Displaying publications 1 - 20 of 57 in total

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  1. Cheong EV, Ho GF
    Clin Case Rep, 2021 Apr;9(4):2264-2268.
    PMID: 33936677 DOI: 10.1002/ccr3.4009
    The development of resistance to trastuzumab in HER2-positive gastroesophageal cancer remains a problem. The use of dual HER2 blockade to overcome this is a therapeutic strategy that should be researched more extensively.
  2. Lee DW, Ho GF
    Gynecol Oncol Rep, 2020 Nov;34:100626.
    PMID: 32953960 DOI: 10.1016/j.gore.2020.100626
    Serous ovarian cancers are typically high grade and recur within a short interval. The currently available therapeutic options provide a relatively low response rate and the progress-free survival are short-lived. There is emerging data that CDK4/6 may be effective in metastatic ovarian cancer. This case describes the use of palbociclib after multiple lines of cytotoxic chemotherapy and hormonal therapy. At 30 months upon commencement of palbociclib and letrozole, this patient continues to respond to the treatment radiologically and in the suppression of CA125.
  3. Jabir RS, Ho GF, Annuar MABA, Stanslas J
    Biomarkers, 2018 Mar;23(2):142-146.
    PMID: 28554261 DOI: 10.1080/1354750X.2017.1334152
    CONTEXT: Rash and oral mucositis are major non-haematological adverse events (AEs) of docetaxel, in addition to fatigue, nausea, vomiting and diarrhoea, which restrict the use of the drug in cancer therapy. Alpha-1-acid glycoprotein (AAG) is an acute phase reactant glycoprotein and is a primary carrier of docetaxel in the blood. Docetaxel has extensive binding (>98%) to plasma proteins such as AAG, lipoproteins and albumin.

    OBJECTIVE: To study the association between plasma AAG level and non-haematological AEs of docetaxel in Malaysian breast cancer patients of three major ethnic groups (Malays, Chinese and Indians).

    MATERIALS AND METHODS: One hundred and twenty Malaysian breast cancer patients receiving docetaxel as single agent chemotherapy were investigated for AAG plasma level using enzyme-linked immunosorbent assay technique. Toxicity assessment was determined using Common Terminology Criteria of Adverse Events v4.0. The association between AAG and toxicity were then established.

    RESULTS: There was interethnic variation of plasma AAG level; it was 182 ± 85 mg/dl in Chinese, 237 ± 94 mg/dl in Malays and 240 ± 83 mg/dl in Indians. It was found that low plasma levels of AAG were significantly associated with oral mucositis and rash.

    CONCLUSIONS: This study proposes plasma AAG as a potential predictive biomarker of docetaxel non-haematological AEs namely oral mucositis and rash.

  4. Jamalludin Z, Jong WL, Ho GF, Rosenfeld AB, Ung NM
    Australas Phys Eng Sci Med, 2019 Dec;42(4):1099-1107.
    PMID: 31650362 DOI: 10.1007/s13246-019-00809-7
    The MOSkin, a metal-oxide semiconductor field-effect transistor based detector, is suitable for evaluating skin dose due to its water equivalent depth (WED) of 0.07 mm. This study evaluates doses received by target area and unavoidable normal skin during a the case of skin brachytherapy. The MOSkin was evaluated for its feasibility as detector of choice for in vivo dosimetry during skin brachytherapy. A high-dose rate Cobalt-60 brachytherapy source was administered to the tumour located at the medial aspect of the right arm, complicated with huge lymphedema thus limiting the arm motion. The source was positioned in the middle of patients' right arm with supine, hands down position. A 5 mm lead and 5 mm bolus were sandwiched between the medial aspect of the arm and lateral chest to reduce skin dose to the chest. Two calibrated MOSkin detectors were placed on the target and normal skin area for five treatment sessions for in vivo dose monitoring. The mean dose to the target area ranged between 19.9 and 21.1 Gy and was higher in comparison with the calculated dose due to contribution of backscattered dose from lead. The mean measured dose at normal skin chest area was 1.6 Gy (1.3-1.9 Gy), less than 2 Gy per fraction. Total dose in EQD2 received by chest skin was much lower than the recommended skin tolerance. The MOSkin detector presents a reliable real-time dose measurement. This study has confirmed the applicability of the MOSkin detector in monitoring skin dose during brachytherapy treatment due to its small sensitive volume and WED 0.07 mm.
  5. Jabir RS, Ho GF, Annuar MABA, Stanslas J
    Clin Breast Cancer, 2018 10;18(5):e1173-e1179.
    PMID: 29885788 DOI: 10.1016/j.clbc.2018.04.018
    PURPOSE: Nonhematologic adverse events (AEs) of docetaxel constitute an extra burden in the treatment of cancer patients and necessitate either a dose reduction or an outright switch of docetaxel for other regimens. These AEs are frequently associated with genetic polymorphisms of genes encoding for proteins involved docetaxel disposition. Therefore, we investigated that association in Malaysian breast cancer patients.

