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Troeltzsch D, Shnayien S, Gaudin R, Bressem K, Kreutzer K, Heiland M, Hamm B, Niehues S. Diagnostic performance of dynamic volume perfusion CT for differentiation of head and neck cancer from healthy tissue and post-therapeutic changes. Clin Hemorheol Microcirc 2021; 78:93-101. [PMID: 33554889 DOI: 10.3233/ch-200919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Post-therapeutic tissue is bradytrophic and thus has low perfusion values in PCT. In contrast, malignant tissue is expected to show higher perfusion values as cancer growth partially depends on angiogenesis. OBJECTIVES This prospective study investigates perfusion computed tomography (PCT) for the post-therapeutic detection of cancer in the head and neck region. METHODS 85 patients underwent PCT for 1) initial work-up of head and neck cancer (HNC; n=22) or 2) for follow-up (n=63). Regions of interest (ROIs) were placed in confirmed tumour, a corresponding location of benign tissue, and reference tissue. Perfusion was calculated using a single input maximum slope algorithm. Statistical analysis was performed with the Mann-Whitney U-test. RESULTS PCT allowed significant differentiation of malignant tissue from post-therapeutic tissue after treatment for HNC (p=0.018). Significance was even greater after normalization of perfusion values (p=0.007). PCT allowed highly significant differentiation of HNC from reference tissue (p<0.001). CONCLUSIONS PCT provides significantly distinct perfusion values for malignant and benign as well as post-therapeutically altered tissue in the head and neck area, thus allowing differentiation of cancer from healthy tissue. Our results show that PCT in conjunction with a standard algorithm is a potentially powerful HNC diagnostic tool.
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Affiliation(s)
- Daniel Troeltzsch
- Department of Oral and Maxillofacial Surgery, Charité -Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
| | - Seyd Shnayien
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
| | - Robert Gaudin
- Department of Oral and Maxillofacial Surgery, Charité -Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
| | - Keno Bressem
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
| | - Kilian Kreutzer
- Department of Oral and Maxillofacial Surgery, Charité -Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
| | - Max Heiland
- Department of Oral and Maxillofacial Surgery, Charité -Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
| | - Bernd Hamm
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
| | - Stefan Niehues
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
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Johnson GB, Harms HJ, Johnson DR, Jacobson MS. PET Imaging of Tumor Perfusion: A Potential Cancer Biomarker? Semin Nucl Med 2020; 50:549-561. [PMID: 33059824 DOI: 10.1053/j.semnuclmed.2020.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Perfusion, as measured by imaging, is considered a standard of care biomarker for the evaluation of many tumors. Measurements of tumor perfusion may be used in a number of ways, including improving the visual detection of lesions, differentiating malignant from benign findings, assessing aggressiveness of tumors, identifying ischemia and by extension hypoxia within tumors, and assessing treatment response. While most clinical perfusion imaging is currently performed with CT or MR, a number of methods for PET imaging of tumor perfusion have been described. The inert PET radiotracer 15O-water PET represents the recognized gold standard for absolute quantification of tissue perfusion in both normal tissue and a variety of pathological conditions including cancer. Other cancer PET perfusion imaging strategies include the use of radiotracers with high first-pass uptake, analogous to those used in cardiac perfusion PET. This strategy produces more visually pleasing high-contrast images that provide relative rather than absolute perfusion quantification. Lastly, multiple timepoint imaging of PET tracers such as 18F-FDG, are not specifically optimized for perfusion, but have advantages related to availability, convenience, and reimbursement. Multiple obstacles have thus far blocked the routine use of PET imaging for tumor perfusion, including tracer production and distribution, image processing, patient body coverage, clinical validation, regulatory approval and reimbursement, and finally feasible clinical workflows. Fortunately, these obstacles are being overcome, especially within larger imaging centers, opening the door for PET imaging of tumor perfusion to become standard clinical practice. In the foreseeable future, it is possible that whole-body PET perfusion imaging with 15O-water will be able to be performed in a single imaging session concurrent with standard PET imaging techniques such as 18F-FDG-PET. This approach could establish an efficient clinical workflow. The resultant ability to measure absolute tumor blood flow in combination with glycolysis will provide important complementary information to inform prognosis and clinical decisions.
