| 1. |
- Adjeiwaah, Mary, et al.
(författare)
-
Quantifying the Effect of 3T Magnetic Resonance Imaging Residual System Distortions and Patient-Induced Susceptibility Distortions on Radiation Therapy Treatment Planning for Prostate Cancer
- 2018
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier. - 0360-3016 .- 1879-355X. ; 100:2, s. 317-324
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the effect of magnetic resonance system- and patient-induced susceptibility distortions from a 3T scanner on dose distributions for prostate cancers.Methods and Materials: Combined displacement fields from the residual system and patient-induced susceptibility distortions were used to distort 17 prostate patient CT images. VMAT dose plans were initially optimized on distorted CT images and the plan parameters transferred to the original patient CT images to calculate a new dose distribution.Results: Maximum residual mean distortions of 3.19 mm at a radial distance of 25 cm and maximum mean patient-induced susceptibility shifts of 5.8 mm were found using the lowest bandwidth of 122 Hz per pixel. There was a dose difference of <0.5% between distorted and undistorted treatment plans. The 90% confidence intervals of the mean difference between the dCT and CT treatment plans were all within an equivalence interval of (−0.5, 0.5) for all investigated plan quality measures.Conclusions: Patient-induced susceptibility distortions at high field strengths in closed bore magnetic resonance scanners are larger than residual system distortions after using vendor-supplied 3-dimensional correction for the delineated regions studied. However, errors in dose due to disturbed patient outline and shifts caused by patient-induced susceptibility effects are below 0.5%.
|
|
| 2. |
|
|
| 3. |
- Bosco, Cecilia, et al.
(författare)
-
Prostate Cancer Radiation Therapy and Risk of Thromboembolic Events
- 2017
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : ELSEVIER SCIENCE INC. - 0360-3016 .- 1879-355X. ; 97:5, s. 1026-1031
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the risk of thromboembolic disease (TED) after radiation therapy (RT) with curative intent for prostate cancer (PCa).Patients and Methods: We identified all men who received RT as curative treatment (n=9410) and grouped according to external beam RT (EBRT) or brachytherapy (BT). By comparing with an age-and county-matched comparison cohort of PCa-free men (n = 46,826), we investigated risk of TED after RT using Cox proportional hazard regression models. The model was adjusted for tumor characteristics, demographics, comorbidities, PCa treatments, and known risk factors of TED, such as recent surgery and disease progression.Results: Between 2006 and 2013, 6232 men with PCa received EBRT, and 3178 underwent BT. A statistically significant association was found between EBRT and BT and risk of pulmonary embolism in the crude analysis. However, upon adjusting for known TED risk factors these associations disappeared. No significant associations were found between BT or EBRT and deep venous thrombosis.Conclusion: Curative RT for prostate cancer using contemporary methodologies was not associated with an increased risk of TED.
|
|
| 4. |
- Brændengen, Morten, et al.
(författare)
-
Delineation of gross tumor volume (GTV) for radiation treatment planning of locally advanced rectal cancer using information from MRI or FDG-PET/CT : a prospective study
- 2011
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 81:4, s. e439-e445
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:Accurate delineation of target volumes is important to maximize radiation dose to the tumor and minimize it to nontumor tissue. Computed tomography (CT) and magnetic resonance imaging (MRI) are standard imaging modalities in rectal cancer. The aim was to explore whether functional imaging with F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET), combined with CT (FDG-PET/CT) gives additional information to standard pretreatment evaluation and changes the shape and size of the gross tumor volume (GTV).METHODS AND MATERIALS:From 2007 to 2009, 77 consecutive patients with locally advanced rectal cancer were prospectively screened for inclusion in the study at two university hospitals in Sweden, and 68 patients were eligible. Standard GTV was delineated using information from clinical examination, CT, and MRI (GTV-MRI). Thereafter, a GTV-PET was defined in the fused PET-CT, and the target volume delineations were compared for total volume, overlap, and mismatch. Pathologic uptake suspect of metastases was also registered.RESULTS:The median volume of GTV-MRI was larger than that of GTV-PET: 111 cm3 vs. 87 cm3 (p < 0.001). In many cases, the GTV-MRI contained the GTV defined on the PET/CT images as subvolumes, but when a GTV total was calculated after the addition of GTV-PET to GTV-MRI, the volume increased, with median 11% (range, 0.5–72%). New lesions were seen in 15% of the patients for whom PET/CT was used.CONCLUSIONS:FDG-PET/CT facilitates and adds important information to the standard delineation procedure of locally advanced rectal cancer, mostly resulting in a smaller GTV, but a larger total GTV using the union of GTV-MRI and GTV-PET. New lesions were sometimes seen, potentially changing the treatment strategy.
