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Title: SU-F-T-494: A Multi-Institutional Study of Independent Dose Verification Using Golden Beam Data

Abstract

Purpose: In general, beam data of individual linac is measured for independent dose verification software program and the verification is performed as a secondary check. In this study, independent dose verification using golden beam data was compared to that using individual linac’s beam data. Methods: Six institutions were participated and three different beam data were prepared. The one was individual measured data (Original Beam Data, OBD) .The others were generated by all measurements from same linac model (Model-GBD) and all linac models (All-GBD). The three different beam data were registered to the independent verification software program for each institute. Subsequently, patient’s plans in eight sites (brain, head and neck, lung, esophagus, breast, abdomen, pelvis and bone) were analyzed using the verification program to compare doses calculated using the three different beam data. Results: 1116 plans were collected from six institutes. Compared to using the OBD, the results shows the variation using the Model-GBD based calculation and the All-GBD was 0.0 ± 0.3% and 0.0 ± 0.6%, respectively. The maximum variations were 1.2% and 2.3%, respectively. The plans with the variation over 1% shows the reference points were located away from the central axis with/without physical wedge. Conclusion: The confidence limitmore » (2SD) using the Model-GBD and the All-GBD was within 0.6% and 1.2%, respectively. Thus, the use of golden beam data may be feasible for independent verification. In addition to it, the verification using golden beam data provide quality assurance of planning from the view of audit. This research is partially supported by Japan Agency for Medical Research and Development(AMED)« less

Authors:
;  [1]; ;  [2];  [3];  [4]; ;  [5];  [6];  [7];  [8];  [9]
  1. Inagi Municipal Hospital, Inagi, Tokyo (Japan)
  2. National Cancer Center Hospital East, Kashiwa, Chiba (Japan)
  3. Kobe City Medical Center General Hospital, Kobe, Hyogo (Japan)
  4. Kitasato University Medical Center, Kitamoto, Saitama (Japan)
  5. National Center for Global Health and Medicine, Shinjuku, Tokyo (Japan)
  6. Cancer Institute Hospital Japanese Foundation for Cancer Research, Koto, Tokyo (Japan)
  7. Cancer Institute Hospital of Japanese Foundation for Cancer Research, Koto, Tokyo (Japan)
  8. Sasebo City General Hospital, Sasebo, Nagasaki (Japan)
  9. National Cancer Center, Kashiwa, Chiba (Japan)
Publication Date:
OSTI Identifier:
22649081
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; BEAMS; COMPUTER CODES; DOSES; LINEAR ACCELERATORS; MAMMARY GLANDS; PLANNING; QUALITY ASSURANCE; VARIATIONS; VERIFICATION