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Affiliation(s)
- Geoffrey B Johnson
- Department of Radiology, Mayo Clinic, Rochester, MNDepartment of Neurology, Mayo Clinic, Rochester, MN; Department of Immunology, Mayo Clinic, Rochester, MN.
| | - Hendrik J Harms
- Department of Surgical Sciences, Nuclear Medicine, PET and Radiology, Uppsala University, Uppsala Sweden
| | - Derek R Johnson
- Department of Radiology, Mayo Clinic, Rochester, MNDepartment of Neurology, Mayo Clinic, Rochester, MN
| | - Mark S Jacobson
- Department of Radiology, Mayo Clinic, Rochester, MNDepartment of Neurology, Mayo Clinic, Rochester, MN
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Niazi M, Mohammadzadeh M, Aghazadeh K, Sharifian H, Karimi E, Shakiba M, Baniasadi M, Rahmaty B, Adel S, Moharreri M. Perfusion Computed Tomography Scan Imaging in Differentiation of Benign from Malignant Parotid Lesions. Int Arch Otorhinolaryngol 2020; 24:e160-e169. [PMID: 32256836 PMCID: PMC6828566 DOI: 10.1055/s-0039-1697005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 07/08/2019] [Indexed: 12/03/2022] Open
Abstract
Introduction
The most common site of salivary gland tumors is the parotid gland. Computed tomography (CT), magnetic resonance imaging (MRI), and sonography are imaging modalities to differentiate benign from malignant parotid tumors.
Objective
The aim of this study is the evaluation of the diagnostic value of perfusion CT for differentiating histological categorization of benign and malignant parotid tumors.
Methods
A total of 29 patients with parotid neoplasms were enrolled in this study. Mean age and all CT perfusion variables (gradient and permeability, blood flow [BF], blood volume [BV], mean transit time [MTT], permeability surface [PS], maximum intensity projection [MIP], time-density curve [TDC], and time to peak [TTP]) were compared among three groups (malignant tumors [MTs], Warthin's tumor [WT] and pleomorphic adenomas [PA]).
Results
The mean age of the patients was 55.9 ± 14.1 (26–77), and 15 of them were male (51.7%). Eleven lesions were PAs [37.9%], 8 lesions were WTs (27.6%0 and 10 lesions (34.5%) were MTs (6 acinic cell carcinomas [ACCs], 3 adenocystic carcinomas [AdCCs], and 1 mucoepidermoid carcinoma [MEC]). The mean age of the patients with WTs was 62 ± 7.5 years; 52 ± 14.2 for patients with Pas, and 55.2 ± 17.2 for those with MTs (
p
= 0.32). The mean MIP was 122.7 ± 12.2 in WT, while it was 80.5 ± 19.5 in PA, and 76.2 ± 27.1 in MTs (
p
< 0.001); The mean MIP for WT was higher than for PAs and MTs; the values of MTs and PAs were not statistically different. The average of BF, BV, and curve peak were higher in WTs in comparison with the other two groups, and curve time 2 and TTP were higher in PAs in comparison with MTs.
Conclusion
Based on this study, perfusion CT of the parotid gland and its parameters can distinguish between benign and malignant parotid masses.
