Sheng-Yow Ho - Academia.edu (original) (raw)

Papers by Sheng-Yow Ho

Research paper thumbnail of Metachronous intramedullary anaplastic astrocytoma and liposarcoma complicated by neurofibromatosis type 1: A family history analysis

Journal of Medical Sciences

Research paper thumbnail of Rhabdomyosarcoma of the Vagina in a Postmenopausal Woman: Report of a Case and Review of the Literature

Gynecologic Oncology, 1995

Most rhabdomyosarcomas (RMSs) of the female genital tract occur in infants and young children as ... more Most rhabdomyosarcomas (RMSs) of the female genital tract occur in infants and young children as sarcoma botryoides. Vaginal RMS occurring in a postmenopausal woman is extremely rare. To our knowledge, only three vaginal RMSs have been reported in patients who were over 50 years of age. Herein, the first case in Taiwan and the fourth case in the world is reported, and the pertinent literature is briefly reviewed. A 63-year-old woman complained of a few days of abnormal vaginal bleeding. Vaginal examination demonstrated two black polypoid tumors located at the left-lateral and posterior wall of the vagina. The patient had previously undergone a vaginal total hysterectomy for rectocele and urine incontinence, so surgical treatment including local wide excision and bilateral salpingo-oophorectomy were performed under the diagnosis of malignant vaginal tumor. The clinical, histopathological, and immunohistochemical studies revealed a group Ia pleomorphic RMS. Postoperative radiotherapy was performed. The patient remains alive and well 12 months after a combined therapy.

Research paper thumbnail of Cordycepin enhances radiosensitivity to induce apoptosis through cell cycle arrest, caspase pathway and ER stress in MA-10 mouse Leydig tumor cells

American Journal of Cancer Research, 2022

Research paper thumbnail of The Effect of Radiotherapy on the Outcome of Primary Gliosarcoma: A Clinical Study of Three Cases and a Literature Review

Research paper thumbnail of Additional file 2: of Bortezomib enhances radiosensitivity in oral cancer through inducing autophagy-mediated TRAF6 oncoprotein degradation

Figure S1. Bortezomib inhibits TRAF6-mediated Akt activation. Figure S2. Combined treatment syner... more Figure S1. Bortezomib inhibits TRAF6-mediated Akt activation. Figure S2. Combined treatment synergistically inhibits tumorigenesis of human oral cancer cells in vivo. (DOCX 2226Â kb)

Research paper thumbnail of Usefulness of Vaginal/Rectal Cylinders or Interstitial Needles for Dosimetric Verification and Uncertainty Analysis of Brachytherapy Treatment

Journal of Medical and Biological Engineering, 2021

Research paper thumbnail of Paraneoplastic leukemoid reaction associated with poor prognosis in oral squamous cell carcinoma: A case report and literature review

Journal of Medical Sciences, 2020

Paraneoplastic leukemoid reaction (PLR) is exceedingly uncommon syndrome in oral cancer and has i... more Paraneoplastic leukemoid reaction (PLR) is exceedingly uncommon syndrome in oral cancer and has implicated a worse outcome. This report describes a case of buccal mucosa cancer encountered PLR syndrome during the course of tumor progression. We conduct a literature review to highlight the relationship between PLR and the outcome in oral cancer. PLR is associated with rapid tumor growth and worse outcome in head-and-neck cancer.

Research paper thumbnail of Calibration of gafchromic EBT film using the Microtek ScanMaker 9800XL plus flatbed scanner with a modified one red-channel after three-channel method

Journal of Medical Physics, 2019

Purpose: Using the Microtek ScanMaker 9800XL Plus (9800XL+) flatbed scanner, a method is presente... more Purpose: Using the Microtek ScanMaker 9800XL Plus (9800XL+) flatbed scanner, a method is presented to accurately calibrate EBT film, which cannot be calibrated simply using a general three-channel method because of the nonhomogeneous scanning. Materials and Methods: Through the percentage-depth-dose method, 6-MV photon beams with two different monitor units were delivered to eight EBT2 films, each of which was tightly sandwiched in a 30-cm cubic polystyrene phantom and positioned parallel to the central axis of the beam. Before and after irradiation, all films were scanned using the Microtek 9800XL+ scanner and the pixel values (PVs) were measured along the central axis of the beam on the film and fitted to the corresponding depth doses. Before calibration, the irradiated film image was first modified using a template matrix, which was generated using the prescanned background images. Then, a modified one red-channel after three-channel method was used to calibrate the film. Results: Without a template matrix, the three-channel method cannot be used because the PVs do not correspond to a rational fitting form. Using the proposed method, the difference between the fitted dose and the delivered dose is <2%. The green channel, and not the red, is found to have the largest dynamic range. Conclusion: The proposed technique allows the use of the three-channel method to calibrate film using a Microtek 9800XL+ scanner.

