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Wakabayashi K, Monzen H, Doi H, Inagaki T, Sonomura T. Initial Clinical Experience of a Novel Shapeable Bolus for Radiotherapy in a Patient With a Facial Cutaneous Squamous Cell Carcinoma: A Case Report. Cureus 2024; 16:e57415. [PMID: 38694646 PMCID: PMC11061871 DOI: 10.7759/cureus.57415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2024] [Indexed: 05/04/2024] Open
Abstract
Radiation therapy with X-rays for skin cancer uses a bolus to increase the surface dose. Commercial gel sheet boluses adhere poorly to the patient's body because of surface irregularities. This causes an air gap and reduces the surface dose. We have developed a novel shapeable bolus (HM bolus; Hayakawa Rubber Co., Ltd., Hiroshima, Japan), and we describe the first clinical application of this bolus here. The case was an 82-year-old male with a facial cutaneous squamous cell carcinoma. The postoperative radiotherapy plan using the HM bolus provided a more uniform dose to the target compared with a plan without the HM bolus. The HM bolus adhered stably to the patient's skin, and there were no issues with its clinical use.
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Affiliation(s)
- Kazuki Wakabayashi
- Department of Central Radiology, Wakayama Medical University Hospital, Wakayama, JPN
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, JPN
| | - Takaya Inagaki
- Department of Radiology, Wakayama Medical University, Wakayama, JPN
| | - Tetsuo Sonomura
- Department of Radiology, Wakayama Medical University, Wakayama, JPN
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Uehara T, Nishimura Y, Ishikawa K, Inada M, Matsumoto K, Doi H, Monzen H, Matsuo Y. Cone-beam computed tomography-guided online adaptive radiotherapy for pharyngeal cancer with whole neck irradiation: dose-volume histogram analysis between adapted and scheduled plans. J Radiat Res 2024; 65:223-230. [PMID: 38264828 PMCID: PMC10959439 DOI: 10.1093/jrr/rrad103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/24/2023] [Indexed: 01/25/2024]
Abstract
The present study aimed to evaluate whether an adapted plan with Ethos™ could be used for pharyngeal cancer. Ten patients with pharyngeal cancer who underwent chemoradiotherapy with available daily cone-beam computed tomography (CBCT) data were included. Simulated treatments were generated on the Ethos™ treatment emulator using CBCTs every four to five fractions for two plans: adapted and scheduled. The simulated treatments were divided into three groups: early (first-second week), middle (third-fourth week), and late (fifth-seventh week) periods. Dose-volume histogram parameters were compared for each period between the adapted and scheduled plans in terms of the planning target volume (PTV) (D98%, D95%, D50% and D2%), spinal cord (Dmax and D1cc), brainstem (Dmax) and ipsilateral and contralateral parotid glands (Dmedian and Dmean). The PTV D98%, D95% and D2% of the adapted plan were significantly higher than those of the scheduled plans in all periods, except for D98% in the late period. The adapted plan significantly reduced the spinal cord Dmax and D1cc compared with the scheduled plan in all periods. Ipsilateral and contralateral parotid glands Dmean of the adapted plan were lower than those of scheduled plan in the late period. In conclusion, the present study revealed that the adapted plans could maintain PTV coverage while reducing the doses to organs at risk in each period compared with scheduled plans.
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Affiliation(s)
- Takuya Uehara
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka 589-8511, Japan
- Department of Radiation Oncology, Yamatotakada Municipal Hospital, Nara 635-8501, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka 589-8511, Japan
- Radiation Therapy Center, Fuchu Hospital, Osaka 594-0076, Japan
| | - Kazuki Ishikawa
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka 589-8511, Japan
- Department of Radiation Oncology, Nara Prefecture General Medical Center, Nara 630-8581, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka 589-8511, Japan
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka 589-8511, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka 589-8511, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka 589-8511, Japan
| | - Yukinori Matsuo
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka 589-8511, Japan
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Nakayama S, Hirose M, Kaneshige S, Nakamura K, Matsuo Y, Monzen H. Development and evaluation of a novel water-based pigment marker for radiation therapy skin marking. Radiol Phys Technol 2023; 16:543-551. [PMID: 37839000 DOI: 10.1007/s12194-023-00743-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 09/08/2023] [Accepted: 09/20/2023] [Indexed: 10/17/2023]
Abstract
Skin marks are widely used in external radiation therapy to ensure the accuracy of the irradiation position. However, conventional skin markers contain harmful substance, so we developed an alternative skin marker. The purpose of this study was to investigate the feasibility of using a novel water-based pigment marker comprising safe materials commonly used in cosmetics for clinical radiation therapy. We investigated various properties of the marker, namely marker longevity, color variety, line visibility, ink bleeding, and line durability, and improved the marker in response to the feel when drawing or being drawn on. The durability of the ink was evaluated by simultaneously applying the new marker and oil-based pen and comparing the period until the marks faded and became invisible. In clinical trial, we applied marks on the skin of 56 patients over three months to observe symptoms and visible changes in the skin. There were no complications of discomfort or pain, owing to the improvements in the marker tip. The marks drawn on the arms of volunteers with the new marker and the oil-based pen remained visible for a mean of 7.2 days and 3.6 days, respectively (P value < 0.001). The percentages of participants with no symptoms and no visible changes were 100%, respectively. We developed an alternative skin marker that complies with current regulatory standards by excluding crystal violet. The newly developed marker has features suitable for clinical use, such as resistance to smudging and water, marker tip shape and texture, and color variations.
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Affiliation(s)
- Shinichi Nakayama
- Division of Clinical Radiology Service, Okayama Central Hospital, 6-3, Ishimakitamachi, Kitaku, Okayama, 700-0017, Japan
| | - Miduki Hirose
- Department of Radiation Oncology, Okayama Central Hospital, 6-3, Ishimakitamachi, Kitaku, Okayama, 700-0017, Japan
| | - Soichiro Kaneshige
- Department of Radiation Oncology, Okayama Central Hospital, 6-3, Ishimakitamachi, Kitaku, Okayama, 700-0017, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2, Onohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Yukinori Matsuo
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2, Onohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Hajime Monzen
- Division of Clinical Radiology Service, Okayama Central Hospital, 6-3, Ishimakitamachi, Kitaku, Okayama, 700-0017, Japan.
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2, Onohigashi, Osakasayama, Osaka, 589-8511, Japan.
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Okuhata K, Monzen H, Nakamura Y, Takai G, Nagano K, Nakamura K, Kubo K, Hosono M. Effectiveness of shielding materials against 177Lu gamma rays and the corresponding distance relationship. Ann Nucl Med 2023; 37:629-634. [PMID: 37596439 DOI: 10.1007/s12149-023-01860-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 08/07/2023] [Indexed: 08/20/2023]
Abstract
OBJECTIVE The purpose of this study is to determine the dose reduction of different shielding materials at various distances from a 177Lu photon radiation source. METHODS Two protective aprons with lead equivalent thicknesses of 0.25 mm and 0.35 mm and tungsten-containing rubber (TCR) were used as shielding materials. A vial containing 177Lu was sealed in a lead container so that a narrow beam went out through a 3 mm-diameter hole. The dose rate was measured at distances of 0, 10, 50, 100, and 200 cm from the source using a NaI scintillation survey meter to obtain the rate of dose reduction. TCR was tested with thicknesses ranging from 0.3 to 1.0 mm at 0.1 mm intervals and from 1.0 to 4.0 mm at 0.5 mm intervals. RESULTS At distances of 0, 10, 50, 100, and 200 cm, the dose reduction for the lead equivalent thickness of 0.25 mm were 32.7%, 54.5%, 93.1%, 97.9%, and 99.6%, respectively; and for the lead equivalent thickness of 0.35 mm were 53.4%, 70.6%, 95.6%, 98.9%, and 99.6%, respectively. Without any shielding, the dose rate decreased by 34.4% at 10 cm and by 88.8% at 50 cm from the radiation source. The dose reduction for the TCR thickness of 3.5 mm was 89.8% at 0 cm and 93.3% at 10 cm. The TCR thickness of 0.4 mm provided a dose reduction comparable to or greater than that of the 0.25 mm lead equivalent, whereas the TCR thickness of 1.0 mm or greater provided a dose reduction comparable to that of the 0.35 mm lead equivalent. CONCLUSIONS Achieving a reduction of 95% or more requires the 0.25 mm lead equivalent for a distance of 100 cm, the 0.35 mm lead equivalent for 50 cm, the TCR thickness of 0.3 mm for 100 cm, or the TCR thickness of 0.9 mm for 50 cm. Without wearing a protective apron, a reduction of approximately 95% is observed at distances greater than 100 cm. These findings would be useful for medical staff engaging in related activities.
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Affiliation(s)
- Katsuya Okuhata
- Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan.
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan
| | - Yasunori Nakamura
- Department of Radiology, University Hospital, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 6028566, Japan
| | - Go Takai
- Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan
| | - Keiji Nagano
- Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan
| | - Makoto Hosono
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan
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Yanagi Y, Kubo K, Ito T, Nakamura K, Hirata M, Doi H, Monzen H. Comparing Dose Calculation Algorithms for Heterogeneous Media: Analytical Anisotropic Algorithm Versus Acuros XB (Dm/Dw) With Continuous CT Value Variation. Cureus 2023; 15:e46805. [PMID: 37954761 PMCID: PMC10635741 DOI: 10.7759/cureus.46805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2023] [Indexed: 11/14/2023] Open
Abstract
BACKGROUND To compare the doses calculated by the analytical anisotropic algorithm (AAA) and two dose reporting modes of Acuros XB (AXB(Dm) and AXB(Dw)) with varied CT values on the Eclipse (Varian Medical Systems, Palo Alto, CA). MATERIALS AND METHODS Virtual phantoms with a central layer of heterogeneous material (thickness = 2 or 5 cm) were created with Eclipse. Using single or opposed fields, the field sizes were 5 x 5 cm2 or 10 x 10 cm2. The photon energies were 6 or 10 MV, and the source-to-target distance was 100 cm. The relative doses at the center of the heterogeneous material layer were evaluated with varied CT values, from -1000 to 3000 HU. Values were normalized with the dose at 0 HU (100%) for comparative analysis. RESULTS The results obtained from continuous data for a single field, 6 MV, 5 x 5 cm2, and the heterogeneous material 5 cm, where the differences between algorithms were most pronounced, were as follows. In the low-density region (-1000 HU and -800 HU), the dose differences for AXB with reference to AAA were, respectively, -54.5% and +4.6% (AXB(Dm)) and -47.0% and +3.5% (AXB(Dw)), and in the high-density regions (1000 HU and 3000 HU) were -5.7% and -8.8% (AXB(Dm)) and +7.4% and +3.5% (AXB(Dw)), respectively. Consequently, dose differences at arbitrary CT values could be obtained. CONCLUSION Dose differences between these algorithms were clarified for heterogeneous materials. The risk of dose reduction or escalation in clinical use was clearly visible between CT values from -1000 to 3000 HU.
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Affiliation(s)
- Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
- Department of Radiology, Shiga University of Medical Science Hospital, Otsu, JPN
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Takaaki Ito
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Makoto Hirata
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, JPN
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
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Uehara T, Nishimura Y, Ishikawa K, Inada M, Matsumoto K, Doi H, Monzen H. Online Adaptive Radiotherapy for Pharyngeal Cancer: Dose-Volume Histogram Analysis between Adapted and Scheduled Plan. Int J Radiat Oncol Biol Phys 2023; 117:e729. [PMID: 37786121 DOI: 10.1016/j.ijrobp.2023.06.2247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) The present study aimed to evaluate whether online adapted plan with artificial intelligence (AI) driven work flow could be used in clinical settings with variable changes of the targets and organs at risk (OARs) for pharyngeal cancer. MATERIALS/METHODS Ten patients with pharyngeal cancer who underwent chemoradiotherapy at our institution between January and July 2020 were included for the analysis. All patients had been previously aligned daily with cone-beam computed tomography (CBCT) and treated by O-ring Linac. A simulated treatment was performed on the treatment emulator. Weekly fractions, once in every 4-5 fractions, were simulated in the treatment emulator for each patient using their previous on-treatment CBCTs. The dataset was divided into three groups according to the treatment period (1st-2nd week, 20 CBCTs), middle (3rd-4th week, 20 CBCTs), and late (5th-7th week, 30 CBCTs) period. In the present study, all of reference plan generation in treatment emulator were created on the initial plans of two-step method using 12 equidistant field IMRT. The prescribed dose was 70 Gy in 35 fractions and normalized to the dose of 68.6 Gy (98% dose) to 95% of the planning target volume (PTV). The adaptation process on treatment emulator includes auto-segmentation of daily anatomy, calculation of the dose in scheduled plans using the same monitor units and optimization and calculation of the dose in adapted plan. Dose-volume histogram (DVH) parameters between adapted and scheduled plans in terms of PTV (D98%, D95%, D50% and D2%), spinal cord (Dmax and D1cc), brain stem (Dmax), ipsilateral and contralateral parotid glands (Dmedian and Dmean) were evaluated in each period. RESULTS D98% of PTV of adapted plan was significantly higher than that of scheduled plan in early and middle period (p = 0.02 and <0.01, respectively). D95% of PTV of adapted plan was significantly higher than that of scheduled plan in all periods (p<0.01). D2% of PTV of adapted plan was significantly lower than that of scheduled plan in all periods (p = 0.04, 0.04 and 0.02 in each period, respectively). There was not significant difference in D50% of PTV between adapted and scheduled plan in all periods. In terms of OARs, Dmax of spinal cord of adapted plan was significantly lower than that of scheduled plan in all periods (p<0.01). Similarly, D1cc of spinal cord of adapted plan was lower than that of scheduled plan. Dmean of ipsilateral and contralateral parotid glands of adapted plan were lower than those of scheduled plan in the late period (p<0.01 and 0.03, respectively). CONCLUSION The present study revealed that adapted plan with AI driven work flow could create dosimetrically better plans for pharyngeal cancer compared to scheduled plan. It was suggested that online adaptive radiotherapy could be necessary to maintain PTV coverage while reducing the dose to OARs in all periods for pharyngeal cancer.
