Publications

@article{Weiner2016,

title = {Stereotactic body radiotherapy for primary hepatic malignancies – Report of a phase I/II institutional study},

author = {Ashley A. Weiner and Jeffrey Olsen and Daniel Ma and Pawel Dyk and Todd DeWees and Robert J. Myerson and Parag Parikh},

doi = {10.1016/j.radonc.2016.07.020},

issn = {0167-8140},

year  = {2016},

date = {2016-10-00},

journal = {Radiotherapy and Oncology},

volume = {121},

number = {1},

pages = {79--85},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pollock2016,

title = {The impact of breathing guidance and prospective gating during thoracic 4DCT imaging: an XCAT study utilizing lung cancer patient motion},

author = {Sean Pollock and John Kipritidis and Danny Lee and Kinga Bernatowicz and Paul Keall},

doi = {10.1088/0031-9155/61/17/6485},

issn = {1361-6560},

year  = {2016},

date = {2016-09-07},

journal = {Phys. Med. Biol.},

volume = {61},

number = {17},

pages = {6485--6501},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zwan2016,

title = {An EPID‐based system for gantry‐resolved MLC quality assurance for VMAT},

author = {Benjamin J. Zwan and Michael P. Barnes and Todsaporn Fuangrod and Cameron J. Stanton and Daryl J. O'Connor and Paul J. Keall and Peter B. Greer},

doi = {10.1120/jacmp.v17i5.6312},

issn = {1526-9914},

year  = {2016},

date = {2016-09-00},

journal = {J Applied Clin Med Phys},

volume = {17},

number = {5},

pages = {348--365},

publisher = {Wiley},

abstract = {Multileaf collimator (MLC) positions should be precisely and independently measured as a function of gantry angle as part of a comprehensive quality assurance (QA) program for volumetric‐modulated arc therapy (VMAT). It is also ideal that such a QA program has the ability to relate MLC positional accuracy to patient‐specific dosimetry in order to determine the clinical significance of any detected MLC errors. In this work we propose a method to verify individual MLC trajectories during VMAT deliveries for use as a routine linear accelerator QA tool. We also extend this method to reconstruct the 3D patient dose in the treatment planning system based on the measured MLC trajectories and the original DICOM plan file. The method relies on extracting MLC positions from EPID images acquired at 8.41 fps during clinical VMAT deliveries. A gantry angle is automatically tagged to each image in order to obtain the MLC trajectories as a function of gantry angle. This analysis was performed for six clinical VMAT plans acquired at monthly intervals for three months. The measured trajectories for each delivery were compared to the MLC positions from the DICOM plan file. The maximum mean error detected was 0.07 mm and a maximum root‐mean‐square error was 0.8 mm for any leaf of any delivery. The sensitivity of this system was characterized by introducing random and systematic MLC errors into the test plans. It was demonstrated that the system is capable of detecting random and systematic errors on the range of 1–2 mm and single leaf calibration errors of 0.5 mm. The methodology developed in the work has potential to be used for efficient routine linear accelerator MLC QA and pretreatment patient‐specific QA and has the ability to relate measured MLC positional errors to 3D dosimetric errors within a patient volume.PACS number(s): 87.55.Qr},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{O’Brien2016,

title = {The first implementation of respiratory triggered 4DCBCT on a linear accelerator},

author = {Ricky T O’Brien and Benjamin J Cooper and Chun-Chien Shieh and Uros Stankovic and Paul J Keall and Jan-Jakob Sonke},

doi = {10.1088/0031-9155/61/9/3488},

issn = {1361-6560},

year  = {2016},

date = {2016-05-07},

journal = {Phys. Med. Biol.},

volume = {61},

number = {9},

pages = {3488--3499},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Colvill2016,

title = {A dosimetric comparison of real-time adaptive and non-adaptive radiotherapy: A multi-institutional study encompassing robotic, gimbaled, multileaf collimator and couch tracking},

author = {Emma Colvill and Jeremy Booth and Simeon Nill and Martin Fast and James Bedford and Uwe Oelfke and Mitsuhiro Nakamura and Per Poulsen and Esben Worm and Rune Hansen and Thomas Ravkilde and Jonas Scherman Rydhög and Tobias Pommer and Per Munck af Rosenschold and Stephanie Lang and Matthias Guckenberger and Christian Groh and Christian Herrmann and Dirk Verellen and Kenneth Poels and Lei Wang and Michael Hadsell and Thilo Sothmann and Oliver Blanck and Paul Keall},

