Korean Society of Medical Physics

Original Article 2023-09-30 2023-09-30 0 3681 1096

Influence of Two-Dimensional and Three-Dimensional Acquisitions of Radiomic Features for Prediction Accuracy

Ryohei Fukui , Ryutarou Matsuura , Katsuhiro Kida , Sachiko Goto

Progress in Medical Physics 2023; 34(3): 23-32

https://doi.org/10.14316/pmp.2023.34.3.23

Abstract

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Purpose: In radiomics analysis, to evaluate features, and predict genetic characteristics and survival time, the pixel values of lesions depicted in computed tomography (CT) and magnetic resonance imaging (MRI) images are used. CT and MRI offer three-dimensional images, thus producing three-dimensional features (Features_3d) as output. However, in reports, the superiority between Features_3d and two-dimensional features (Features_2d) is distinct. In this study, we aimed to investigate whether a difference exists in the prediction accuracy of radiomics analysis of lung cancer using Features_2d and Features_3d.
Methods: A total of 38 cases of large cell carcinoma (LCC) and 40 cases of squamous cell carcinoma (SCC) were selected for this study. Two- and three-dimensional lesion segmentations were performed. A total of 774 features were obtained. Using least absolute shrinkage and selection operator regression, seven Features_2d and six Features_3d were obtained.
Results: Linear discriminant analysis revealed that the sensitivities of Features_2d and Features_3d to LCC were 86.8% and 89.5%, respectively. The coefficients of determination through multiple regression analysis and the areas under the receiver operating characteristic curve (AUC) were 0.68 and 0.70 and 0.93 and 0.94, respectively. The P-value of the estimated AUC was 0.87.
Conclusions: No difference was found in the prediction accuracy for LCC and SCC between Features_2d and Features_3d.
Technical Note 2023-03-31 2023-03-31 0 3312 1121

Clinical Impact of Patient’s Head Position in Supraclavicular Irradiation of the Whole Breast Radiotherapy

Surega Anbumani , Lohith G. Reddy , Priyadarshini V , Sasikala P , Ramesh S. Bilimagga

Progress in Medical Physics 2023; 34(1): 10-13

https://doi.org/10.14316/pmp.2023.34.1.10

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Patients with breast cancer can be positioned with their head turned to the contra lateral side or with their head straight during the radiation therapy treatment set-up. In our hospital, patients with locally advanced breast cancer who were receiving radiation therapy have experienced swallowing difficulty after 2 weeks of irradiation. In this pilot study, the impact of head position on reducing dysphagia occurrence was dosimetrically evaluated. Patients were divided into two groups viz., HT (head turned to the contra lateral side of the breast) and HS (head straight) with 10 members in each. Treatment planning was performed, and the dosimetric parameters such as Dmin, Dmax, Dmean, V₅, V₁₀, V₂₀, V₃₀, V₄₀, and V₅₀ of both groups were extracted from the dose volume histogram (DVH) of esophagus. The target coverage in the supraclavicular fossa (SCF) region was analyzed using D₉₅ and D₉₈; moreover, the dose heterogeneity was assessed with D₂ from the DVHs. The average values of the dose volume parameters were 27.6%, 58.6%, 35.4%, 19%, 13.8%, 14.1%, 11.8%, 8.4%, and 8.1% higher in the HT group compared with those in the HS group. Furthermore, for the SCF, the mean values of D₉₈, D₉₅, and D₂ were 42.4, 47.5, and 54 Gy, respectively, in the HS group and 38.9, 45.35, and 55.5 Gy, respectively, in the HT group. This pilot study attempts to give a solution for the poor quality of life of patients after breast radiotherapy due to dysphagia. The findings confirm that the head position could play a significant role in alleviating esophageal toxicity without compromising tumor control.
Original Article 2023-09-30 2023-09-30 0 3308 928

Initial Dosimetry of a Prototype Ultra-High Dose Rate Electron-Beam Irradiator for FLASH RT Preclinical Studies

Hyun Kim , Heuijin Lim , Sang Koo Kang , Sang Jin Lee , Tae Woo Kang , Seung Wook Kim , Wung-Hoa Park , Manwoo Lee , Kyoung Won Jang , Dong Hyeok Jeong