    MATERIALS AND METHODS: A total of 110 Malaysian breast cancer patients were enrolled in the present study, and their blood samples were investigated for different single nucleotide polymorphisms using polymerase chain reaction restriction fragment length polymorphism. AEs were evaluated using the Common Terminology Criteria for Adverse Events, version 4.0.

    RESULTS: Fatigue, nausea, oral mucositis, and vomiting were the most common nonhematologic AEs. Rash was associated with heterozygous and mutant genotypes of ABCB1 3435C>T (P < .05). Moreover, patients carrying the GG genotype of ABCB1 2677G>A/T reported more fatigue than those carrying the heterozygous genotype GA (P < .05). The presence of ABCB1 3435-T, ABCC2 3972-C, ABCC2 1249-G, and ABCB1 2677-G alleles was significantly associated with nausea and oral mucositis. The coexistence of ABCB1 3435-C, ABCC2 3972-C, ABCC2 1249-G, and ABCB1 2677-A was significantly associated with vomiting (P < .05).

    CONCLUSION: The prevalence of nonhematologic AEs in breast cancer patients treated with docetaxel has been relatively high. The variant allele of ABCB1 3435C>T polymorphism could be a potential predictive biomarker of docetaxel-induced rash, and homozygous wild-type ABCB1 2677G>A/T might predict for a greater risk of fatigue. In addition, the concurrent presence of specific alleles could be predictive of vomiting, nausea, and oral mucositis.

  6. Chan CM, Wan Ahmad WA, Yusof MM, Ho GF, Krupat E
    Psychooncology, 2015 Jun;24(6):718-25.
    PMID: 25345781 DOI: 10.1002/pon.3714
    Distress and psychiatric morbidity in cancer patients are associated with poorer outcomes including mortality. In this study, we examined the prevalence of psychiatric morbidity and its association with cancer survival over time.
  7. Hashim N, Jamalludin Z, Ung NM, Ho GF, Malik RA, Phua VC
    Asian Pac J Cancer Prev, 2014;15(13):5259-64.
    PMID: 25040985
    BACKGROUND: CT based brachytherapy allows 3-dimensional (3D) assessment of organs at risk (OAR) doses with dose volume histograms (DVHs). The purpose of this study was to compare computed tomography (CT) based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the cervix treated with high-dose-rate (HDR) intracavitary brachytherapy (ICBT).

    MATERIALS AND METHODS: Between March 2011 and May 2012, 20 patients were treated with 55 fractions of brachytherapy using tandem and ovoids and underwent post-implant CT scans. The external beam radiotherapy (EBRT) dose was 48.6 Gy in 27 fractions. HDR brachytherapy was delivered to a dose of 21 Gy in three fractions. The ICRU bladder and rectum point doses along with 4 additional rectal points were recorded. The maximum dose (DMax) to rectum was the highest recorded dose at one of these five points. Using the HDR plus 2.6 brachytherapy treatment planning system, the bladder and rectum were retrospectively contoured on the 55 CT datasets. The DVHs for rectum and bladder were calculated and the minimum doses to the highest irradiated 2cc area of rectum and bladder were recorded (D2cc) for all individual fractions. The mean D2cc of rectum was compared to the means of ICRU rectal point and rectal DMax using the Student's t-test. The mean D2cc of bladder was compared with the mean ICRU bladder point using the same statistical test .The total dose, combining EBRT and HDR brachytherapy, were biologically normalized to the conventional 2 Gy/fraction using the linear-quadratic model. (α/β value of 10 Gy for target, 3 Gy for organs at risk).