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Affiliation(s)
- Masume Niazi
- Department of Otorhinolaryngology, Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Mohammadzadeh
- Division of Neuroradiology, Department of Radiology, Amir Aalam Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Kayvan Aghazadeh
- Department of Otorhinolaryngology, Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Hashem Sharifian
- Department of Radiology, Amir Aalam Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ebrahim Karimi
- Department of Otorhinolaryngology, Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Madjid Shakiba
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
| | - Maria Baniasadi
- Department of Radiology, Amir Aalam Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Benyamin Rahmaty
- Department of Otorhinolaryngology, Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Suzan Adel
- Department of Otorhinolaryngology, Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Melorina Moharreri
- Department of Otorhinolaryngology, Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran
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Yu C, Li T, Zhang R, Yang X, Yang Z, Xin L, Zhao Z. Dual-energy CT perfusion imaging for differentiating WHO subtypes of thymic epithelial tumors. Sci Rep 2020; 10:5511. [PMID: 32218504 PMCID: PMC7098982 DOI: 10.1038/s41598-020-62466-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/13/2020] [Indexed: 11/09/2022] Open
Abstract
To evaluate the role of conventional contrast-enhanced CT (CECT) imaging and dual-energy spectral CT (DECT) perfusion imaging in differentiating the WHO histological subtypes of thymic epithelial tumours (TETs). Eighty-eight patients with TETs who underwent DECT perfusion scans (n = 51) and conventional CT enhancement scans (n = 37) using a GE Discovery CT750 HD scanner were enrolled in this study. The mean maximal contrast-enhanced range (mean CEmax) and the perfusion and spectral parameters of the lesions were analysed. Among the six WHO subtypes (Type A, AB, B1, B2, and B3 thymoma and thymic carcinoma), the mean CEmax values and most of the perfusion and spectral parameter values of Type A and Type AB were significantly higher than those of the other subtypes (all P < 0.05), and there was no difference among Type B1, B2 and B3 (all P > 0.05). The mean CEmax value was not different between Type B (including Type B1, B2, and B3) and thymic carcinoma (P = 1.000). The PS, IC, NIC and λHU values in the optimal venous phase of thymic carcinoma were higher than those of Type B (all P < 0.05). The parameters of conventional CECT imaging and DECT perfusion imaging can help identify the subtype of TETs, especially those of DECT perfusion imaging in type B thymomas and thymic carcinomas.
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Affiliation(s)
- Chunhai Yu
- Imaging Department, Shanxi Tumor Hospital, The Affiliated Tumor Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030013, P.R. China
| | - Ting Li
- Department of Nephrology, Taiyuan People's Hospital, Taiyuan, Shanxi, 030001, P.R. China
| | - Ruiping Zhang
- Imaging Department, Shanxi Tumor Hospital, The Affiliated Tumor Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030013, P.R. China.
| | - Xiaotang Yang
- Imaging Department, Shanxi Tumor Hospital, The Affiliated Tumor Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030013, P.R. China
| | - Zhao Yang
- Imaging Department, Shanxi Tumor Hospital, The Affiliated Tumor Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030013, P.R. China
| | - Lei Xin
- Imaging Department, Shanxi Tumor Hospital, The Affiliated Tumor Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030013, P.R. China
| | - Zhikai Zhao
- Imaging Department, Shanxi Tumor Hospital, The Affiliated Tumor Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030013, P.R. China
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Mahajan A, Ahuja A, Sable N, Stambuk HE. Imaging in oral cancers: A comprehensive review. Oral Oncol 2020; 104:104658. [PMID: 32208340 DOI: 10.1016/j.oraloncology.2020.104658] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 03/11/2020] [Accepted: 03/17/2020] [Indexed: 02/08/2023]
Abstract
This review aims at simplifying the relevant imaging anatomy, guiding the optimal imaging method and highlighting the key imaging findings that influence prognosis and management of oral cavity squamous cell carcinoma (OSCC). Early OSCC can be treated with either surgery alone while advanced cancers are treated with a combination of surgery, radiotherapy and/or chemotherapy. Considering the complex anatomy of the oral cavity and its surrounding structures, imaging plays an indispensable role not only in locoregional staging but also in the distant metastatic work-up and post treatment follow-up. Knowledge of the anatomy with understanding of common routes of spread of cancer, allows the radiologist to accurately determine disease extent and augment clinical findings to plan appropriate therapy. This review aims at simplifying the relevant imaging anatomy, guiding the optimal imaging method and highlighting the key imaging findings that influence prognosis and management.