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Affiliation(s)
- T Uehara
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - Y Nishimura
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - K Ishikawa
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - M Inada
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - K Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - H Doi
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - H Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
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Monzen H, Kubo K, Nakamura K, Uehara T, Otsuka M, Matsumoto K. The Development and Evaluation of an All-Purpose Bolus for Radiotherapy. Int J Radiat Oncol Biol Phys 2023; 117:e698-e699. [PMID: 37786045 DOI: 10.1016/j.ijrobp.2023.06.2181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) The purpose of this study was to develop on a new bolus (HM bolus) which had tissue equivalence, transparency, reusability, and free shaping at approximately 40°C for excellent adhesion, and to evaluate its features could be satisfy ideal bolus conditions for clinical use. MATERIALS/METHODS The newly developed HM bolus was controlled to prevent phase separation by adjusting the contents of ethylene propylene rubber, styrene, butadiene rubber, thermoplastic resin, temperature-sensitive adjuster, and silica. The element ratios (wt%) in the HM bolus are H: 10.2%, C: 63.5%, O: 17.1%, and Si: 9.2%. The density was adjusted to 0.96 g cm-3. We evaluated dose characteristics, a vinyl gel sheet bolus (Gel bolus) and HM bolus placed on a water-equivalent phantom were used to obtain the percent depth dose (PDD) of electron (6 MeV, 9 MeV) and photon (4 MV,6 MV) beams. The average dose difference of the HM bolus and Gel bolus was calculated. The Gel bolus, a soft rubber bolus (SR bolus), and HM bolus were placed in adherence to a pelvic phantom. CT images taken after shaping and 1, 2, and 3 weeks after shaping were used to evaluate the adhesion and reproducibility using air gap and dice similarity coefficient (DSC) metrics. The visibility of letters (maximum: 80 pt, minimum: 10 pt) through a plate-shaped bolus and the visibility of markers when each bolus was set up on the pelvic phantom under normal room lighting were evaluated. RESULTS The average dose difference for electron beams was 0.16% ± 0.79% and photon beams was 0.06% ± 0.34%, both within 1% of the PDD results. The HM bolus showed the same build-up effect and dose characteristics as the Gel bolus. The mean air gap values for the Gel bolus, SR bolus, and HM bolus were 96.02 ± 43.77 cm3, 34.93 ± 21.44 cm3, and 4.40 ± 1.50 cm3 44, respectively. The mean DSC values for the Gel bolus, SR bolus, and HM bolus were 0.363 ± 0.035, 0.556 ± 0.042, and 0.837±0.018. The HM bolus showed the smallest air gap at all time points and the DSC closest to 1. Excellent adhesion was observed in the CT simulation and during the treatment period. The letter visibility through the HM bolus and Gel bolus was sufficient, and when the HM bolus was set up on the pelvic phantom, the markers that were completely invisible with the SR bolus were visible. CONCLUSION We succeeded in developing an all-purpose bolus with unique characteristics for clinical use. The HM bolus had the same build-up effect and dose characteristics as a Gel bolus. Therefore, it can be used for CT simulation and dose calculation. The other advantages of the new bolus are tissue equivalence, transparency, reusability, and free shaping at approximately 40°C, providing excellent adhesion at each setup during the treatment period.
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Affiliation(s)
- H Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - K Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - K Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan; Takarazuka City Hospital, Takarazuka, Hyogo, Japan
| | - T Uehara
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - M Otsuka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - K Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
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Ito T, Kubo K, Monzen H, Yanagi Y, Nakamura K, Sakai Y, Nishimura Y. Overcoming Problems Caused by Offset Distance of Multiple Targets in Single-isocenter Volumetric Modulated Arc Therapy Planning for Stereotactic Radiosurgery. J Med Phys 2023; 48:365-372. [PMID: 38223796 PMCID: PMC10783189 DOI: 10.4103/jmp.jmp_8_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 09/06/2023] [Accepted: 09/12/2023] [Indexed: 01/16/2024] Open
Abstract
Purpose The purpose of the study is to investigate the impact of large target offset distances on the dose distribution and gamma passing rate (GPR) in single-isocenter multiple-target stereotactic radiosurgery (SIMT SRS) using volumetric modulated arc therapy (VMAT) with a flattening filter-free (FFF) beam from a linear accelerator. Methods Two targets with a diameter of 1 cm were offset by "±2, ±4, and ±6 cm from the isocenter in a verification phantom for head SRS (20 Gy/fr). The VMAT plans were created using collimator angles that ensured the two targets did not share a leaf pair from the multi-leaf collimator. To evaluate the low-dose spread intermediate dose spill (R50%), GPRs were measured with a criterion of 3%/2 mm using an electronic portal imaging device and evaluated using monitor unit (MU), modulation complexity score for VMAT (MCSv), and leaf travel (LT) parameters. Results For offsets of 2, 4, and 6 cm, the respective parameters were: R50%, 4.75 ± 0.36, 5.13 ± 0.36, and 5.11 ± 0.33; GPR, 95.01%, 93.82%, and 90.67%; MU, 5893 ± 186, 5825 ± 286, and 5810 ± 396; MCSv, 0.24, 0.16, and 0.13; and LT, 189.21 ± 36.04, 327.69 ± 67.01, and 430.39 ± 114.34 mm. There was a spread in the low-dose region from offsets of ≥4 cm and the GPR negatively correlated with LT (r = -0.762). There was minimal correlation between GPR and MU or MCSv. Conclusions In SIMT SRS VMAT plans with an FFF beam from a linear accelerator, target offsets of <4 cm from the isocenter can minimize the volume of the low-dose region receiving 10 Gy or more. During treatment planning, it is important to choose gantry, couch, and collimator angles that minimize LT and thereby improve the GPR.
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Affiliation(s)
- Takaaki Ito
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
- Department of Radiological Technology, Kobe City Nishi Kobe Medical Center, Kobe, Hyogo, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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Ueda Y, Fukunaga JI, Kamima T, Shimizu Y, Kubo K, Doi H, Monzen H. Standardization of knowledge-based volumetric modulated arc therapy planning with a multi-institution model (broad model) to improve prostate cancer treatment quality. Phys Eng Sci Med 2023; 46:1091-1100. [PMID: 37247102 DOI: 10.1007/s13246-023-01278-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 05/08/2023] [Indexed: 05/30/2023]
Abstract
PURPOSE To evaluate whether knowledge-based volumetric modulated arc therapy plans for prostate cancer with a multi-institution model (broad model) are clinically useful and effective as a standardization method. METHODS A knowledge-based planning (KBP) model was trained with 561 prostate VMAT plans from five institutions with different contouring and planning policies. Five clinical plans at each institution were reoptimized with the broad and single institution model, and the dosimetric parameters and relationship between Dmean and the overlapping volume (rectum or bladder and target) were compared. RESULTS The differences between the broad and single institution models in the dosimetric parameters for V50, V80, V90, and Dmean were: rectum; 9.5% ± 10.3%, 3.3% ± 1.5%, 1.7% ± 1.6%, and 3.6% ± 3.6%, (p < 0.001), bladder; 8.7% ± 12.8%, 1.5% ± 2.6%, 0.7% ± 2.4%, and 2.7% ± 4.6% (p < 0.02), respectively. The differences between the broad model and clinical plans were: rectum; 2.4% ± 4.6%, 1.7% ± 1.7%, 0.7% ± 2.4%, and 1.5% ± 2.0%, (p = 0.004, 0.015, 0.112, and 0.009) bladder; 2.9% ± 5.8%, 1.6% ± 1.9%, 0.9% ± 1.7%, and 1.1% ± 4.8%, (p < 0.018), respectively. Positive values indicate that the broad model has a lower value. Strong correlations were observed (p < 0.001) in the relationship between Dmean and the rectal and bladder volume overlapping with the target in the broad model (R = 0.815 and 0.891, respectively). The broad model had the smallest R2 of the three plans. CONCLUSIONS KBP with the broad model is clinically effective and applicable as a standardization method at multiple institutions.
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Affiliation(s)
- Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69, Otemae, Chuo-ku, Osaka, 537-8567, Japan.
| | - Jun-Ichi Fukunaga
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, 3-1-1, Maidashi, Higashi- ku, Fukuoka, 812-8582, Japan
| | - Tatsuya Kamima
- Radiation Oncology Department, Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Yumiko Shimizu
- Department of Radiology, Seirei Hamamatsu General Hospital, 2-12-12 Sumiyoshi, Naka Ward, Hamamatsu, Shizuoka, 430-8558, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
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Ito T, Monzen H, Kubo K, Kosaka H, Yanagi Y, Sakai Y, Inada M, Doi H, Nishimura Y. Dose difference between anisotropic analytical algorithm (AAA) and Acuros XB (AXB) caused by target's air content for volumetric modulated arc therapy of head and neck cancer. Rep Pract Oncol Radiother 2023; 28:399-406. [PMID: 37795404 PMCID: PMC10547402 DOI: 10.5603/rpor.a2023.0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/23/2022] [Indexed: 10/06/2023] Open
Abstract
Background We clarified the dose difference between the anisotropic analytical algorithm (AAA) and Acuros XB (AXB) with increasing target's air content using a virtual phantom and clinical cases. Materials and methods Whole neck volumetric modulated arc therapy (VMAT) plan was transferred into a virtual phantom with a cylindrical air structure at the center. The diameter of the air structure was changed from 0 to 6 cm, and the target's air content defined as the air/planning target volume (PTV) in percent (air/PTV) was varied. VMAT plans were recalculated by AAA and AXB with the same monitor unit (MU) and multi-leaf collimator (MLC) motions. The dose at each air/PTV (5%-30%) was compared between each algorithm with D98%, D95%, D50% and D2% for the PTV. In addition, MUs were also compared with the same MLC motions between the D95% prescription with AAA (AAA_D95%), AXB_D95%, and the prescription to 100% minus air/PTV (AXB_D100%-air/PTV) in clinical cases of head and neck (HNC). Results When air/PTV increased (5-30%), the dose differences between AAA and AXB for D98%, D95%, D50% and D2% were 3.08-15.72%, 2.35-13.92%, 0.63-4.59%, and 0.14-6.44%, respectively. At clinical cases with air/PTV of 5.61% and 28.19%, compared to AAA_D95%, the MUs differences were, respectively, 2.03% and 6.74% for AXB_D95% and 1.80% and 0.50% for AXB_D100%-air/PTV. Conclusion The dose difference between AAA and AXB increased as the target's air content increased, and AXB_D95% resulted in a dose escalation over AAA_D95% when the target's air content was ≥ 5%. The D100%-air/PTV of PTV using AXB was comparable to the D95% of PTV using AAA.
