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Biomedical subjects

A Kuten

Publications and source records attributed to A Kuten.

At least 37 records · Page 2Linked to original sources
PubMed1999

Spreadsheet calculations of absorbed dose to water for photons and electrons according to established dosimetry protocols.

The calculation of absorbed dose to water according to a Code of Practice demands a strict adherence to the rules and data of the protocol. To ease the calculations and to avoid computational and methodological errors, we have developed a number of spreadsheets to perform the calculations in accordance with an established dosimetry protocol-in our case those of the International Atomic Energy Agency (IAEA) and the Institution of Physics and Engineering in Medicine and Biology (IPEMB). The spreadsheets are implemented as Microsoft Excel V5.0 worksheets. Only a limited selection of dosimetry equipment is used for calibration, which is performed according to only one of the methods allowed by the protocol. This voluntary limitation of equipment and methods is reflected in a spreadsheet that is beam-specific, compact, focused, and very practical. There are four main spreadsheets: high-energy photons (IAEA), high-energy electrons (IAEA), medium energy X rays (IPEMB), and low-energy X rays (IPEMB). The sheets allow the input of setup and measured data, but tabulated data and formulas are protected. Parameter values are copied from the protocols, and the relevant value is found by linear interpolation. Once the spreadsheets are drawn up correctly and thoroughly checked, protocol calculations are performed easily and accurately. The spreadsheets presented are tailored to suit our specific needs but can easily be modified to conform to the practices of any other institution. They are not intended as "cookbooks" but need to be filled in by a radiation physicist with the input data checked by a second professional. The same method is also used for calculating the Reference Air Kerma Rate of brachytherapy sources.

Calibration↗
PubMed1999

T-cell subpopulation in patients with metastatic renal cell carcinoma treated by recombinant interleukin-2, recombinant interferon-alpha, 5-fluorouracil, and vinblastine.

T-cell subpopulations were evaluated in 10 patients with metastatic renal cell carcinoma treated with recombinant interleukin-2, recombinant interferon-alpha, 5-fluorouracil, and vinblastine. T-cell subpopulation was tested by flow cytometry, and the results were compared with healthy control subjects. Mean T-cell values before treatment as compared with control were as follows: CD3, 68 vs. 73%; CD4, 34 vs. 53%; CD8, 38 vs. 31%; CD4/CD8, 1.1 vs. 1.8; CD4CD69, 20 vs. 47%, and CD8CD69, 24 vs. 19%. The difference in CD4, CD4/CD8, and CD4CD69 was statistically significant. After treatment (8 weeks), the values of CD4/CD8 ratio and CD4CD69 increased. Three patients achieved complete response, two partial response, and two had stabilization of the disease. After treatment, the CD4/CD8 ratio increased in complete responders, from 1.1 to 2.0, and CD4CD69 increased in complete and partial responders, from 11 to 37% and 23 to 31%, respectively. In nonresponders, no similar change was observed. In conclusion, increases in CD4/CD8 ratio and CD4CD69 levels in metastatic renal cell carcinoma patients may be associated with response to immunochemotherapy.

Adult↗
PubMed1999

[Breast conservation: safe for early breast cancer].

Between 1981-1993 581 women with primary breast cancer were treated by breast conservation. Their mean age was 56 +/- 12 years and 63% were postmenopausal and 37% pre- or perimenopausal. The median follow-up time was 56 months. 45% had pathological Stage I disease, 49% Stage II, 2.5% Stage III and 3.5% clinical Stage I-II disease. 54% of lesions were excised with good margins, 10% with close margins (< 0.5 cm), 9% with microscopic residual, 3% with macroscopic residual, and in 24% margins were not reported. Adjuvant therapy, consisting of combination chemotherapy and/or hormones, was given to 69%. Radiotherapy, usually 50 Gy tangential photon irradiation to the whole breast, was given to 564 (97%); an electron or photon "boost" to the tumor with a median dose of 17.5 Gy was given to 378 (65%). Most of those with positive nodes received 50 Gy to the lymphatic drainage system. 1 year after radiotherapy cosmetic results were rated as "good" or "excellent" in 80%, "moderate" in 17% and "poor" in 3%. The 5-year actuarial survival was 97% in Stage I and 88% in Stage II. 37 patients (6.5%) developed breast recurrence; 11 of these (2%) had simultaneous distant metastases. 5 (< 1%) developed axillary or supraclavicular lymph node metastases, and 81 (14%) developed distant metastases. Most local recurrences were in those younger than 40, and in those with primary tumors > 1.75 cm. The satisfactory level of local control achieved is attributed to the high doses of radiation (up to 75 Gy) administered to those with high risk lesions.

