scholarly journals Conversion and Validation of Rectal Constraints for Prostate Carcinoma Receiving Hypofractionated Carbon-ion Radiotherapy With a Local Effect Model

2020 ◽  
Author(s):  
Weiwei Wang ◽  
Ping Li ◽  
Yinxiangzi Sheng ◽  
Zhijie Huang ◽  
Jingfang Zhao ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Prostate Carcinoma ◽  
Local Effect ◽  
Carbon Ion Radiotherapy ◽  
Study Objective ◽  
Carbon Ion ◽  
Conversion Model ◽  
Biophysical Models ◽  
Effect Model

Abstract Purpose: The study objective was to convert the microdosimetric kinetic model (MKM) rectum constraints for 16-fraction carbon-ion radiotherapy (CIRT) to local effect model (LEM) constraints for 12-fraction, 8-fraction, and 4-fraction CIRT for prostate carcinoma patients (PCAs).Methods: Two strategies were employed. To understand the fractionation effects, MKM linear-quadric (LQ) strategy first converted MKM rectum constraints for 16-fraction CIRT to 12-fraction, 8-fraction, and 4-fraction CIRT. To examine the differences in the biophysical models, MKM constraints were converted to LEM constraints using an RBE-conversion model. The LEM LQ strategy first converted MKM rectum constraints for 16-fraction CIRT to LEM constraints using the RBE-conversion model. Then, the LEM constraints converted the 16-fraction constraints to the rectum constraints for 12-fraction, 8-fraction, and 4-fraction CIRT using the LQ model. The LEM rectum constraints for 16 and 12-fraction CIRTs were compared to the rectum doses and the clinical follow-ups in 40 patients.Results: The 16-fraction NIRS rectum constraint Dmax < 60.8 Gy(RBE) and CNAO rectum constraint D1cc < 66.00 Gy(RBE) were converted by MKM LQ strategy to LEM constraints 58.01 and 55.97 Gy(RBE) (12fx), 45.47 and 43.97 Gy(RBE) (8fx), and 29.64 and 28.67 Gy(RBE) (4fx) and by LEM LQ strategy to 61.73 and 59.69 Gy(RBE) (12fx), 53.03 and 51.33 Gy(RBE) (8fx), and 40.10 and 38.88 Gy(RBE) (4fx). Differences of 36.13% were found. No late rectum complications were reported.Conclusions: The LEM rectum constraints from MKM LQ strategy were more conservative and can be used as the reference constraints for starting the hypofractionated CIRT.

scholarly journals Conversion and validation of rectal constraints for prostate carcinoma receiving hypofractionated carbon-ion radiotherapy with a local effect model

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Weiwei Wang ◽  
Ping Li ◽  
Yinxiangzi Sheng ◽  
Zhijie Huang ◽  
Jingfang Zhao ◽  
...  
Keyword(s):  
Prostate Carcinoma ◽  
Local Effect ◽  
Carbon Ion Radiotherapy ◽  
Linear Quadratic ◽  
Study Objective ◽  
Carbon Ion ◽  
Conversion Model ◽  
Effect Model ◽  
Long Term Follow Up

Abstract Background The study objective was to establish the local effect model (LEM) rectum constraints for 12-, 8-, and 4-fraction carbon-ion radiotherapy (CIRT) in patients with localized prostate carcinoma (PCA) using microdosimetric kinetic model (MKM)-defined and LEM-defined constraints for 16-fraction CIRT. Methods We analyzed 40 patients with PCA who received 16- or 12-fraction CIRT at our center. Linear-quadratic (LQ) and RBE-conversion models were employed to convert the constraints into various fractionations and biophysical models. Based on them, the MKM LQ strategy converted MKM rectum constraints for 16-fraction CIRT to 12-, 8-, and 4-fraction CIRT using the LQ model. Then, MKM constraints were converted to LEM using the RBE-conversion model. Meanwhile the LEM LQ strategy converted MKM rectum constraints for 16-fraction CIRT to LEM using the RBE-conversion model. Then, LEM constraints were converted from 16-fraction constraints to the rectum constraints for 12-, 8-, and 4-fraction CIRT using the LQ model. The LEM constraints for 16- and 12-fraction CIRT were evaluated using rectum doses and clinical follow-up. To adapt them for the MKM LQ strategy, CNAO LEM constraints were first converted to MKM constraints using the RBE-conversion model. Results The NIRS (i.e. DMKM|v, V-20%, 10%, 5%, and 0%) and CNAO rectum constraints (i.e. DLEM|v, V-10 cc, 5 cc, and 1 cc) were converted for 12-fraction CIRT using the MKM LQ strategy to LEM 37.60, 49.74, 55.27, and 58.01 Gy (RBE), and 45.97, 51.70, and 55.97 Gy (RBE), and using the LEM LQ strategy to 39.55, 53.08, 58.91, and 61.73 Gy (RBE), and 49.14, 55.30, and 59.69 Gy (RBE). We also established LEM constraints for 8- and 4-fraction CIRT. The 10-patient RBE-conversion model was comparable to 30-patient model. Eight patients who received 16-fraction CIRT exceeded the corresponding rectum constraints; the others were within the constraints. After a median follow-up of 10.8 months (7.1–20.8), No ≥ G1 late rectum toxicities were observed. Conclusions The LEM rectum constraints from the MKM LQ strategy were more conservative and might serve as the reference for hypofractionated CIRT. However, Long-term follow-up plus additional patients is necessary.