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Affiliation(s)
- Takaaki Ito
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
- Department of Radiological Technology, Kobe City Nishi-Kobe Medical Center, Kobe, Hyogo, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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Yanagi Y, Monzen H, Kubo K, Sugiyama J, Noma K, Ito T, Sakai Y, Nakamura K, Kida T, Doi H, Nishimura Y. Comparison of the Characteristics of Two Types of Parallel-plate Ionization Chamber Under Small-field Electron Irradiation. Anticancer Res 2023; 43:1967-1972. [PMID: 37097686 DOI: 10.21873/anticanres.16356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 04/26/2023]
Abstract
BACKGROUND/AIM This study compared two types of parallel-plate ionization chamber to clarify the pitfalls of dosimetry in electron radiation therapy. MATERIALS AND METHODS The ion recombination correction factor and polarity effect correction factor, sensitivity, and percentage depth doses (PDDs) of PPC05 and PPC40 parallel-plate ionization chambers were compared in a small-field electron beam. The output ratios were measured for 4-20 MeV electron beams with field sizes of 10 cm × 10 cm, 6 cm × 6 cm, and 4 cm × 4 cm. Furthermore, the films were placed in water and positioned in the beam with their surface perpendicular to the beam axis, and lateral profiles were obtained for each beam energy and each field. RESULTS Regarding PDDs, at depths greater than the peak dose, the percentage depth dose for PPC40 was smaller than that for PPC05 in small fields and at beam energies greater than 12 MeV, which could be attributed to the lack of lateral electron equilibrium at small depths and multiple scattering events at large depths. The output ratio of PPC40 was approximately 0.025-0.038, which was lower than that of PPC05 in a 4 cm × 4 cm field. For large fields, the lateral profiles were similar, regardless of the beam energy, however, for small fields, the flatness of the lateral profile was beam energy dependent. CONCLUSION The PPC05 chamber, which has a smaller ionization volume, is therefore more suitable than the PPC40 chamber for small-field electron dosimetry, in particular at high beam energies.
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Affiliation(s)
- Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan;
- Department of Radiology, Shiga University of Medical Science Hospital, Otsu, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Junko Sugiyama
- Department of Radiology, Shiga University of Medical Science Hospital, Otsu, Japan
| | - Kazuo Noma
- Department of Radiology, Shiga University of Medical Science Hospital, Otsu, Japan
| | - Takaaki Ito
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Tetsuo Kida
- Department of Radiology, Shiga University of Medical Science Hospital, Otsu, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Japan
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Wada Y, Monzen H, Ishida N, Ri A, Tatsuno S, Uehara T, Inada M, Doi H, Nakamatsu K, Hosono M, Nishimura Y. Impact of rectal gas on the planning target volume margin for pelvic bone and prostate matching in prostate cancer patients receiving volumetric-modulated arc therapy. Med Dosim 2023:S0958-3947(23)00030-4. [PMID: 37080819 DOI: 10.1016/j.meddos.2023.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/14/2023] [Accepted: 03/27/2023] [Indexed: 04/22/2023]
Abstract
We performed daily cone-beam computed tomography (CBCT) to determine the impact of rectal gas on the movements of prostate and seminal vesicles (SVs). We aimed to determine the relationship between planning target volume (PTV) margins and rectal gas. In 30 treatments of 15 prostate cancer patients, excessive rectal gas was removed and CBCT images were analyzed. Image registration between planning CT and daily CBCT images before and after rectal gas removal was performed for pelvic bone and prostate matching. The couch movement distance between each matching was considered the prostate movement. In addition, we measured SV tip movement between each matching. The anterior-posterior movement of the prostate before rectal gas removal (3.1 ± 2.9 mm) was significantly greater than that after rectal gas removal (1.2 ± 1.2 mm; p < 0.01). The left-right and superior-inferior movements were similar regardless of the presence or absence of rectal gas. The SV movement distances before and after rectal gas removal were 11.0 ± 5.8 mm and 4.6 ± 3.8 mm, respectively (p < 0.01), in pelvic bone matching, and 8.0 ± 4.2 mm and 3.8 ± 3.2 mm, respectively (p < 0.01), in prostate matching. After rectal gas removal, the SV position did not differ significantly between each matching. In 26 of the 30 treatments, SV movement distance in the presence of rectal gas was >6 mm, which is the minimum PTV margin at our institution. In comparison, after rectal gas removal and prostate matching, only 6 treatments demonstrated an SV movement distance of >6 mm. In the presence of rectal gas, the SVs require greater PTV margins than the prostate. Rectal gas removal should be considered if the movement distance on prostate matching is greater than the minimum PTV margin at treating institution.
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Affiliation(s)
- Yutaro Wada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan.
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Naoko Ishida
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Aritoshi Ri
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Saori Tatsuno
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Takuya Uehara
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Kiyoshi Nakamatsu
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Makoto Hosono
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
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Sakai Y, Monzen H, Takei Y, Kosaka H, Nakamura K, Yanagi Y, Wakabayashi K, Hosono M, Nishimura Y. Evaluation of In-room Volumetric Imaging Doses for Image-guided Radiotherapy: A Multi-institutional Study. J Med Phys 2023; 48:189-194. [PMID: 37576099 PMCID: PMC10419753 DOI: 10.4103/jmp.jmp_109_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 05/10/2023] [Accepted: 05/22/2023] [Indexed: 08/15/2023] Open
Abstract
Aims We investigated imaging dose and noise under clinical scan conditions at multiple institutions using a simple and unified method, and demonstrated the need for diagnostic reference levels in image-guided radiotherapy (IGRT). Materials and Methods Nine cone-beam and helical computed tomography (CT) scanners (Varian, Elekta, Accuray Inc., and BrainLAB) from seven institutions were investigated in this study. The weighted cone-beam dose index (CBDIw) was calculated for head and pelvic protocols using a 100 mm pencil chamber under the conditions used in actual clinical practice at each institution. Cone-beam CT image noise was evaluated using polymethylmethacrylate head and body phantoms with diameters of 16 and 32 cm, respectively. Results For head and pelvic protocols, CBDIw values ranged from 0.94-6.59 and 1.47-20.9 mGy, respectively. Similarly, standard deviation (SD) values ranged from 9.3-34.0 and 26.9-97.4 HU, respectively. The SD values tended to increase with decreasing imaging dose (r = -0.33 and -0.61 for the head and pelvic protocols, respectively). Conclusions Among the nine machines, the imaging dose for high imaging dose institutions was approximately 20 mGy to the pelvic phantom, and there was a 14-fold difference in dose compared with the other institutions. These results suggest the need to establish DRLs for IGRT to guide clinical decision-making.
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Affiliation(s)
- Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
- Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Yoshiki Takei
- Department of Radiology, Kindai University Nara Hospital, Ikoma, Nara, Japan
| | - Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Kazuki Wakabayashi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Makoto Hosono
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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Nakamura K, Monzen H, Kubo K, Kosaka H, Ito T, Sakai Y, Yanagi Y, Nishimura Y. The development and characterization of an all-purpose bolus for radiotherapy. Phys Med Biol 2023; 68. [PMID: 36972591 DOI: 10.1088/1361-6560/acc7e0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 03/27/2023] [Indexed: 03/29/2023]
Abstract
OBJECTIVE The purpose of this study was to develop a new bolus (HM bolus), with tissue equivalence, transparency, reusability, and free shaping at approximately 40 °C for excellent adhesion, and to evaluate the feasibility of clinically using this bolus as an ideal bolus. APPROACH We summarized the advantages and disadvantages of existing boluses. To evaluate dose characteristics, a vinyl gel sheet bolus (Gel bolus) and HM bolus placed on a water-equivalent phantom were used to obtain the percent depth dose (PDD) of electron (6 MeV, 9 MeV) and photon (4 MV, 6 MV) beams. The average dose difference of the HM bolus and Gel bolus was calculated. The Gel bolus, a soft rubber bolus (SR bolus), and HM bolus were placed in adherence to a pelvic phantom. CT images taken after shaping and 1, 2, and 3 weeks after shaping were used to evaluate the adhesion and reproducibility using air gap and dice similarity coefficient (DSC). MAIN RESULTS The average dose difference for electron beams was 0.16% ± 0.79% and photon beams was 0.06% ± 0.34%, both within 1% of the PDD results. The HM bolus showed the same build-up effect and dose characteristics as the Gel bolus. The mean air gap values for the Gel bolus, SR bolus, and HM bolus were 96.02 ± 43.77 cm3, 34.93 ± 21.44 cm3, and 4.40 ± 1.50 cm3, respectively. The mean DSC values compared to initial images for the Gel bolus, SR bolus, and HM bolus were 0.363 ± 0.035, 0.556 ± 0.042, and 0.837 ± 0.018, respectively. Excellent adhesion was observed in the CT simulation and during the treatment period. SIGNIFICANCE The HM bolus has unique features, such as tissue equivalence, transparency, reusability, and free shaping for excellent adhesion, and is thus an ideal bolus for use in clinical cases.
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Affiliation(s)
- Kenji Nakamura
- Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, JAPAN
| | - Hajime Monzen
- Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, JAPAN
| | - Kazuki Kubo
- Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, JAPAN
| | - Hiroyuki Kosaka
- Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, JAPAN
| | - Takaaki Ito
- Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, JAPAN
| | - Yusuke Sakai
- Medical Physics, Graduate School of Medical Sciences, Kindai University, 377‑2, Onohigashi, Osakasayama, Osaka, 589-8511, JAPAN
| | - Yuya Yanagi
- Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, JAPAN
| | - Yasumasa Nishimura
- Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, JAPAN
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Kosaka H, Tamura M, Hattori S, Monzen H. REDUCTION OF THE COMPUTED TOMOGRAPHY DOSE TO THE GONADS OF ADOLESCENT AND YOUNG ADULT MALES THROUGH USE OF A TUNGSTEN-CONTAINING RUBBER SHEET. Radiat Prot Dosimetry 2023; 199:366-372. [PMID: 36617526 DOI: 10.1093/rpd/ncac295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 11/30/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
This study aims to measure the shielding effect of a novel tungsten rubber sheet (TRS) on the exposure of male gonads to ionizing radiation during upper abdominal and abdominal plus pelvic computed tomography (CT) examinations. The air kerma at the gonad with and without shielding was measured using an anthropomorphic body phantom. Gonads were shielded using: (1) 360° wrap with TRS (0.5-mm thick) and (2) 180° wrap with TRS. The air kerma at a position of male gonads in a pelvic scan was 21.8 mGy, even when the gonads were in the off-axis range. The TRS reduced the dose to the male gonads in abdominal plus pelvic CT examinations by 61% and 38% for the 360° and 180° TRS wrap, respectively.
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Affiliation(s)
- Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan
- Department of Radiology Center, Kindai University Hospital, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan
| | - Shota Hattori
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan
- Department of Radiology Center, Kindai University Hospital, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan
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Sakai Y, Monzen H, Tamura M, Nakamura K, Nishimura Y. Double enhancement effect of a surface dose with tungsten rubber bolus in photon radiotherapy for keloids and superficial tumors. Phys Eng Sci Med 2023; 46:179-184. [PMID: 36484890 DOI: 10.1007/s13246-022-01208-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022]
Abstract
To clarify the dosimetric characteristics of a real-time variable shape rubber-containing tungsten (STR) bolus in a clinical plan and investigate the efficacy of the STR bolus in photon radiotherapy for keloids and other superficial tumors. A 5 mm gel bolus or 1 mm STR bolus was placed on a solid water phantom. Tangential irradiation was performed using a TomoTherapy Radixact-X9 and 6 MV X-ray flattening-filter-free beam, and the surface dose was measured with radiochromic film. Clinical-like plans (TomoDirect; TD and TomoHelical; TH) were applied with the same geometry and the dose distributions were measured. The increase in surface dose by the build-up effect and backscatter was 37.7% and 8.0% for the gel bolus, and 40.5% and 26.4% for the STR bolus, respectively. In the TD and TH plans, the increase in surface dose was 27.4% and 48.3% for the gel bolus, and 39.0% and 63.2% for the STR bolus. Similary, changes in the sagittal plane dose were - 3.9% and 6.1% for the gel bolus, and - 6.3% and 6.9% for the STR bolus. The STR bolus effectively increased the surface dose by the build-up effect and backscatter in photon radiotherapy for keloids and other superficial tumors.
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Affiliation(s)
- Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, Japan
- Department of Radiotherapy, Takarazuka City Hospital, 4-5-1 Kohama, Takarazuka, Hyogo, 665-0827, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, Japan.
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, Japan
- Department of Radiotherapy, Takarazuka City Hospital, 4-5-1 Kohama, Takarazuka, Hyogo, 665-0827, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, Japan
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Matsumoto K, Monzen H, Kubo K, Otsuka M, Nambu H, Nishimura Y. Volumetric Modulated Arc Therapy Planning for Craniospinal Irradiation With a New O-ring Linac. Cureus 2023; 15:e36493. [PMID: 37090359 PMCID: PMC10118905 DOI: 10.7759/cureus.36493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2023] [Indexed: 04/25/2023] Open
Abstract
This study aims to determine the feasibility of using a new O-ring linear accelerator (Halcyon, Varian Medical Systems, CA, USA) to perform treatment planning using volumetric modulated arc therapy (VMAT) for craniospinal irradiation (CSI). A 20-year-old male patient with leukemia was selected. The planning target volume (PTV) was contoured to include the entire contents of the brain and spinal canal. The PTV margin was 10 mm applied to the clinical target volume (CTV). VMAT (RapidArc, Varian Medical Systems, CA, USA) planning was performed using four isocenter with five arcs, two full rotation arcs to cover the brain and upper part of the spinal cord, and one full rotation arc for the lower part of the spinal cord. The plan was created using the auto-feathering photon optimizer calculation of the planning system. The conformity index (CI) and heterogeneity index (HI) as well as dose-volume histograms of organs at risk (OAR) were evaluated. The patient position of ±3.0 mm in the craniocaudal direction was moved in to simulate the effect of treatment inaccuracy. The total treatment time was also measured. The CI and HI were 1.09 and 8.44, respectively. The mean dose (PTV) was 105.5%, and the mean dose (OARs) was lower than the planning dose constraints. Simulations with a patient position shift of ±3.0 mm resulted in an error of less than ±10.0% of the planned dose to the spinal cord. The total treatment time was within 15 minutes. VMAT planning for CSI with Halcyon achieved high conformality, uniform dose distribution, low dose to the surrounding normal tissues, and reduced treatment time.
