LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 3 of total 3

Search options

  1. Article ; Online: Correlation between target volume and electron transport effects affecting heterogeneity corrections in stereotactic body radiotherapy for lung cancer.

    Akino, Yuichi / Das, Indra J / Cardenes, Higinia R / Desrosiers, Colleen M

    Journal of radiation research

    2014  Volume 55, Issue 4, Page(s) 754–760

    Abstract: Recently, stereotactic body radiotherapy (SBRT) for lung cancer is conducted with heterogeneity-corrected treatment plans, as the correction greatly affects the dose delivery to the lung tumor. In this study, the correlation between the planning target ... ...

    Abstract Recently, stereotactic body radiotherapy (SBRT) for lung cancer is conducted with heterogeneity-corrected treatment plans, as the correction greatly affects the dose delivery to the lung tumor. In this study, the correlation between the planning target volume (PTV) and the dose delivery is investigated by separation of the heterogeneity correction effects into photon attenuation and electron transport. Under Institutional Review Board exemption status, 74 patients with lung cancer who were treated with SBRT were retrospectively evaluated. All treatment plans were generated using an anisotropic analytical algorithm (AAA) of an Eclipse (Varian Medical Systems, Palo Alto, CA) treatment planning system. Two additional plans were created using the same treatment parameters (monitor units, beam angles and energy): a plan with no heterogeneity correction (NC), and a plan calculated with a pencil beam convolution algorithm (PBC). Compared with NC, AAA and PBC isocenter doses were on average 13.4% and 21.8% higher, respectively. The differences in the isocenter dose and the dose coverage for 95% of the PTV (D95%) between PBC and AAA were correlated logarithmically (ρ = 0.78 and ρ = 0.46, respectively) with PTV. Although D95% calculated with AAA was in general 2.9% larger than that for NC, patients with a small PTV showed a negative ΔD95% for AAA due to the significant effect of electron transport. The PTV volume shows logarithmic correlation with the effects of the lateral electron transport. These findings indicate that the dosimetric metrics and prescription, especially in clinical trials, should be clearly evaluated in the context of target volume characteristics and with proper heterogeneity correction.
    MeSH term(s) Algorithms ; Electron Transport ; Humans ; Lung Neoplasms/pathology ; Lung Neoplasms/surgery ; Radiometry/statistics & numerical data ; Radiosurgery/statistics & numerical data ; Retrospective Studies
    Language English
    Publishing date 2014-02-11
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 603983-2
    ISSN 1349-9157 ; 0449-3060
    ISSN (online) 1349-9157
    ISSN 0449-3060
    DOI 10.1093/jrr/rrt231
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Evaluation of rotational errors in treatment setup of stereotactic body radiation therapy of liver cancer.

    Cao, Minsong / Lasley, Foster D / Das, Indra J / Desrosiers, Colleen M / Slessinger, Eric D / Cardenes, Higinia R

    International journal of radiation oncology, biology, physics

    2012  Volume 84, Issue 3, Page(s) e435–40

    Abstract: Purpose: To evaluate the dosimetric impact of rotational setup errors in stereotactic body radiotherapy (SBRT) treatment of liver tumors and to investigate whether translational shifts can compensate for rotation.: Methods and materials: The ... ...