scholarly journals RBE-weighted dose conversions for patients with recurrent nasopharyngeal carcinoma receiving carbon-ion radiotherapy from the local effect model to the microdosimetric kinetic model

2020 ◽  
Author(s):  
Liwen Zhang ◽  
Weiwei Wang ◽  
Jiyi Hu ◽  
Jiade Lu ◽  
Lin Kong
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Kinetic Model ◽  
Target Volume ◽  
Local Effect ◽  
Carbon Ion Radiotherapy ◽  
Carbon Ion ◽  
Effect Model ◽  
Target Volumes ◽  
Treatment Plans ◽  
Recurrent Nasopharyngeal Carcinoma

Abstract Background We sought to establish a conversion curve to convert the local effect model I (LEM) based RBE-weighted doses (LEM doses) in patients with locally recurrent nasopharyngeal carcinoma (rNPC) to the microdosimetric kinetic model (MKM) based RBE-weighted dose (MKM doses) model. We also converted the relevant organ at risk (OAR) constraints based on this curve. Methods Data from 13 patients with rNPC receiving carbon-ion radiotherapy (CIRT) in our hospital were collected. LEM in Raystation (V8A, Raystation, Sweden) was used to generate treatment plans. Clinical target volume CTV1(GTV+5mm)was given 63 Gy (RBE) in 21 fractions. Ninety-nine percent of target volumes should be covered by 95% of the prescriptions; the maximum doses of the brainstem and spinal cord were < 45 Gy (RBE) and < 30 Gy (RBE), respectively. The doses covering 20% volumes of optical nerves/chiasms D20 were < 30 Gy (RBE). Then physical doses of the LEM plans were recalculated by using MKM in Raystation to generate MKM plans. A series of the ratio of LEM dose to MKM dose was obtained as the conversion factor to obtain the conversion curve by using an isovolumetric dose method. Using prescriptions and OAR, constraints were converted to MKM doses with this curve. Results Conversion factors (LEM dose/MKM dose) from 1.37±0.02 to 3.09±0.09 corresponded to the LEM fractionated doses from 0.24 Gy (RBE) to 2.86 Gy (RBE), including the doses constraining upon OARs. LEM doses of 30 Gy (RBE) and 45 Gy (RBE) in 21 fractions were converted to MKM doses of 16.64 Gy (RBE) and 30.98 Gy (RBE) in 16 fractions. Conclusions This conversion curve could be used to convert LEM doses to MKM doses for patients with rNPC receiving CIRT, providing dose references for re-irradiation therapy.

scholarly journals RBE-weighted dose conversions for patients with recurrent nasopharyngeal carcinoma receiving carbon-ion radiotherapy from the local effect model to the microdosimetric kinetic model

2020 ◽  
Author(s):  
Liwen Zhang ◽  
Weiwei Wang ◽  
Jiyi Hu ◽  
Jiade Lu ◽  
Lin Kong
Keyword(s):  
Spinal Cord ◽  
Nasopharyngeal Carcinoma ◽  
Kinetic Model ◽  
Local Effect ◽  
Carbon Ion Radiotherapy ◽  
Conversion Factors ◽  
Carbon Ion ◽  
Effect Model ◽  
Recurrent Nasopharyngeal Carcinoma ◽  
Dose Constraints