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Affiliation(s)
- Kenji Matsumoto
- Department of Radiology Service, Kindai University Hospital, Osakasayama, JPN
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, JPN
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, JPN
| | - Masakazu Otsuka
- Department of Radiology Service, Kindai University Hospital, Osakasayama, JPN
| | - Hidekazu Nambu
- Department of Radiology Service, Kindai University Hospital, Osakasayama, JPN
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Muacevic A, Adler JR, Nakamura K, Yanagi Y, Sakai Y, Kubo K, Kosaka H, Monzen H. Development of a Novel Tabletop Device With Suction and Sanitization of Droplets against COVID-19. Cureus 2023; 15:e34287. [PMID: 36843808 PMCID: PMC9957588 DOI: 10.7759/cureus.34287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Background Coronavirus disease 2019 and other viruses are transmissible by aerosols and droplets from infected persons. This study aimed to develop a portable device that can trap droplets and deactivate viruses, and verify whether the device in an enclosed room can suction droplets and sanitize them using a filter and an ultraviolet-C (UVC) light-emitting diode. Materials and methods The portable device was evaluated by placing it 50 cm away from the droplet initiation point. A particle image velocimetry laser dispersed into a sheet form was used to visualize the droplets splashed on the irradiated sagittal plane and captured using a charge-coupled device camera at 60 frames per second. The images were overlaid and calculated to determine the percentage of the droplets beyond the portable device. Droplets with a particle size larger than 50 µm that dispersed and were deposited more than 100 cm away were measured using a water-sensitive paper. The effect of UVC sanitization on viruses captured by a high-efficiency particulate air (HEPA) filter was determined using a plaque assay. Results The percentage of droplets was 13.4% and 1.1% with the portable device OFF and ON, respectively, indicating a 91.8% reduction. The deposited droplets were 86 pixels and 26 pixels with the portable device OFF and ON, respectively, indicating a 68.7% reduction. The UVC deactivated more than 99% of the viruses on the HEPA filter surface in 5 minutes. Conclusions Our novel portable device can suck and fall the dispersed droplets, and an active virus was not observed on the exhaust side.
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Sagawa T, Ueda Y, Tsuru H, Kamima T, Ohira S, Tamura M, Miyazaki M, Monzen H, Konishi K. Dosimetric potential of knowledge-based planning model trained with HyperArc plans for brain metastases. J Appl Clin Med Phys 2022; 24:e13836. [PMID: 36333969 PMCID: PMC9924102 DOI: 10.1002/acm2.13836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/07/2022] [Accepted: 10/13/2022] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVE Dosimetric potential of knowledge-based RapidPlan planning model trained with HyperArc plans (Model-HA) for brain metastases has not been reported. We developed a Model-HA and compared its performance with that of clinical volumetric modulated arc therapy (VMAT) plans. METHODS From 67 clinical stereotactic radiosurgery (SRS) HyperArc plans for brain metastases, 47 plans were used to build and train a Model-HA. The other 20 clinical HyperArc plans were recalculated in RapidPlan system with Model-HA. The model performance was validated with the 20 plans by comparing dosimetric parameters for normal brain tissue between clinical plans and model-generated plans. The 20 clinical conventional VMAT-based SRS or stereotactic radiotherapy plans (CL-VMAT) were reoptimized with Model-HA (RP) and HyperArc system (HA), respectively. The dosimetric parameters were compared among three plans (CL-VMAT vs. RP vs. HA) in terms of planning target volume (PTV), normal brain excluding PTVs (Brain - PTV), brainstem, chiasm, and both optic nerves. RESULTS In model validation, the optimization performance of Model-HA was comparable to that of HyperArc system. In comparison to CL-VMAT, there were no significant differences among three plans with respect to PTV coverage (p > 0.17) and maximum dose for brainstem, chiasm, and optic nerves (p > 0.40). RP provided significantly lower V20 Gy , V12 Gy , and V4 Gy for Brain - PTV than CL-VMAT (p < 0.01). CONCLUSION The Model-HA has the potential to significantly reduce the normal brain dose of the original VMAT plans for brain metastases.
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Affiliation(s)
- Tomohiro Sagawa
- Department of Radiation OncologyOsaka International Cancer InstituteOsakaJapan
| | - Yoshihiro Ueda
- Department of Radiation OncologyOsaka International Cancer InstituteOsakaJapan
| | - Haruhi Tsuru
- Department of Medical Physics and EngineeringGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Tatsuya Kamima
- Radiation Oncology DepartmentCancer Institute HospitalJapanese Foundation for Cancer ResearchTokyoJapan
| | - Shingo Ohira
- Department of Radiation OncologyOsaka International Cancer InstituteOsakaJapan
| | - Mikoto Tamura
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversitySayamaJapan
| | - Masayoshi Miyazaki
- Department of Radiation OncologyOsaka International Cancer InstituteOsakaJapan
| | - Hajime Monzen
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversitySayamaJapan
| | - Koji Konishi
- Department of Radiation OncologyOsaka International Cancer InstituteOsakaJapan
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20
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Kubo K, Tamura M, Matsumoto K, Otsuka M, Monzen H. Independent monitor unit verification for dynamic flattened beam plans on the Halcyon linac. J Appl Clin Med Phys 2022; 24:e13807. [PMID: 36265085 PMCID: PMC9859998 DOI: 10.1002/acm2.13807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 08/17/2022] [Accepted: 09/22/2022] [Indexed: 01/26/2023] Open
Abstract
Independent monitor unit verification (MUV) methods for the dynamic beam-flattening (DBF) technique have not been established. The purpose of this study was to clarify whether MU values for the DBF technique can be calculated using in-air and in-water output ratios (Sc and Scp ). Sc and Scp were measured in the DBF mode, and the phantom scatter factor (Sp ) was calculated. The difference between calculated and planned MUs with square and rectangle fields and clinical plans for different treatment sites was also evaluated. Sc values for the 4 × 4 to 24 × 24 cm2 fields of the distal multi-leaf collimator (MLC) layer at 2-cm intervals were 0.887, 0.815, 0.715, 0.716, 0.611, 0.612, 0.511, 0.373, 0.374, 0.375, and 0.374, respectively. No collimator exchange effect was observed. Sc also depends slightly on the field size of the distal MLC layer. If the distal-MLC-layered field size was less than 20% of the corresponding MLC sequence size in the proximal MLC layer, Sc was affected by >1%, which was compensated using a correction factor (CF). Sp increased as the field sizes of the MLC sequence and distal MLC leaves increased. MUs calculated using measured Sc , Sp , and CF for square and rectangle fields agreed with planned MUs within ±1.2%. A larger difference (-1.5%) between calculated and planned MUs was observed for clinical plans, whereas differences in MUs were within 2 MU for most fields (56 out of 64 fields). MU calculation for the DBF technique can be performed with Sc , Sp , and CF for independent MUV.
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Affiliation(s)
- Kazuki Kubo
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsaka‐sayamaOsakaJapan
| | - Mikoto Tamura
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsaka‐sayamaOsakaJapan
| | - Kenji Matsumoto
- Department of Radiology CenterKindai University HospitalOsaka‐sayamaOsakaJapan
| | - Masakazu Otsuka
- Department of Radiology CenterKindai University HospitalOsaka‐sayamaOsakaJapan
| | - Hajime Monzen
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsaka‐sayamaOsakaJapan
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21
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Yanagi Y, Monzen H, Tamura M, Otsuka M, Nishimura Y. New strategy of a lung compensating technique with STR for total body irradiation. J Appl Clin Med Phys 2022; 23:e13791. [PMID: 36197733 PMCID: PMC9588260 DOI: 10.1002/acm2.13791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/14/2022] Open
Abstract
Purpose To determine the thickness of a soft variable shape tungsten rubber (STR) as a lung compensating filter in total body irradiation. Methods A tough water (TW) phantom and tough lung (TL) phantom were used as water and lung‐equivalent phantoms. The TW with a thickness of 3 cm simulating the thoracic wall was used (upper layer). The TW or TL with a thickness from 1 to 15 cm (1 cm increments) was placed beneath the upper layer (middle layer). The TW with a thickness of 5 cm simulating the mediastinum was placed beneath the middle layer (lower layer), and a farmer ionization chamber was placed beneath this layer. The relative doses of a 10 MV X‐rays were then measured. The TL was compensated in 1 mm increments from 1 to 11 mm of the STR, and the thickness of the STR at the same dose of TW (water equivalent) was obtained. Results The compensating ability of STR increased as the thickness of the TL increased, and an STR with a thickness of 1 mm reduced the dose by 2%–4%, depending on the thickness of lung. The STR thickness as an equivalent dose of TW per cm of TL was approximately linear, and the thickness was 0.62 mm/cm of TL. Conclusion The STR can be used as a lung compensating filter for a water equivalent dose with 0.62 mm of STR per cm of lung.
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Affiliation(s)
- Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan.,Department of Radiology, Shiga University of Medical Science Hospital, Otsu, Shiga, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Masakazu Otsuka
- Department of Radiology Center, Kindai University Hospital, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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22
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Nakamura Y, Monzen H, Tamura M, Kosaka H, Kijima K, Nishimura Y. Development of a radiopaque tiltmeter to improve reproducibility for Fowler's position on chest radiography. Radiography (Lond) 2022; 28:912-918. [PMID: 35810623 DOI: 10.1016/j.radi.2022.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 11/16/2022]
Abstract
INTRODUCTION We have developed a novel radiopaque tiltmeter (ROT) that can indicate patient tilt during a radiography examination and display it on X-ray images. This study evaluated the effect of variation of patient tilt on the reproducibility of Fowler's position for chest radiography and the accuracy of the ROT. METHODS We evaluated the reproducibility of Fowler's position based on changes from the first day in the central venous catheter (CVC) tip position and the cardiothoracic ratio (CTR) with and without a digital tiltmeter to verify its efficacy in patients who underwent mobile chest radiography. The ROT contains radiopaque liquid consisting of white barium sulfate solution and oil and has a scale bar of 15°-75° with increments of 15° to indicate ROT tilt. The ROT tilt was increased from 10° to 80° in increments of 10°. We then evaluated (1) the difference between the ROT tilt and the tilt measured with a digital tiltmeter, and (2) the ROT tilt displayed on the X-ray image. RESULTS With regard to reproducibility in Fowler's position, changes in the CVC tip position were 2.8 ± 3.9 mm and 10.7 ± 10.6 mm with and without the tiltmeter, respectively (p < 0.05) and the respective rates of change in the CTR were 0.7% ± 0.6% and 4.0% ± 2.1% (p < 0.05). Differences between the ROT tilt and the tilt measured by the digital tiltmeter were within ±2.5°. All ROT tilts displayed on the X-ray images were recognized exactly as each tilt. CONCLUSION Our novel ROT had the potential to accurately indicate patient tilt during chest radiography, which could be helpful in terms of reproducibility and precise follow-up. IMPLICATIONS FOR PRACTICE Use of the ROT for determination of patient tilt can improve reproducibility in Fowler's position, allowing more accurate serial X-ray imaging.
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Affiliation(s)
- Y Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan; Department of Radiological Technology, University Hospital, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
| | - H Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan.
| | - M Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan.
| | - H Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan.
| | - K Kijima
- Department of Radiological Technology, University Hospital, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
| | - Y Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan.