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Affiliation(s)
- Abhishek Mahajan
- Department of Radiodiagnosis and Imaging, Tata Memorial Hospital, Mumbai 400012, India.
| | - Ankita Ahuja
- Department of Radiodiagnosis and Imaging, Tata Memorial Hospital, Mumbai 400012, India
| | - Nilesh Sable
- Department of Radiodiagnosis and Imaging, Tata Memorial Hospital, Mumbai 400012, India
| | - Hilda E Stambuk
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA
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Prospective observational study to estimate set-up errors and optimise PTV margins in patients undergoing IMRT for head and neck cancers from a Government cancer centre of Eastern India. JOURNAL OF RADIOTHERAPY IN PRACTICE 2020. [DOI: 10.1017/s1460396919000487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AbstractBackground:The head and neck cancers as a whole are the most common cancers among males in India. Technological advancements have led to an improvement in radiation therapy (RT) techniques with subsequent reduction in normal tissue complications. To correct patient set-up errors, an off-line correction method like no action level (NAL) protocol may be used as a preferred protocol particularly for a busy department. The objectives of the study were to measure the translational set-up errors using kV cone-beam computed tomography (CBCT) in patients undergoing intensity modulated radiotherapy (IMRT) in head and neck cancers and also to optimise clinical target volume (CTV) to planning target volume (PTV) margin using NAL protocol.Material and methods:On the first 5 days of RT, patient’s position was verified by kV-CBCT and then weekly during the course of treatment. The comparison between the reference and kV-CBCT images was performed, and the shifts measured and recorded. The mean error from the initial five consecutive fractions was corrected on the sixth daily fraction. Displacements in all the directions were measured. The population systematic and random errors were determined and used to estimate PTV margins according to the van Herk formula.Results:A total of 322 images were analysed. Before correction, 15, 12 and 9% patients had systematic error ≥3 mm on X, Y and Z axes, but after correction this was reduced to 9, 0 and 0%. The total percentage of patients whose set-up margin was ≥5 mm before correction was 5, 6·25, 3·75%, but after correction it reduced to 1·88, 0, and 0·63%. The margins of total population were reduced to 63, 65 and 56% after correction on X, Y and Z axes, respectively.Conclusion:A simple off-line NAL protocol can correct the set-up errors without daily on-line imaging in patients undergoing IMRT and hence acting as a resource sparing alternative. Five millimetre margin to CTVs was adequate and safe to overcome the problem of set-up errors in head and neck IMRT.
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Emerging Functional Imaging Biomarkers of Tumour Responses to Radiotherapy. Cancers (Basel) 2019; 11:cancers11020131. [PMID: 30678055 PMCID: PMC6407112 DOI: 10.3390/cancers11020131] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 12/11/2022] Open
Abstract
Tumour responses to radiotherapy are currently primarily assessed by changes in size. Imaging permits non-invasive, whole-body assessment of tumour burden and guides treatment options for most tumours. However, in most tumours, changes in size are slow to manifest and can sometimes be difficult to interpret or misleading, potentially leading to prolonged durations of ineffective treatment and delays in changing therapy. Functional imaging techniques that monitor biological processes have the potential to detect tumour responses to treatment earlier and refine treatment options based on tumour biology rather than solely on size and staging. By considering the biological effects of radiotherapy, this review focusses on emerging functional imaging techniques with the potential to augment morphological imaging and serve as biomarkers of early response to radiotherapy.
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Martens RM, Noij DP, Ali M, Koopman T, Marcus JT, Vergeer MR, de Vet H, de Jong MC, Leemans CR, Hoekstra OS, de Bree R, de Graaf P, Boellaard R, Castelijns JA. Functional imaging early during (chemo)radiotherapy for response prediction in head and neck squamous cell carcinoma; a systematic review. Oral Oncol 2018; 88:75-83. [PMID: 30616800 DOI: 10.1016/j.oraloncology.2018.11.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 11/02/2018] [Accepted: 11/05/2018] [Indexed: 10/27/2022]
Abstract
This systematic review gives an extensive overview of the current state of functional imaging during (chemo)radiotherapy to predict locoregional control (LRC) and overall survival (OS) for head and neck squamous cell carcinoma. MEDLINE and EMBASE were searched for literature until April 2018 assessing the predictive performance of functional imaging (computed tomography perfusion (CTp), MRI and positron-emission tomography (PET)) within 4 weeks after (chemo)radiotherapy initiation. Fifty-two studies (CTp: n = 4, MRI: n = 19, PET: n = 26, MRI/PET: n = 3) were included involving 1623 patients. Prognostic information was extracted according the PRISMA protocol. Pooled estimation and subgroup analyses were performed for comparable parameters and outcome. However, the heterogeneity of included studies limited the possibility for comparison. Early tumoral changes from (chemo)radiotherapy can be captured by functional MRI and 18F-FDG-PET and could allow for personalized treatment adaptation. Lesions showed potentially prognostic intratreatment changes in perfusion, diffusion and metabolic activity. Intratreatment ADCmean increase (decrease of diffusion restriction) and low SUVmax (persistent low or decrease of 18F-FDG uptake) were most predictive of LRC. Intratreatment persistent high or increase of perfusion on CT/MRI (i.e. blood flow, volume, permeability) also predicted LRC. Low SUVmax and total lesion glycolysis (TLG) predicted favorable OS. The optimal timing to perform functional imaging to predict LRC or OS was 2-3 weeks after treatment initiation.