Breast Neoplasms↗
PubMed1998

Radiation-induced tumors in irradiated stage I testicular seminoma: results of a 25-year follow-up (1968-1993).

BACKGROUND AND OBJECTIVES: Testicular seminoma is a very radiosensitive and curable cancer, with survival rates following radiation therapy within the range of 90-98% without apparent severe side effects. However, long-term survival following exposure to moderate-dose radiation therapy can result in radiation-induced tumors. METHODS: The incidence of radiation-induced tumors was determined in 81 irradiated stage I testicular seminoma patients treated at the Northern Israel Oncology Center (NIOC) from 1968 through 1993. RESULTS: Three (4%) patients developed second cancers within the high-dose volume. Indeed, those patients received a higher than usual dose to the para-aortic and pelvic regions. One patient, who developed inoperable pancreatic carcinoma, was treated with "hockey stick" field and mediastinal irradiation, plus, as a result of relapses, multiple cisplatin and VP-16 based regimens. CONCLUSIONS: The elimination of causative factors through lower total doses and field size reduction may reduce the, albeit very low, incidence of radiation-induced cancer in cured testicular seminoma.

Adenocarcinoma↗
PubMed1998

A simple oral cone attachment for the Varian linear accelerator.

Lesions in the oral cavity are often treated with two opposed lateral fields. These include a significant amount of normal healthy tissue whose radiation tolerance is dose-limiting. The tumor dose can be boosted to tumorcidal levels by brachytherapy or by small electron fields directed straight on the lesion. We have developed a simple attachment to the standard electron applicator of the Varian Clinac 1800 that allows irradiation of small electron fields through acrylic tubes-the oral cones. These tubes have been evaluated in terms of depth dose and field profiles for 6, 9, 12, 16, and 20 MeV electrons using film for relative dosimetry. At these small field sizes there are significant changes in output factors, in the depth dose as well as in the effective size of the field, and a thorough dosimetric evaluation is imperative prior to treatment. The attachment can be manufactured locally at low cost. For reasons of patient safety the assembly is collapsible. In clinical practice the cone is directed directly on the tumor. For deep-seated lesions we use a penlight and a mirror for positioning.

Humans↗
PubMed1998

Cutaneous lymphoma in Israel, 1985-1993: a population-based incidence study.

The incidence rate of cutaneous lymphomas (CL) [including mycosis fungoides (MF) and non-mycosis fungoides (non-MF)] for the period 1985-93 in Israel was determined using data from the population-based Cancer Registry supplemented by a field survey that covered approximately 80% of lymphoma cases. After the field survey, corrected rates were 49% and 24% higher for MF and non-MF respectively (37% for CL overall). The age-adjusted incidence rates per 100,000 were 1.18 and 0.63 for Jewish men and women respectively. MF rates (0.77 in men and 0.35 in women) were higher than non-MF (0.41 and 0.28 respectively). Rates of CL were significantly lower in non-Jews. There were no significant differences in incidence among Jewish ethnic subgroups. However, the lack of variability in the incidence of these neoplasms among subpopulations is in contrast with findings for cutaneous malignant melanoma; the observed high rates of CL could, nonetheless, be consistent with the sunlight exposure hypothesis, operating perhaps through a different mechanism.

Cohort Studies↗
PubMed1998

Postsurgical etoposide-ifosfamide regimen in poor-risk nonmetastatic osteogenic sarcoma.

This prospective study was designed to test the activity of an ifosfamide-etoposide (VP-16) regimen on poor-risk, nonmetastatic, osteogenic sarcoma. A total of 13 patients with nonmetastatic osteogenic sarcoma with a poor histologic response to primary high-dose methotrexate-doxorubicin (Adriamycin)-cisplatinum chemotherapy received a total of six 5-day courses of ifosfamide (1,800 mg/m2) and etoposide (100 mg/m2) at three weekly intervals. The protocol was well tolerated, with only one case of transient renal failure. At present, eight patients (62%) have been in sustained complete remission with no evidence of recurrent disease for a mean follow-up of 3.4 years (range, 1.5-7.0 years). One patient is alive with lung metastases, and four have died of progressive disease. This prospective, albeit small, study confirms the efficacy of an ifosfamide-VP-16-based regimen in poor-risk, extremity, nonmetastatic osteogenic sarcoma. The demonstrated activity should spark large trials of ifosfamide-containing regimens in osteogenic sarcoma.