Abstract Background: We sought to establish a conversion curve to convert the RBE-weighted doses calculated by local effect model I (LEM) (LEM RBE-weighted doses) in patients with locally recurrent nasopharyngeal carcinoma (rNPC) to the RBE-weighted doses calculated by microdosimetric kinetic model (MKM) (MKM RBE-weighted doses). We also converted the LEM dose constraints (RBE-weighted dose constraints in LEM plans) for the brain stem, spinal cord, and optic nerve based on this curve.Methods: Data from 20 patients with rNPC receiving carbon-ion radiotherapy (CIRT) in our hospital were collected. LEM in Raystation (V8A, Raystation, Sweden) was used to generate treatment plans. The clinical target volume CTV1（GTV+5mm）was given 3 Gy (RBE) per fraction. Ninety-nine percent of target volumes should be covered by 95% of the prescriptions; the maximum doses of the brainstem and spinal cord were < 45 Gy (RBE) and < 30 Gy (RBE), respectively. The doses covering 20% volumes of optical nerves/chiasms D20 were < 30 Gy (RBE). Then physical doses of the LEM plans were recalculated by using MKM in Raystation to generate MKM plans. A series of conversion factors (i.e., the ratio of LEM RBE-weighted dose to MKM RBE-weighted dose) was then obtained by using an isovolumetric dose method. The LEM plan prescriptions (LEM prescription) and dose constraints of the organs at risk (OARs) (OAR constraints) were converted to the corresponding MKM prescriptions and dose constraints using this conversion curve. Results: For the CTV1 fractional RBE-weighted dose prescription of 3.00 Gy (RBE) and CTV2 of 2.70 Gy (RBE) in LEM plans, the conversion factors (LEM RBE-weighted dose/MKM RBE-weighted dose) were 1.37 (CI 95％ 1.35–1.39) and 1.46 (1.41–1.51), respectively. The average conversion factors from 1.37(CI 95％ 1.33–1.41) to 3.09 (2.94–3.24) corresponded to the LEM fractionated doses from 2.86 Gy (RBE) to 0.24 Gy (RBE), including the doses constraining upon OARs. LEM RBE-weighted doses of 30 Gy (RBE) and 45 Gy (RBE) in 21 fractions were converted to MKM RBE-weighted doses of 16.64 Gy (RBE) and 30.72 Gy (RBE) in 16 fractions. Conclusions: This conversion curve could be used to convert LEM RBE-weighted doses to MKM RBE-weighted doses for patients with rNPC receiving CIRT, providing dose references for re-irradiation therapy.

scholarly journals RBE-weighted dose conversions for patients with recurrent nasopharyngeal carcinoma receiving carbon-ion radiotherapy from the local effect model to the microdosimetric kinetic model

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Liwen Zhang ◽  
Weiwei Wang ◽  
Jiyi Hu ◽  
Jiade Lu ◽  
Lin Kong
Keyword(s):  
Spinal Cord ◽  
Nasopharyngeal Carcinoma ◽  
Kinetic Model ◽  
Local Effect ◽  
Carbon Ion Radiotherapy ◽  
Conversion Factors ◽  
Carbon Ion ◽  
Effect Model ◽  
Recurrent Nasopharyngeal Carcinoma ◽  
Dose Constraints

Abstract Background We sought to establish a conversion curve to convert the RBE-weighted doses calculated by local effect model I (LEM) (LEM RBE-weighted doses) in patients with locally recurrent nasopharyngeal carcinoma (rNPC) to the RBE-weighted doses calculated by microdosimetric kinetic model (MKM) (MKM RBE-weighted doses). We also converted the LEM dose constraints (RBE-weighted dose constraints in LEM plans) for the brain stem, spinal cord, and optic nerve based on this curve. Methods Data from 20 patients with rNPC receiving carbon-ion radiotherapy (CIRT) in our hospital were collected. LEM in Raystation (V8A, Raystation, Sweden) was used to generate treatment plans. The clinical target volume CTV1 (GTV + 5 mm) was given 3 Gy (RBE) per fraction. Ninety-nine percent of target volumes should be covered by 95% of the prescriptions; the maximum doses of the brainstem and spinal cord were < 45 Gy (RBE) and < 30 Gy (RBE), respectively. The doses covering 20% volumes of optical nerves/chiasms D20 were < 30 Gy (RBE). Then physical doses of the LEM plans were recalculated by using MKM in Raystation to generate MKM plans. A series of conversion factors (i.e., the ratio of LEM RBE-weighted dose to MKM RBE-weighted dose) was then obtained by using an isovolumetric dose method. The LEM plan prescriptions (LEM prescription) and dose constraints of the organs at risk (OARs) (OAR constraints) were converted to the corresponding MKM prescriptions and dose constraints using this conversion curve. Results For the CTV1 fractional RBE-weighted dose prescription of 3.00 Gy (RBE) and CTV2 of 2.70 Gy (RBE) in LEM plans, the conversion factors (LEM RBE-weighted dose/MKM RBE-weighted dose) were 1.37 (CI 95% 1.35–1.39) and 1.46 (1.41–1.51), respectively. The average conversion factors from 1.37 (CI 95% 1.33–1.41) to 3.09 (2.94–3.24) corresponded to the LEM fractionated doses from 2.86 Gy (RBE) to 0.24 Gy (RBE), including the doses constraining upon OARs. LEM RBE-weighted doses of 30 Gy (RBE) and 45 Gy (RBE) in 21 fractions were converted to MKM RBE-weighted doses of 16.64 Gy (RBE) and 30.72 Gy (RBE) in 16 fractions. Conclusions This conversion curve could be used to convert LEM RBE-weighted doses to MKM RBE-weighted doses for patients with rNPC receiving CIRT, providing dose references for re-irradiation therapy.