Research paper thumbnail of Evaluation of Multiple-Sampling Function used with a Microtek flatbed scanner for Radiation Dosimetry Calibration of EBT2 Film

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2016

The radiochromic EBT2 film is a widely used quality assurance device for radiation therapy. This ... more The radiochromic EBT2 film is a widely used quality assurance device for radiation therapy. This study evaluated the film calibration performance of the multiple-sampling function, a function of the Scan-Wizard Pro scanning software provided by the manufacturer, when used with Microtek 9800XL plus (9800XL þ) flatbed scanner. By using the PDD method, each one of the eight EBT2 films, four delivered by 290 monitor unit (MU) and four by 88 MU via 6-MV photon beams, was tightly sandwiched in a 30 3-cm 3 water equivalent polystyrene phantom prior to irradiation. Before and after irradiation, all films were scanned using the Microtek 9800XL þ scanner with five different modes of the multiple-sampling function, which could generate the image with the averaged result of multiple-sampling. The net optical densities (netOD) on the beam central axis of film were assigned to corresponding depth doses for calibration. For each sampling mode with either delivered MU, the depth-dose uncertainty of a single film from repeated scans and that of a single scan of the four films were analyzed. Finally, the calibration error and the combined calibration uncertainty between film determined depth-doses and delivered depthdoses were calculated and evaluated for each sampling mode. All standard deviations and the calibration error were demonstrated to be unrelated to the number of sampling lines. The calibration error of the 2-line and 16-line mode was within 3 cGy and better than that of the other modes. The combined uncertainty of the 2-line mode was the lowest, which was generally less than 6 cGy except for the delivered dose around 100 cGy. The evaluation described herein revealed that the EBT2 film calibrated with the 2-line mode has relatively lower error, scanning time and combined uncertianty. Therefore, it is recommended for routine EBT2 film calibration and verification of treatment plans.

Research paper thumbnail of Perihippocampal failure after hippocampal-avoidance whole-brain radiotherapy in cancer patients with brain metastases

Medicine

Abstract Perihippocampal failure is a rare clinical scenario in brain metastatic cancer patients ... more Abstract Perihippocampal failure is a rare clinical scenario in brain metastatic cancer patients following hippocampal-avoidance (HA) whole-brain radiotherapy (HA-WBRT). The clinical features have not been fully identified because clinical data on intracranial failure after HA-WBRT are limited. It is thus necessary to accumulate clinical data. We retrospectively analyzed cancer patients with brain metastases who were diagnosed between January 2014 and September 2020 at a regional referral hospital. The medical records of patients who underwent HA-WBRT were reviewed. The clinical features of intracranial recurrence were described. Dosimetry parameters were compared in terms of deviation from the recommended protocol of the Radiation Therapy Oncology Report 0933. Twenty-four eligible patients with brain metastases who underwent HA-WBRT were identified; 13 (54%) were male. Seventeen patients (71%) had lung cancer, 6 (25%) had breast cancer, and 1 (4%) had liver cancer. The median overall survival was 12 months. Three patients developed intracranial failure during clinical follow-up, and 2 relapsed with intracranial failure in the perihippocampal region at 13 and 22 months, respectively. The perihippocampal failure rate was about 8%. One patient with small cell lung cancer received HA-prophylactic cranial irradiation; the minimum and maximum doses to the hippocampi were 6.8 and 10.7 Gy, respectively. Another patient with brain metastases from lung adenocarcinoma received HA-WBRT; the minimum and maximum doses to the hippocampi were 5.4 and 10.6 Gy, respectively. We reported unusual cases of intracranial failure in the perihippocampal region following HA-WBRT. Perihippocampal failure could be attributed to an under-dose of radiation partially or be resulted from aggressiveness of cancer per se. Further research on this topic is encouraged.

Research paper thumbnail of Impact of adjuvant hysterectomy for bulky cervical cancer after definitive chemoradiotherapy with insufficient brachytherapy dose: a retrospective analysis

Therapeutic Radiology and Oncology

Background: Concurrent chemoradiotherapy (CCRT) plus intracavitary brachytherapy (ICBT) is standa... more Background: Concurrent chemoradiotherapy (CCRT) plus intracavitary brachytherapy (ICBT) is standard of care for locally advanced cervical cancer (LACC). However, Because of differences in tissue response and anatomy, brachytherapy sometimes fails to deliver adequate doses and may result in higher recurrence rates. Thus, there have been studies discussing the role of adjuvant hysterectomy (AH). National Comprehensive Cancer Network cervical guidelines (NCCN ver. 2022.1) listed AH as an option after CCRT when patient has bulky tumor, disease extended or poor response to CCRT. The purpose of this study was to analyze the impact of AH on bulky cervical cancer patients after CCRT with insufficient brachytherapy dose. Methods: Forty-two patients had bulky (>4 cm) cervical cancer were treated with CCRT +/− ICBT with insufficient brachytherapy dose, after CCRT, 16 patients received observation and 26 patients received AH. The median follow-up of the study was 39 months. Survival analysis used the Kaplan-Meier method, logrank test, and Cox proportional hazards model. Post-operative complication assessment is based on the need for long-term urological follow-up. Results: Forty-two patients who had bulky tumor (>4 cm), CCRT with insufficient brachytherapy dose followed by AH a tended to prolong the disease specific survival (DSS) (OR: 0.25, 95% CI: 0.09-0.71, P=0.001) compared with CCRT alone. In multivariate analysis, AH (OR: 0.27, 95% CI: 0.08-0.90, P=0.032) was reported as independent risk factors of DSS. Urinary complications occurred in 5 of 26 patients received hysterectomy and in 2 of 18 patients who received modified radical hysterectomy (Piver class II). Conclusions: In conclusion, patients with bulky cervical cancer failed to deliver adequate brachytherapy doses may achieve better outcomes combined with AH. Modified radical hysterectomy (Piver class II) was safe with complication rate of 11%. However, the advantage of AH on survival needs to be evaluated through further randomized control trials.

