| 1. |
- Areberg, Johan, et al.
(författare)
-
Antitumor effect of radioactive cisplatin (191Pt) on nude mice
- 2001
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - 0360-3016. ; 49:3, s. 827-832
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate the effect of (191)Pt-cisplatin in vivo in terms of the antitumor effect and general toxicity on tumor-bearing nude mice. METHODS AND MATERIALS: Tumor-bearing (human squamous cell carcinoma, AB) nude mice were divided into four groups and given, i.p., physiological saline (controls), cisplatin, (191)Pt-cisplatin (80 MBq/mg), or (191)Pt-cisplatin (160 MBq/mg), respectively. Mortality and weight were used as parameters for monitoring general toxic effect, while specific growth delay (SGD) and the area under the logarithm of the relative tumor size curve (AUC-log[RTS]) were used to evaluate the antitumor effect of the treatments. RESULTS: Both SGD and AUC-log(RTS) values showed that (191)Pt-cisplatin was significantly (P < 0.05) more effective in retarding tumor growth than nonradioactive cisplatin. No differences in mortality between the different groups could be observed and no significant differences in weight change between the mice treated with cisplatin or (191)Pt-cisplatin could be seen. CONCLUSION: (191)Pt-cisplatin is a more effective drug than nonradioactive cisplatin in retarding tumor growth on nude mice without adding systemic toxic effects. We believe that radioactive cisplatin may prove to be an alternative to conventional cisplatin; however, the possible toxic effects on organs at risk have to be thoroughly investigated.
|
|
| 2. |
- Björk, Peter, et al.
(författare)
-
Design and dosimetry characteristics of a soft-docking system for intraoperative radiation therapy
- 2000
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - 0360-3016. ; 47:2, s. 527-533
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The design concept and the dosimetric characteristics of an applicator system for intraoperative radiation therapy (IORT) with special emphasis on alignment methods, the effect of a plastic scatterer in the beam, radiation leakage, and misalignment dosimetry, are presented in this paper. MATERIALS AND METHODS: A soft-docking system for a linear accelerator, which enables collimation of electron beams (4-22 MeV) for IORT has been developed. The system includes twenty-one circular polymethylmethacrylate (PMMA) treatment cones of different lengths, diameters and end angles. All in-water measurements are made using p-type silicon diode detectors. RESULTS: The effect of introducing a PMMA scatterer in the therapeutic beam includes increased surface dose values (above 83% for all nominal electron energies and for all cones) and improved dose homogeneity within the therapeutic range. Electrons scattered from the inside wall of the cone result in dose profile horns at depth of dose maximum always lower than 109%. The radiation leakage outside the cone is less than 13%. Large changes in the dose profiles occur if the intraoperative cone is misaligned more than 0.5. CONCLUSION: The alignment procedure of the soft-docking system is easy to handle and the applicator design provides adequate collimation of electron beams for IORT.
|
|
| 3. |
|
|
| 4. |
- Cheng, Chee-Wai, et al.
