Interfractional variations in the setup of pelvic bony anatomy and soft tissue, and their implications on the delivery of proton therapy for localized prostate cancer.

نویسندگان

  • Alexei Trofimov
  • Paul L Nguyen
  • Jason A Efstathiou
  • Yi Wang
  • Hsiao-Ming Lu
  • Martijn Engelsman
  • Scott Merrick
  • Chee-Wai Cheng
  • James R Wong
  • Anthony L Zietman
چکیده

PURPOSE To quantify daily variations in the anatomy of patients undergoing radiation therapy for prostate carcinoma, to estimate their effect on dose distribution, and to evaluate the effectiveness of current standard planning and setup approaches employed in proton therapy. METHODS We used series of computed tomography data, which included the pretreatment scan, and between 21 and 43 in-room scans acquired on different treatment days, from 10 patients treated with intensity-modulated radiation therapy at Morristown Memorial Hospital. Variations in femur rotation angles, thickness of subcutaneous adipose tissue, and physical depth to the distal surface of the prostate for lateral beam arrangement were recorded. Proton dose distributions were planned with the standard approach. Daily variations in the location of the prescription isodose were evaluated. RESULTS In all 10 datasets, substantial variation was observed in the lateral tissue thickness (standard deviation of 1.7-3.6 mm for individual patients, variations of >5 mm from the planning computed tomography observed in all series), and femur rotation angle (standard deviation between 1.3° and 4.8°, with the maximum excursion exceeding 10° in 6 of 10 datasets). Shifts in the position of treated volume (98% isodose) were correlated with the variations in the lateral tissue thickness. CONCLUSIONS Analysis suggests that, combined with image-guided setup verification, the range compensator expansion technique prevents loss of dose to target from femur rotation and soft-tissue deformation, in the majority of cases. Anatomic changes coupled with the uncertainties of particle penetration in tissue restrict possibilities for margin reduction in proton therapy of prostate cancer.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Superiority of a soft tissue‐based setup using cone‐beam computed tomography over a bony structure‐based setup in intensity‐modulated radiotherapy for prostate cancer *

The purpose of this study was to test the superiority of a soft tissue-based setup using cone-beam computed tomography (CBCT) to a bony structure-based setup using the ExacTrac system in intensity-modulated radiotherapy (IMRT) for prostate cancer. We studied 20 patients with localized prostate cancer who received IMRT between November 2010 and February 2012. After the initial setup, the pelvic ...

متن کامل

The Impact of Residual Geometric Inaccuracies on Normal Organ Doses in Image Guided-Radiation Therapy of Prostate Cancer Using On-Board Kilovoltage Cone-Beam Computed Tomography

Introduction: The aim of this retrospective study was to evaluate the variations in delivered dose to the bladder, rectum, and femoral heads of prostate cancer patients during a course of treatment by image-guided radiation therapy (IGRT). Materials and Methods: Overall, 15 patients with prostate cancer were selected and. Each week, for each patient five consecutive cone beam computed tomograph...

متن کامل

Proton therapy of prostate cancer by anterior-oblique beams: implications of setup and anatomy variations.

Proton therapy of prostate by anterior beams could offer an attractive option for treating patients with hip prosthesis and limiting the high-dose exposure to the rectum. We investigated the impact of setup and anatomy variations on the anterior-oblique (AO) proton plan dose, and strategies to manage these effects via range verification and adaptive delivery. Ten patients treated by bilateral (...

متن کامل

Ideal Soft Tissue Facial Profile in Iranian Males and Females: Clinical Implications

BACKGROUND Proper pre-operative facial analysis that includes a thorough evaluation of both the bony and soft tissue anatomy is paramount to success in performing aesthetic surgery of the face. Ethnic variations in soft tissue profile add an important variable to pre-operative facial analysis. The aim of our study was to determine the role of ethnic variations in soft tissue facial profiles th...

متن کامل

Early toxicity of moderate hypofractionated volumetric modulated Arc radiotherapy for localized prostate cancer

Background: Based on the radiation biology model of prostate cancer, hypofractionated radiotherapy can improve the treatment outcomes without increasing toxicity. Although hypofractionated radiotherapy is implemented over a short period of time, it is more convenient and cheaper compared with conventional fractionated treatment. The aim of this study was to investigate the early toxicity of mod...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • International journal of radiation oncology, biology, physics

دوره 80 3  شماره 

صفحات  -

تاریخ انتشار 2011