Research paper thumbnail of Retrospective analysis of dosimetry on hippocampal-avoidance whole-brain radiotherapy in a regional hospital

Therapeutic Radiology and Oncology

Background: Hippocampal-avoidance whole-brain radiotherapy presents a significant technical chall... more Background: Hippocampal-avoidance whole-brain radiotherapy presents a significant technical challenge in terms of treatment planning in order to spare the hippocampus. To ensure dose homogeneity and precision, the Radiation Therapy Oncology Group (RTOG) 0933 recommends strict dose criteria. To balance the clinical workload with these time-consuming treatments is a challenge. Noncompliance adversely might affect clinical outcomes in cancer patients with brain metastasis. We intend to retrospectively evaluate the quality and dosimetry differences in delivering hippocampal-avoidance whole-brain radiotherapy in a regional hospital. Methods: We retrospectively analyzed cancer patients with brain metastases who were diagnosed between January 2014 and December 2020. Dosimetry parameters were compared in terms of deviation from the RTOG 0933 protocol. Results: We identified 21 eligible cancer patients with brain metastasis who underwent hippocampalavoidance whole-brain radiotherapy. The patients' ages ranged from 36 to 81 years (median, 58 years). Sixteen patients (76%) received linear accelerator-based treatment, while five received TomoTherapy. The maximal dose to bilateral hippocampi ranged from 9.2 to 25.8 Gy, with a median of 14.4 Gy. In our crossmodality analysis of the planning target volume (PTV) coverage, linear accelerator planning was comparable to TomoTherapy (P=0.29), and both treatments met the RTOG 0933 criteria in (D 2% ≤37.5 Gy) hotspot evaluation. TomoTherapy was statistically superior to linear accelerator in the minimum PTV dose criteria (D 98% >25 Gy) (P=0.03). Regarding the constraint dose of hippocampi, TomoTherapy tend to outperform linear accelerator treatment (P=0.1). The TomoTherapy technique had the longest delivery time (median: 437 sec), compared to 364 sec for the linear accelerator, with statistical significance (P=0.03). Conclusions: In this study, we presented a dosimetry analysis of hippocampal-avoidance whole-brain radiotherapy in clinical settings. The dilemma does exist in balancing clinical workload with the timeconsuming planning, so daily treatment may come at the expense of noncompliance and non-conformity on planning targets. In determining the final plan, the choice of the physician should depend on patient's clinical situation and institutional facility.

Research paper thumbnail of Mechanisms of Nanotoxicology and the Important Role of Alternative Testing Strategies

International Journal of Molecular Sciences

Recently, rapid advances in nanotechnology have provided a lot of opportunities for the mass prod... more Recently, rapid advances in nanotechnology have provided a lot of opportunities for the mass production of engineered nanomaterials of various types of chemicals, including metals and nonmetals, promoting the development of a new generation of industrial and commercial products and the field of nanomedicine [...]

Research paper thumbnail of An adaptive method for recalibrating Gafchromic EBT3 film

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2021

Abstract Ashland Inc. EBT3 film has high 2D dosimetry resolution and is self-developing so it is ... more Abstract Ashland Inc. EBT3 film has high 2D dosimetry resolution and is self-developing so it is widely used as a dosimetry quality assurance tool. However, the film must be calibrated every half year or three months because the unexposed film slowly develops due to the aging effect. A new calibration method is proposed that uses an adaptive power function and no dose need be delivered to allow recalibration. EBT3 film is calibrated separately on different dates over several months. All calibrations use the one red-channel after three-channel method (Chang et al., 2015). The dose-dependent optical density (OD) for the red channel is fitted to the delivered dose using a power function with a constant fitting parameter. Instead of a general recalibration, the film-dose is calculated using all of the fitting parameters for the first calibration and by changing the constant parameter using a fresh measured background OD. The film-dose that is calculated using the proposed adaptive method is compared with the administered dose and the percentage difference is compared with that for a new set of recalibrated fitting parameters and that for all of the first fitting parameters. The results demonstrate that the difference between the film-dose and the dose that is delivered using the adaptive calibration method is less than 3%. However, if the first calibration fitting parameters are used, the percentage difference is more than 50% for a delivered dose of around 50 cGy at a calibration date of eight months after the first calibration. The film-dose is calculated using the first calibrated equation, but using a new measured background OD, so the constant fitting parameter is changed, rather than recalibrating the film. To precisely calculate the film-dose, the equation must be adapted for each individual film. The proposed method is convenient, rapid and cost effective because recalibration does not require the exposure of film. This new technique is a practical method for clinical use.

Research paper thumbnail of Additional file 1: of Combination of the novel histone deacetylase inhibitor YCW1 and radiation induces autophagic cell death through the downregulation of BNIP3 in triple-negative breast cancer cells in vitro and in an orthotopic mouse model

Supplementary results. (DOC 3159 kb)

Research paper thumbnail of Additional file 1: of Subsequent thyroid disorders associated with treatment strategy in head and neck cancer patients: a nationwide cohort study

Figure S1. The cumulative incidence of subsequent thyroid disorders in PTE and PTE+ ND groups wer... more Figure S1. The cumulative incidence of subsequent thyroid disorders in PTE and PTE+ ND groups were present as solid and dotted curve, respectively. In our study design, the subjects with thyroid disorder occurred within one year after allocation were excluded, which is to prevent ill-defined cause-effect relationship, leading to no outcome obtained in the first year. (DOCX 219 kb)

Research paper thumbnail of Relationship between Semi-Quantitative Parameters of Thallium-201 Myocardial Perfusion Imaging and Coronary Artery Disease

Diagnostics, 2020

This study aimed to investigate the diagnostic performance of semi-quantitative parameters of tha... more This study aimed to investigate the diagnostic performance of semi-quantitative parameters of thallium-201 myocardial perfusion imaging (MPI) for coronary artery disease (CAD). From January to December 2017, patients were enrolled who had undergone Tl-201 MPI and received cardiac catheterization for coronary artery disease within three months of MPI. Receiver operating characteristics (ROC) analysis was used to determine the optimal cutoff values of semi-quantitative parameters. A comparison of the sensitivity and specificity of these parameters based on different subgroupings was further performed. A total of 130 patients were enrolled for further analysis. Among the collected parameters, the stress total perfusion deficit (sTPD) had the highest value of the area under curve (0.813) under the optimal cutoff value of 3.5%, with a sensitivity and specificity of 73.5% and 74.5%, respectively (p = 0.0000), for the diagnosis of CAD. With further subgrouping analysis based on history of ...