(författare)
-
Dosimetric comparison of treatment planning systems in irradiation of breast with tangential fields
- 1997
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - 0360-3016. ; 38:4, s. 835-842
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The objectives of this study are: (1) to investigate the dosimetric differences of the different treatment planning systems (TPS) in breast irradiation with tangential fields, and (2) to study the effect of beam characteristics on dose distributions in tangential breast irradiation with 6 MV linear accelerators from different manufacturers. METHODS AND MATERIALS: Nine commercial and two university-based TPS are evaluated in this study. The computed tomographic scan of three representative patients, labeled as "small", "medium" and "large" based on their respective chest wall separations in the central axis plane (CAX) were used. For each patient, the tangential fields were set up in each TPS. The CAX distribution was optimized separately with lung correction, for each TPS based on the same set of optimization conditions. The isodose distributions in two other off-axis planes, one 6 cm cephalic and the other 6 cm caudal to the CAX plane were also computed. To investigate the effect of beam characteristics on dose distributions, a three-dimensional TPS was used to calculate the isodose distributions for three different linear accelerators, the Varian Clinac 6/100, the Siemens MD2 and the Philips SL/7 for the three patients. In addition, dose distributions obtained with 6 MV X-rays from two different accelerators, the Varian Clinac 6/100 and the Varian 2100C, were compared. RESULTS: For all TPS, the dose distributions in all three planes agreed qualitatively to within +/- 5% for the "small" and the "medium" patients. For the "large" patient, all TPS agreed to within +/- 4% on the CAX plane. The isodose distributions in the caudal plane differed by +/- 5% among all TPS. In the cephalic plane in which the patient separation is much larger than that in the CAX plane, six TPS correctly calculated the dose distribution showing a cold spot in the center of the breast contour. The other five TPS showed that the center of the breast received adequate dose. Isodose distributions for 6 MV X-rays from three different accelerators differed by about +/- 3% for the "small" patient and more than +/- 5% for the "large" patient. For two different 6 MV machines of the same manufacturer, the isodose distribution agreed to within +/- 2% for all three planes for the "large" patient. CONCLUSION: The differences observed among the various TPS in this study were within +/- 5% for both the "small" and the "medium" patients while doses at the hot spot exhibit a larger variation. The large discrepancy observed in the off-axis plane for the "large" patient is largely due to the inability of most TPS to incorporate the collimator angles in the dose calculation. Only six systems involved agreed to within +/- 5% for all three patients in all calculation planes. The difference in dose distributions obtained with three accelerators from different manufacturers is probably due to the difference in beam profiles. On the other hand, the 6 MV X-rays from two different models of linear accelerators from the same manufacturer have similar beam characteristics and the dose distributions are within +/- 2% of each other throughout the breast volume. In general, multi-institutional breast treatment data can be compared within a +/- 5% accuracy.
|
|
| 5. |
- Gustavsson, Anita, et al.
(författare)
-
No serious late cardiac effects after adjuvant radiotherapy following mastectomy in premenopausal women with early breast cancer
- 1999
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - 0360-3016. ; 43:4, s. 745-754
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To assess cardiac mortality, coronary artery disease, myocardial dysfunction, and valvular heart disease in women younger than 65 years of age, at least 10 years after adjuvant radiotherapy following mastectomy in early breast cancer. METHODS AND MATERIALS: Ninety women (45-64 years old) with Stage II breast cancer without relapse, included in the South Sweden Breast Cancer Trial (premenopausal arm), with or without adjuvant postoperative radiotherapy +/- cyclophosphamide were examined with myocardial scintigraphy and echocardiography/Doppler, 10-17 years after radiotherapy. Thirty-four patients had been irradiated for left-sided tumors, 33 for right-sided tumors, and 23 patients had not been treated with radiotherapy. The radiotherapy (conventional roentgen, electron beams, and high-energy photon beams combined, in each patient) included the chest wall and the regional lymph nodes, with a specified target dose of 38-48 Gy, administered in daily fractions of 1.9-2.4 Gy, 5 days/week. RESULTS: No cardiac deaths were found among the original 275 patients randomized to adjuvant therapy. In the 90 patients examined, abnormal findings were recorded for ECG (14 patients), exercise test (5 patients), myocardial scintigraphy (6 patients), thickening of valve cusps (14 patients), and mild valvular regurgitation (20 patients). All patients had normal systolic function. Diastolic dysfunction was observed in 6 patients (abnormal relaxation in 4 patients and restrictive filling abnormality in 2 patients). Although no significant differences were found between the 3 study groups, there was a tendency to more abnormal findings after radiotherapy. CONCLUSION: Women younger than 50 years of age at the time of adjuvant radiotherapy following mastectomy in early breast cancer, had no serious cardiac sequelae 13 years (median) later, despite partly old-fashioned radiation techniques.
|
|
| 6. |
- Knöös, Tommy, et al.