doi = {10.1016/j.radonc.2016.03.006},

issn = {0167-8140},

year  = {2016},

date = {2016-04-00},

journal = {Radiotherapy and Oncology},

volume = {119},

number = {1},

pages = {159--165},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Susko2016,

title = {Vaginal Dose Is Associated With Toxicity in Image Guided Tandem Ring or Ovoid-Based Brachytherapy},

author = {Matthew Susko and Oana Craciunescu and Sheridan Meltsner and Yun Yang and Beverly Steffey and Jing Cai and Junzo Chino},

doi = {10.1016/j.ijrobp.2015.12.360},

issn = {0360-3016},

year  = {2016},

date = {2016-04-00},

journal = {International Journal of Radiation Oncology*Biology*Physics},

volume = {94},

number = {5},

pages = {1099--1105},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Eslick2015,

title = {Measurement of preoperative lobar lung function with computed tomography ventilation imaging: progress towards rapid stratification of lung cancer lobectomy patients with abnormal lung function},

author = {Enid M. Eslick and Dale L. Bailey and Benjamin Harris and John Kipritidis and Mark Stevens and Bob T. Li and Elizabeth Bailey and Denis Gradinscak and Sean Pollock and Chris Htun and Robin Turner and Thomas Eade and Ali Aslani and Graeme Snowdon and Paul J. Keall},

doi = {10.1093/ejcts/ezv276},

issn = {1873-734X},

year  = {2016},

date = {2016-04-00},

journal = {Eur J Cardiothorac Surg},

volume = {49},

number = {4},

pages = {1075--1082},

publisher = {Oxford University Press (OUP)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kida2016,

title = {CT ventilation functional image-based IMRT treatment plans are comparable to SPECT ventilation functional image-based plans},

author = {Satoshi Kida and Matthieu Bal and Sven Kabus and Mohammadreza Negahdar and Xin Shan and Billy W. Loo and Paul J. Keall and Tokihiro Yamamoto},

doi = {10.1016/j.radonc.2016.02.019},

issn = {0167-8140},

year  = {2016},

date = {2016-03-00},

journal = {Radiotherapy and Oncology},

volume = {118},

number = {3},

pages = {521--527},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nguyen2016,

title = {High-Dose-Rate Monotherapy for Localized Prostate Cancer—What More Will It Take to Make This a Standard Therapy?},

author = {Paul L. Nguyen and Jay P. Ciezki},

doi = {10.1016/j.ijrobp.2015.12.375},

issn = {0360-3016},

year  = {2016},

date = {2016-03-00},

journal = {International Journal of Radiation Oncology*Biology*Physics},

volume = {94},

number = {4},

pages = {655--656},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pan2016,

title = {Acute esophagitis for patients with local–regional advanced non small cell lung cancer treated with concurrent chemoradiotherapy},

author = {Yi Pan and Carsten Brink and Marianne Knap and Azza A. Khalil and Christa H. Nyhus and Tine McCulloch and Bente Holm and Yi-long Wu and Tine Schytte and Olfred Hansen},

doi = {10.1016/j.radonc.2016.01.007},

issn = {0167-8140},

year  = {2016},

date = {2016-03-00},

journal = {Radiotherapy and Oncology},

volume = {118},

number = {3},

pages = {465--470},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Seregni2016,

title = {Motion prediction in MRI-guided radiotherapy based on interleaved orthogonal cine-MRI},

author = {M Seregni and C Paganelli and D Lee and P B Greer and G Baroni and P J Keall and M Riboldi},

doi = {10.1088/0031-9155/61/2/872},

issn = {1361-6560},

year  = {2016},

date = {2016-01-21},

journal = {Phys. Med. Biol.},

volume = {61},

number = {2},

pages = {872--887},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Oborn2015,

title = {Dose enhancement in radiotherapy of small lung tumors using inline magnetic fields: A Monte Carlo based planning study},

author = {B. M. Oborn and Y. Ge and N. Hardcastle and P. E. Metcalfe and P. J. Keall},

doi = {10.1118/1.4938580},

issn = {0094-2405},

year  = {2016},

date = {2016-01-00},

journal = {Med. Phys.},

volume = {43},

number = {1},

pages = {368--377},

publisher = {Wiley},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Li2015,

title = {A robust noise reduction technique for time resolved CT},

author = {Zhoubo Li and Lifeng Yu and Shuai Leng and Eric E. Williamson and Amy L. Kotsenas and David R. DeLone and Armando Manduca and Cynthia H. McCollough},