    RESULTS: The total prescribed dose was 77.5 Gy α/β10. The mean dose to the rectum was 4.58 ± 1.22 Gy for D 2cc, 3.76 ± 0.65 Gy at D ICRU and 4.75 ± 1.01 Gy at DMax. The mean rectal D 2cc dose differed significantly from the mean dose calculated at the ICRU reference point (p<0.005); the mean difference was 0.82 Gy (0.48 -1.19 Gy). The mean EQD2 was 68.52 ± 7.24 Gy α/β3 for D 2cc, 61.71 ± 2.77 Gy α/β3 at D ICRU and 69.24 ± 6.02 Gy α/β3 at DMax. The mean ratio of D 2cc rectum to D ICRU rectum was 1.25 and the mean ratio of D 2cc rectum to DMax rectum was 0.98 for all individual fractions. The mean dose to the bladder was 6.00 ± 1.90 Gy for D 2cc and 5.10 ± 2.03 Gy at D ICRU. However, the mean D 2cc dose did not differ significantly from the mean dose calculated at the ICRU reference point (p=0.307); the mean difference was 0.90 Gy (0.49-1.25 Gy). The mean EQD2 was 81.85 ± 13.03 Gy α/β3 for D 2cc and 74.11 ± 19.39 Gy α/β3 at D ICRU. The mean ratio of D 2cc bladder to D ICRU bladder was 1.24. In the majority of applications, the maximum dose point was not the ICRU point. On average, the rectum received 77% and bladder received 92% of the prescribed dose.

    CONCLUSIONS: OARs doses assessed by DVH criteria were higher than ICRU point doses. Our data suggest that the estimated dose to the ICRU bladder point may be a reasonable surrogate for the D 2cc and rectal DMax for D 2cc. However, the dose to the ICRU rectal point does not appear to be a reasonable surrogate for the D 2cc.

  8. Mei Hsien CC, Wan Azman WA, Md Yusof M, Ho GF, Krupat E
    BMJ Open, 2012;2(5).
    PMID: 23035016 DOI: 10.1136/bmjopen-2012-001799
    Psychological distress is common in patients with cancer. We need a rapid means of screening for and identifying depression and anxiety in patients with cancer. The present study evaluates the potential of the Eastern Cooperative Oncology Group (ECOG) performance status (PS) scoring as a brief screening tool to assess psychological distress in routine cancer care. The ECOG PS is widely used by oncologists and the WHO, as a standardised measure to assess general well-being in patients with cancer and quality of life in cancer trials. We examine the discrepancy between patient-rated and oncologist-rated PS scores on the ECOG in a comparative assessment against the Hospital Anxiety and Depression Scale (HADS).
  9. Jabir RS, Naidu R, Annuar MA, Ho GF, Munisamy M, Stanslas J
    Pharmacogenomics, 2012 Dec;13(16):1979-88.
    PMID: 23215890 DOI: 10.2217/pgs.12.165
    Interindividual variability in drug response and the emergence of adverse drug effects are the main causes of treatment failure in cancer therapy. Functional membrane drug transporters play important roles in altering pharmacokinetic profile, resistance to treatment, toxicity and patient survival. Pharmacogenetic studies of these transporters are expected to provide new approaches for optimizing therapy. Taxanes are approved for the treatment of various cancers. Circulating taxanes are taken up by SLCO1B3 into hepatocytes. The CYP450 enzymes CYP3A4, CYP3A5 and CYP2C8 are responsible for the conversion of taxanes into their metabolites. Ultimately, ABCB1 and ABCC2 will dispose the metabolites into bile canaliculi. Polymorphisms of genes encoding for proteins involved in the transport and clearance of taxanes reduce excretion of the drugs, leading to development of toxicity in patients. This review addresses current knowledge on genetic variations of transporters affecting taxanes pharmacokinetics and toxicity, and provides insights into future direction for personalized medicine.
  10. Chan CM, Wan Ahmad WA, Yusof MM, Ho GF, Krupat E
    Asian Pac J Cancer Prev, 2015;16(16):6895-8.
    PMID: 26514463
    BACKGROUND: We aimed to explore whether levels of patient-centredness, job satisfaction and psychological distress varied between oncology nurses and doctors.

    MATERIALS AND METHODS: In a cross-sectional study using self-administered questionnaires, a total of 24 nurses and 43 doctors were assessed for patient-centredness, psychological distress, and job satisfaction using the Patient-Practitioner Orientation Scale, Hospital Anxiety and Depression Scale, and Job Satisfaction Scale. Data were analysed using descriptive statistics, independent samples t-test and MANCOVA, with p<0.05 considered significant.