(författare)
-
Volumetric and dosimetric evaluation of radiation treatment plans: radiation conformity index
- 1998
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - 0360-3016. ; 42:5, s. 1169-1176
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The use of conformal radiation therapy has grown substantially during the last years since three-dimensional (3D) treatment planning systems with beams-eye-view planning has become commercially available. We studied the degree of conformity reached in clinical routines for some common diagnoses treated at our department by calculating a radiation conformity index (RCI). METHODS AND MATERIALS: The radiation conformity index, determined as the ratio between the target volume (PTV) and the irradiated volume, has been evaluated for 57 patients treated with 3D treatment plans. RESULTS AND CONCLUSION: The RCI was found to vary from 0.3 to 0.6 (average 0.4), a surprisingly low figure. The higher RCI is typical for pelvic treatments (e.g., prostate) and stereotactic treatments. The lower RCI is found for extended tumors, such as mammary carcinomas where the adjacent nodes are included. The latter is also valid for most lung cancer patients studied. The RCI gives a consistent method for quantifying the degree of conformity based on isodose surfaces and volumes. Care during interpretation of RCI must always be taken, since small changes in the minimum dose can dramatically change the treated volume.
|
|
| 7. |
|
|
| 8. |
- Adell, Gunnar, 1953-, et al.
(författare)
-
Decreased tumor cell proliferation as an indicator of the effect of preoperative radiotherapy of rectal cancer
- 2001
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - 0360-3016 .- 1879-355X. ; 50:3, s. 659-663
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Rectal cancer is a common malignancy, with significant local recurrence and death rates. Preoperative radiotherapy and refined surgical technique can improve local control rates and disease-free survival.PURPOSE: To investigate the relationship between the tumor growth fraction in rectal cancer measured with Ki-67 and the outcome, with and without short-term preoperative radiotherapy.Method: Ki-67 (MIB-1) immunohistochemistry was used to measure tumor cell proliferation in the preoperative biopsy and the surgical specimen.MATERIALS: Specimens from 152 patients from the Southeast Swedish Health Care region were included in the Swedish rectal cancer trial 1987-1990.RESULTS: Tumors with low proliferation treated with preoperative radiotherapy had a significantly reduced recurrence rate. The influence on death from rectal cancer was shown only in the univariate analysis. Preoperative radiotherapy of tumors with high proliferation did not significantly improve local control and disease-free survival. The interaction between Ki-67 status and the benefit of radiotherapy was significant for the reduced recurrence rate (p = 0.03), with a trend toward improved disease-free survival (p = 0.08). In the surgery-alone group, Ki-67 staining did not significantly correlate with local recurrence or survival rates.CONCLUSION: Many Ki-67 stained tumor cells in the preoperative biopsy predicts an increased treatment failure rate after preoperative radiotherapy of rectal cancer.
|
|
| 9. |
- Björk-Eriksson, Thomas, 1960, et al.
(författare)
-
The immunohistochemical expression of DNA-PKCS and Ku (p70/p80) in head and neck cancers: relationships with radiosensitivity
- 1999
-
Ingår i: Int J Radiat Oncol Biol Phys. - 0360-3016. ; 45:4, s. 1005-10
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The DNA-PK complex is one of the major pathways by which mammalian cells respond to DNA double-strand breaks induced by ionizing radiation. This study evaluated the relationship between the immunohistochemical expression of the individual components of DNA-PK and cellular radiosensitivity in head and neck cancers. METHODS AND MATERIALS: Biopsies from patients with previously untreated squamous cell carcinomas of the head and neck were assessed for inherent tumor radiosensitivity measured as the surviving fraction at 2 Gy (SF2) using a soft agar clonogenic assay. Paraffin-embedded tumor material from 64 successfully grown specimens was immunohistochemically stained for expression of DNA-PKcs and Ku (p70/p80). The same tumor material was previously analyzed for the immunohistochemical expression of p53. RESULTS: A significant correlation was found between the degree of expression of DNA-PKcs and Ku (p70/p80) (r = 0.55, p<0.001). There were no overall significant differences in the levels of expression of DNA-PKcs and Ku (p70/p80) in tumors from patients of either sex, different sites, histologies, and stages. No relationship was found between SF2 and the expression of either DNA-PKcs (r = 0.22, p = 0.081) or Ku (p70/p80) (r = 0.064, p = 0.62). Comparison with previous immunohistochemical characterization showed no significant correlations between the expression levels of p53 and either DNA-PKcs (r = 0.093, p = 0.46) or Ku (p70/p80) (r = -0.17, p = 0.17). CONCLUSIONS: This study suggests that determining the immunohistochemical expression of DNA-PK in head and neck cancers from multiple sites does not have a role as a predictive assay of tumor in vitro radiosensitivity.
|
|
| 10. |
|
|