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Nakamura K, Okuhata K, Otsuka M, Tamura M, Monzen H. An improvement process of knowledge-based plan (KBP) model to standardize VMAT plan quality for prostate cancer. J Med Imaging Radiat Sci 2022. [DOI: 10.1016/j.jmir.2022.03.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Tsuru H, Ueda Y, Tamura M, Monzen H, Ohira S, Masaoka A, Inui S, Konishi K, Fukunaga J, Mizuno H, Miyazaki M, Koizumi M. Effects of Mechanical Performance on Deliverability and Dose Distribution by Comparing Multi Institutions' Knowledge-based Models for Prostate Cancer in Volumetric Modulated Arc Therapy. In Vivo 2022; 36:687-693. [PMID: 35241523 DOI: 10.21873/invivo.12754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 01/29/2022] [Accepted: 01/31/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM The aim of this study was to evaluate the mechanical performance and the effect on dose distribution and deliverability of volumetric modulated arc therapy (VMAT) plans for prostate cancer created with the commercial knowledge-based planning (KBP) system (RapidPlan™). MATERIALS AND METHODS Three institutions, A, B, and C were enrolled in this study. Each institution established and trained a KBP model with their own cases. CT data and structures for 45 patients at institution B were utilized to validate the dose-volume parameters (D2(%), D95(%), and D98(%) for target, and V50(%), V75(%), and V90(%) for rectum and bladder), and the following mechanical performance parameters and gamma passing rates of each KBP model: leaf sequence variability (LSV), aperture area variability (AAV), total monitor unit (MU), modulation complexity score for VMAT (MCSv), MU/control point (CP), aperture area (AA)/CP, and MU×AA/CP. RESULTS Significant differences (p<0.01) in dosimetric parameters such as D2 and D98 for target and V50, V75, and V90 for bladder were observed among the three institutions. The means and standard deviations of MCSv were 0.31±0.03, 0.29±0.02, and 0.32±0.03, and the angles of maximum and minimum MU×AA/CP were 269° and 13°, 269° and 13°, and 273° and 153° at institutions A, B, and C, respectively. The mean gamma passing rate (1%/1 mm.) was >95% for all cases in each institution. Dose distribution and mechanical performance significantly differed between the three models. CONCLUSION Each KBP model had different dose distributions and mechanical performance but could create an acceptable plan for deliverability regardless of mechanical performance.
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Affiliation(s)
- Haruhi Tsuru
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan.,Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan;
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Shingo Ohira
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Akira Masaoka
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Shouki Inui
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan.,Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Koji Konishi
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Junichi Fukunaga
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - Hirokazu Mizuno
- Division of central radiology, Osaka Rosai Hospital, Osaka, Japan
| | - Masayoshi Miyazaki
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Masahiko Koizumi
- Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka University, Osaka, Japan
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Hattori S, Monzen H, Tamura M, Kosaka H, Nakamura Y, Nishimura Y. Estimating radiation exposure of the brain of a physician with a protective flap in interventional radiology: A phantom study. J Appl Clin Med Phys 2022; 23:e13532. [PMID: 35045212 PMCID: PMC8906205 DOI: 10.1002/acm2.13532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/30/2021] [Accepted: 12/18/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The efficiency of protective equipment for the brain has not been verified at the left anterior oblique (LAO) position, which is commonly used in clinical procedures. The purpose of this study was to investigate radiation exposure of the brain in interventional radiology (IR) and the shielding ability of a new protective flap. METHODS We made a flap that combined a protective cap with a left lateral face shield. The flap was made of tungsten-containing rubber (TCR). An anthropomorphic head phantom was placed at the physician's position, and air kerma rates (μGy/min and μGy/15s) were measured by electronic dosimeter at three locations: the surface of the left side of the head, and the left and right temporal lobes with the protective cap and the flap in fluoroscopy and cine modes. The X-ray tube was at the lower left side of the physician, and its angles were LAO60 and LAO60CAU40. The tube voltage (95-125 kV), tube current (4.7-732 mA), and air kerma rate (27.8-1078 mGy/min) were automatically adjusted by the X-ray system. We obtained the cap and the flap shielding efficiencies. RESULTS In cine mode at LAO60CAU40, the shielding efficiencies on the surface of the left side of the head and left temporal lobe with the cap were 92.6% and 5.1%, respectively, and the corresponding shielding efficiencies with the flap were 92.5% and 86.1%, respectively. The flap can reduce radiation exposure of the brain more than the cap alone. CONCLUSIONS At the left anterior oblique in interventional radiology, the flap can reduce exposure to the brain.
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Affiliation(s)
- Shota Hattori
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan.,Department of Radiological Center, Kindai University Hospital, Osakasayama, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan.,Department of Radiological Center, Kindai University Hospital, Osakasayama, Osaka, Japan
| | - Yasunori Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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Uehara T, Monzen H, Tamura M, Inada M, Otsuka M, Doi H, Matsumoto K, Nishimura Y. Feasibility study of volumetric modulated arc therapy with Halcyon™ linac for total body irradiation. Radiat Oncol 2021; 16:236. [PMID: 34906180 PMCID: PMC8670260 DOI: 10.1186/s13014-021-01959-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/29/2021] [Indexed: 01/11/2023] Open
Abstract
Background The use of total body irradiation (TBI) with linac-based volumetric modulated arc therapy (VMAT) has been steadily increasing. Helical tomotherapy has been applied in TBI and total marrow irradiation to reduce the dose to critical organs, especially the lungs. However, the methodology of TBI with Halcyon™ linac remains unclear. This study aimed to evaluate whether VMAT with Halcyon™ linac can be clinically used for TBI. Methods VMAT planning with Halcyon™ linac was conducted using a whole-body computed tomography data set. The planning target volume (PTV) included the body cropped 3 mm from the source. A dose of 12 Gy in six fractions was prescribed for 50% of the PTV. The organs at risk (OARs) included the lens, lungs, kidneys, and testes. Results The PTV D98%, D95%, D50%, and D2% were 8.9 (74.2%), 10.1 (84.2%), 12.6 (105%), and 14.2 Gy (118%), respectively. The homogeneity index was 0.42. For OARs, the Dmean of the lungs, kidneys, lens, and testes were 9.6, 8.5, 8.9, and 4.4 Gy, respectively. The V12Gy of the lungs and kidneys were 4.5% and 0%, respectively. The Dmax of the testes was 5.8 Gy. Contouring took 1–2 h. Dose calculation and optimization was performed for 3–4 h. Quality assurance (QA) took 2–3 h. The treatment duration was 23 min. Conclusions A planning study of TBI with Halcyon™ to set up VMAT-TBI, dosimetric evaluation, and pretreatment QA, was established. Supplementary Information The online version contains supplementary material available at 10.1186/s13014-021-01959-3.
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Affiliation(s)
- Takuya Uehara
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan.
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Masakazu Otsuka
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
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27
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Wada Y, Monzen H, Otsuka M, Doi H, Nakamatsu K, Nishimura Y. Difference in VMAT dose distribution for prostate cancer with/without rectal gas removal and/or adaptive replanning. Med Dosim 2021; 47:87-91. [PMID: 34702634 DOI: 10.1016/j.meddos.2021.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/29/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022]
Abstract
We investigated differences in the volumetric-modulated arc therapy (VMAT) dose distribution in prostate cancer patients treated by rectal gas removal and/or adaptive replanning. Cone-beam computed tomography (CBCT) scans were performed daily for 22 treatments in eight prostate cancer patients with excessive rectal gas, and the CBCT images were analyzed. Rectal gas removal was performed, and irradiation was delivered after prostate matching. We compared dose-volume histograms for the daily CBCT images before and after rectal gas removal. Plan A was the original plan on CBCT images before rectal gas removal. Plan B was a single reoptimized plan on CBCT images before rectal gas removal. Plan C was the original plan on CBCT images after rectal gas removal. Plan D was a single reoptimized plan on CBCT images after rectal gas removal. D95 of the planning target volume (PTV) minus the rectum of Plan C (94.7% ± 6.6%) was significantly higher than that of Plan A (88.5% ± 10.4%). All dosimetric parameters of Plan C were improved by rectal gas removal compared with Plan A, regardless of the initial rectal gas volume. Dosimetric parameters of PTV minus the rectum of Plan B were significantly improved compared with Plan C. Additionally, the V78 of the rectal wall of Plan B (0.2% ± 0.5%) was significantly improved compared with Plan C (3.9% ± 6.3%, p = 0.003). The dosimetric parameters of Plan D were not significantly different from Plan B. The dose distribution of prostate VMAT was improved by rectal gas removal and/or adaptive replanning. An adaptive replanning on daily CBCT images might be a better method than rectal gas removal for prostate cancer patients with excessive rectal gas.
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Affiliation(s)
- Yutaro Wada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan.
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Masakazu Otsuka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Kiyoshi Nakamatsu
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, 589-8511, Japan
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Okuhata K, Tamura M, Monzen H, Nishimura Y. Dosimetric characteristics of a thin bolus made of variable shape tungsten rubber for photon radiotherapy. Phys Eng Sci Med 2021; 44:1249-1255. [PMID: 34542835 DOI: 10.1007/s13246-021-01059-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/09/2021] [Indexed: 10/20/2022]
Abstract
In this study, we aim to clarify the dosimetric characteristics of a real time variable shape rubber containing tungsten (STR) as a thin bolus in 6-MV photon radiotherapy. The percentage depth doses (PDDs) and lateral dose profiles (irradiation field = 10 × 10 cm2) in the water-equivalent phantom were measured and compared between no bolus, a commercial 5-mm gel bolus, and 0.5-, 1-, 2-, and 3-mm STR boluses. The characteristics of the PDDs were evaluated according to relative doses at 1 mm depth (D1mm) and depth of maximum dose (dmax). To determine the distance of the shift caused by the STR bolus, the PDD value at a depth of 100 mm without a bolus was obtained. For each STR thickness, the difference between the depth corresponding to this PDD value and 100 mm was calculated. The penumbra size and width of the 50% dose were evaluated using lateral dose profiles. The D1mm with no bolus, 5-mm gel bolus, and 0.5-, 1-, 2-, and 3-mm STR boluses were 47.6%, 91.5%, 78.2%, 86.6%, 89.3%, and 89.4%, respectively, and the respective dmax values were 15, 10, 13, 12, 11, and 10 mm. The shifting distance of the 0.5-, 1-, 2-, and 3-mm STR boluses were 2.7, 4.4, 4.8, and 4.9 mm, respectively. There were no differences for those in lateral dose profiles. The 1-mm-thick STR thin bolus shifted the depth dose profile by 4.4 mm and could be used as a customized bolus for photon radiotherapy.
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Affiliation(s)
- Katsuya Okuhata
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 5898511, Japan.,Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 5898511, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 5898511, Japan.
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 5898511, Japan
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29
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Wakabayashi K, Monzen H, Tamura M, Takei Y, Okuhata K, Anami S, Doi H, Nishimura Y. A novel real-time shapeable soft rubber bolus for clinical use in electron radiotherapy. Phys Med Biol 2021; 66. [PMID: 34438390 DOI: 10.1088/1361-6560/ac215b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 08/26/2021] [Indexed: 11/12/2022]
Abstract
We have developed soft rubber (SR) bolus that can be shaped in real-time by heating flexibly and repeatedly. This study investigated whether the SR bolus could be used as an ideal bolus, such as not changing of the beam characteristics and homogeneity through the bolus and high plasticity to adhere a patient in addition to real-time shapeable and reusability, in electron radiotherapy. Percentage depth doses (PDDs) and lateral dose profiles (LDPs) were obtained for 4, 6, and 9 MeV electron beams and were compared between the SR and conventional gel boluses. For the LDP at depth of 90% dose, the penumbra as lateral distance between the 80% and 20% isodose lines (P80-20) and the width of 90% dose level (r90) were compared. To evaluate adhesion, the air gap volume between the boluses and nose of a head phantom was evaluated on CT image. The dose profiles along the center axis for the 6 MeV electron beam with SR, gel, and virtual boluses (thickness = 5 mm) on the head phantom were also calculated for the irradiation of 200 monitor unit with a treatment planning system and the depth of the maximum dose (dmax) and maximum dose (Dmax) were compared. The PDDs,P80-20, andr90between the SR and gel boluses corresponded well (within 2%, 0.4 mm, and 0.7 mm, respectively). The air gap volumes of the SR and gel boluses were 3.14 and 50.35 cm3, respectively. Thedmaxwith SR, gel and virtual boluses were 8.0, 6.0, and 7.0 mm (no bolus: 12.0 mm), and theDmaxvalues were 186.4, 170.6, and 186.8 cGy, respectively. The SR bolus had the equivalent electron beam characteristics and homogeneity to the gel bolus and achieved excellent adhesion to a body surface, which can be used in electron radiotherapy as an ideal bolus.