Progress in Medical Physics 2023; 34(3): 33-39

https://doi.org/10.14316/pmp.2023.34.3.33

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Purpose: FLASH radiotherapy (RT) using ultra-high dose rate (>40 Gy/s) radiation is being studied worldwide. However, experimental studies such as preclinical studies using small animals are difficult to perform due to the limited availability of irradiation devices and methods for generating a FLASH beam. In this paper, we report the initial dosimetry results of a prototype electron linear accelerator (LINAC)-based irradiation system to perform ultra-high dose rate (UHDR) preclinical experiments.
Methods: The present study used the prototype electron LINAC developed by the Research Center of Dongnam Institute of Radiological and Medical Sciences (DIRAMS) in Korea. We investigated the beam current dependence of the depth dose to determine the optimal beam current for preclinical experiments. The dose rate in the UHDR region was measured by film dosimetry.
Results: Depth dose measurements showed that the optimal beam current for preclinical experiments was approximately 33 mA, corresponding to a mean energy of 4.4 MeV. Additionally, the average dose rates of 80.4 Gy/s and 162.0 Gy/s at a source-to-phantom surface distance of 30 cm were obtained at pulse repetition frequencies of 100 Hz and 200 Hz, respectively. The dose per pulse and instantaneous dose rate were estimated to be approximately 0.80 Gy and 3.8×10⁵ Gy/s, respectively.
Conclusions: Film dosimetry verified the appropriate dose rates to perform FLASH RT preclinical studies using the developed electron-beam irradiator. However, further research on the development of innovative beam monitoring systems and stabilization of the accelerator beam is required.
Technical Note 2023-06-30 2023-06-30 0 3275 901

Comparison between Old and New Versions of Electron Monte Carlo (eMC) Dose Calculation

Seongmoon Jung^1,2,3,4 , Jaeman Son^1,2,3 , Hyeongmin Jin^1,2,3 , Seonghee Kang^1,2,3 , Jong Min Park^1,2,3,5 , Jung-in Kim^1,3,5 , Chang Heon Choi^1,3,5

Progress in Medical Physics 2023; 34(2): 15-22

https://doi.org/10.14316/pmp.2023.34.2.15

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This study compared the dose calculated using the electron Monte Carlo (eMC) dose calculation algorithm employing the old version (eMC V13.7) of the Varian Eclipse treatment-planning system (TPS) and its newer version (eMC V16.1). The eMC V16.1 was configured using the same beam data as the eMC V13.7. Beam data measured using the VitalBeam linear accelerator were implemented. A box-shaped water phantom (30×30×30 cm³) was generated in the TPS. Consequently, the TPS with eMC V13.7 and eMC V16.1 calculated the dose to the water phantom delivered by electron beams of various energies with a field size of 10×10 cm². The calculations were repeated while changing the dose-smoothing levels and normalization method. Subsequently, the percentage depth dose and lateral profile of the dose distributions acquired by eMC V13.7 and eMC V16.1 were analyzed. In addition, the dose-volume histogram (DVH) differences between the two versions for the heterogeneous phantom with bone and lung inserted were compared. The doses calculated using eMC V16.1 were similar to those calculated using eMC V13.7 for the homogenous phantoms. However, a DVH difference was observed in the heterogeneous phantom, particularly in the bone material. The dose distribution calculated using eMC V16.1 was comparable to that of eMC V13.7 in the case of homogenous phantoms. The version changes resulted in a different DVH for the heterogeneous phantoms. However, further investigations to assess the DVH differences in patients and experimental validations for eMC V16.1, particularly for heterogeneous geometry, are required.
Original Article 2023-03-31 2023-03-31 0 3132 936

Feasibility of a Linear Diode Array Detector for Commissioning of a Radiotherapy Planning System

Seung Mo Hong , Uiseob Lee , Sung-woo Kim , Youngmoon Goh , Min-Jae Park , Chiyoung Jeong , Jungwon Kwak , Byungchul Cho