scholarly journals RBE-weighted dose conversions for patients with recurrent nasopharyngeal carcinoma receiving carbon-ion radiotherapy from the local effect model to the microdosimetric kinetic model

2020 ◽  
Author(s):  
Liwen Zhang ◽  
Weiwei Wang ◽  
Jiyi Hu ◽  
Jiade Lu ◽  
Lin Kong
Keyword(s):  
Spinal Cord ◽  
Nasopharyngeal Carcinoma ◽  
Kinetic Model ◽  
Local Effect ◽  
Carbon Ion Radiotherapy ◽  
Conversion Factors ◽  
Carbon Ion ◽  
Effect Model ◽  
Recurrent Nasopharyngeal Carcinoma ◽  
Dose Constraints

Abstract Background We sought to establish a conversion curve to convert the RBE-weighted doses calculated by local effect model I (LEM) (LEM RBE-weighted doses) in patients with locally recurrent nasopharyngeal carcinoma (rNPC) to the RBE-weighted doses calculated by microdosimetric kinetic model (MKM) (MKM RBE-weighted doses). We also converted the LEM dose constraints (RBE-weighted dose constraints in LEM plans) for the brain stem, spinal cord, and optic nerve based on this curve. Methods Data from 20 patients with rNPC receiving carbon-ion radiotherapy (CIRT) in our hospital were collected. LEM in Raystation (V8A, Raystation, Sweden) was used to generate treatment plans. The clinical target volume CTV1（GTV+5mm）was given 3 Gy (RBE) per fraction. Ninety-nine percent of target volumes should be covered by 95% of the prescriptions; the maximum doses of the brainstem and spinal cord were < 45 Gy (RBE) and < 30 Gy (RBE), respectively. The doses covering 20% volumes of optical nerves/chiasms D20 were < 30 Gy (RBE). Then physical doses of the LEM plans were recalculated by using MKM in Raystation to generate MKM plans. A series of conversion factors (i.e., the ratio of LEM RBE-weighted dose to MKM RBE-weighted dose) was then obtained by using an isovolumetric dose method. The LEM plan prescriptions (LEM prescription) and dose constraints of the organs at risk (OARs) (OAR constraints) were converted to the corresponding MKM prescriptions and dose constraints using this conversion curve. Results For the CTV1 fractional RBE-weighted dose prescription of 3.00 Gy (RBE) and CTV2 of 2.70 Gy (RBE) in LEM plans, the conversion factors (LEM RBE-weighted dose/MKM RBE-weighted dose) were 1.37 (CI 95％ 1.35–1.39) and 1.46 (1.41–1.51), respectively. The average conversion factors from 1.37(CI 95％ 1.33–1.41) to 3.09 (2.94–3.24) corresponded to the LEM fractionated doses from 2.86 Gy (RBE) to 0.24 Gy (RBE), including the doses constraining upon OARs. LEM RBE-weighted doses of 30 Gy (RBE) and 45 Gy (RBE) in 21 fractions were converted to MKM RBE-weighted doses of 16.64 Gy (RBE) and 30.72 Gy (RBE) in 16 fractions. Conclusions This conversion curve could be used to convert LEM RBE-weighted doses to MKM RBE-weighted doses for patients with rNPC receiving CIRT, providing dose references for re-irradiation therapy.

scholarly journals Carbon Ion Dose Constraints in the Head and Neck and Skull Base: Review of MedAustron Institutional Protocols

2021 ◽  
Vol 8 (1) ◽  
pp. 25-35
Author(s):  
Piero Fossati ◽  
Ana Perpar ◽  
Markus Stock ◽  
Petra Georg ◽  
Antonio Carlino ◽  
...  
Keyword(s):  
Head And Neck ◽  
Local Effect ◽  
Brain Parenchyma ◽  
Carbon Ion Radiotherapy ◽  
Carbon Ion ◽  
Effect Model ◽  
Dose Volume ◽  
Ion Therapy ◽  
Dose Constraints ◽  
Fractionation Schedules