doi = {10.1118/1.4938576},

issn = {0094-2405},

year  = {2016},

date = {2016-01-00},

journal = {Med. Phys.},

volume = {43},

number = {1},

pages = {347--359},

publisher = {Wiley},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Shieh2015b,

title = {Markerless tumor tracking using short kilovoltage imaging arcs for lung image-guided radiotherapy},

author = {Chun-Chien Shieh and Paul J Keall and Zdenka Kuncic and Chen-Yu Huang and Ilana Feain},

doi = {10.1088/0031-9155/60/24/9437},

issn = {1361-6560},

year  = {2015},

date = {2015-12-21},

journal = {Phys. Med. Biol.},

volume = {60},

number = {24},

pages = {9437--9454},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Cooper2015,

title = {Quantifying the image quality and dose reduction of respiratory triggered 4D cone-beam computed tomography with patient-measured breathing},

author = {Benjamin J Cooper and Ricky T O’Brien and John Kipritidis and Chun-Chien Shieh and Paul J Keall},

doi = {10.1088/0031-9155/60/24/9493},

issn = {1361-6560},

year  = {2015},

date = {2015-12-21},

journal = {Phys. Med. Biol.},

volume = {60},

number = {24},

pages = {9493--9513},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pollock2015,

title = {Audiovisual biofeedback breathing guidance for lung cancer patients receiving radiotherapy: a multi-institutional phase II randomised clinical trial},

author = {Sean Pollock and Ricky O’Brien and Kuldeep Makhija and Fiona Hegi-Johnson and Jane Ludbrook and Angela Rezo and Regina Tse and Thomas Eade and Roland Yeghiaian-Alvandi and Val Gebski and Paul J Keall},

doi = {10.1186/s12885-015-1483-7},

issn = {1471-2407},

year  = {2015},

date = {2015-12-00},

journal = {BMC Cancer},

volume = {15},

number = {1},

publisher = {Springer Science and Business Media LLC},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Juneja2015,

title = {Prostate motion during radiotherapy of prostate cancer patients with and without application of a hydrogel spacer: a comparative study},

author = {Prabhjot Juneja and Andrew Kneebone and Jeremy T. Booth and David I. Thwaites and Ramandeep Kaur and Emma Colvill and Jin A. Ng and Paul J. Keall and Thomas Eade},

doi = {10.1186/s13014-015-0526-1},

issn = {1748-717X},

year  = {2015},

date = {2015-12-00},

journal = {Radiat Oncol},

volume = {10},

number = {1},

publisher = {Springer Science and Business Media LLC},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Splatt2015,

title = {Major complications of high‐energy microwave ablation for percutaneous CT‐guided treatment of lung malignancies: Single‐centre experience after 4 years},

author = {Alexander M Splatt and Karin Steinke},

doi = {10.1111/1754-9485.12345},

issn = {1754-9485},

year  = {2015},

date = {2015-10-00},

journal = {J Med Imag Rad Onc},

volume = {59},

number = {5},

pages = {609--616},

publisher = {Wiley},

abstract = {AbstractPurposeTo evaluate the rate of major complications related to percutaneous computed tomography (CT)‐guided microwave ablation (MWA) of primary and secondary lung malignancies performed at our institution over a 4‐year period.MethodsFrom May 2010 to September 2014, 70 MWAs were performed on 51 patients. All major intra‐ and post‐procedural complications (as defined by the classification proposed by the Society of Interventional Radiology) were retrospectively analysed. The results were correlated with a systematic review of the available literature on MWA in the lung.ResultsMajor complications were encountered in 14 out of 70 ablations (20%). Twenty‐one separate major complications were encountered (some ablations lead to more than one major complication). One death occurred within 30 days of ablation, though the relationship to the procedure remains uncertain. Other major complications included: nine pneumothoraces requiring drain insertion (12.9%), four cases of large effusion requiring drainage (5.7%), two cases of significant pulmonary haemorrhage altering clinical management (2.9%), two infections (2.9%), one case of mechanical failure (1.4%), one chest wall burn (1.4%) and one case of pleural seeding (1.4%). Major complications were much more likely to occur if the nodule was located within 7 mm from the pleura.ConclusionMWA of pulmonary tumours carries moderate risk; nevertheless, the usually manageable complications should not deter from undertaking a potentially curative therapy for poor surgical candidates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Paganelli2015,