Research paper thumbnail of The Crucial Role of the Establishment of Computed Tomography Density Conversion Tables for Treating Brain or Head/Neck Tumors

Progress in Medical Physics, 2021

The relationship between computed tomography (CT) number and electron density (ED) has been inves... more The relationship between computed tomography (CT) number and electron density (ED) has been investigated in previous studies. However, the role of these measures for guiding cancer treatment remains unclear. Methods: The CT number was plotted against ED for different imaging protocols. The CT number was imported into ED tables for the Pinnacle treatment planning system (TPS) and was used to determine the effect on dose calculations. Conversion tables for radiation dose calculations were generated and subsequently monitored using a dosimeter to determine the effect of different CT scanning protocols and treatment sites. These tables were used to retrospectively recalculate the radiation therapy plans for 41 patients after an incorrect scanning protocol was inadvertently used. The gamma index was further used to assess the dose distribution, percentage dose difference (DD), and distance-to-agreement (DTA). Results: For densities <1.1 g/cm 3 , the standard deviation of the CT number was ±0.6% and the greatest variation was noted for brain protocol conditions. For densities >1.1 g/cm 3 , the standard deviation of the CT number was ±21.2% and the greatest variation occurred for the tube voltage and head and neck (H&N) protocol conditions. These findings suggest that the factors most affecting the CT number are the tube voltage and treatment site (brain and H&N). Gamma index analyses for the 41 retrospective clinical cases, as well as brain metastases and H&N tumors, showed gamma passing rates >90% and <90% for the passing criterion of 2%/2 and 1%/1 mm, respectively. Conclusions: The CT protocol should be carefully decided for TPS. The correct protocol should be used for the corresponding TPS based on the treatment site because this especially affects the dose distribution for brain metastases and H&N tumor recognition. Such steps could help reduce systematic errors.

Research paper thumbnail of Subsequent thyroid disorders associated with treatment strategy in head and neck cancer patients: a nationwide cohort study

BMC Cancer, 2019

Background: We investigated the risk of thyroid disorders, namely hypothyroidism, thyrotoxicosis ... more Background: We investigated the risk of thyroid disorders, namely hypothyroidism, thyrotoxicosis and thyroiditis, in head and neck cancer patients undergoing multimodal treatment. Methods: A cohort study design using Taiwan's National Health Insurance Research Database was used to assess head and neck cancer patients over 20 years old. The cohort was divided into one group who underwent primary tumor excision only (PTE) and another with additional neck dissection (PTE + ND). The tumor sites were stratified to estimate the tumor-site-specific risk of thyroid disorders. The effect of subsequent resurgery, radiotherapy (RT), chemotherapy (CT), and concomitant (CCRT) or sequential chemoradiation therapy (sequential CT+ RT) on the risk of thyroid disorders was explored. Results: For 1999-2012, 7460 patients who underwent PTE + ND and 3730 who underwent PTE were enrolled and followed-up until the end of 2013. There were 122 and 50 patients in the two groups, respectively, who developed thyroid disorders, with no statistical difference between the groups. Patients with hypopharyngeal, oropharyngeal, or laryngeal cancer in the PTE + ND group had a higher risk of thyroid disorders (adjusted HR: 1.50, 95% CI: 0.67-3.38) than those in the PTE group when adjusted for covariates and mortality. Patients who underwent subsequent RT (adjusted HR: 3.64, 95% CI: 1.05-2.77) and CCRT (adjusted HR: 1.70, 95% CI: 1.05-2.77) after PTE + ND had a significantly higher risk of thyroid disorders. Conclusion: RT results in a major risk of subsequent thyroid disorders, and ND may exacerbate this effect. Physicians should monitor thyroid function from two years after treatment initiation, especially in patients who undergo ND and subsequent RT.

Research paper thumbnail of Geometric error of cervical point A calculated through traditional reconstruction procedures for brachytherapy treatment

Journal of applied clinical medical physics / American College of Medical Physics, Sep 8, 2015

Brachytherapy used in local cervical cancer is still widely based on 2D standard dose planning wi... more Brachytherapy used in local cervical cancer is still widely based on 2D standard dose planning with the prescription to point A, which is invisible on imaging and located at a high-dose gradient. In this study, the geometric location error of point A was investigated. It is traditionally reconstructed in the treatment planning system after carefully digitizing the point marks that were previously drawn on the orthogonal radiographs into the system. Two Cartesian coordinates of point A were established and compared. One was built up based on the geometric definition of point A and would be taken as the true coordinate, while the other was built up through traditional clinical treatment procedures and named as the practical coordinate. The orthogonal-film reconstruction technique was used and the location error between the practical and the true coordinate introduced from the variations of, first, the angle between the tandem and the simulator gantry-rotation-axis, and second, the int...