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Affiliation(s)
- Kazuki Wakabayashi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8511, Japan.,Department of Central Radiology, Wakayama Medical University Hospital, 811-1 Kimiidera, Wakayama, Wakayama, 641-8510, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Yoshiki Takei
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8511, Japan.,Department of Radiology, Kindai University Nara Hospital, 1248-1 Otoda-cho, Ikoma, Nara 630-0293, Japan
| | - Katsuya Okuhata
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Shimpei Anami
- Department of Radiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, Wakayama, 641-8510, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan
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Nakamura K, Okuhata K, Tamura M, Otsuka M, Kubo K, Ueda Y, Nakamura Y, Nakamatsu K, Tanooka M, Monzen H, Nishimura Y. An updating approach for knowledge-based planning models to improve plan quality and variability in volumetric-modulated arc therapy for prostate cancer. J Appl Clin Med Phys 2021; 22:113-122. [PMID: 34338435 PMCID: PMC8425874 DOI: 10.1002/acm2.13353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The purpose of this study was to compare the dose-volume parameters and regression scatter plots of the iteratively improved RapidPlan (RP) models, specific knowledge-based planning (KBP) models, in volumetric-modulated arc therapy (VMAT) for prostate cancer over three periods. METHODS A RP1 model was created from 47 clinical intensity-modulated radiation therapy (IMRT)/VMAT plans. A RP2 model was created to exceed dosimetric goals which set as the mean values +1SD of the dose-volume parameters of RP1 (50 consecutive new clinical VMAT plans). A RP3 model was created with more strict dose constraints for organs at risks (OARs) than RP1 and RP2 models (50 consecutive anew clinical VMAT plans). Each RP model was validated against 30 validation plans (RP1, RP2, and RP3) that were not used for model configuration, and the dose-volume parameters were compared. The Cook's distances of regression scatterplots of each model were also evaluated. RESULTS Significant differences (p < 0.05) between RP1 and RP2 were found in Dmean (101.5% vs. 101.9%), homogeneity index (3.90 vs. 4.44), 95% isodose conformity index (1.22 vs. 1.20) for the target, V40Gy (47.3% vs. 45.7%), V60Gy (27.9% vs. 27.1%), V70Gy (16.4% vs. 15.2%), and V78Gy (0.4% vs. 0.2%) for the rectal wall, and V40Gy (43.8% vs. 41.8%) and V70Gy (21.3% vs. 20.5%) for the bladder wall, whereas only V70Gy (15.2% vs. 15.8%) of the rectal wall differed significantly between RP2 and RP3. The proportions of cases with a Cook's distance of <1.0 (RP1, RP2, and RP3 models) were 55%, 78%, and 84% for the rectal wall, and 77%, 68%, and 76% for the bladder wall, respectively. CONCLUSIONS The iteratively improved RP models, reflecting the clear dosimetric goals based on the RP feedback (dose-volume parameters) and more strict dose constraints for the OARs, generated superior dose-volume parameters and the regression scatterplots in the model converged. This approach could be used to standardize the inverse planning strategies.
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Affiliation(s)
- Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan.,Department of Radiotherapy, Takarazuka City Hospital, Kohama, Takarazuka, Japan
| | - Katsuya Okuhata
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Masakazu Otsuka
- Department of Radiology, Kindai University Hospital, Osakasayama, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, Chuo-ku, Japan
| | - Yasunori Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Kiyoshi Nakamatsu
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Japan
| | - Masao Tanooka
- Department of Radiotherapy, Takarazuka City Hospital, Kohama, Takarazuka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Japan
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Abstract
Positron emission tomography (PET–CT) is an essential imaging modality for the management of various diseases. Increasing numbers of PET–CT examinations are carried out across the world and deliver benefits to patients; however, there are concerns about the cumulative radiation doses from these examinations in patients. Compared to the radiation exposure delivered by CT, there have been few reports on the frequency of patients with a cumulative effective radiation dose of ≥100 mSv from repeated PET–CT examinations. The emerging dose tracking system facilitates surveys on patient cumulative doses by PET–CT because it can easily wrap up exposure doses of PET radiopharmaceuticals and CT. Regardless of the use of a dose tracking system, implementation of justification for PET–CT examinations and utilisation of dose reduction measures are key issues in coping with the cumulative dose in patients. Despite all the advantages of PET/MRI such as eliminating radiation exposure from CT and providing good tissue contrast in MRI, it is expensive and cannot be introduced at every facility; thus, it is still necessary to utilise PET–CT with radiation reduction measures in most clinical situations.
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Affiliation(s)
- Makoto Hosono
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, Japan
| | - Mamoru Takenaka
- Department of Gastroenterology, Faculty of Medicine, Kindai University, Ohno-Higashi, Osaka-Sayama, Osaka, Japan
| | - Hajime Monzen
- . Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Ohno-Higashi, Osaka-Sayama, Osaka, Japan
| | - Mikoto Tamura
- . Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Ohno-Higashi, Osaka-Sayama, Osaka, Japan
| | - Masatoshi Kudo
- Department of Gastroenterology, Faculty of Medicine, Kindai University, Ohno-Higashi, Osaka-Sayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, Japan
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Tamura M, Monzen H, Matsumoto K, Otsuka M, Nishimura Y. Feasibility study of a photochromic diarylethene film as a clinical dosimeter for kV X-rays. RADIAT MEAS 2021. [DOI: 10.1016/j.radmeas.2021.106608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Okuhata K, Monzen H, Tamura M, Matsumoto K, Otsuka M, Kubo K, Ueda Y, Uehara T, Doi H, Ishikawa K, Nishimura Y. Plan Complexity and Delivery Accuracy of Knowledge-based Volumetric Modulated Arc Therapy Plans with Single Optimization for Oropharyngeal Cancer. Anticancer Res 2021; 41:2925-2931. [PMID: 34083283 DOI: 10.21873/anticanres.15074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/15/2021] [Accepted: 05/17/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM We investigated the plan complexity of volumetric modulated arc therapy (VMAT) with knowledge-based plan (KBP) for oropharyngeal cancer (OPC) with a single optimization and whether it could be used clinically. MATERIALS AND METHODS KBP model was configured using 55 consecutive OPC and nasopharyngeal cancer plans. Plan complexity as a characteristic of multileaf collimator (MLC) motion and γ pass rate (2%/2 mm criterion) were compared between clinical manual plan (CMP) and KBP for other 10 plans. RESULTS Plan complexity metrics that had significant differences (p<0.05) (CMP vs. KBP), were mean lateral displacement of MLC from central axis (15.82 mm vs. 18.90 mm), proportions of MLC aperture sizes of ≤5 mm (0.14 vs. 0.11), ≤10 mm (0.24 vs. 0.19), and ≤20 mm (0.41 vs. 0.34), and monitor units (578.68 vs. 505.04). The γ pass rate was 91.3% vs. 93.3%. CONCLUSION Single optimized KBP for OPC had simple plan complexity features and comparable delivery accuracy to CMP, and could be clinically applied.
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Affiliation(s)
- Katsuya Okuhata
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan.,Department of Radiology, Kansai Electric Power Hospital, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan;
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Masakazu Otsuka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka Japan
| | - Takuya Uehara
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Kazuki Ishikawa
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
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Wada Y, Monzen H, Tamura M, Otsuka M, Inada M, Ishikawa K, Doi H, Nakamatsu K, Nishimura Y. Dosimetric Evaluation of Simplified Knowledge-Based Plan with an Extensive Stepping Validation Approach in Volumetric-Modulated Arc Therapy-Stereotactic Body Radiotherapy for Lung Cancer. J Med Phys 2021; 46:7-15. [PMID: 34267484 PMCID: PMC8240912 DOI: 10.4103/jmp.jmp_67_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 03/05/2021] [Accepted: 03/05/2021] [Indexed: 11/18/2022] Open
Abstract
Purpose: We investigated the performance of the simplified knowledge-based plans (KBPs) in stereotactic body radiotherapy (SBRT) with volumetric-modulated arc therapy (VMAT) for lung cancer. Materials and Methods: For 50 cases who underwent SBRT, only three structures were registered into knowledge-based model: total lung, spinal cord, and planning target volume. We performed single auto-optimization on VMAT plans in two steps: 19 cases used for the model training (closed-loop validation) and 16 new cases outside of training set (open-loop validation) for TrueBeam (TB) and Halcyon (Hal) linacs. The dosimetric parameters were compared between clinical plans (CLPs) and KBPs: CLPclosed, KBPclosed-TB and KBPclosed-Hal in closed-loop validation, CLPopen, KBPopen-TB and KBPopen-Hal in open-loop validation. Results: All organs at risk were comparable between CLPs and KBPs except for contralateral lung: V5 of KBPs was approximately 3%–7% higher than that of CLPs. V20 of total lung for KBPs showed comparable to CLPs; CLPclosed vs. KBPclosed-TB and CLPclosed vs. KBPclosed-Hal: 4.36% ± 2.87% vs. 3.54% ± 1.95% and 4.36 ± 2.87% vs. 3.54% ± 1.94% (P = 0.54 and 0.54); CLPopen vs. KBPopen-TB and CLPopen vs. KBPopen-Hal: 4.18% ± 1.57% vs. 3.55% ± 1.27% and 4.18% ± 1.57% vs. 3.67% ± 1.26% (P = 0.19 and 0.27). CI95 of KBPs with both linacs was superior to that of the CLP in closed-loop validation: CLPclosed vs. KBPclosed-TB vs. KBPclosed-Hal: 1.32% ± 0.12% vs. 1.18% ± 0.09% vs. 1.17% ± 0.06% (P < 0.01); and open-loop validation: CLPopen vs. KBPopen-TB vs. KBPopen-Hal: 1.22% ± 0.09% vs. 1.14% ± 0.04% vs. 1.16% ± 0.05% (P ≤ 0.01). Conclusions: The simplified KBPs with limited number of structures and without planner intervention were clinically acceptable in the dosimetric parameters for lung VMAT-SBRT planning.
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Affiliation(s)
- Yutaro Wada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Masakazu Otsuka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Kazuki Ishikawa
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Kiyoshi Nakamatsu
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
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Wakabayashi K, Monzen H, Tamura M, Matsumoto K, Takei Y, Nishimura Y. Dosimetric evaluation of skin collimation with tungsten rubber for electron radiotherapy: A Monte Carlo study. J Appl Clin Med Phys 2021; 22:63-70. [PMID: 33634955 PMCID: PMC8035551 DOI: 10.1002/acm2.13210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 11/15/2022] Open
Abstract
PURPOSE Skin collimation provides a sharp penumbra for electron beams, while the effect of bremsstrahlung from shielding materials is a concern. This phantom study was conducted to evaluate the safety and efficacy of a real-time variable shape rubber containing-tungsten (STR) that can be placed on a patient's skin. METHODS Electron beam profiles were acquired with the STR placed on a water-equivalent phantom and low melting-point alloy (LMA) placed at the applicator according to commonly used procedures (field sizes: 20- and 40-mm diameters). Depth and lateral dose profiles for 6- and 12-MeV electron beams were obtained by Monte Carlo (MC) simulations and were benchmarked against film measurements. The width of the off-axis distance between 80% and 20% doses (P80-20 ) and the maximum dose were obtained from the lateral dose profiles. Bremsstrahlung emission was analyzed by MC simulations at the depth of maximum dose (R100 ). RESULTS The depth dose profiles calculated by the MC simulations were consistently within 2% of the measurements. The P80-20 at R100 for 20- and 40-mm diameters were 4.0 mm vs. 7.6 mm (STR vs. LMA) and 4.5 mm vs. 9.2 mm, respectively, for the 6-MeV electron beam with 7.0-mm-thick STR, and 2.7 mm vs. 5.6 mm and 4.5 mm vs. 7.1 mm, respectively, for the 12-MeV electron beam with 12.0-mm-thick STR. A hotspot was not observed on the lateral dose profiles obtained with the STR at R100 . The bremsstrahlung emission under the region shielded by the STR was comparable to that obtained with the LMA, even though the STR was placed on the surface of the phantom. CONCLUSIONS Skin collimator with STR provided superior dosimetric characteristics and comparable bremsstrahlung emission to LMA collimator at the applicator. STR could be a new tool for the safe and efficient delivery of electron radiotherapy.
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Affiliation(s)
- Kazuki Wakabayashi
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsakaJapan
| | - Hajime Monzen
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsakaJapan
| | - Mikoto Tamura
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsakaJapan
| | - Kenji Matsumoto
- Department of Central RadiologyKindai University HospitalOsakaJapan
| | - Yoshiki Takei
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsakaJapan
| | - Yasumasa Nishimura
- Department of Radiation OncologyFaculty of MedicineKindai UniversityOsakaJapan
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Inoue E, Doi H, Monzen H, Tamura M, Inada M, Ishikawa K, Nakamatsu K, Nishimura Y. Dose-volume Histogram Analysis of Knowledge-based Volumetric-modulated Arc Therapy Planning in Postoperative Breast Cancer Irradiation. In Vivo 2021; 34:1095-1101. [PMID: 32354897 DOI: 10.21873/invivo.11880] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/04/2020] [Accepted: 02/10/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND/AIM We evaluated the dosimetric profiles of manually generated volumetric-modulated arc therapy (VMAT) plans and performance of a commercial knowledge-based planning system (KBP) in treating breast cancer. MATERIALS AND METHODS We defined the manually generated VMAT plan as the manual plan (MP). Twenty MPs were generated for left-sided breast cancer patients who underwent breast-conserving surgery and used to develop a KBP training set. The other five patients were used for validation. The dosimetric parameters among MPs, tangential irradiation plans (TPs), and KBP-VMAT plans (KBP-Ps) were compared. RESULTS D95 and homogeneity of the planning target volume (PTV) were significantly higher and greater in MPs and KBP-Ps than in TPs. Lung V20, V40 The Dmean for the left anterior descending artery was lower in MPs and KBP-Ps than in TPs. KBP could save time in generating VMAT plans. CONCLUSION MPs and KBP-Ps could ensure higher dose uniformity of PTV than TPs. KBP could faster generate comparable MPs for breast cancer.