|
|
| 5. |
- Braendengen, Morten, et al.
(författare)
-
Late patient-reported toxicity after preoperative radiotherapy or chemoradiotherapy in nonresectable rectal cancer : Results from a randomized phase III study
- 2011
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 81:4, s. 1017-1024
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: Preoperative chemoradiotherapy (CRT) is superior to radiotherapy (RT) in locally advanced rectal cancer, but the survival gain is limited. Late toxicity is, therefore, important. The aim was to compare late bowel, urinary, and sexual functions after CRT or RT. Methods and Materials: Patients (N = 207) with nonresectable rectal cancer were randomized to preoperative CRT or RT (2 Gy x 25 +/- 5-fluorouracil/leucovorin). Extended surgery was often required. Self-reported late toxicity was scored according to the LENT SOMA criteria in a structured telephone interview and with questionnaires European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30), International Index of Erectile Function (IIEF), and sexual function -vaginal changes questionnaire (SVQ). Results: Of the 105 patients alive in Norway and Sweden after 4 to 12 years of follow-up, 78 (74%) responded. More patients in the CRT group had received a stoma (73% vs. 52%, p = 0.09). Most patients without a stoma (7 of 12 in CRT group and 9 of 16 in RT group) had incontinence for liquid stools or gas. No stoma and good anal function were seen in 5 patients (11%) in the CRT group and in 11 (30%) in the RT group (p = 0.046). Of 44 patients in the CRT group, 12 (28%) had had bowel obstruction compared with 5 of 33 (15%) in the RT group (p = 0.27). One-quarter of the patients reported urinary incontinence. The majority of men had severe erectile dysfunction. Few women reported sexual activity during the previous month. However, the majority did not have concerns about their sex life. Conclusions: Fecal incontinence and erectile dysfunction are frequent after combined treatment for locally advanced rectal cancer. There was a clear tendency for the problems to be more common after CRT than after RT.
|
|
| 6. |
- Carlsson, J, et al.
(författare)
-
Strategy for boron neutron capture therapy against tumor cells with over-expression of the epidermal growth factor-receptor.
- 1994
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - 0360-3016 .- 1879-355X. ; 30:1, s. 105-15
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Gliomas, squamous carcinomas and different adenocarcinomas from breast, colon and prostate might have an increased number of epidermal growth factor (EGF) receptors. The receptors are, in these cases, candidates for binding of receptor specific toxic conjugates that might inactivate cellular proliferation. The purpose of this study was to evaluate whether it is reasonable to try ligand-dextran based conjugates for therapy.METHODS AND MATERIALS: EGF or TGF alpha were conjugated to dextran and binding, internalization, retention and degradation of eight types of such conjugates were analyzed in EGF-receptor amplified glioma cells. The conjugates were labelled with radioactive nuclides to allow detection and two of the conjugates were carrying boron in the form of carboranyl amino acids or aminoalkyl-carboranes. Comparative binding tests, applying 125I-EGF, were made with cultured breast, colon and prostate adenocarcinoma, glioma and squamous carcinoma cells. Some introductory tests to label with 76Br for positron emission tomography and with 131I for radionuclide therapy were also made.RESULTS: The dextran part of the conjugates did not prevent receptor specific binding. The amount of receptor specific binding varied between the different types of conjugates and between the tested cell types. The dextran part improved intracellular retention and radioactive nuclides were retained for at least 20-24 h. The therapeutical effect improved when 131I was attached to EGF-dextran instead of native EGF.CONCLUSION: The improved cellular retention of the ligand-dextran conjugates is an important property since it gives extended exposure time when radionuclides are applied and flexibility in the choice of time for application of neutrons in boron neutron capture therapy (BNCT). It is possible that ligand-dextran mediated BNCT might allow, if the applied neutron fields covers rather wide areas around the primary tumor, locally spread cells that otherwise would escape treatment to be inactivated.