Research paper thumbnail of Metachronous intramedullary anaplastic astrocytoma and liposarcoma complicated by neurofibromatosis type 1: A family history analysis

Journal of Medical Sciences

Research paper thumbnail of Rhabdomyosarcoma of the Vagina in a Postmenopausal Woman: Report of a Case and Review of the Literature

Gynecologic Oncology, 1995

Most rhabdomyosarcomas (RMSs) of the female genital tract occur in infants and young children as ... more Most rhabdomyosarcomas (RMSs) of the female genital tract occur in infants and young children as sarcoma botryoides. Vaginal RMS occurring in a postmenopausal woman is extremely rare. To our knowledge, only three vaginal RMSs have been reported in patients who were over 50 years of age. Herein, the first case in Taiwan and the fourth case in the world is reported, and the pertinent literature is briefly reviewed. A 63-year-old woman complained of a few days of abnormal vaginal bleeding. Vaginal examination demonstrated two black polypoid tumors located at the left-lateral and posterior wall of the vagina. The patient had previously undergone a vaginal total hysterectomy for rectocele and urine incontinence, so surgical treatment including local wide excision and bilateral salpingo-oophorectomy were performed under the diagnosis of malignant vaginal tumor. The clinical, histopathological, and immunohistochemical studies revealed a group Ia pleomorphic RMS. Postoperative radiotherapy was performed. The patient remains alive and well 12 months after a combined therapy.

Research paper thumbnail of Cordycepin enhances radiosensitivity to induce apoptosis through cell cycle arrest, caspase pathway and ER stress in MA-10 mouse Leydig tumor cells

American Journal of Cancer Research, 2022

Research paper thumbnail of The Effect of Radiotherapy on the Outcome of Primary Gliosarcoma: A Clinical Study of Three Cases and a Literature Review

Research paper thumbnail of Additional file 2: of Bortezomib enhances radiosensitivity in oral cancer through inducing autophagy-mediated TRAF6 oncoprotein degradation

Figure S1. Bortezomib inhibits TRAF6-mediated Akt activation. Figure S2. Combined treatment syner... more Figure S1. Bortezomib inhibits TRAF6-mediated Akt activation. Figure S2. Combined treatment synergistically inhibits tumorigenesis of human oral cancer cells in vivo. (DOCX 2226Â kb)

Research paper thumbnail of Usefulness of Vaginal/Rectal Cylinders or Interstitial Needles for Dosimetric Verification and Uncertainty Analysis of Brachytherapy Treatment

Journal of Medical and Biological Engineering, 2021

Research paper thumbnail of Paraneoplastic leukemoid reaction associated with poor prognosis in oral squamous cell carcinoma: A case report and literature review

Journal of Medical Sciences, 2020

Paraneoplastic leukemoid reaction (PLR) is exceedingly uncommon syndrome in oral cancer and has i... more Paraneoplastic leukemoid reaction (PLR) is exceedingly uncommon syndrome in oral cancer and has implicated a worse outcome. This report describes a case of buccal mucosa cancer encountered PLR syndrome during the course of tumor progression. We conduct a literature review to highlight the relationship between PLR and the outcome in oral cancer. PLR is associated with rapid tumor growth and worse outcome in head-and-neck cancer.

Research paper thumbnail of Calibration of gafchromic EBT film using the Microtek ScanMaker 9800XL plus flatbed scanner with a modified one red-channel after three-channel method

Journal of Medical Physics, 2019

Purpose: Using the Microtek ScanMaker 9800XL Plus (9800XL+) flatbed scanner, a method is presente... more Purpose: Using the Microtek ScanMaker 9800XL Plus (9800XL+) flatbed scanner, a method is presented to accurately calibrate EBT film, which cannot be calibrated simply using a general three-channel method because of the nonhomogeneous scanning. Materials and Methods: Through the percentage-depth-dose method, 6-MV photon beams with two different monitor units were delivered to eight EBT2 films, each of which was tightly sandwiched in a 30-cm cubic polystyrene phantom and positioned parallel to the central axis of the beam. Before and after irradiation, all films were scanned using the Microtek 9800XL+ scanner and the pixel values (PVs) were measured along the central axis of the beam on the film and fitted to the corresponding depth doses. Before calibration, the irradiated film image was first modified using a template matrix, which was generated using the prescanned background images. Then, a modified one red-channel after three-channel method was used to calibrate the film. Results: Without a template matrix, the three-channel method cannot be used because the PVs do not correspond to a rational fitting form. Using the proposed method, the difference between the fitted dose and the delivered dose is <2%. The green channel, and not the red, is found to have the largest dynamic range. Conclusion: The proposed technique allows the use of the three-channel method to calibrate film using a Microtek 9800XL+ scanner.

