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1.  Evaluation of imaging performance of megavoltage cone-beam CT over an extended period 
Journal of Radiation Research  2013;55(1):191-199.
A linear accelerator vendor and the AAPM TG-142 report propose that quality assurance testing for image-guided devices such megavoltage cone-beam CT (MV-CBCT) be conducted on a monthly basis. In clinical settings, however, unpredictable errors such as image artifacts can occur even when quality assurance results performed at this frequency are within tolerance limits. Here, we evaluated the imaging performance of MV-CBCT on a weekly basis for ∼ 1 year using a Siemens ONCOR machine with a 6-MV X-ray and an image-quality phantom. Image acquisition was undertaken using 15 monitor units. Geometric distortion was evaluated with beads evenly distributed in the phantom, and the results were compared with the expected position in three dimensions. Image-quality characteristics of the system were measured and assessed qualitatively and quantitatively, including image noise and uniformity, low-contrast resolution, high-contrast resolution and spatial resolution. All evaluations were performed 100 times each. For geometric distortion, deviation between the measured and expected values was within the tolerance limit of 2 mm. However, a subtle systematic error was found which meant that the phantom was rotated slightly in a clockwise manner, possibly due to geometry calibration of the MV-CBCT system. Regarding image noise and uniformity, two incidents over tolerance occurred in 100 measurements. This phenomenon disappeared after dose calibration of beam output for MV-CBCT. In contrast, all results for low-contrast resolution, high-contrast resolution and spatial resolution were within their respective tolerances.
doi:10.1093/jrr/rrt100
PMCID: PMC3885132  PMID: 23979076
Cone-beam CT; QA; image-guided radiation therapy; IGRT; tolerance; calibration
2.  Dose reduction trial from 60 Gy in 10 fractions to 54 Gy in 9 fractions schedule in high-dose-rate interstitial brachytherapy for early oral tongue cancer 
Journal of Radiation Research  2012;53(5):722-726.
To compare the effects of 60 Gy/10 fractions (twice a day) with those of 54 Gy/9 fractions in high-dose-rate interstitial brachytherapy (HDR-ISBT) for early tongue cancer, we performed a matched-pair analysis of patients with early tongue cancer (T1-2N0M0), who were treated with 60 or 54 Gy of radiation between 1996 and 2004. Seventeen patients treated with 54 Gy and 34 matched-pair patients treated with 60 Gy were extracted and analyzed. Local recurrence occurred in two patients in the 54-Gy arm and five patients in the 60-Gy arm. The 2-year local control rates were 88% for both the 54-Gy arm and 60-Gy arm (not significant). The 2-year overall survival rates were 88% in the 60-Gy arm and 82% in the 54-Gy arm. Two-year actuarial complication-free rates were 91% in the 60-Gy arm and 83% in the 54-Gy arm (not significant), respectively. There was no significant association between the total dose and local control rate and late complications. The outcome of 54 Gy/ 9 fractions was similar to that of 60 Gy/ 10 fractions in patients with early tongue cancer.
doi:10.1093/jrr/rrs027
PMCID: PMC3430427  PMID: 22843365
tongue cancer; brachytherapy; interstitial radiotherapy; high dose rate
3.  Age is not a limiting factor for brachytherapy for carcinoma of the node negative oral tongue in patients aged eighty or older 
Background
To examine the role of brachytherapy for aged patients 80 or more in the trend of rapidly increasing number.
Methods
We examined the outcomes for elderly patients with node negative oral tongue cancer (T1-3N0M0) treated with brachytherapy. The 21 patients (2 T1, 14 T2, and 5 T3 cases) ranged in age from 80 to 89 years (median 81), and their cancer was pathologically confirmed. All patients underwent definitive radiation therapy, with low dose rate (LDR) Ra-226 brachytherapy (n = 4; median 70Gy), with Ir-192 (n = 12; 70Gy), with Au-198 (n = 1) or with high dose rate (HDR) Ir-192 brachytherapy (n = 4; 60 Gy). Eight patients also underwent external radiotherapy (median 30 Gy). The period of observation ranged from 13 months to 14 years (median 2.5 years). We selected 226 population matched younger counterpart from our medical chart.
Results
Definitive radiation therapy was completed for all 21 patients (100%), and acute grade 2-3 mucositis related to the therapy was tolerable. Local control (initial complete response) was attained in 19 of 21 patients (90%). The 2-year and 5-year local control rates were 91%, (100% for T1, 83% for T2 and 80% for T3 tumors after 2 years). These figures was not inferior to that of younger counterpart (82% at 5-year, n.s.). The cause-specific survival rate was 83% and the regional control rate 84% at the 2-years follow-up. However, 12 patients died because of intercurrent diseases or senility, resulting in overall survival rates of 55% at 2 years and 34% at 5 years.
Conclusion
Age is not a limiting factor for brachytherapy for appropriately selected elderly patients, and brachytherapy achieved good local control with acceptable morbidity.
doi:10.1186/1748-717X-5-116
PMCID: PMC3016284  PMID: 21143904

Results 1-3 (3)