    Abstract Purpose: To evaluate the dosimetric impact of rotational setup errors in stereotactic body radiotherapy (SBRT) treatment of liver tumors and to investigate whether translational shifts can compensate for rotation.
    Methods and materials: The positioning accuracy in 20 patients with liver malignancies treated with SBRT was reevaluated offline by matching the patients' cone-beam computed tomography (CT) scans (n=75) to the planning CT scans and adjusting the 3 rotational angles (pitch, roll, and yaw). Systematic and random setup errors were calculated. The dosimetric changes caused by rotational setup errors were quantified for both simulated and observed patient rotations. Dose distributions recalculated on the rotated CT scans were compared with the original planned doses. Translational corrections were simulated based on manual translational registration of the rotated images to the original CT scans. The correction efficacy was evaluated by comparing the recalculated plans with the original plans.
    Results: The systematic rotational setup errors were -0.06° ± 0.68°, -0.29° ± 0.62°, and -0.24° ± 0.61°; the random setup errors were 0.80°, 1.05°, and 0.61° for pitch, roll, and yaw, respectively. Analysis of CBCT images showed that 56.0%, 14.7%, and 1.3% of treated fractions had rotational errors of >1°, >2°, and >3°, respectively, in any one of the rotational axes. Rotational simulations demonstrated that the reduction of gross tumor volume (GTV) coverage was <2% when rotation was <3°. Recalculated plans using actual patient roll motions showed similar reduction (<2%) in GTV coverage. Translational corrections improved the GTV coverage to within 3% of the original values. For organs at risk (OAR), the dosimetric impact varied case by case.
    Conclusion: Actual rotational setup errors in SBRT for liver tumors are relatively small in magnitude and are unlikely to affect GTV coverage significantly. Translational corrections can be optimized to compensate for rotational setup errors. However, caution regarding possible dose increases to OAR needs to be exercised.
    MeSH term(s) Cone-Beam Computed Tomography/methods ; Humans ; Liver Neoplasms/diagnostic imaging ; Liver Neoplasms/pathology ; Liver Neoplasms/surgery ; Organs at Risk/diagnostic imaging ; Organs at Risk/radiation effects ; Radiosurgery/methods ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted/methods ; Radiotherapy Setup Errors/prevention & control ; Retrospective Studies ; Rotation ; Tumor Burden ; Uncertainty
    Language English
    Publishing date 2012-11-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 197614-x
    ISSN 1879-355X ; 0360-3016
    ISSN (online) 1879-355X
    ISSN 0360-3016
    DOI 10.1016/j.ijrobp.2012.05.018
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article: The role of Gamma Knife Radiosurgery in the management of unresectable gross disease or gross residual disease after surgery in ependymoma.

    Lo, Simon S / Abdulrahman, Ramzi / Desrosiers, Paul M / Fakiris, Achilles J / Witt, Thomas C / Worth, Robert M / Dittmer, Phil H / Desrosiers, Colleen M / Frost, Stephanie / Timmerman, Robert D

    Journal of neuro-oncology

    2006  Volume 79, Issue 1, Page(s) 51–56

    Abstract: Purpose/objective: To evaluate the efficacy and the toxicity of Gamma Knife (GK)-based stereotactic radiosurgery (SRS) in the management of gross disease in ependymoma.: Materials and methods: Eight patients with 13 ependymomas were treated with GK- ... ...

    Abstract Purpose/objective: To evaluate the efficacy and the toxicity of Gamma Knife (GK)-based stereotactic radiosurgery (SRS) in the management of gross disease in ependymoma.
    Materials and methods: Eight patients with 13 ependymomas were treated with GK-based SRS in our institution for gross disease. Five patients were treated for recurrent disease that developed after surgery and external beam radiotherapy (EBRT), two received SRS to the gross disease after surgery and EBRT, and one received SRS alone (in a 1.3 year old child). Median EBRT dose was 54.4 Gy (range 50-55.8 Gy). Median SRS dose was 14 Gy (range 12-20 Gy). Seven of eight (87.5%) patients had SRS to a single lesion and one of eight (12.5%) patients had treatment to six tumors in three different sessions.
    Results: The median follow up was 30.2 months (range 8-65.4 months). Out of the eight patients treated with SRS, six (75%) were alive, four (50%) were alive with no recurrence, two (25%) were alive with recurrence, and two (25%) died of recurrent disease. Both patients treated with SRS as a boost were alive and without recurrence. Out of the five patients who received SRS as salvage treatment, three (60%) were alive, two (40%) were alive without recurrence, two (40%) developed distant failure, and three (60%) had in-field control. Two patients who received SRS to their brainstem lesions developed symptoms related to radionecrosis and were successfully treated with steroid with good control of symptoms.
    Conclusions: GK-based SRS appears to be a feasible and safe treatment modality for patients with ependymoma with unresectable gross disease or gross residual disease after surgery. SRS provides reasonable local control but out-of-field tumor progression remains an issue. For patients who receive SRS as a boost, the local control appears to be excellent.
    MeSH term(s) Adolescent ; Adult ; Brain Neoplasms/mortality ; Brain Neoplasms/surgery ; Child ; Child, Preschool ; Ependymoma/mortality ; Ependymoma/surgery ; Female ; Humans ; Infant ; Male ; Neoplasm Recurrence, Local/surgery ; Neoplasm, Residual ; Radiosurgery/adverse effects ; Survival Analysis ; Survival Rate ; Treatment Outcome
    Language English
    Publishing date 2006-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 604875-4
    ISSN 1573-7373 ; 0167-594X
    ISSN (online) 1573-7373
    ISSN 0167-594X
    DOI 10.1007/s11060-005-9112-y
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top