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Affiliation(s)
- Roland M Martens
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands.
| | - Daniel P Noij
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Meedie Ali
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Thomas Koopman
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - J Tim Marcus
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Marije R Vergeer
- Department of Radiation Oncology, VU University Medical Center, Amsterdam, the Netherlands
| | - Henrica de Vet
- Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Marcus C de Jong
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - C René Leemans
- Department of Otolaryngology - Head and Neck Surgery, VU University Medical Center, Amsterdam, the Netherlands
| | - Otto S Hoekstra
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Remco de Bree
- Department of Head and Neck Surgical Oncology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Pim de Graaf
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Ronald Boellaard
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Jonas A Castelijns
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
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Delishaj D, Ursino S, Pasqualetti F, Matteucci F, Cristaudo A, Soatti CP, Barcellini A, Paiar F. Set-up errors in head and neck cancer treated with IMRT technique assessed by cone-beam computed tomography: a feasible protocol. Radiat Oncol J 2018; 36:54-62. [PMID: 29621873 PMCID: PMC5903362 DOI: 10.3857/roj.2017.00493] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/04/2017] [Accepted: 12/18/2017] [Indexed: 11/03/2022] Open
Abstract
PURPOSE To investigate set-up errors, suggest the adequate planning target volume (PTV) margin and image-guided radiotherapy frequency in head and neck (H&N) cancer treated with intensity-modulated radiotherapy (IMRT) assessed by kV cone-beam computed tomography (CBCT). METHODS We analyzed 360 CBCTs in 60 patients with H&N cancer treated with IMRT. The target delineation was contoured according to ICRU62. PTVs were generated by adding a 3-5 mm margin in all directions to the respective clinical target volumes. The kV CBCT images were obtained at first three days of irradiation and weekly thereafter. The overall mean displacement, range, systematic (∑) and random (σ) errors were calculated. Adequate PTV margins were calculated according to the van Herk formula (2.5∑ + 0.7r). RESULTS The mean of set-up errors was less than 2 mm in any direction. The overall frequency of set-up displacements greater than 3 mm was 3.9% in medial-lateral (ML) direction, 8% in superior-inferior (SI) direction, and 15.5% in anterior-posterior (AP) direction. The range of translations shifts was 0-9 mm in ML direction, 0-5 mm in SI direction and 0-10 mm in AP direction, respectively. After systematic set-up errors correction, the adequate margin to overcome the problem of set-up errors was found to be less than 3 mm. CONCLUSION Image-guided kV CBCT was effective for the evaluation of set-up accuracy in H&N cancer. The kV CBCT at first three fractions and followed-by weekly appears adequate for reducing significantly set-up errors in H&N cancer treated with IMRT technique. Finally, 3-5 mm PTV margins appear adequate and safe to overcome the problem of set-up errors.
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Affiliation(s)
- Durim Delishaj
- Department of Radiation Oncology, University Hospital Santa Chiara, Pisa, Italy
| | - Stefano Ursino
- Department of Radiation Oncology, University Hospital Santa Chiara, Pisa, Italy
| | | | - Fabrizio Matteucci
- Department of Radiation Oncology, University Hospital Santa Chiara, Pisa, Italy
| | - Agostino Cristaudo
- Department of Radiation Oncology, University Hospital Santa Chiara, Pisa, Italy
| | | | - Amelia Barcellini
- Radiotherapy Unit, IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Fabiola Paiar
- Department of Radiation Oncology, University Hospital Santa Chiara, Pisa, Italy
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