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Affiliation(s)
- Eri Inoue
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Kazuki Ishikawa
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Kiyoshi Nakamatsu
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Kindai University Faculty of Medicine, Osaka, Japan
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Kawai Y, Tamura M, Amano M, Kosugi T, Monzen H. First Clinical Experience of Tungsten Rubber Electron Adaptive Therapy With Real-time Variable-shape Tungsten Rubber. Anticancer Res 2021; 41:919-925. [PMID: 33517298 DOI: 10.21873/anticanres.14845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/18/2020] [Accepted: 01/04/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM We investigated the dosimetric characteristics of electron radiotherapy for auricular keloid using real-time variable-shape tungsten rubber (STR). PATIENTS AND METHODS For the first evaluation, STR was shaped into a rectangular irradiation field (3.0×5.0 cm2). In the next step, the STR was reshaped to fit the target (3.5×6.5 cm2) for the second evaluation. Percentage depth doses (PDDs) and lateral dose profiles were obtained with 6-MeV electron beams and compared with those of low-melting-point lead (LML). RESULTS Compared to the LML on electron applicator, PDD differences were within 0.4 mm, while the penumbras as width of 20-80% dose levels were smaller (maximum reductions: 75.8% and 82.9% at first and second evaluations, respectively). The treatment process of shaping the STR, decision on output, and irradiation was completed within 45 min. CONCLUSION Electron radiotherapy using STR for keloid can be performed with excellent dose distribution in a short time. First clinical experience found the STR is suitable for use in individualized and immediate electron radiotherapy.
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Affiliation(s)
- Yoshihiro Kawai
- Department of Radiology, Fujieda Municipal General Hospital, Shizuoka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Morikazu Amano
- Department of Radiology, Fujieda Municipal General Hospital, Shizuoka, Japan
| | - Takashi Kosugi
- Department of Radiation Oncology, Fujieda Municipal General Hospital, Shizuoka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan;
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Ito T, Tamura M, Monzen H, Matsumoto K, Nakamatsu K, Harada T, Fukui T. [Impact of Aperture Shape Controller on Knowledge-based VMAT Planning of Prostate Cancer]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2021; 77:23-31. [PMID: 33473076 DOI: 10.6009/jjrt.2021_jsrt_77.1.23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE Knowledge-based planning (KBP) has disadvantages of high monitor unit (MU) and complex multi-leaf collimator (MLC) motion. We investigated the optimal aperture shape controller (ASC) level for the KBP to reduce these factors in volumetric modulated arc therapy (VMAT) for prostate cancer. METHODS The KBP model was created based on 51 clinical plans (CPs) of patients who underwent the VMAT for prostate cancer. Another 10 CPs were selected randomly, and the KBPs with/without ASC, changed stepwise from very low (KBP-VL) to very high (KBP-VH), were performed with a single auto-optimization. The parameters of dose-volume histograms (DVHs) and MLC performance metrics were evaluated. We obtained the modulation complexity score for VMAT (MCSv), closed leaf score (CLS), small aperture score (SAS), leaf travel (LT), and total MU. RESULTS The ASC did not affect the DVH parameters negatively. The following comparisons of MLC performance were obtained (KBP vs. KBP-VL vs. KBP-VH, respectively): 0.25 vs. 0.27 vs. 0.30 (MCSv), 0.19 vs. 0.18 vs. 0.16 (CLS), 0.50 vs. 0.45 vs. 0.40 (SAS10 mm), 0.73 vs. 0.68 vs. 0.63 (SAS20 mm), 768.35 mm vs. 671.50 mm vs. 551.32 mm (LT), and 672.87 vs. 642.36 vs. 607.59 (MU). There were significant differences between KBP and KBP-VH for MCSv and LT (p<0.05). CONCLUSIONS The KBP using an ASC set to the very high level could reduce the complexity of MLC motion significantly more without deterioration of the DVH parameters compared with the KBP in VMAT for prostate cancer.
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Affiliation(s)
- Takaaki Ito
- Department of Radiological Technology, Kobe City Nishi-Kobe Medical Center
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University.,Department of Radiology, Kindai University Hospital
| | - Kiyoshi Nakamatsu
- Department of Radiation Oncology, Faculty of Medicine, Kindai University
| | - Tomoko Harada
- Department of Radiological Technology, Kobe City Nishi-Kobe Medical Center
| | - Tatsuya Fukui
- Department of Radiological Technology, Kobe City Nishi-Kobe Medical Center
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Tamura M, Monzen H, Matsumoto K, Otsuka M, Hanaoka K, Asai Y. [Introduction of Medical Physics Course in Kindai University-Department of Medical Physics, Graduate School of Medical Sciences, Kindai University]. Igaku Butsuri 2021; 41:44-47. [PMID: 33853984 DOI: 10.11323/jjmp.41.1_44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Masakazu Otsuka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Kohei Hanaoka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Yoshiyuki Asai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
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Yanagi Y, Tamura M, Monzen H, Matsumoto K, Takei Y, Noma K, Kida T. [Application of Real-time Variable Shape Tungsten Rubber for Nail Radiation Protection in the Total Skin Electron Beam (TSEB) Therapy]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2021; 77:145-152. [PMID: 33612692 DOI: 10.6009/jjrt.2021_jsrt_77.2.145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
PURPOSE This study investigated whether real-time variable shape tungsten rubber (STR) could be applied for nail radiation protection in total skin electron beam (TSEB) therapy. METHODS Simulated finger phantoms were made from syringes filled with physiological saline of volumes 5, 10, 20, and 30 ml (inner diameters of 14.1, 17.0, 21.7, and 25.3 mm, respectively). Gafchromic film was applied to the phantom, and lead (thickness 1-3 mm) or STR (thickness 1-4 mm) with an area of 4´1.5 cm was used to cover the film. A 6 MeV electron beam with an 8 mm acrylic board was then used to irradiate the phantom. The source-surface distance (SSD) was 444 cm, the field size was 36´36 cm at SSD of 100 cm without an electron applicator, and the monitor unit was 2000 MU. The shielding rates were obtained from the dose profiles. RESULTS The mean values of the shielding rate values for all phantoms were 50.1, 97.6, and 98.7% for 1, 2, and 3 mm of lead, respectively, and -13.6, 53.9, 91.2, and 99.4% for 1, 2, 3, and 4 mm of STR, respectively. CONCLUSION STR with a thickness of 4 mm had the same shielding properties as lead with a thickness of 3 mm, which was an approximately 100% shielding rate. STR could therefore be used in TSEB therapy instead of lead.
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Affiliation(s)
- Yuya Yanagi
- Department of Radiology, Shiga University of Medical Science Hospital
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
- Department of Radiology, Kindai University Hospital
| | - Yoshiki Takei
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
- Department of Radiology, Kindai University Nara Hospital
| | - Kazuo Noma
- Department of Radiology, Shiga University of Medical Science Hospital
| | - Tetsuo Kida
- Department of Radiology, Shiga University of Medical Science Hospital
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Matsumoto K, Tamura M, Otsuka M, Wakabayashi K, Kijima K, Monzen H. [Dosimetric Characteristics of a Real Time Shapeable Tungsten Containing Rubber with Electron Beams]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2020; 76:1248-1255. [PMID: 33342943 DOI: 10.6009/jjrt.2020_jsrt_76.12.1248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE This study investigated the dosimetric characteristics of electron beams shaped with a real-time shapeable tungsten-containing rubber (STR) collimator. METHODS Circular irradiation fields of 40 mm diameter were shaped using STR or low melting-point alloy (LMA) placed on the electron applicator. The STR heated with approximately 70-degree warm water was molded into the template bottom of the applicator. Percent depth doses (PDDs) and lateral dose profiles of 6 and 12 MeV electron beams were measured and compared between STR and LMA. For the PDDs, the depths of maximum dose (dmax), 90% dose (d90), and 80% dose (d80) were evaluated. For the lateral dose profiles, penumbra as the width of the off-axis distance from 80% to 20% doses and treatment diameter covering over 90% dose were evaluated at the surface, dmax, d90, and d80. The transmission of the STR was also investigated at thicknesses fit to electron applicator for 6 and 12 MeV electron beams. RESULTS The STR was softened with 70-degree warm water. Therefore, it was easy to mold it and attach the applicator. The PDDs and penumbras at the surface, dmax, d90, and d80 for the STR were almost equal to those for the LMA with 6 and 12 MeV electron beams. The treatment diameters covering over 90% dose for the irradiation fields with 40 mm diameter at dmax (LMA vs. STR) were 20.9 vs. 21.1 mm and 19.2 vs. 18.4 mm for 6 and 12 MeV electron beams, respectively. The transmission of the STR was almost same as that of LMA. CONCLUSIONS The dosimetric characteristics of the STR on the electron applicator were almost same as those of the LMA. The heated STR was shaped easily, flexibly, and immediately. The STR can be used as a substitute for LMA in electron radiotherapy.
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Affiliation(s)
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | | | - Kazuki Wakabayashi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University.,Department of Central Radiology, Wakayama Medical University Hospital
| | - Kenta Kijima
- Department of Medical Technology, University Hospital, Kyoto Prefectural University of Medicine
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
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Choi MG, Law M, Yoon DK, Tamura M, Matsumoto K, Otsuka M, Kim MS, Djeng SK, Monzen H, Suh TS. Simplified sigmoidal curve fitting for a 6 MV FFF photon beam of the Halcyon to determine the field size for beam commissioning and quality assurance. Radiat Oncol 2020; 15:273. [PMID: 33287828 PMCID: PMC7720380 DOI: 10.1186/s13014-020-01709-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 11/06/2020] [Indexed: 11/22/2022] Open
Abstract
Background An O-ring gantry-type linear accelerator (LINAC) with a 6-MV flattening filter-free (FFF) photon beam, Halcyon, includes a reference beam that contains representative information such as the percent depth dose, profile and output factor for commissioning and quality assurance. However, because it does not provide information about the field size, we proposed a method to determine all field sizes according to all depths for radiation therapy using simplified sigmoidal curve fitting (SCF). Methods After mathematical definition of the SCF using four coefficients, the defined curves were fitted to both the reference data (RD) and the measured data (MD). For good agreement between the fitting curve and the profiles in each data set, the field sizes were determined by identifying the maximum point along the third derivative of the fitting curve. The curve fitting included the field sizes for beam profiles of 2 × 2, 4 × 4, 6 × 6, 8 × 8, 10 × 10, 20 × 20 and 28 × 28 cm2 as a function of depth (at 1.3, 5, 10 and 20 cm). The field size results from the RD were compared with the results from the MD using the same condition. Results All fitting curves show goodness of fit, R2, values that are greater than 0.99. The differences in field size between the RD and the MD were within the range of 0 to 0.2 cm. The smallest difference in the field sizes at a depth of 10 cm, which is a surface-to-axis distance, was reported. Conclusion Application of the SCF method has been proven to accurately capture the field size of the preconfigured RD and the measured FFF photon beam data for the Halcyon system. The current work can be useful for beam commissioning as a countercheck methodology to determine the field size from RD in the treatment planning system of a newly installed Halcyon system and for routine quality assurance to ascertain the correctness of field sizes for clinical use of the Halcyon system.
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Affiliation(s)
- Min-Geon Choi
- Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea
| | - Martin Law
- Proton Therapy Pte Ltd., 1 Biopolis Drive, Singapore, 138622, Singapore
| | - Do-Kun Yoon
- Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama-Shi, 377-2, Ohno-Higashi, Osaka-Sayama-Shi, Osaka, 589-8511, Japan
| | - Kenji Matsumoto
- Department of Radiology, Kindai University Hospital, Osaka-Sayama-Shi, 377-2, Ono-Higashi, Osaka-Sayama-Shi, Osaka, 589-8511, Japan
| | - Masakazu Otsuka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama-Shi, 377-2, Ohno-Higashi, Osaka-Sayama-Shi, Osaka, 589-8511, Japan
| | - Moo-Sub Kim
- Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea
| | - Shih-Kien Djeng
- Proton Therapy Pte Ltd., 1 Biopolis Drive, Singapore, 138622, Singapore
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama-Shi, 377-2, Ohno-Higashi, Osaka-Sayama-Shi, Osaka, 589-8511, Japan.
| | - Tae Suk Suh
- Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea.