Research paper thumbnail of Evaluation of Multiple-Sampling Function used with a Microtek flatbed scanner for Radiation Dosimetry Calibration of EBT2 Film

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2016

The radiochromic EBT2 film is a widely used quality assurance device for radiation therapy. This ... more The radiochromic EBT2 film is a widely used quality assurance device for radiation therapy. This study evaluated the film calibration performance of the multiple-sampling function, a function of the Scan-Wizard Pro scanning software provided by the manufacturer, when used with Microtek 9800XL plus (9800XL þ) flatbed scanner. By using the PDD method, each one of the eight EBT2 films, four delivered by 290 monitor unit (MU) and four by 88 MU via 6-MV photon beams, was tightly sandwiched in a 30 3-cm 3 water equivalent polystyrene phantom prior to irradiation. Before and after irradiation, all films were scanned using the Microtek 9800XL þ scanner with five different modes of the multiple-sampling function, which could generate the image with the averaged result of multiple-sampling. The net optical densities (netOD) on the beam central axis of film were assigned to corresponding depth doses for calibration. For each sampling mode with either delivered MU, the depth-dose uncertainty of a single film from repeated scans and that of a single scan of the four films were analyzed. Finally, the calibration error and the combined calibration uncertainty between film determined depth-doses and delivered depthdoses were calculated and evaluated for each sampling mode. All standard deviations and the calibration error were demonstrated to be unrelated to the number of sampling lines. The calibration error of the 2-line and 16-line mode was within 3 cGy and better than that of the other modes. The combined uncertainty of the 2-line mode was the lowest, which was generally less than 6 cGy except for the delivered dose around 100 cGy. The evaluation described herein revealed that the EBT2 film calibrated with the 2-line mode has relatively lower error, scanning time and combined uncertianty. Therefore, it is recommended for routine EBT2 film calibration and verification of treatment plans.

Research paper thumbnail of Perihippocampal failure after hippocampal-avoidance whole-brain radiotherapy in cancer patients with brain metastases

Medicine

Abstract Perihippocampal failure is a rare clinical scenario in brain metastatic cancer patients ... more Abstract Perihippocampal failure is a rare clinical scenario in brain metastatic cancer patients following hippocampal-avoidance (HA) whole-brain radiotherapy (HA-WBRT). The clinical features have not been fully identified because clinical data on intracranial failure after HA-WBRT are limited. It is thus necessary to accumulate clinical data. We retrospectively analyzed cancer patients with brain metastases who were diagnosed between January 2014 and September 2020 at a regional referral hospital. The medical records of patients who underwent HA-WBRT were reviewed. The clinical features of intracranial recurrence were described. Dosimetry parameters were compared in terms of deviation from the recommended protocol of the Radiation Therapy Oncology Report 0933. Twenty-four eligible patients with brain metastases who underwent HA-WBRT were identified; 13 (54%) were male. Seventeen patients (71%) had lung cancer, 6 (25%) had breast cancer, and 1 (4%) had liver cancer. The median overall survival was 12 months. Three patients developed intracranial failure during clinical follow-up, and 2 relapsed with intracranial failure in the perihippocampal region at 13 and 22 months, respectively. The perihippocampal failure rate was about 8%. One patient with small cell lung cancer received HA-prophylactic cranial irradiation; the minimum and maximum doses to the hippocampi were 6.8 and 10.7 Gy, respectively. Another patient with brain metastases from lung adenocarcinoma received HA-WBRT; the minimum and maximum doses to the hippocampi were 5.4 and 10.6 Gy, respectively. We reported unusual cases of intracranial failure in the perihippocampal region following HA-WBRT. Perihippocampal failure could be attributed to an under-dose of radiation partially or be resulted from aggressiveness of cancer per se. Further research on this topic is encouraged.

Research paper thumbnail of Impact of adjuvant hysterectomy for bulky cervical cancer after definitive chemoradiotherapy with insufficient brachytherapy dose: a retrospective analysis

Therapeutic Radiology and Oncology

Background: Concurrent chemoradiotherapy (CCRT) plus intracavitary brachytherapy (ICBT) is standa... more Background: Concurrent chemoradiotherapy (CCRT) plus intracavitary brachytherapy (ICBT) is standard of care for locally advanced cervical cancer (LACC). However, Because of differences in tissue response and anatomy, brachytherapy sometimes fails to deliver adequate doses and may result in higher recurrence rates. Thus, there have been studies discussing the role of adjuvant hysterectomy (AH). National Comprehensive Cancer Network cervical guidelines (NCCN ver. 2022.1) listed AH as an option after CCRT when patient has bulky tumor, disease extended or poor response to CCRT. The purpose of this study was to analyze the impact of AH on bulky cervical cancer patients after CCRT with insufficient brachytherapy dose. Methods: Forty-two patients had bulky (>4 cm) cervical cancer were treated with CCRT +/− ICBT with insufficient brachytherapy dose, after CCRT, 16 patients received observation and 26 patients received AH. The median follow-up of the study was 39 months. Survival analysis used the Kaplan-Meier method, logrank test, and Cox proportional hazards model. Post-operative complication assessment is based on the need for long-term urological follow-up. Results: Forty-two patients who had bulky tumor (>4 cm), CCRT with insufficient brachytherapy dose followed by AH a tended to prolong the disease specific survival (DSS) (OR: 0.25, 95% CI: 0.09-0.71, P=0.001) compared with CCRT alone. In multivariate analysis, AH (OR: 0.27, 95% CI: 0.08-0.90, P=0.032) was reported as independent risk factors of DSS. Urinary complications occurred in 5 of 26 patients received hysterectomy and in 2 of 18 patients who received modified radical hysterectomy (Piver class II). Conclusions: In conclusion, patients with bulky cervical cancer failed to deliver adequate brachytherapy doses may achieve better outcomes combined with AH. Modified radical hysterectomy (Piver class II) was safe with complication rate of 11%. However, the advantage of AH on survival needs to be evaluated through further randomized control trials.

