ABSTRACT
BACKGROUND AND PURPOSE: Diffusion weighted imaging (DWI) as a functional MR technique allows for both qualitative and quantitative assessment of tumour cellularity and changes during therapy. The objective of this study was to evaluate changes of apparent diffusion coefficient (ADC) in biopsy proven prostate cancer (PCa) under intensity modulated radiotherapy (IMRT) at 3T. MATERIAL & METHODS: Thirteen patients with biopsy proven PCa treated with intensity modulated external beam radiotherapy (IMRT) underwent four standardized MR examinations after approval of the local institutional review board. These included DWI at 3T on a strict time table: before, in between, directly after (between 1 and 4 days after the last radiation), as well as 3 months after IMRT. Quantitative analysis of two different ADCs, - the ADC(0,800) and the ADC(50,800), was performed dynamically over 4 time points in PCa, gluteal muscle and healthy prostate tissue. RESULTS: In PCa, a significant increase of ADC(0,800)/ADC(50,800) values was measured under IMRT by about 16%/15% (P=0.00008/0.00017), 21%/21% (P=0.00006/0.00030), and 33%/34% (P=0.00004/0.00002) at the three time points compared to initial value. Healthy prostate tissue did not show any significant increase. CONCLUSION: DWI is suitable as a biomarker for radiation therapy response of PCa by allowing the dynamic monitoring of treatment effectiveness.
Subject(s)
Prostatic Neoplasms/radiotherapy , Radiotherapy, Intensity-Modulated , Aged , Aged, 80 and over , Biopsy , Diffusion Magnetic Resonance Imaging/methods , Humans , Male , Middle Aged , Neoplasm Grading , Prospective Studies , Prostatectomy , Prostatic Neoplasms/pathology , Prostatic Neoplasms/surgery , Treatment OutcomeABSTRACT
PURPOSE: determine the value of MR studies in patients undergoing radiotherapy for glioblastomas pre and during radiotherapy to predict the clinical course. PATIENTS AND METHODS: MR follow-up studies were performed in 33 patients with glioblastomas before radiotherapy, after 30 Gy, after 60 Gy, and in the treatment follow-up. Findings on MR were categorized into: definite progress, questionable progress, status idem. Patients were followed clinically (median for 11 months). RESULTS: after 30 Gy 23/33 (70%) of the MR examination showed status idem. 10/33 (30%) demonstrated definite (n = 6) or questionable (n = 4) progress. Further tumor progress was faster in these patients and patients succumb to their disease earlier (9 vs. 22 months). The 60 Gy study showed definite (n = 8) and questionable (n = 6) progress in 14/33 (42%) cases. All these tumors were progressing faster and were associated with a comparatively reduced life expectancy. CONCLUSION: MR follow-up studies after 30 Gy in patients undergoing radiotherapy for glioblastomas allow for prognostic appraisal, and potentially early modification of treatment.
Subject(s)
Brain Neoplasms/pathology , Brain Neoplasms/radiotherapy , Cranial Irradiation , Diffusion Magnetic Resonance Imaging , Glioblastoma/pathology , Glioblastoma/radiotherapy , Image Enhancement , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Adult , Aged , Brain Neoplasms/drug therapy , Brain Neoplasms/mortality , Brain Neoplasms/surgery , Chemotherapy, Adjuvant , Combined Modality Therapy , Disease Progression , Female , Follow-Up Studies , Glioblastoma/drug therapy , Glioblastoma/mortality , Glioblastoma/surgery , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/mortality , Prognosis , Radiotherapy Dosage , Survival RateABSTRACT
BACKGROUND AND PURPOSE: Radiotherapy can induce tissue reactions with an edema leading to increased breast volume. The aim of the present study was to quantify this increase and analyze its effect on the electron boost technique. PATIENTS AND METHODS: 140 patients with breast cancer treated with breast-conserving surgery underwent CT planning before, during and/or after radiotherapy in order to evaluate breast volume changes due to radiotherapy. CT data were analyzed using the HELAX planning system and dose distribution was assessed. Determination of the breast volume was achieved using an interpolation algorithm. Three subgroups were analyzed: group 1 (n = 47): < or = 670 cm(3), group 2 (n = 46): 671-999 cm(3), and group 3 (n = 47): > or = 1000 cm(3) breast volume. RESULTS: The mean initial breast volume was 907 cm(3) (100-3073 cm(3)). After radiotherapy, mean breast volume increased by 81 cm(3) to 988 cm(3) (109-3185 cm(3)). Significant changes in volume were observed after a dose of 40 Gy. According to the subgroups mean volume increase was as follows: group 1: 53 cm(3) (3-120 cm(3)), group 2: 85 cm(3) (20-200 cm(3)), and group 3: 105 cm(3) (5-340 cm(3)). This difference was statistically significant for all subgroups (p < 0.001). Corresponding to the volume increase, depth of the boost target volume changed up to 1.0 cm. CONCLUSION: As radiotherapy may lead to a significant increase in breast volume, it seems appropriate to perform a second planning CT after about 40 Gy in order to optimize dose distribution for boost irradiation.