    RESULTS: Overall response rate was 95.6% (43/45) for physicians and 85.7% (24/28) for nurses. Even after adjusting for known covariates, our principal finding was that doctors reported greater psychological distress compared to nurses (p=0.009). Doctors also reported lower job satisfaction compared to nurses (p = 0.017), despite higher levels of patient-centredness found in nurses (p=0.001). Findings may be explained in part by differences in job characteristics and demands.

    CONCLUSIONS: Mental health is an important concern not just in cancer patients but among healthcare professionals in oncology.

  11. Chan CM, Wan Ahmad WA, Md Yusof M, Ho GF, Krupat E
    Eur J Cancer Care (Engl), 2015 Nov;24(6):938-44.
    PMID: 25810106 DOI: 10.1111/ecc.12312
    Defaulting is an important issue across all medical specialties, but much more so in cancer as delayed or incomplete treatment has been shown to result in worse clinical outcomes such as treatment resistance, disease progression as well as lower survival. Our objective was to identify psychosocial variables and characteristics associated with default among cancer patients. A total of 467 consecutive adult cancer patients attending the oncology clinic at a single academic medical centre completed the Hospital Anxiety and Depression Scale and reported their preference for psychological support at baseline, 4-6 weeks and 12-18 months follow-up. Default was defined as refusal, delay or discontinuation of treatment or visit, despite the ability to do so. A total of 159 of 467 (34.0%) cancer patients were defaulters. Of these 159 defaulters, 89 (56.0%) desired psychological support, compared to only 13 (4.2%) of 308 non-defaulters. Using a logistic regression, patients who were defaulters had 52 times higher odds (P = 0.001; 95% confidence interval 20.61-134.47) of desiring psychological support than non-defaulters after adjusting for covariates. These findings suggest that defaulters should be offered psychological support which may increase cancer treatment acceptance rates and improve survival.
    Study site: Oncology clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
  12. Kadravello A, Tan SB, Ho GF, Kaur R, Yip CH
    Medicina (Kaunas), 2021 Jul 07;57(7).
    PMID: 34356974 DOI: 10.3390/medicina57070693
    Background and Objective: Despite the increasing treatment options for patients with metastatic breast cancer (MBC), unmet needs remain common, especially in low and middle-income countries where resources are limited and MBC patients face many challenges. They often join support groups to cope with their unmet needs. Currently, many MBC patients connect with each other via online support group in view of the constant availability of support and rapid information exchange. The objective of this study is to determine the unmet needs of women with MBC from an online support group. Material and Methods: Messages in an online support group of twenty-two MBC patients over a period of three years from August 2016 till August 2019 were thematically analyzed. Results: Three themes were generated, (1) unmet information needs (2) unmet financial needs (3) unmet support needs. Women needed information on side effects of treatment, new treatment options and availability of clinical trials. Although Malaysia has universal health care coverage, access to treatment remains a major challenge. When treatment was not available in the public hospitals, or waiting lists were too long, women were forced to seek treatment in private hospitals, incurring financial catastrophe. Insufficient private insurance and inadequate social security payments force many women to consider stopping treatment. Women felt that they were not getting support from their clinicians in the public sector, who were quick to stop active treatment and advise palliation. On the other hand, clinicians in the private sector advise expensive treatment beyond the financial capability of the patients. Women with families also face the challenge of managing their family and household in addition to coping with their illness. Conclusions: There is a need for healthcare professionals, policy makers, and civil society to better address the needs of MBC patients through patient-centered, multidisciplinary and multi-organizational collaboration.
  13. Golkhalkhali B, Rajandram R, Paliany AS, Ho GF, Wan Ishak WZ, Johari CS, et al.
    Asia Pac J Clin Oncol, 2018 Jun;14(3):179-191.
    PMID: 28857425 DOI: 10.1111/ajco.12758
    AIM: Colorectal cancer patients on chemotherapy usually have elevated levels of inflammatory markers and experience numerous side effects from chemotherapy thereby leading to poor quality of life. Omega-3 fatty acid and microbial cell preparation (MCP) have been known to provide significant benefits in patients on chemotherapy. The aim of this study was to determine the effect of supplementation of omega-3 fatty acid and MCP in quality of life, chemotherapy side effects and inflammatory markers in colorectal cancer patients on chemotherapy.

