.

Adenocarcinoma↗
PubMed1987

Normal brain irradiation during stereotactic brain implants using radioactive iodine-125.

Stereotactic interstitial brain implants deliver locally high radiation doses to treat malignant gliomas. Dose to the surrounding normal brain from an 125I implant has been compared with the dose from an external irradiation technique. Results show that an implant offers a higher dose gradient around the tumor and hence a lower dose to the normal brain. Moreover, some irregular-shaped tumors, while ideal for a stereotactic implant, may be very difficult to treat with external beams without delivering a significant radiation dose to the normal brain. An implant seems to be dosimetrically superior to external irradiation for delivering large tumor doses.

Brachytherapy↗
PubMedDate not supplied

Gadolinium-enhanced MR imaging in the management of a midline cerebral dysgerminoma.

Magnetic Resonance (MR) imaging has proved to be an excellent modality for the evaluation of CNS tumors and detection of metastatic seeding through CNS pathways. We present a case of cerebral dysgerminoma in which the use of gadopentetate dimeglumine (Gd-DTPA) enhancement added important information in lesion detection and delineation for treatment planning. Our results, and a review of recent literature, suggest that Gd-DTPA-enhanced MR imaging may be useful for initial and follow-up evaluation of CNS dysgerminomas.

Adolescent↗
PubMedDate not supplied

Leakage radiation from electron applicators on a medical accelerator.

The leakage characteristics of electron applicators on our Clinac 2500 linear accelerator have been measured. The leakage radiation in the patient plane and at the surface of the electron applicators has been measured for applicator sizes from 6 cm X 6 cm to 25 cm X 25 cm and beam energies from 6 to 22 MeV. For certain applicator/energy combinations the leakage radiation was significant. The leakage radiation, relative to the central axis dose, was found to be up to 7% in the patient plane and up to 39% at the applicator surface. Reducing the collimator setting or adding lead at select locations on the applicator surface was effective in reducing the magnitude of the radiation leakage.

Biophysical Phenomena↗