Abstract Background Dose constraints are of paramount importance for the outcome of any radiotherapy treatment. In this article, we report dose-volume constraints as well as currently used fractionation schedules for carbon ion radiotherapy as applied in MedAustron (Wiener Neustadt, Austria). Materials and Methods For fractionation schedules, both German and Japanese regimes were used. From the clinical experience of National Institute of Radiological Sciences (Chiba, Japan) and Heidelberg Ion Therapy (Heidelberg, Germany; formerly GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany) and the work by colleagues in Centro Nazionale Adroterapia Oncologica (Pavia, Italy) recalculating the dose from the microdosimetric kinetic model to the local effect model, we have set the dose constraints for critical organs of the head and neck area. Where no clinical data was available, an educated guess was made, based on data available from photon and proton series. Results We report the constraints for the optic nerve and chiasm, brainstem, spinal cord, cochlea, brain parenchyma, salivary gland, eye and adnexa, and mandibular/maxillary bone; constraints are grouped based on a fractionation scheme (German versus Japanese) and the risk of toxicity (safe, low to middle, and middle to high). Conclusion We think validation of dose constraints should present a relevant part of the activity of any carbon ion radiotherapy facility, and we anticipate future multicentric, joint evaluations.

Local effect and gastrointestinal toxicity for carbon-ion radiotherapy in patients with unresectable locally advanced pancreatic cancer.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 410-410
Author(s):  
Makoto Shinoto ◽  
Yoshiyuki Shioyama ◽  
Hiroaki Suefuji ◽  
Akira Matsunobu ◽  
Shingo Toyama ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Gastric Ulcer ◽  
Fdg Pet ◽  
Locally Advanced ◽  
Advanced Pancreatic Cancer ◽  
Local Effect ◽  
Locally Advanced Pancreatic Cancer ◽  
Carbon Ion Radiotherapy ◽  
Carbon Ion ◽  
Gi Toxicity

410 Background: Carbon-ion radiotherapy (CIRT) is a unique external radiotherapy that has an excellent dose conformity and higher biological effectiveness compared to conventional radiotherapy. The sensitivity of the organs in upper abdomen has limited the radiation dose to levels that are ineffective against pancreatic cancer, which has extreme radioresisnatnce. We investigated effectiveness and gastrointestinal (GI) toxicity of CIRT. Methods: From April 2014 to June 2015, 41 patients with pancreatic cancer were treated with definitive CIRT. 26 patients who were confirmed as unresectable locally advanced pancreatic cancer pathologically and by imaging techniques were included in this retrospective analysis. 15 patients were excluded because of resectable disease (n = 3), borderline disease (n = 4), no cell evidence (n = 11). CIRT was performed with 55.2 Gy (RBE) at 12 fractions. The maximal absolute dose with covered 2cm3 of the organ (D2) was restricted under 46 Gy (RBE). All patients were followed up using CT, FDG-PET and upper gastrointestinal endoscopy at least every six months. Anti-tumor effect was evaluated using CT and FDG-PET according to RECIST. If FDG accumulation was negative or equal to normal pancreatic tissue after CIRT, it was defined CR even no decreasing in seize on CT. GI toxicity was evaluated using CTCAE. Results: Tumor location were head in 7, head-body in 2, body-tail in 16. Median tumor size was 35mm (range 21-50). In all patients, sequential and/or concurrent chemotherapy was performed. The median follow-up period was 7.7 months. Local effect using CT criteria was CR in 0, PR in 2, SD in 22, and PD in 2. The evaluation adding FDG-PET criteria was CR in 12, PR in 4, SD in 8, and PD in 2. Two patients who were SD by CT and CR by FDG-PET performed tumor resection and were revealed pCR. The actual incidence of gastric ulcer/bleeding was 15% (n = 4). Only one patient (4%) received blood transfusion because of grade 3 gastric ulcer. The other patients experienced grade 1/2 gastric ulcer. There was no duodenal ulcer. Conclusions: CIRT were effective and well tolerated under the restriction of D2 < 46 Gy (RBE). FDG-PET was useful for the evaluation of local effect after CIRT.

Analysis of the reliability of the local effect model for the use in carbon ion treatment planning systems

2010 ◽  
Vol 143 (2-4) ◽  
pp. 497-502 ◽  
Author(s):  
G. Russo ◽  
A. Attili ◽  
F. Bourhaleb ◽  
F. Marchetto ◽  
C. Peroni ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Local Effect ◽  
Planning Systems ◽  
Carbon Ion ◽  
Treatment Planning Systems ◽  
Effect Model ◽  
Ion Treatment
Sign in / Sign up

Export Citation Format

Share Document