Research paper thumbnail of Retrospective analysis of dosimetry on hippocampal-avoidance whole-brain radiotherapy in a regional hospital

Therapeutic Radiology and Oncology

Background: Hippocampal-avoidance whole-brain radiotherapy presents a significant technical chall... more Background: Hippocampal-avoidance whole-brain radiotherapy presents a significant technical challenge in terms of treatment planning in order to spare the hippocampus. To ensure dose homogeneity and precision, the Radiation Therapy Oncology Group (RTOG) 0933 recommends strict dose criteria. To balance the clinical workload with these time-consuming treatments is a challenge. Noncompliance adversely might affect clinical outcomes in cancer patients with brain metastasis. We intend to retrospectively evaluate the quality and dosimetry differences in delivering hippocampal-avoidance whole-brain radiotherapy in a regional hospital. Methods: We retrospectively analyzed cancer patients with brain metastases who were diagnosed between January 2014 and December 2020. Dosimetry parameters were compared in terms of deviation from the RTOG 0933 protocol. Results: We identified 21 eligible cancer patients with brain metastasis who underwent hippocampalavoidance whole-brain radiotherapy. The patients' ages ranged from 36 to 81 years (median, 58 years). Sixteen patients (76%) received linear accelerator-based treatment, while five received TomoTherapy. The maximal dose to bilateral hippocampi ranged from 9.2 to 25.8 Gy, with a median of 14.4 Gy. In our crossmodality analysis of the planning target volume (PTV) coverage, linear accelerator planning was comparable to TomoTherapy (P=0.29), and both treatments met the RTOG 0933 criteria in (D 2% ≤37.5 Gy) hotspot evaluation. TomoTherapy was statistically superior to linear accelerator in the minimum PTV dose criteria (D 98% >25 Gy) (P=0.03). Regarding the constraint dose of hippocampi, TomoTherapy tend to outperform linear accelerator treatment (P=0.1). The TomoTherapy technique had the longest delivery time (median: 437 sec), compared to 364 sec for the linear accelerator, with statistical significance (P=0.03). Conclusions: In this study, we presented a dosimetry analysis of hippocampal-avoidance whole-brain radiotherapy in clinical settings. The dilemma does exist in balancing clinical workload with the timeconsuming planning, so daily treatment may come at the expense of noncompliance and non-conformity on planning targets. In determining the final plan, the choice of the physician should depend on patient's clinical situation and institutional facility.

Research paper thumbnail of Mechanisms of Nanotoxicology and the Important Role of Alternative Testing Strategies

International Journal of Molecular Sciences

Recently, rapid advances in nanotechnology have provided a lot of opportunities for the mass prod... more Recently, rapid advances in nanotechnology have provided a lot of opportunities for the mass production of engineered nanomaterials of various types of chemicals, including metals and nonmetals, promoting the development of a new generation of industrial and commercial products and the field of nanomedicine [...]

Research paper thumbnail of An adaptive method for recalibrating Gafchromic EBT3 film

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2021

Abstract Ashland Inc. EBT3 film has high 2D dosimetry resolution and is self-developing so it is ... more Abstract Ashland Inc. EBT3 film has high 2D dosimetry resolution and is self-developing so it is widely used as a dosimetry quality assurance tool. However, the film must be calibrated every half year or three months because the unexposed film slowly develops due to the aging effect. A new calibration method is proposed that uses an adaptive power function and no dose need be delivered to allow recalibration. EBT3 film is calibrated separately on different dates over several months. All calibrations use the one red-channel after three-channel method (Chang et al., 2015). The dose-dependent optical density (OD) for the red channel is fitted to the delivered dose using a power function with a constant fitting parameter. Instead of a general recalibration, the film-dose is calculated using all of the fitting parameters for the first calibration and by changing the constant parameter using a fresh measured background OD. The film-dose that is calculated using the proposed adaptive method is compared with the administered dose and the percentage difference is compared with that for a new set of recalibrated fitting parameters and that for all of the first fitting parameters. The results demonstrate that the difference between the film-dose and the dose that is delivered using the adaptive calibration method is less than 3%. However, if the first calibration fitting parameters are used, the percentage difference is more than 50% for a delivered dose of around 50 cGy at a calibration date of eight months after the first calibration. The film-dose is calculated using the first calibrated equation, but using a new measured background OD, so the constant fitting parameter is changed, rather than recalibrating the film. To precisely calculate the film-dose, the equation must be adapted for each individual film. The proposed method is convenient, rapid and cost effective because recalibration does not require the exposure of film. This new technique is a practical method for clinical use.

Research paper thumbnail of Additional file 1: of Combination of the novel histone deacetylase inhibitor YCW1 and radiation induces autophagic cell death through the downregulation of BNIP3 in triple-negative breast cancer cells in vitro and in an orthotopic mouse model

Supplementary results. (DOC 3159 kb)

Research paper thumbnail of Additional file 1: of Subsequent thyroid disorders associated with treatment strategy in head and neck cancer patients: a nationwide cohort study

Figure S1. The cumulative incidence of subsequent thyroid disorders in PTE and PTE+ ND groups wer... more Figure S1. The cumulative incidence of subsequent thyroid disorders in PTE and PTE+ ND groups were present as solid and dotted curve, respectively. In our study design, the subjects with thyroid disorder occurred within one year after allocation were excluded, which is to prevent ill-defined cause-effect relationship, leading to no outcome obtained in the first year. (DOCX 219 kb)

Research paper thumbnail of Relationship between Semi-Quantitative Parameters of Thallium-201 Myocardial Perfusion Imaging and Coronary Artery Disease

Diagnostics, 2020

This study aimed to investigate the diagnostic performance of semi-quantitative parameters of tha... more This study aimed to investigate the diagnostic performance of semi-quantitative parameters of thallium-201 myocardial perfusion imaging (MPI) for coronary artery disease (CAD). From January to December 2017, patients were enrolled who had undergone Tl-201 MPI and received cardiac catheterization for coronary artery disease within three months of MPI. Receiver operating characteristics (ROC) analysis was used to determine the optimal cutoff values of semi-quantitative parameters. A comparison of the sensitivity and specificity of these parameters based on different subgroupings was further performed. A total of 130 patients were enrolled for further analysis. Among the collected parameters, the stress total perfusion deficit (sTPD) had the highest value of the area under curve (0.813) under the optimal cutoff value of 3.5%, with a sensitivity and specificity of 73.5% and 74.5%, respectively (p = 0.0000), for the diagnosis of CAD. With further subgrouping analysis based on history of ...