Adolescent↗
PubMed1998

Total skin electron irradiation in mycosis fungoides dose and fractionation considerations.

This study was undertaken to analyze the influence of total skin dose and dose-fractionation schedules on the response rate, survival and skin toxicity of patients with mycosis fungoides [MF] treated with total skin electron irradiation [TSEI]. From 1979 to 1992, 40 patients with MF were treated with TSEI using a modified Christie Hospital technique. Mean follow-up time was 48 months [median 20 months]. 37/40 patients completed TSEI; three died due to non-treatment-related conditions during therapy. 34/37 [92%] treated patients achieved complete remission [CR] and 16/40 [40%] are alive with no evidence of disease. Over the years, changes in dose-fractionation schedules were made and correlated with the pattern of CR and skin toxicity. The 5-year actuarial survival [Stanford staging] was 84% in Stages IA-IB [all Stage IA patients are alive] and 59% in Stage II. The probability of survival of Stage III-IV patients was 30% at 30 months. Late skin toxicity was mild to moderate in 60% and severe in 25% of patients. A reduction of the total dose and dose-per-fraction resulted in an acceptable CR rate and a significantly lower toxicity. TSEI is effective in early stage MF. Skin control and late skin toxicity seem to be dose-fractionation-schedule related. For the early stages, the optimal treatment schedule seems to be 24-30 Gy to the whole skin surface in 2.4-3.0 Gy fractions, given twice weekly over a period of four to six weeks. Total doses of 24-30 Gy at 2.4-3.0 Gy per fraction yielded comparable skin control rates with lower skin toxicity.

Adult↗
PubMed1998

[Optic glioma in children with type 1 neurofibromatosis].

During the period 1985-95 we treated 5 girls and 13 boys with optic glioma associated with Type 1 neurofibromatosis (median age 3 years, range 2-10 years). 6 were treated with radiotherapy alone, 1 with surgery and radiation therapy and 1 with chemotherapy in order to postpone irradiation to an older age; 1 is being followed with no therapy. All children are alive, 2-10 years from diagnosis (mean follow-up time 5.4 years). 3 had improvement of vision following therapy and in 4 visual ability stabilized, including the child being followed without treatment. In 1 vision deteriorated despite therapy.

Child↗
PubMed1997

[Radiotherapy of localized prostatic carcinoma].

112 patients with localized prostate cancer, clinical stage A2-C, were treated by definitive radiotherapy between 1982-1988. Radiation volume encompassed the prostate, seminal vesicles and pelvic lymph nodes. The 10-year actuarial survival figures were: overall 51%; stage A2 87%; stage B 50%; stage C 36%; well differential tumors 67%; moderately differentiated 50%; poorly differentiated 32%; patients with local tumor control 55%; and patients with minimal local control 36%. It is concluded that external beam irradiation is effective in localized prostatic cancer. Stage and grade are prognosticators of survival.

Aged↗
PubMed1997

Improved survival in patients with locally advanced prostate cancer treated with radiotherapy and goserelin.

BACKGROUND: We conducted a randomized, prospective trial comparing external irradiation with external irradiation plus goserelin (an agonist analogue of gonadotropin-releasing hormone that reduces testosterone secretion) in patients with locally advanced prostate cancer. METHODS: From 1987 to 1995, 415 patients with locally advanced prostate cancer were randomly assigned to receive radiotherapy alone or radiotherapy plus immediate treatment with goserelin. The patients had a median age of 71 years (range, 51 to 80). Patients in both groups received 50 Gy of radiation to the pelvis over a period of five weeks and an additional 20 Gy over an additional two weeks as a prostatic boost. Patients in the combined-treatment group received 3.6 mg of goserelin (Zoladex) subcutaneously every four weeks starting on the first day of irradiation and continuing for three years; those patients also received cyproterone acetate (150 mg orally per day) during the first month of treatment to inhibit the transient rise in testosterone associated with the administration of goserelin. RESULTS: Data were available for analysis on 401 patients. The median follow-up was 45 months. Kaplan-Meier estimates of overall survival at five years were 79 percent (95 percent confidence interval, 72 to 86 percent) in the combined-treatment group and 62 percent (95 percent confidence interval, 52 to 72 percent) in the radiotherapy group (P=0.001). The proportion of surviving patients who were free of disease at five years was 85 percent (95 percent confidence interval, 78 to 92 percent) in the combined-treatment group and 48 percent (95 percent confidence interval, 38 to 58 percent) in the radiotherapy group (P<0.001). CONCLUSIONS: Adjuvant treatment with goserelin, when started simultaneously with external irradiation, improves local control and survival in patients with locally advanced prostate cancer.