Progress in Medical Physics 2023; 34(1): 1-9

https://doi.org/10.14316/pmp.2023.34.1.1

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Purpose: Although ionization chambers are widely used to measure beam commissioning data, point-by-point measurements of all the profiles with various field size and depths are timeconsuming tasks. As an alternative, we investigated the feasibility of a linear diode array for commissioning a treatment planning system.
Methods: The beam data of a Varian TrueBeam^® radiotherapy system at 6 and 10 MV with/without a flattening filter were measured for commissioning of an Eclipse Analytical Anisotropic Algorithm (AAA) ver.15.6. All of the necessary beam data were measured using an IBA CC13 ionization chamber and validated against Varian “Golden Beam” data. After validation, the measured CC13 profiles were used for commissioning the Eclipse AAA (AAA_CC13). In addition, an IBA LDA-99SC linear diode array detector was used to measure all of the beam profiles and for commissioning a separate model (AAA_LDA99). Finally, the AAA_CC13 and AAA_LDA99 dose calculations for each of the 10 clinical plans were compared.
Results: The agreement of the CC13 profiles with the Varian Golden Beam data was confirmed within 1% except in the penumbral region, where ≤2% of a discrepancy related to machinespecific jaw calibration was observed. Since the volume was larger for the CC13 chamber than for the LDA-99SC chamber, the penumbra widths were larger in the CC13 profiles, resulting in ≤5% differences. However, after beam modeling, the penumbral widths agreed within 0.1 mm. Finally the AAA_LDA99 and AAA_CC13 dose distributions agreed within 1% for all voxels inside the body for the 10 clinical plans.
Conclusions: In conclusion, the LDA-99SC diode array detector was found to be accurate and efficient for measuring photon beam profiles to commission treatment planning systems.
Review Article 2024-03-31 2024-03-31 0 3072 994

Impact of Planning Target Volume Margins in Stereotactic Radiosurgery for Brain Metastasis: A Review

Emmanuel Fiagbedzi^1,2 , Francis Hasford¹ , Samuel Nii Tagoe¹

Progress in Medical Physics 2024; 35(1): 1-9

https://doi.org/10.14316/pmp.2024.35.1.1

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Margin inclusion or exclusion remains the most critical and controversial aspect of stereotactic radiosurgery (SRS) for metastatic brain tumors. This review aimed to examine the available literature on the impact of margins in SRS of brain metastasis and to assess the response of some medical physicists on the use of these margins. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses method was used to review articles published in PubMed, Embase, and Science Direct databases from January 2012 to December 2022 using the following keywords: planning target volume, brain metastasis, margin, and stereotactic radiosurgery. A simple survey consisting of five questions was completed by ten medical physicists with experience in SRS treatment planning. The results were analyzed using IBM SPSS Statistics version 26.0. Of the 1,445 articles identified, only 38 articles were chosen. Of these, eight papers were deemed relevant to the focus of this review. These papers showed an increase in the risk of radionecrosis, whereas differences in local control were variable as the margin increased. In the survey, the response rate to whether or not to use margins in SRS, a critical question, was 50%. Margin addition increases the risk of radio necrosis. The local control rate varies among treatment modalities and cannot be generalized. From the survey, no consensus was reached regarding the use of these margins. This calls for further deliberations among professionals directly involved in SRS.
Original Article 2023-12-31 2023-12-31 1 2523 1042

Dosimetric Comparison of Three-Dimensional Conformal, Intensity-Modulated Radiotherapy, Volumetric Modulated Arc Therapy, and Dynamic Conformal Arc Therapy Techniques in Prophylactic Cranial Irradiation

Ismail Faruk Durmuş¹ , Dursun Esitmez² , Guner Ipek Arslan¹ , Ayse Okumus¹

Progress in Medical Physics 2023; 34(4): 41-47

https://doi.org/10.14316/pmp.2023.34.4.41

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Purpose: This study aimed to dosimetrically compare the technique of three-dimensional conformal radiotherapy (3D CRT), which is a traditional prophylactic cranial irradiation method, and the intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques used in the last few decades with the dynamic conformal arc therapy (DCAT) technique.
Methods: The 3D CRT, VMAT, IMRT, and DCAT plans were prepared with 25 Gy in 10 fractions in a Monaco planning system. The target volume and the critical organ doses were compared. A comparison of the body V₂, V₅, and V₁₀ doses, monitor unit (MU), and beam on-time values was also performed.
Results: In planned target volume of the brain (PTV_Brain), the highest D99 dose value (P<0.001) and the most homogeneous (P =0.049) dose distribution according to the heterogeneity index were obtained using the VMAT technique. In contrast, the lowest values were obtained using the 3D CRT technique in the body V₂, V₅, and V₁₀ doses. The MU values were the lowest when DCAT (P =0.001) was used. These values were 0.34% (P =0.256) lower with the 3D CRT technique, 66% (P =0.001) lower with IMRT, and 72% (P =0.001) lower with VMAT. The beam on-time values were the lowest with the 3D CRT planning (P<0.001), 3.8% (P =0.008) lower than DCAT, 65% (P =0.001) lower than VMAT planning, and 76% (P =0.001) lower than IMRT planning.
Conclusions: Without sacrificing the homogeneous dose distribution and the critical organ doses in IMRTs, three to four times less treatment time, less low-dose volume, less leakage radiation, and less radiation scattering could be achieved when the DCAT technique is used similar to conventional methods. In short, DCAT, which is applicable in small target volumes, can also be successfully planned in large target volumes, such as the whole-brain.
Original Article 2024-03-31 2024-03-31 0 2519 870