title = {Quantification of lung tumor rotation with automated landmark extraction using orthogonal cine MRI images},

author = {Chiara Paganelli and Danny Lee and Peter B Greer and Guido Baroni and Marco Riboldi and Paul Keall},

doi = {10.1088/0031-9155/60/18/7165},

issn = {1361-6560},

year  = {2015},

date = {2015-09-21},

journal = {Phys. Med. Biol.},

volume = {60},

number = {18},

pages = {7165--7178},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pollock2015b,

title = {Breathing guidance in radiation oncology and radiology: A systematic review of patient and healthy volunteer studies},

author = {Sean Pollock and Robyn Keall and Paul Keall},

doi = {10.1118/1.4928488},

issn = {2473-4209},

year  = {2015},

date = {2015-09-00},

journal = {Medical Physics},

volume = {42},

number = {9},

pages = {5490--5509},

publisher = {Wiley},

abstract = {Purpose:The advent of image‐guided radiation therapy has led to dramatic improvements in the accuracy of treatment delivery in radiotherapy. Such advancements have highlighted the deleterious impact tumor motion can have on both image quality and radiation treatment delivery. One approach to reducing tumor motion irregularities is the use of breathing guidance systems during imaging and treatment. These systems aim to facilitate regular respiratory motion which in turn improves image quality and radiation treatment accuracy. A review of such research has yet to be performed; it was therefore their aim to perform a systematic review of breathing guidance interventions within the fields of radiation oncology and radiology.Methods:From August 1–14, 2014, the following online databases were searched: Medline, Embase, PubMed, and Web of Science. Results of these searches were filtered in accordance to a set of eligibility criteria. The search, filtration, and analysis of articles were conducted in accordance with preferred reporting items for systematic reviews and meta‐analyses. Reference lists of included articles, and repeat authors of included articles, were hand‐searched.Results:The systematic search yielded a total of 480 articles, which were filtered down to 27 relevant articles in accordance to the eligibility criteria. These 27 articles detailed the intervention of breathing guidance strategies in controlled studies assessing its impact on such outcomes as breathing regularity, image quality, target coverage, and treatment margins, recruiting either healthy adult volunteers or patients with thoracic or abdominal lesions. In 21/27 studies, significant (p < 0.05) improvements from the use of breathing guidance were observed.Conclusions:There is a trend toward the number of breathing guidance studies increasing with time, indicating a growing clinical interest. The results found here indicate that further clinical studies are warranted that quantify the clinical impact of breathing guidance, along with the health technology assessment to determine the advantages and disadvantages of breathing guidance.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jakobi2015,

title = {Identification of Patient Benefit From Proton Therapy for Advanced Head and Neck Cancer Patients Based on Individual and Subgroup Normal Tissue Complication Probability Analysis},

author = {Annika Jakobi and Anna Bandurska-Luque and Kristin Stützer and Robert Haase and Steffen Löck and Linda-Jacqueline Wack and David Mönnich and Daniela Thorwarth and Damien Perez and Armin Lühr and Daniel Zips and Mechthild Krause and Michael Baumann and Rosalind Perrin and Christian Richter},

doi = {10.1016/j.ijrobp.2015.04.031},

issn = {0360-3016},

year  = {2015},

date = {2015-08-00},

journal = {International Journal of Radiation Oncology*Biology*Physics},

volume = {92},

number = {5},

pages = {1165--1174},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wallace2015,

title = {Determining appropriate imaging parameters for kilovoltage intrafraction monitoring: an experimental phantom study},

author = {D Wallace and J A Ng and P J Keall and R T O’Brien and P R Poulsen and P Juneja and J T Booth},

doi = {10.1088/0031-9155/60/12/4835},

issn = {1361-6560},

year  = {2015},

date = {2015-06-21},

journal = {Phys. Med. Biol.},

volume = {60},

number = {12},

pages = {4835--4847},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Petasecca2015,

title = {MagicPlate-512: A 2D silicon detector array for quality assurance of stereotactic motion adaptive radiotherapy},

author = {M. Petasecca and M. K. Newall and J. T. Booth and M. Duncan and A. H. Aldosari and I. Fuduli and A. A. Espinoza and C. S. Porumb and S. Guatelli and P. Metcalfe and E. Colvill and D. Cammarano and M. Carolan and B. Oborn and M. L. F. Lerch and V. Perevertaylo and P. J. Keall and A. B. Rosenfeld},