Citation Formats

Itano, M, Yamazaki, T, Tachibana, R, Uchida, Y, Yamashita, M, Shimizu, H, Sugawara, Y, Kotabe, K, Kamima, T, Takahashi, R, Ishibashi, S, and Tachibana, H. SU-F-T-494: A Multi-Institutional Study of Independent Dose Verification Using Golden Beam Data. United States: N. p., 2016. Web. doi:10.1118/1.4956679.
Itano, M, Yamazaki, T, Tachibana, R, Uchida, Y, Yamashita, M, Shimizu, H, Sugawara, Y, Kotabe, K, Kamima, T, Takahashi, R, Ishibashi, S, & Tachibana, H. SU-F-T-494: A Multi-Institutional Study of Independent Dose Verification Using Golden Beam Data. United States. doi:10.1118/1.4956679.
Itano, M, Yamazaki, T, Tachibana, R, Uchida, Y, Yamashita, M, Shimizu, H, Sugawara, Y, Kotabe, K, Kamima, T, Takahashi, R, Ishibashi, S, and Tachibana, H. 2016. "SU-F-T-494: A Multi-Institutional Study of Independent Dose Verification Using Golden Beam Data". United States. doi:10.1118/1.4956679.
@article{osti_22649081,
title = {SU-F-T-494: A Multi-Institutional Study of Independent Dose Verification Using Golden Beam Data},
author = {Itano, M and Yamazaki, T and Tachibana, R and Uchida, Y and Yamashita, M and Shimizu, H and Sugawara, Y and Kotabe, K and Kamima, T and Takahashi, R and Ishibashi, S and Tachibana, H},
abstractNote = {Purpose: In general, beam data of individual linac is measured for independent dose verification software program and the verification is performed as a secondary check. In this study, independent dose verification using golden beam data was compared to that using individual linac’s beam data. Methods: Six institutions were participated and three different beam data were prepared. The one was individual measured data (Original Beam Data, OBD) .The others were generated by all measurements from same linac model (Model-GBD) and all linac models (All-GBD). The three different beam data were registered to the independent verification software program for each institute. Subsequently, patient’s plans in eight sites (brain, head and neck, lung, esophagus, breast, abdomen, pelvis and bone) were analyzed using the verification program to compare doses calculated using the three different beam data. Results: 1116 plans were collected from six institutes. Compared to using the OBD, the results shows the variation using the Model-GBD based calculation and the All-GBD was 0.0 ± 0.3% and 0.0 ± 0.6%, respectively. The maximum variations were 1.2% and 2.3%, respectively. The plans with the variation over 1% shows the reference points were located away from the central axis with/without physical wedge. Conclusion: The confidence limit (2SD) using the Model-GBD and the All-GBD was within 0.6% and 1.2%, respectively. Thus, the use of golden beam data may be feasible for independent verification. In addition to it, the verification using golden beam data provide quality assurance of planning from the view of audit. This research is partially supported by Japan Agency for Medical Research and Development(AMED)},
doi = {10.1118/1.4956679},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Purpose: To show the results of a multi-institutional study of the independent dose verification for conventional, Stereotactic radiosurgery and body radiotherapy (SRS and SBRT) plans based on the action level of AAPM TG-114. Methods: This study was performed at 12 institutions in Japan. To eliminate the bias of independent dose verification program (Indp), all of the institutions used the same CT-based independent dose verification software (Simple MU Analysis, Triangle Products, JP) with the Clarkson-based algorithm. Eclipse (AAA, PBC), Pinnacle{sup 3} (Adaptive Convolve) and Xio (Superposition) were used as treatment planning system (TPS). The confidence limits (CL, Mean±2SD) for 18 sitesmore » (head, breast, lung, pelvis, etc.) were evaluated in comparison in dose between the TPS and the Indp. Results: A retrospective analysis of 6352 treatment fields was conducted. The CLs for conventional, SRS and SBRT were 1.0±3.7 %, 2.0±2.5 % and 6.2±4.4 %, respectively. In conventional plans, most of the sites showed within 5 % of TG-114 action level. However, there were the systematic difference (4.0±4.0 % and 2.5±5.8 % for breast and lung, respectively). In SRS plans, our results showed good agreement compared to the action level. In SBRT plans, the discrepancy between the Indp was variable depending on dose calculation algorithms of TPS. Conclusion: The impact of dose calculation algorithms for the TPS and the Indp affects the action level. It is effective to set the site-specific tolerances, especially for the site where inhomogeneous correction can affect dose distribution strongly.« less
  • Purpose: AAPM TG114 does not cover the independent verification for IMRT. We conducted a study of independent dose verification for IMRT in seven institutes to show the feasibility. Methods: 384 IMRT plans in the sites of prostate and head and neck (HN) were collected from the institutes, where the planning was performed using Eclipse and Pinnacle3 with the two techniques of step and shoot (S&S) and sliding window (SW). All of the institutes used a same independent dose verification software program (Simple MU Analysis: SMU, Triangle Product, Ishikawa, JP), which is Clarkson-based and CT images were used to compute radiologicalmore » path length. An ion-chamber measurement in a water-equivalent slab phantom was performed to compare the doses computed using the TPS and an independent dose verification program. Additionally, the agreement in dose computed in patient CT images between using the TPS and using the SMU was assessed. The dose of the composite beams in the plan was evaluated. Results: The agreement between the measurement and the SMU were −2.3±1.9 % and −5.6±3.6 % for prostate and HN sites, respectively. The agreement between the TPSs and the SMU were −2.1±1.9 % and −3.0±3.7 for prostate and HN sites, respectively. There was a negative systematic difference with similar standard deviation and the difference was larger in the HN site. The S&S technique showed a statistically significant difference between the SW. Because the Clarkson-based method in the independent program underestimated (cannot consider) the dose under the MLC. Conclusion: The accuracy would be improved when the Clarkson-based algorithm should be modified for IMRT and the tolerance level would be within 5%.« less
