Four-dimensional computed tomography-based interfractional reproducibility study of lung tumor intrafractional motion.

PURPOSE: To evaluate the interfractional reproducibility of respiration-induced lung tumors motion, defined by their centroids and the intrafractional target motion range. METHODS AND MATERIALS: Twentythree pairs of four-dimensional/computed tomography scans were acquired for 22 patients. Gross tumor volumes were contoured, Clinical target volumes (CTVs) were generated. Geometric data for CTVs and lung volumes were extracted. The motion tracks of CTV centroids, and CTV edges along the cranio-caudal, anterior-posterior, and lateral directions were evaluated. The Pearson correlation coefficient for motion tracks along the cranio-caudal direction was determined for the entire respiratory cycle and for five phases about the end of expiration. RESULTS: The largest motion extent was along the cranio-caudal direction. The intrafractional motion extent for five CTVs was <0.5 cm, the largest motion range was 3.59 cm. Three CTVs with respiration-induced displacement >0.5 cm did not exhibit the similarity of motion, and for 16 CTVs with motion >0.5 cm the correlation coefficient was >0.8. The lung volumes in corresponding phases for cases that demonstrated CTVs motion similarity were reproducible. No correlation between tumor size and mobility was found. CONCLUSION: Target motion reproducibility seems to be present in 87% of cases in our dataset. Three cases with dissimilar motion indicate that it is advisable to verify target motion during treatment. The adaptive adjustment to compensate the possible interfractional shifts in a target position should be incorporated as a routine policy for lung cancer radiotherapy.

Assessment of "best practice" treatment patterns for a "radiation oncology community outreach group" engaged in cancer disparities outcomes.

OBJECTIVE: Minority patients with cancer have higher recurrence rates than the general population and are more likely to be treated at community centers where the standard of care has been reported to be inferior to that at academic centers. These issues are being explored by Radiation Oncology Community Outreach Group (ROCOG), a consortium of 5 Community Radiation Oncology centers participating in a National Cancer Institute-funded Disparities Grant. As a quality assurance/quality improvement initiative, this study was undertaken to ensure that treatment was at a "best practice" level. METHODS: With the use of the American College of Radiology (ACR) accreditation criteria, an initial self-evaluation was done on 10 randomly selected cases at each of 5 radiation oncology clinics for patients treated between July 2002 and December 2003. The results were analyzed and presented to the centers with recommendations for improvements in April 2004. As part of an application to the ACR for accreditation, a second self-evaluation was performed on randomly selected cases treated between July and December 2004. ACR surveyors conducted the last randomly selected case evaluation. RESULTS: All centers had acceptable standards at baseline. The ROCOG average compliance rate at first evaluation was 88% vs 92% for ACR-accredited facilities. At reevaluation, the ROCOG average compliance rate was 95% vs 92% (ACR-accredited facilities). At the final evaluation, the ROCOG average compliance rate was 92% vs 90% (ACR-accredited facilities). All 5 sites received ACR accreditation. CONCLUSION: Despite a small sample, patients served by these institutions, regardless of minority status, received radiation oncology care at or above the accepted standards. A quality assessment/quality improvement initiative using ACR accreditation to ensure that "best practice" levels led to improved standards. Accreditation is one method that could be used to support a "pay-for-performance" program.

Dosimetric and toxicity comparison between prone and supine position IMRT for endometrial cancer.

PURPOSE: To determine the dosimetric and toxicity differences between prone and supine position intensity-modulate radiotherapy in endometrial cancer patients treated with adjuvant radiotherapy. METHODS: Forty-seven consecutive endometrial cancer patients treated with adjuvant RT were analyzed. Of these, 21 were treated in prone position and 26 in the supine position. Dose-volume histograms for normal tissue structures and targets were compared between the two groups. Acute and chronic toxicity were also compared between the cohorts. RESULTS: The percentage of volume receiving 10, 20, 30, 40, 45, and 50 Gy for small bowel was 89.5%, 69%, 33%, 12.2%, 5%, and 0% in the prone group and 87.5%, 62.7%, 26.4%, 8%, 4.3%, and 0% in the supine group, respectively. The difference was not statistically significant. The dose-volume histograms for bladder and rectum were also comparable, except for a slightly greater percentage of volume receiving 10 Gy (1.5%) and 20 Gy (5%) for the rectum in the prone group. Acute small bowel toxicities were Grade 1 in 7 patients and Grade 2 in 14 patients in the prone group vs. Grade 1 in 6 patients and Grade 2 in 19 patients in the supine group. Chronic toxicity was Grade 1 in 7 patients and Grade 3 in 1 patient in the prone group and Grade 1 in 5 patients in the supine group. CONCLUSION: These preliminary results suggest that no difference exists in the dose to the normal tissue and toxicity between prone and supine intensity-modulated radiotherapy for endometrial cancer. Longer follow-up and more outcome studies are needed to determine whether any differences exist between the two approaches.

Radiation Treatment Planning for Head and Neck Malignancies.

Innovative approaches have been incorporated to radiation therapy over the last decades. The technologic advances, such as intensity modulated radiation therapy and image guided radiation have resulted in a modern era for this oncologic modality. The mix of imaging approach using computed tomography (CT), magnetic resonance, and positron emission tomography (PET) have been of great value to ascertain the accuracy of tumor target delineation. The use of functional imaging, especially PET/CT, has been incorporated to the modern radiation oncology practice to better define the tumor extent and augment the treatment plan design, as well as response assessment. This article focuses on radiation treatment planning and the integration of PET/CT for head and neck cancer radiation therapy.