Adenocarcinoma↗
PubMed1997

Low acute gastrointestinal and genitourinary toxicities in whole pelvic irradiation of prostate cancer.

PURPOSE: This retrospective study was done to determine the frequency and severity of acute gastrointestinal (GI) and genitourinary (GU) toxicity associated with whole pelvic radiotherapy of localized prostate cancer. METHODS AND MATERIALS: Between 1989 and 1994, we treated 156 patients with localized prostate cancer, ranging in age from 54 to 86 (median 71), of which 86 were older than 70 years of age. No attempt at selection was made, and many were from the Veteran's Administration Hospital where they had been precluded from their surgical program because of comorbidities and/or advanced age. Of 156 patients, 45 (28.8%) underwent pretreatment laparoscopic lymphadenectomy (LAP); 40 had negative findings. Four-field box technique was used for all patients. We treated the whole pelvis to 45 Gy, followed by a cone-down and a final boost to a total dose of 72 Gy. The cone-down to the lower pelvis and boost to the prostate were based on computed tomography and/or magnetic resonance imaging findings for volume reconstruction with field size of approximately 8 x 8 and 6 x 6 cm, respectively. Diet instructions were given before treatment and emphasized weekly. Toxicities were evaluated weekly by physicians and nurses independently using Cancer and Leukemia Group B (CALGB) grading criteria. RESULTS: The acute GI and GU toxicities gradually increased from Week 2, peaked at Week 5, and then declined after that. During Week 5, acute Grade 1-3 GI morbidities were observed in 19 (12.2%), 2 (1.3%), and 1 (0.6%) patients, respectively. Genitourinary toxicity was similar, accounting for 17 (10.9%), 6 (3.8%), and 1 (0.6%), respectively. Overall Grade 2 toxicities occurred in 30 of 156 patients (19%). Comorbidity was associated with more GI toxicity. Patients over 70 years of age tended to reach the maximal GI and GU toxicity 1-2 weeks earlier than did patients under the age of 70. Of the patients who did not follow the diet instruction, all experienced side effects. CONCLUSIONS: Whole pelvic irradiation was very well tolerated in this group of patients. The frequency of acute Grade 2 GI and GU toxicity compared favorably with the reported results of conformal treatment. Diet restriction and psychosocial input may have had a positive impact. Late sequelae will be evaluated in long-term follow-up.

Acute Disease↗
PubMed1997

[Differentiated thyroid cancer in Arabs in northern Israel].

Prognostic factors and survival rate of 53 Arabs with differentiated carcinoma of the thyroid treated here were reviewed. Papillary carcinoma was diagnosed in 35 (66%) and follicular carcinoma in 18 (34%): the female/male ratio was 2.3/1 and the median age 32. Age, gender, tumor size, histology and tumor stage were important prognostic factors. The 20-year actuarial survival rate of the entire group was 96%. The probable reason for the high survival rate was the low median age.

Adenocarcinoma, Follicular↗
PubMed1997

Cisplatin-based chemotherapy in advanced seminoma: experience of the Northern Israel Oncology Center: 1981-1994.

BACKGROUND: The efficacy of cisplatinum combined chemotherapy modalities was investigated in a variety of trials for patients with advanced seminoma. Results regarding remission rates and survival are encouraging. METHODS: Between December 1981 and January 1994, 13 patients with either relapsed (following radiotherapy failure) or primarily advanced seminoma were treated with cisplatin-based chemotherapy at the Northern Israel Oncology Center. RESULTS: Eleven (84%) patients achieved complete clearance of all sites of disease. One patient demonstrated clinically and radiographically remarkable shrinkage of an abdominal mass, and laparotomy revealed fibrotic/necrotic tissue without viable tumor cells. After a mean follow-up of 58 months (range 4-168), 12 patients (92%) are alive and well without evidence of malignancy. One patient, in whom a 2-cm abdominal mass is stable radiographically, is under observation with no sign of tumor activity. Side effects were tolerable; no patient developed chemotherapy-induced sepsis. One patient developed spontaneous pneumothorax a few days after completion of his first chemotherapy cycle, which resolved with treatment. CONCLUSIONS: Our results confirm the efficacy and safety of cisplatin-based chemotherapy in the treatment of advanced seminoma, even in pre-irradiated patients.