Evaluations of a Commercial CLEANBOLUS-WHITE for Clinical Application

Geum Bong Yu^1,2 , Jung-in Kim^1,2 , Jaeman Son^1,2

Progress in Medical Physics 2024; 35(1): 10-15

https://doi.org/10.14316/pmp.2024.35.1.10

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Purpose: This study aimed to comprehensively investigate the diverse characteristics of a novel commercial bolus, CLEANBOLUS-WHITE (CBW), to ascertain its suitability for clinical application.
Methods: The evaluation of CBW encompassed both physical and biological assessments. Physical parameters such as mass density and shore hardness were measured alongside analyses of element composition. Biological evaluations included assessments for skin irritation and cytotoxicity. Dosimetric properties were examined by calculating surface dose and beam quality using a treatment planning system (TPS). Additionally, doses were measured at maximum and reference depths, and the results were compared with those obtained using a solid water phantom. The effect of air gap on dose measurement was also investigated by comparing measured doses on the RANDO phantom, under the bolus, with doses calculated from the TPS.
Results: Biological evaluation confirmed that CBW is non-cytotoxic, nonirritant, and non-sensitizing. The bolus exhibited a mass density of 1.02 g/cm³ and 14 shore 00. Dosimetric evaluations revealed that using the 0.5 cm CBW resulted in less than a 1% difference compared to using the solid water phantom. Furthermore, beam quality calculations in the TPS indicated increased surface dose with the bolus. The air gap effect on dose measurement was deemed negligible, with a difference of approximately 1% between calculated and measured doses, aligning with measurement uncertainty.
Conclusions: CBW demonstrates outstanding properties for clinical utilization. The dosimetric evaluation underscores a strong agreement between calculated and measured doses, validating its reliability in both planning and clinical settings.
Review Article 2024-06-30 2024-06-30 1 2477 680

Motion Management and Image-Guided Technique in Photon Radiation Therapy: A Review of an Advanced Technology

Jin Jegal^1,2 , Hyojun Park^1,2 , Seonghee Kang^1,2,3,4 , Chang Heon Choi^1,2,3,4 , Jung-in Kim^1,2,3,4

Progress in Medical Physics 2024; 35(2): 21-35

https://doi.org/10.14316/pmp.2024.35.2.21

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Herein, we provide a concise review of the critical role of motion management in radiation therapy, with a focus on photon radiation therapy, real-time control of respiratory motion, and image-guided radiation therapy (IGRT) in lung stereotactic body radiation therapy (SBRT). The dynamic nature of human anatomy, particularly in regions prone to movement such as the thoracic and abdominal areas, poses significant challenges in accurately targeting tumors during radiation therapy. This review explores the implications of organ and tumor motion, emphasizing the necessity for precise treatment delivery. We assess the advancements in four-dimensional (4D) imaging techniques such as 4D computed tomography, which provide time-resolved images for enhanced treatment planning. The review highlights various motion management strategies, including motionencompassing methods, respiratory-gating, breath-hold techniques, and real-time tumor tracking, discussing their implementation and impact on treatment efficacy. The role of IGRT in lung SBRT is particularly emphasized, showcasing how real-time imaging and advanced targeting techniques enhance the precision of high-dose radiation delivery while minimizing exposure to surrounding healthy tissues. This comprehensive review aims to underscore the significance of integrating motion management in radiation therapy, highlighting its pivotal role in improving treatment accuracy, reducing toxicity, and ultimately enhancing patient outcomes in cancer care.
Original Article 2023-12-31 2023-12-31 0 2241 796

Dosimetric Analysis of Lung Stereotactic Body Radiotherapy Using Halcyon Linear Accelerator

Shinhaeng Cho¹ , Ick Joon Cho¹ , Yong Hyub Kim¹ , Jea-Uk Jeong² , Mee Sun Yoon² , Taek-Keun Nam² , Sung-Ja Ahn² , Ju-Young Song²