  • Purpose: The accuracy of dose distribution depends on treatment planning system especially in heterogeneity-region. The tolerance level (TL) of the secondary check using the independent dose verification may be variable in lung SBRT plans. We conducted a multi-institutional study to evaluate the tolerance level of lung SBRT plans shown in the AAPM TG114. Methods: Five institutes in Japan participated in this study. All of the institutes used a same independent dose verification software program (Simple MU Analysis: SMU, Triangle Product, Ishikawa, JP), which is Clarkson-based and CT images were used to compute radiological path length. Analytical Anisotropic Algorithm (AAA), Pencilmore » Beam Convolution with modified Batho-method (PBC-B) and Adaptive Convolve (AC) were used for lung SBRT planning. A measurement using an ion-chamber was performed in a heterogeneous phantom to compare doses from the three different algorithms and the SMU to the measured dose. In addition to it, a retrospective analysis using clinical lung SBRT plans (547 beams from 77 patients) was conducted to evaluate the confidence limit (CL, Average±2SD) in dose between the three algorithms and the SMU. Results: Compared to the measurement, the AAA showed the larger systematic dose error of 2.9±3.2% than PBC-B and AC. The Clarkson-based SMU showed larger error of 5.8±3.8%. The CLs for clinical plans were 7.7±6.0 % (AAA), 5.3±3.3 % (AC), 5.7±3.4 % (PBC -B), respectively. Conclusion: The TLs from the CLs were evaluated. A Clarkson-based system shows a large systematic variation because of inhomogeneous correction. The AAA showed a significant variation. Thus, we must consider the difference of inhomogeneous correction as well as the dependence of dose calculation engine.« less
  • Purpose: To use end-to-end testing to validate a 6 MV high dose rate photon beam, configured for Eclipse AAA algorithm using Golden Beam Data (GBD), for SBRT treatments using RapidArc. Methods: Beam data was configured for Varian Eclipse AAA algorithm using the GBD provided by the vendor. Transverse and diagonals dose profiles, PDDs and output factors down to a field size of 2×2 cm2 were measured on a Varian Trilogy Linac and compared with GBD library using 2% 2mm 1D gamma analysis. The MLC transmission factor and dosimetric leaf gap were determined to characterize the MLC in Eclipse. Mechanical andmore » dosimetric tests were performed combining different gantry rotation speeds, dose rates and leaf speeds to evaluate the delivery system performance according to VMAT accuracy requirements. An end-to-end test was implemented planning several SBRT RapidArc treatments on a CIRS 002LFC IMRT Thorax Phantom. The CT scanner calibration curve was acquired and loaded in Eclipse. PTW 31013 ionization chamber was used with Keithley 35617EBS electrometer for absolute point dose measurements in water and lung equivalent inserts. TPS calculated planar dose distributions were compared to those measured using EPID and MapCheck, as an independent verification method. Results were evaluated with gamma criteria of 2% dose difference and 2mm DTA for 95% of points. Results: GBD set vs. measured data passed 2% 2mm 1D gamma analysis even for small fields. Machine performance tests show results are independent of machine delivery configuration, as expected. Absolute point dosimetry comparison resulted within 4% for the worst case scenario in lung. Over 97% of the points evaluated in dose distributions passed gamma index analysis. Conclusion: Eclipse AAA algorithm configuration of the 6 MV high dose rate photon beam using GBD proved efficient. End-to-end test dose calculation results indicate it can be used clinically for SBRT using RapidArc.« less
  • Purpose: To assess the relationship between the dose to the bulb of the penis and the risk of impotence in men treated on Radiation Therapy Oncology Group (RTOG) 9406. Methods and materials: Men enrolled on a Phase I/II dose-escalation study, RTOG 9406, who were reported to be potent at entry and evaluable (n = 158) were selected for inclusion. Follow-up evaluations were scheduled every 3, 4, and 6 months for the first, second, and the third through fifth years, then annually. At each follow-up visit an assessment of potency status was made. Penile structures were defined by a single observermore » blinded to the potency status, using Web-based, on-line software. The dosimetry for penile structures was calculated at the Quality Assurance Center at Washington University and provided to RTOG Statistical Headquarters to determine whether there was a relationship between dose and impotence. Results: Patients whose median penile dose was {>=}52.5 Gy had a greater risk of impotence compared with those receiving <52.5 Gy (p = 0.039). In a multivariate analysis neither age, the dose to the prostate, nor the use of hormonal therapy correlated with the risk of impotence. Conclusions: Dose to the bulb of the penis seems to be associated with the risk of radiation-induced impotence.« less