    METHODS: A double-blind randomized study was carried out with 140 colorectal cancer patients on chemotherapy. Subjects were separated into two groups to receive either placebo or MCP [30 billion colony-forming unit (CFUs) per sachet] at a dose of two sachets daily for 4 weeks, and omega-3 fatty acid at a dose of 2 g daily for 8 weeks. Outcomes measured were quality of life, side effects of chemotherapy and levels of inflammatory markers such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and C-reactive protein.

    RESULTS: The supplementation with MCP and omega-3 fatty acid improved the overall quality of life and alleviated certain side effects of chemotherapy. The supplementation with MCP and omega-3 fatty acid also managed to reduce the level of IL-6 (P = 0.002). There was a significant rise in the placebo group's serum TNF-α (P = 0.048) and IL-6 (P = 0.004).

    CONCLUSION: The combined supplementation with MCP and omega-3 fatty acid may improve quality of life, reduce certain inflammatory biomarkers and relieve certain side effects of chemotherapy in colorectal patients on chemotherapy.

  14. Ng CH, Pathy NB, Taib NA, Ho GF, Mun KS, Rhodes A, et al.
    Asian Pac J Cancer Prev, 2014;15(18):7959-64.
    PMID: 25292095
    The significance of the single hormone receptor positive phenotype of breast cancer is still poorly understood. The use of hormone therapy has been found to be less effective for this type, which has a survival outcome midway between double positive and double negative phenotypes. The aim of this study was to investigate differences in patient and tumor characteristics and survival between double-receptor positive (ER+PR+), double receptor negative (ER-PR-) and single receptor positive (ER+PR- and ER-PR+) breast cancer in an Asian setting. A total of 1,992 patients with newly diagnosed stage I to IV breast cancer between 2003 and 2008, and where information on ER and PR were available, were included in this study. The majority of patients had ER+PR+ tumors (n=903: 45.3%), followed by 741 (37.2%) ER-PR-, 247 (12.4%) ER+PR-, and 101 (5.1%) ER-PR+ tumors. Using multivariate analysis, ER+PR- tumors were 2.4 times more likely to be grade 3 compared to ER+PR+ tumors. ER+PR- and ER-PR+ tumors were 82% and 86% respectively less likely to be grade 3 compared with ER-PR- tumors. ER-PR+ tumours were associated with younger age. There were no survival differences between patients with ER+PR+ and ER-PR+ tumors. However, ER+PR- tumors have poorer survival compared with ER+PR+ tumours. ER-PR- tumours had the worst survival. Adjuvant hormonal therapy with tamoxifen was found to have identical survival advantage in patients with ER+PR+ and ER-PR+ tumors whereas impact was slightly lower in patients with ER+PR- tumors. In conclusion, we found ER+PR- tumors to be more aggressive and have poorer survival when compared to ER+PR+ tumors, while patients with ER-PR+ tumours were younger, but had a similar survival to their counterparts with ER+PR+ tumours.
  15. Zaman ZK, Ung NM, Malik RA, Ho GF, Phua VC, Jamalludin Z, et al.
    Phys Med, 2014 Dec;30(8):980-4.
    PMID: 25086486 DOI: 10.1016/j.ejmp.2014.07.002
    Cobalt-60 (Co-60) is a relatively new source for the application of high-dose rate (HDR) brachytherapy. Radiation dose to the rectum is often a limiting factor in achieving the full prescribed dose to the target during brachytherapy of cervical cancer. The aim of this study was to measure radiation doses to the rectum in-vivo during HDR Co-60 brachytherapy. A total of eleven HDR brachytherapy treatments of cervical cancer were recruited in this study. A series of diodes incorporated in a rectal probe was inserted into the patient's rectum during each brachytherapy procedure. Real-time measured rectal doses were compared to calculated doses by the treatment planning system (TPS). The differences between calculated and measured dose ranged from 8.5% to 41.2%. This corresponds to absolute dose differences ranging from 0.3 Gy to 1.5 Gy. A linear relationship was observed between calculated and measured doses with linear regression R(2) value of 0.88, indicating close association between the measured and calculated doses. In general, absorbed doses for the rectum as calculated by TPS were observed to be higher than the doses measured using the diode probe. In-vivo dosimetry is an important quality assurance method for HDR brachytherapy of cervical cancer. It provides information that can contribute to the reduction of errors and discrepancies in dose delivery. Our study has shown that in-vivo dosimetry is feasible and can be performed to estimate the dose to the rectum during HDR brachytherapy using Co-60.
  16. Abdullah BJ, Yeong CH, Goh KL, Yoong BK, Ho GF, Yim CC, et al.
    Eur Radiol, 2015 Jan;25(1):246-57.
    PMID: 25189152 DOI: 10.1007/s00330-014-3391-7
    OBJECTIVE: This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system.