Progress in Medical Physics 2023; 34(4): 48-54

https://doi.org/10.14316/pmp.2023.34.4.48

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Purpose: In this study, the dosimetric characteristics of lung stereotactic body radiotherapy (SBRT) plans using the new Halcyon system were analyzed to assess its suitability.
Methods: We compared the key dosimetric parameters calculated for the Halcyon SBRT plans with those of a conventional C-arm linear accelerator (LINAC) equipped with a high-definition multileaf collimator (HD-MLC)—Trilogy Tx. A total of 10 patients with non-small-cell lung cancer were selected, and all SBRT plans were generated using the RapidArc technique.
Results: Trilogy Tx exhibited significant superiority over Halcyon in terms of target dose coverage (conformity index, homogeneity index, D_{0.1 cc}, and D_95%) and dose spillage (gradient). Trilogy Tx was more efficient than Halcyon in the lung SBRT beam delivery process in terms of the total number of monitor units, modulation factor, and beam-on time. However, it was feasible to achieve a dose distribution that met SBRT plan requirements using Halcyon, with no significant differences in satisfying organs at risk dose constraints between both plans.
Conclusions: Results confirm that Halcyon is a viable alternative for performing lung SBRT in the absence of a LINAC equipped with HD-MLC. However, extra consideration should be taken in determining whether to use Halcyon when the planning target volume setting is enormous, as in the case of significant tumor motions.

Vol.35 No.4
December 2024

pISSN 2508-4445
eISSN 2508-4453
Formerly ISSN 1226-5829

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Influence of Two-Dimensional and Three-Dimensional Acquisitions of Radiomic Features for Prediction Accuracy

Ryohei Fukui , Ryutarou Matsuura , Katsuhiro Kida , Sachiko Goto

Progress in Medical Physics 2023; 34(3): 23-32

https://doi.org/10.14316/pmp.2023.34.3.23
Clinical Impact of Patient’s Head Position in Supraclavicular Irradiation of the Whole Breast Radiotherapy

Surega Anbumani , Lohith G. Reddy , Priyadarshini V , Sasikala P , Ramesh S. Bilimagga

Progress in Medical Physics 2023; 34(1): 10-13

https://doi.org/10.14316/pmp.2023.34.1.10
Initial Dosimetry of a Prototype Ultra-High Dose Rate Electron-Beam Irradiator for FLASH RT Preclinical Studies

Hyun Kim , Heuijin Lim , Sang Koo Kang , Sang Jin Lee , Tae Woo Kang , Seung Wook Kim , Wung-Hoa Park , Manwoo Lee , Kyoung Won Jang , Dong Hyeok Jeong

Progress in Medical Physics 2023; 34(3): 33-39

https://doi.org/10.14316/pmp.2023.34.3.33
Comparison between Old and New Versions of Electron Monte Carlo (eMC) Dose Calculation

Seongmoon Jung^1,2,3,4 , Jaeman Son^1,2,3 , Hyeongmin Jin^1,2,3 , Seonghee Kang^1,2,3 , Jong Min Park^1,2,3,5 , Jung-in Kim^1,3,5 , Chang Heon Choi^1,3,5

Progress in Medical Physics 2023; 34(2): 15-22

https://doi.org/10.14316/pmp.2023.34.2.15

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Most Read

Influence of Two-Dimensional and Three-Dimensional Acquisitions of Radiomic Features for Prediction Accuracy

Clinical Impact of Patient’s Head Position in Supraclavicular Irradiation of the Whole Breast Radiotherapy

Initial Dosimetry of a Prototype Ultra-High Dose Rate Electron-Beam Irradiator for FLASH RT Preclinical Studies

Comparison between Old and New Versions of Electron Monte Carlo (eMC) Dose Calculation

Feasibility of a Linear Diode Array Detector for Commissioning of a Radiotherapy Planning System

Impact of Planning Target Volume Margins in Stereotactic Radiosurgery for Brain Metastasis: A Review

Dosimetric Comparison of Three-Dimensional Conformal, Intensity-Modulated Radiotherapy, Volumetric Modulated Arc Therapy, and Dynamic Conformal Arc Therapy Techniques in Prophylactic Cranial Irradiation

Evaluations of a Commercial CLEANBOLUS-WHITE for Clinical Application

Motion Management and Image-Guided Technique in Photon Radiation Therapy: A Review of an Advanced Technology

Dosimetric Analysis of Lung Stereotactic Body Radiotherapy Using Halcyon Linear Accelerator

Vol.35 No.4
December 2024

Most Read

Influence of Two-Dimensional and Three-Dimensional Acquisitions of Radiomic Features for Prediction Accuracy

Clinical Impact of Patient’s Head Position in Supraclavicular Irradiation of the Whole Breast Radiotherapy

Initial Dosimetry of a Prototype Ultra-High Dose Rate Electron-Beam Irradiator for FLASH RT Preclinical Studies

Comparison between Old and New Versions of Electron Monte Carlo (eMC) Dose Calculation

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Vol.35 No.4 December 2024

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Vol.35 No.4
December 2024

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