ABSTRACT
OBJECTIVES@#To study the feasibility of ArcCHECK-3DVH system in dosimetric verification for stereotactic body radiaotherapy (SBRT) with flattening filter free (FFF) model.@*METHODS@#SBRT treatment plans for 57 patients were introduced into ArcCHECK phantom and recalculated. The calculated dose distribution of treatment planning system and the measured dose distribution of ArcCHECK phantom were compared by γ analysis. Then the 3 dimensional dose distribution of target and organs at risk was reconstructed by 3DVH software. The reconstructed dose and calculated dose with treatment planning system (TPS) were compared, and the dose volume γ pass rate and deviation of dose volume parameters to the target and organs at risk were quantitatively valuated.@*RESULTS@#Based on the threshold criteria (3%, 3 mm, 10%), namely the deviation of measuring points between the planned value and the measured value was less than 3%, and the proportion of points with similar values in the plane or sphere with the center of the point and the radius of 3 mm was 10%, the relative and absolute dose pass rates of SBRT treatment plans in ArcCHECK system via γ analysis were greater than 95%. Based on the stricter threshold criteria (2%, 2 mm, 10%), the relative and absolute dose pass rates of SBRT treatment plan in ArcCHECK system via γ analysis were about 93%. In 3DVH dose verification, the γ pass rate of target and organs at risk was exceed 97%, and the deviations in 3DVH of the target and organs at risk were less than ±5%.@*CONCLUSIONS@#The ArcCHECK-3DVH system in dose verification can provide more comprehensive dose distribution information to reasonably evaluate the SBRT plan, with more significance for guiding clinical treatment.
Subject(s)
Humans , Phantoms, Imaging , Quality Assurance, Health Care , Radiometry , Radiosurgery , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted , Radiotherapy, Intensity-ModulatedABSTRACT
To study the feasibility of ArcCheck verification system in dosimetric verification for stereotactic radiotherapy (SRT) the stereotactic radiotherapy (SRT) with flattening filter free (FFF) model. Methods: A total of 76 cases under SRT treatment plans were introduced into ArcCheck phantom and recalculated. Threshold criteria was set as (3%, 3 mm, 10%) or (2%, 2 mm, 10%). The calculated dose distribution and the measured dose distribution of ArcCheck phantom were compared by means of distance to agree (DTA) and Gamma analysis method respectively. Results: Based on the threshold criteria (3%, 3 mm, 10%), the relative and absolute mean pass rates of SRT treatment plans by DTA and Gamma analysis were greater than 95%. Based on the threshold criteria (2%, 2 mm, 10%), the relative and absolute mean pass rates of SRT treatment plan by DTA and Gamma analysis were about 90%. The dose pass rate of Gamma analysis method was slightly higher than that of DTA analysis method (P<0.001). Conclusion: The ArcCheck verification system is a rapid and accurate method for SRT dose verification, and discrepancies are found in different analysis methods.
Subject(s)
Humans , Feasibility Studies , Phantoms, Imaging , Radiosurgery , Methods , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted , Radiotherapy, Intensity-ModulatedABSTRACT
OBJECTIVE@#To compare the dosimetric differences of dosiology between intensity-modulated arc radiotherapy (IMAT) and dynamic intensity-modulated radiation therapy (dIMRT) in nasopharyngeal carcinoma.@*METHODS@#CT data from 25 patients treated in our radiotherapy center were selected randomly for this study. For each patient, the IMAT technique and the fixed beam dIMRT technique were accomplished by the simultaneously integrated boost. Dose volume histogram (DVH) data, isodose distribution, monitor units (MUs) and treatment time were compared in the two techniques.@*RESULTS@#There was no significant difference between the IMAT and the dIMRT in dose received by 95% of target volumes (D(95)) (P>0.05). Overall, the mean dose (D(mean)), maximal dose (D(max)) and volume percentage receiving at least of 107% of the prescribed dose (V(107%)) of planning target volume (PTV) for the IMAT were increased slightly ,compared with the dlMRT (P0.05). Compared with the dlMRI, the D(max) of brain stem for the IMAT was increased slightly (P<0.05). Similar trends was observed for the D(mean) and dose received by 50% of volume (D(50)) of the left and right parotid glands (P<0.05). Healthy tissue (defined as the volume of the body minus PTV,B-P) irradiated from 800 cGy in the IMAT was higher, and that from 1200-4500 cGy was lower compared with the dlMRI (P<0.05).The average number of MUs was reduced by 62.7% per fraction, and the treatment time was on average reduced by 60.1% per fraction in the IMAT compared with the dlMRI.@*CONCLUSION@#There is a slight difference in dosiology between the two radiotherapy techniques investigated, but they both meet the clinical requirement. Compared with the dIMRT, the IMAT delivers less irradiation to healthy tissue, uses fewer MUs and takes less time during radiotherapy for nasopharyngeal carcinoma.