    METHODS: Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance.

    RESULTS: Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method.

    CONCLUSION: This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients.

    KEY POINTS: • Clinical experience on liver thermal ablation using CT-guided robotic system is reported. • The technical success, radiation dose, safety and performance level were assessed. • Thermal ablations were successfully performed, with an average performance score of 4.4/5.0. • Robotic-assisted ablation can potentially increase capabilities of less skilled interventional radiologists. • Cost-effectiveness needs to be proven in further studies.

  17. Abdullah BJ, Yeong CH, Goh KL, Yoong BK, Ho GF, Yim CC, et al.
    Eur Radiol, 2014 Jan;24(1):79-85.
    PMID: 23928933 DOI: 10.1007/s00330-013-2979-7
    OBJECTIVE: Computed tomography (CT)-compatible robots, both commercial and research-based, have been developed with the intention of increasing the accuracy of needle placement and potentially improving the outcomes of therapies in addition to reducing clinical staff and patient exposure to radiation during CT fluoroscopy. In the case of highly inaccessible lesions that require multiple plane angulations, robotically assisted needles may improve biopsy access and targeted drug delivery therapy by avoidance of the straight line path of normal linear needles.

    METHODS: We report our preliminary experience of performing radiofrequency ablation of the liver using a robotic-assisted CT guidance system on 11 patients (17 lesions).

    RESULTS/CONCLUSION: Robotic-assisted planning and needle placement appears to have high accuracy, is technically easier than the non-robotic-assisted procedure, and involves a significantly lower radiation dose to both patient and support staff.

    KEY POINTS: • An early experience of robotic-assisted radiofrequency ablation is reported • Robotic-assisted RFA improves accuracy of hepatic lesion targeting • Robotic-assisted RFA makes the procedure technically easier with significant lower radiation dose.

  18. Subramaniam S, Bhoo-Pathy N, Taib NA, Tan GH, See MH, Jamaris S, et al.
    World J Surg, 2015 Oct;39(10):2450-8.
    PMID: 26138872 DOI: 10.1007/s00268-015-3133-2
    Breast cancer can be divided into four subtypes based on the expressions of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor-2 (HER2). Each subtype has different clinicopathological features and outcomes.
  19. Jong WL, Wong JH, Ung NM, Ng KH, Ho GF, Cutajar DL, et al.
    J Appl Clin Med Phys, 2014 Sep 08;15(5):4869.
    PMID: 25207573 DOI: 10.1120/jacmp.v15i5.4869
    In vivo dosimetry is important during radiotherapy to ensure the accuracy of the dose delivered to the treatment volume. A dosimeter should be characterized based on its application before it is used for in vivo dosimetry. In this study, we characterize a new MOSFET-based detector, the MOSkin detector, on surface for in vivo skin dosimetry. The advantages of the MOSkin detector are its water equivalent depth of measurement of 0.07 mm, small physical size with submicron dosimetric volume, and the ability to provide real-time readout. A MOSkin detector was calibrated and the reproducibility, linearity, and response over a large dose range to different threshold voltages were determined. Surface dose on solid water phantom was measured using MOSkin detector and compared with Markus ionization chamber and GAFCHROMIC EBT2 film measurements. Dependence in the response of the MOSkin detector on the surface of solid water phantom was also tested for different (i) source to surface distances (SSDs); (ii) field sizes; (iii) surface dose; (iv) radiation incident angles; and (v) wedges. The MOSkin detector showed excellent reproducibility and linearity for dose range of 50 cGy to 300 cGy. The MOSkin detector showed reliable response to different SSDs, field sizes, surface, radiation incident angles, and wedges. The MOSkin detector is suitable for in vivo skin dosimetry.
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