Adult↗
PubMed1997

Dose perturbation due to the presence of a prostatic urethral stent in patients receiving pelvic radiotherapy: an in vitro study.

Temporary metallic intraprostatic stent is a new alternative treatment for patients with urinary obstructive syndrome caused by prostate cancer. Definitive radiotherapy is a treatment of choice for localized prostate cancer. This study evaluates in vitro the effect of a urethral intraprostatic metallic stent on the dose absorbed by the surrounding tissue. The study was designed to mimic the conditions under which the prostatic stent is placed in the body during pelvic irradiation. A urethral stent composed of a 50% nickel-50% titanium alloy (Uracoil-InStent) was imbedded in material mimicking normal tissue (bolus) at a simulated body depth of 10 cm. The distribution of the absorbed dose of irradiation was determined by film dosimetry using Kodak X-Omat V film. Irradiation was done in a single field at the isocenter of a 6 MV linear accelerator with a field size of 7 x 7 cm. The degree of film blackening was in direct proportion to the absorbed dose. The measurements showed an increase in dose of up to 20% immediately before the stent and a decrease of up to 18% immediately after the stent. These changes occurred within a range of 1-3 mm from both sides of the stent. In practice, irradiation in prostate cancer is given by two pairs of opposed co-axial fields; a total of four fields (Box Technique). The dose perturbations are partly cancelled in a pair of opposed beams resulting in a net variation of +/- 4%; therefore, the presence of the intraprostatic stent should not influence radiotherapy planning for prostate cancer.

Humans↗
PubMed1997

Intensive chemotherapy using cisplatin and fluorouracil followed by radiotherapy in advanced head and neck cancer.

This protocol was designed to achieve an improvement in the overall and disease-free survival in locally advanced, previously untreated carcinoma of the head and neck. 53 patients (pts) with locally advanced Stages III and IV, MO squamous cell carcinoma of the nasopharynx, larynx, paranasal sinuses, oral cavity, oropharynx, hypopharynx and one of unknown origin were treated with intensive chemotherapy followed shortly thereafter by radiotherapy. Induction chemotherapy consisted of two cycles of cisplatin 100 mg/m2 over 60 min on day 1, plus 5FU 1000 mg/m2 continuous infusion over 24 h on days 2-5, with a 10-day interval between the two cycles, followed by definitive radiotherapy after 10 days. The overall response rate to chemotherapy was 79%, with a 28% complete response (CR) rate and a 51% partial response (PR) rate. The overall CR rate after radiotherapy was 70%. With a median follow-up period of 48 months, the 5-year actuarial survival and disease-free survival rates were 67% and 45%, respectively. No difference was found in the survival probability of pts with carcinoma of the nasopharynx, larynx or other primary sites. The survival of pts with a performance status (PS) < or = 1 was better than pts with PS > 1, 72% versus 51% (not significant). The survival probability of complete responders to chemotherapy was superior than the survival of non-complete responders to chemotherapy, 100% versus 54% [P = 0.001]. The main toxicity was mucositis during radiotherapy. In conclusion, this treatment regimen demonstrated a high CR rate and survival probability in pts with locally advanced and mostly inoperable head and neck cancer.

Adolescent↗
PubMed1997

Failure analysis in irradiated stage I testicular seminoma. Results of long-term follow-up (1968-1993).

A retrospective analysis of 81 stage I seminoma patients irradiated at the Northern Israel Oncology Center between 1968 and 1993 was undertaken. During this period, 5 (6%) patients relapsed, all outside the initial treatment volume, with a median time of 6.6 (range 1-12) months to relapse. Three patients were salvaged with cisplatin-based chemotherapy. The policy of adjuvant radiotherapy resulted in a high probability of cure and decreased relapse rate. Early relapse is a rare event in properly irradiated stage I seminoma which is highly curable with a cisplatin-containing regimen. Recurrences tend to occur outside the treated radiation volume.

Antineoplastic Agents↗