Research paper thumbnail of The Crucial Role of the Establishment of Computed Tomography Density Conversion Tables for Treating Brain or Head/Neck Tumors

Progress in Medical Physics, 2021

The relationship between computed tomography (CT) number and electron density (ED) has been inves... more The relationship between computed tomography (CT) number and electron density (ED) has been investigated in previous studies. However, the role of these measures for guiding cancer treatment remains unclear. Methods: The CT number was plotted against ED for different imaging protocols. The CT number was imported into ED tables for the Pinnacle treatment planning system (TPS) and was used to determine the effect on dose calculations. Conversion tables for radiation dose calculations were generated and subsequently monitored using a dosimeter to determine the effect of different CT scanning protocols and treatment sites. These tables were used to retrospectively recalculate the radiation therapy plans for 41 patients after an incorrect scanning protocol was inadvertently used. The gamma index was further used to assess the dose distribution, percentage dose difference (DD), and distance-to-agreement (DTA). Results: For densities <1.1 g/cm 3 , the standard deviation of the CT number was ±0.6% and the greatest variation was noted for brain protocol conditions. For densities >1.1 g/cm 3 , the standard deviation of the CT number was ±21.2% and the greatest variation occurred for the tube voltage and head and neck (H&N) protocol conditions. These findings suggest that the factors most affecting the CT number are the tube voltage and treatment site (brain and H&N). Gamma index analyses for the 41 retrospective clinical cases, as well as brain metastases and H&N tumors, showed gamma passing rates >90% and <90% for the passing criterion of 2%/2 and 1%/1 mm, respectively. Conclusions: The CT protocol should be carefully decided for TPS. The correct protocol should be used for the corresponding TPS based on the treatment site because this especially affects the dose distribution for brain metastases and H&N tumor recognition. Such steps could help reduce systematic errors.

Research paper thumbnail of Subsequent thyroid disorders associated with treatment strategy in head and neck cancer patients: a nationwide cohort study

BMC Cancer, 2019

Background: We investigated the risk of thyroid disorders, namely hypothyroidism, thyrotoxicosis ... more Background: We investigated the risk of thyroid disorders, namely hypothyroidism, thyrotoxicosis and thyroiditis, in head and neck cancer patients undergoing multimodal treatment. Methods: A cohort study design using Taiwan's National Health Insurance Research Database was used to assess head and neck cancer patients over 20 years old. The cohort was divided into one group who underwent primary tumor excision only (PTE) and another with additional neck dissection (PTE + ND). The tumor sites were stratified to estimate the tumor-site-specific risk of thyroid disorders. The effect of subsequent resurgery, radiotherapy (RT), chemotherapy (CT), and concomitant (CCRT) or sequential chemoradiation therapy (sequential CT+ RT) on the risk of thyroid disorders was explored. Results: For 1999-2012, 7460 patients who underwent PTE + ND and 3730 who underwent PTE were enrolled and followed-up until the end of 2013. There were 122 and 50 patients in the two groups, respectively, who developed thyroid disorders, with no statistical difference between the groups. Patients with hypopharyngeal, oropharyngeal, or laryngeal cancer in the PTE + ND group had a higher risk of thyroid disorders (adjusted HR: 1.50, 95% CI: 0.67-3.38) than those in the PTE group when adjusted for covariates and mortality. Patients who underwent subsequent RT (adjusted HR: 3.64, 95% CI: 1.05-2.77) and CCRT (adjusted HR: 1.70, 95% CI: 1.05-2.77) after PTE + ND had a significantly higher risk of thyroid disorders. Conclusion: RT results in a major risk of subsequent thyroid disorders, and ND may exacerbate this effect. Physicians should monitor thyroid function from two years after treatment initiation, especially in patients who undergo ND and subsequent RT.

Research paper thumbnail of Geometric error of cervical point A calculated through traditional reconstruction procedures for brachytherapy treatment

Journal of applied clinical medical physics / American College of Medical Physics, Sep 8, 2015

Brachytherapy used in local cervical cancer is still widely based on 2D standard dose planning wi... more Brachytherapy used in local cervical cancer is still widely based on 2D standard dose planning with the prescription to point A, which is invisible on imaging and located at a high-dose gradient. In this study, the geometric location error of point A was investigated. It is traditionally reconstructed in the treatment planning system after carefully digitizing the point marks that were previously drawn on the orthogonal radiographs into the system. Two Cartesian coordinates of point A were established and compared. One was built up based on the geometric definition of point A and would be taken as the true coordinate, while the other was built up through traditional clinical treatment procedures and named as the practical coordinate. The orthogonal-film reconstruction technique was used and the location error between the practical and the true coordinate introduced from the variations of, first, the angle between the tandem and the simulator gantry-rotation-axis, and second, the int...