|
|
| 7. |
- Daşu, Alexandru, et al.
(författare)
-
In response to Dr. Karger et al.
- 2008
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 70:5, s. 1614-1615
-
Tidskriftsartikel (refereegranskat)
|
|
| 8. |
- Daşu, Alexandru, et al.
(författare)
-
Secondary malignancies from prostate cancer radiation treatment : a risk analysis of the influence of target margins and fractionation patterns
- 2011
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 79:3, s. 738-746
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This study explores the implications for cancer induction of treatment details such as fractionation, planning target volume (PTV) definition, and interpatient variations, which are relevant for the radiation treatment of prostate carcinomas.METHODS AND MATERIALS: Treatment planning data from 100 patients have been analyzed with a risk model based on the United Nations Scientific Committee on the Effects of Atomic Radiation competition model. The risk model can account for dose heterogeneity and fractionation effects characteristic for modern radiotherapy. Biologically relevant parameters from clinical and experimental data have been used with the model.RESULTS: The results suggested that changes in prescribed dose could lead to a modification of the risks for individual organs surrounding the clinical target volume (CTV) but that the total risk appears to be less affected by changes in the target dose. Larger differences are observed for modifications of the margins between the CTV and the PTV because these have direct impact onto the dose level and dose heterogeneity in the healthy tissues surrounding the CTV. Interpatient anatomic variations also have to be taken into consideration for studies of the risk for cancer induction from radiotherapy.CONCLUSIONS: The results have shown the complex interplay between the risk for secondary malignancies, the details of the treatment delivery, and the patient heterogeneity that may influence comparisons between the long-term effects of various treatment techniques. Nevertheless, absolute risk levels seem very small and comparable to mortality risks from surgical interventions, thus supporting the robustness of radiation therapy as a successful treatment modality for prostate carcinomas.
|
|
| 9. |
|
|
| 10. |
- Dasu, Alexandru, et al.
(författare)
-
What is the Clinically Relevant Relative Biologic Effectiveness? A Warning for Fractionated Treatments With High Linear Energy Transfer Radiation
- 2008
-
Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier. - 0360-3016 .- 1879-355X. ; 70:3, s. 867-874
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To study the clinically relevant relative biologic effectiveness (RBE) of fractionated treatments with high linear energy transfer (LET) radiation and to identify the important factors that might influence the transfer of tolerance and curative levels from low LET radiation. These are important questions in the light of the growing interest for the therapeutic use of radiation with higher LET than electrons or photons.METHODS AND MATERIALS: The RBE of various fractionated schedules was analyzed with theoretical models for radiation effect, and the resulting predictions were compared with the published clinical and experimental data regarding fractionated irradiation with high LET radiation.RESULTS: The clinically relevant RBE increased for greater doses per fraction, in contrast to the predictions from single-dose experiments. Furthermore, the RBE for late-reacting tissues appeared to modify more quickly than that for early-reacting tissues. These aspects have quite important clinical implications, because the increased biologic effectiveness reported for this type of radiation would otherwise support the use of hypofractionation. Thus, the differential between acute and late-reacting tissues could put the late-reacting normal tissues at more risk from high LET irradiation; however, at the same time, it could increase the therapeutic window for slow-growing tumors.CONCLUSIONS: The modification of the RBE with the dose per fraction must be carefully taken into consideration when devising fractionated treatments with high LET radiation. Neglecting to do so might result in an avalanche of complications that could obscure the potential advantages of the therapeutic use of this type of radiation.
|
|