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Takei Y, Monzen H, Tamura M, Doi H, Nishimura Y. Dose reduction potential of using gold fiducial markers for kilovoltage image-guided radiotherapy. J Appl Clin Med Phys 2020; 21:151-157. [PMID: 32959957 PMCID: PMC7592977 DOI: 10.1002/acm2.13023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 12/19/2022] Open
Abstract
This study aimed to evaluate the possibility of reducing the imaging dose for image-guided radiotherapy by using planar kilovoltage orthogonal imaging and fiducial markers (kV-FM). We tested kilovoltage planar images under clinical imaging conditions for the pelvis (75 kVp, 200 mA, 50 ms) at a decreasing tube current (from 200 to 10 mA). Imaging doses were measured with a semiconductor detector. The visibility of the kV-FM, aspects of image quality (spatial resolution, low contrast resolution), and the resultant image registration reproducibility were evaluated using various shapes (folded, linear, tadpole-like) of fiducial markers containing 0.5% iron [Gold Anchor™ (GA); Naslund Medical AB, Huddinge, Sweden]. The GA phantom was created by placing these variously shaped GAs in an agar phantom. The imaging doses with 200 and 10 mA were approximately 0.74 and 0.04 mGy and they were correlated to the tube current (R2 = 0.999). Regardless of the marker's shape, the GA phantom ensured visibility even when the tube current was reduced to the minimum value (10 mA). The low contrast resolution was gradually decreased at less than 50 mA, but the spatial resolution did not change. Although the auto-registration function could not be used, manual-registration could be achieved with an accuracy of within 1 mm, even when the imaging dose was reduced to 1/20 of the clinical imaging condition for the pelvis. When using the GA as the fiducial marker, the imaging dose could be reduced to 1/20 of that used clinically while maintaining the accuracy of manual-registration using the kV-FM for image-guided radiotherapy of the pelvis.
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Affiliation(s)
- Yoshiki Takei
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
- Department of Radiology, Kindai University Nara Hospital, Ikoma, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Japan
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Monzen H, Tamura M, Ueda Y, Fukunaga JI, Kamima T, Muraki Y, Kubo K, Nakamatsu K. Dosimetric evaluation with knowledge-based planning created at different periods in volumetric-modulated arc therapy for prostate cancer: a multi-institution study. Radiol Phys Technol 2020; 13:327-335. [PMID: 32986184 DOI: 10.1007/s12194-020-00585-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 09/16/2020] [Accepted: 09/16/2020] [Indexed: 12/22/2022]
Abstract
Dosimetric evaluation and variation assessment were performed with two knowledge-based planning (KBP) models created at different periods for volumetric-modulated arc therapy (VMAT) for prostate cancer at five institutes. The first and second models (F- and S-models) for KBP were created before April 2017 and April 2019, respectively. The S-model was created using feedback plans from the F-model. Dose evaluation was compared between the two models using the same two computed tomography (CT) datasets and structures. The evaluation metrics were the dose received by 95.0% and 2.0% of the planning target volume (PTV); dose-volume parameters to the rectum and bladder as V90, V80, and V50; and monitor unit (MU). Dosimetric variation was compared by exporting estimated dose-volume histograms for each model to the Model Analytics website and assessing the organ at risk volume. There were no dosimetric differences between the two models for PTV. The V50 of the rectum in the S-model had improved compared to that of the F-model (case I: 49.3 ± 15.6 and 43.5 ± 15.2 [p = 0.08]; case II: 42.5 ± 16.9 and 36.0 ± 15.6 [p = 0.138]). The differences in other parameters were within ± 1.8% between the rectum and the bladder. The MU was slightly higher in the S-model than in the F-model, and dosimetric variation was reduced to the rectum and bladder among all the institutes. The polished S-model for KBP could be used for standardization of the plan quality and sharing of KBP models in VMAT for prostate cancer.
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Affiliation(s)
- Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan.
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka, 537-8567, Japan
| | - Jun-Ichi Fukunaga
- Divisin of Radiology, Department of Medical Technology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Tatsuya Kamima
- Department of Radiation Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Yuta Muraki
- Department of Radiology, Seirei Hamamatsu General Hospital, 2-12-12 Sumiyoshi, Naka-ku, Hamamatsu, Shizuoka, 430-8558, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Kiyoshi Nakamatsu
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
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Tamura M, Monzen H, Matsumoto K, Otsuka M, Nishimura Y, Okumura M. Design of commissioning process for Halcyon™ linac with a new rigid board: A clinical experience. Phys Med 2020; 77:121-126. [DOI: 10.1016/j.ejmp.2020.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 06/15/2020] [Accepted: 08/05/2020] [Indexed: 10/23/2022] Open
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Ueda Y, Monzen H, Fukunaga JI, Ohira S, Tamura M, Suzuki O, Inui S, Isono M, Miyazaki M, Sumida I, Ogawa K, Teshima T. Characterization of knowledge-based volumetric modulated arc therapy plans created by three different institutions' models for prostate cancer. Rep Pract Oncol Radiother 2020; 25:1023-1028. [PMID: 33390859 DOI: 10.1016/j.rpor.2020.08.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/26/2020] [Accepted: 08/14/2020] [Indexed: 11/17/2022] Open
Abstract
Background The aim of this study was to clarify factors predicting the performance of knowledge-based planning (KBP) models in volume modulated arc therapy for prostate cancer in terms of sparing the organ at risk (OAR). Materials and methods In three institutions, each KBP model was trained by more than 20 library plans (LP) per model. To validate the characterization of each KBP model, 45 validation plans (VP) were calculated by the KBP system. The ratios of overlap between the OAR volume and the planning target volume (PTV) to the whole organ volume (Voverlap/Vwhole) were analyzed for each LP and VP. Regression lines between dose-volume parameters (V90, V75, and V50) and Voverlap/Vwhole were evaluated. The mean OAR dose, V90, V75, and V50 of LP did not necessarily match those of VP. Results In both the rectum and bladder, the dose-volume parameters for VP were strongly correlated with Voverlap/Vwhole at institutes A, B, and C (R > 0.74, 0.85, and 0.56, respectively). Except in the rectum at institute B, the slopes of the regression lines for LP corresponded to those for VP. For dose-volume parameters for the rectum, the ratios of slopes of the regression lines in VP to those in LP ranged 0.51-1.26. In the bladder, most ratios were less than 1.0 (mean: 0.77). Conclusion For each OAR, each model made distinct dosimetric characterizations in terms of Voverlap/Vwhole. The relationship between dose-volume parameters and Voverlap/Vwhole of OARs in LP predicts the KBP models' performance sparing OARs.
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Affiliation(s)
- Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka 537-8567, Japan
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0071, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka 589-8511, Japan
| | - Jun-Ichi Fukunaga
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shingo Ohira
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka 537-8567, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka 589-8511, Japan
| | - Osamu Suzuki
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0071, Japan
| | - Shoki Inui
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka 537-8567, Japan
| | - Masaru Isono
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka 537-8567, Japan
| | - Masayoshi Miyazaki
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka 537-8567, Japan
| | - Iori Sumida
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0071, Japan
| | - Kazuhiko Ogawa
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0071, Japan
| | - Teruki Teshima
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka 537-8567, Japan
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Takei Y, Kamomae T, Monzen H, Nakaya T, Sugita K, Suzuki K, Oguchi H, Tamura M, Nishimura Y. Feasibility of using tungsten functional paper as a thin bolus for electron beam radiotherapy. Phys Eng Sci Med 2020; 43:1101-1111. [PMID: 32785883 DOI: 10.1007/s13246-020-00910-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 07/25/2020] [Indexed: 11/30/2022]
Abstract
Containing 80% tungsten by weight, tungsten functional paper (TFP) is a radiation-shielding material that is lightweight, flexible, disposable, and easy to cut. Through experimental measurements and Monte Carlo simulations, we investigated the feasibility of using TFP as a bolus in electron beam radiotherapy. Commercial boluses of thickness 5 and 10 mm and from one to nine layers of TFPs (0.3-2.7 mm) were positioned on the surface of water-equivalent phantoms. The percentage depth dose curves and transverse dose profiles were measured using a 9-MeV electron beam from a clinical linear accelerator. Normalized to the value at the depth of maximum dose without bolus, the relative doses at the phantom surface for no bolus, 5-mm bolus, 10-mm bolus, 1 TFP, 3 TFPs, 6 TFPs, and 9 TFPs were 78%, 88%, 92%, 84%, 92%, 102%, and 112%, respectively; the therapeutic depths corresponding to a 90% dose level were 29.1 mm, 22.7 mm, 17.7 mm, 26.6 mm, 23.2 mm, 19.3 mm, and 15.8 mm, respectively. The TFP contributed to increased skin dose and provided dose uniformity within the target volume. However, it also resulted in increased lateral constriction and penumbra width. The results of Monte Carlo simulation produced similar trends as the experimental measurements. Our findings suggest that using TFP as a novel thin and flexible skin bolus for electron beam radiotherapy is feasible.
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Affiliation(s)
- Yoshiki Takei
- Department of Radiology, Kindai University Nara Hospital, 1248-1 Otoda-cho, Ikoma, Nara, 630-0293, Japan.,Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Takeshi Kamomae
- Department of Radiology, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan.
| | - Takayoshi Nakaya
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8560, Japan
| | - Kazuma Sugita
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8560, Japan
| | - Kentaro Suzuki
- Department of Radiological and Medical Laboratory Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan
| | - Hiroshi Oguchi
- Department of Radiological and Medical Laboratory Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
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Tamura M, Monzen H, Matsumoto K, Kubo K, Ueda Y, Kamima T, Inada M, Doi H, Nakamatsu K, Nishimura Y. Influence of Cleaned-up Commercial Knowledge-Based Treatment Planning on Volumetric-Modulated Arc Therapy of Prostate Cancer. J Med Phys 2020; 45:71-77. [PMID: 32831489 PMCID: PMC7416859 DOI: 10.4103/jmp.jmp_109_19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/02/2020] [Accepted: 04/21/2020] [Indexed: 01/23/2023] Open
Abstract
Purpose: This study aimed to investigate the influence of cleaned-up knowledge-based treatment planning (KBP) models on the plan quality for volumetric-modulated arc therapy (VMAT) of prostate cancer. Materials and Methods: Thirty prostate cancer VMAT plans were enrolled and evaluated according to four KBP modeling methods as follows: (1) model not cleaned – trained by fifty other clinical plans (KBPORIG); (2) cases cleaned by removing plans that did not meet all clinical goals of the dosimetric parameters, derived from dose–volume histogram (DVH) (KBPC-DVH); (3) cases cleaned outside the range of ±1 standard deviation through the principal component analysis regression plots (KBPC-REG); and (4) cases cleaned using both methods (2) and (3) (KBPC-ALL). Rectal and bladder structures in the training models numbered 34 and 48 for KBPC-DVH, 37 and 33 for KBPC-REG, and 26 and 33 for KBPC-ALL, respectively. The dosimetric parameters for each model with one-time auto-optimization were compared. Results: All KBP models improved target dose coverage and conformity and provided comparable sparing of organs at risks (rectal and bladder walls). There were no significant differences in plan quality among the KBP models. Nevertheless, only the KBPC-ALL model generated no cases of >1% V78 Gy (prescribed dose) to the rectal wall, whereas the KBPORIG, KBPC-DVH, and KBPC-REG models included two, four, and three cases, respectively, which were difficult to overcome with KBP because the planning target volume (PTV) and rectum regions overlapped. Conclusions: The cleaned-up KBP model based on DVH and regression plots improved plan quality in the PTV–rectum overlap region.
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Affiliation(s)
- Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan
| | - Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Tatsuya Kamima
- Department of Radiation Oncology, The Cancer Institute Hospital, Japanese Foundation for Cancer Research, Koto, Tokyo, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Kiyoshi Nakamatsu
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan
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Tamura M, Matsumoto K, Otsuka M, Monzen H. Plan complexity quantification of dual-layer multi-leaf collimator for volumetric modulated arc therapy with Halcyon linac. Phys Eng Sci Med 2020; 43:947-957. [DOI: 10.1007/s13246-020-00891-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 06/23/2020] [Indexed: 12/31/2022]
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50
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Kijima K, Krisanachinda A, Pasawang P, Hanaoka K, Monzen H, Nishimura Y. Shielding efficiency of novel tungsten rubber against radionuclides of 99mTc, 131I, 18F and 68Ga. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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