doi = {10.1118/1.4921126},

issn = {0094-2405},

year  = {2015},

date = {2015-06-00},

journal = {Med. Phys.},

volume = {42},

number = {6Part1},

pages = {2992--3004},

publisher = {Wiley},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pollock2015c,

title = {SU‐E‐J‐185: A Systematic Review of Breathing Guidance in Radiation Oncology and Radiology},

author = {S Pollock and R Keall and P Keall},

doi = {10.1118/1.4924271},

issn = {2473-4209},

year  = {2015},

date = {2015-06-00},

journal = {Medical Physics},

volume = {42},

number = {6Part10},

pages = {3307--3308},

publisher = {Wiley},

abstract = {Purpose:The advent of image‐guided radiation therapy (IGRT) has led to dramatic improvements in the accuracy of treatment delivery in radiotherapy. Such advancements have highlighted the deleterious impact tumor motion can have on both image quality and radiation treatment delivery. One approach to reducing tumor motion is the use of breathing guidance systems during imaging and treatment. A review of such research had not yet been performed, it was therefore our aim to perform a systematic review of breathing guidance interventions within the fields of radiation oncology and radiology.Methods:Results of online database searches were filtered in accordance to a set of eligibility criteria. The search, filtration, and analysis of articles were conducted in accordance with the PRISMAStatement reporting standard (Preferred Reporting Items for Systematic reviews and Meta‐Analyses) utilizing the PICOS approach (Participants, Intervention, Comparison, Outcome, Study design).Participants:Cancer patients, healthy volunteers.Intervention:Biofeedback breathing guidance systems.Comparison:No breathing guidance of the same breathing type.Outcome:Regularity of breathing signal and anatomic/tumor motion, medical image quality, radiation treatment margins and coverage, medical imaging and radiation treatment times.Study design:Quantitative and controlled prospective or retrospective trials.Results:The systematic search yielded a total of 479 articles, which were filtered down to 27 relevant articles in accordance to the eligibility criteria. The vast majority of investigated outcomes were significantly positively impacted by the use of breathing guidance; however, this was dependent upon the nature of the breathing guidance system and study design. In 25/27 studies significant improvements from the use of breathing guidance were observed.Conclusion:The results found here indicate that further clinical studies are warranted which quantify more comprehensively the clinical impact of The results found here indicate that further clinical studies are warranted which quantify more comprehensively the clinical impact of breathing guidance interventions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Myronakis2015,

title = {SU‐E‐J‐186: Using 4DCT‐Based Motion Modeling to Predict Motion and Duty Cycle On Successive Days of Gated Radiotherapy},

author = {M Myronakis and W Cai and S Dhou and F Cifter and J Lewis},

doi = {10.1118/1.4924272},

issn = {2473-4209},

year  = {2015},

date = {2015-06-00},

journal = {Medical Physics},

volume = {42},

number = {6Part10},

pages = {3308--3308},

publisher = {Wiley},

abstract = {Purpose:To determine if 4DCT‐based motion modeling and external surrogate motion measured during treatment simulation can enhance prediction of residual tumor motion and duty cycle during treatment delivery.Methods:This experiment was conducted using simultaneously recorded tumor and external surrogate motion acquired over multiple fractions of lung cancer radiotherapy. These breathing traces were combined with the XCAT phantom to simulate CT images. Data from the first day was used to estimate the residual tumor motion and duty cycle both directly from the 4DCT (the current clinical standard), and from external‐surrogate based motion modeling. The accuracy of these estimated residual tumor motions and duty cycles are evaluated by comparing to the measured internal/external motions from other treatment days.Results:All calculations were done for 25% and 50% duty cycles. The results indicated that duty cycle derived from 4DCT information alone is not enough to accurately predict duty cycles during treatment. Residual tumor motion was determined from the recorded data and compared with the estimated residual tumor motion from 4DCT. Relative differences in residual tumor motion varied from −30% to 55%, suggesting that more information is required to properly predict residual tumor motion. Compared to estimations made from 4DCT, in three out of four patients examined, the 30 seconds of motion modeling data was able to predict the duty cycle with better accuracy than 4DCT. No improvement was observed in prediction of residual tumor motion for this dataset.Conclusion:Motion modeling during simulation has the potential to enhance 4DCT and provide more information about target motion, duty cycles, and delivered dose. Based on these four patients, 30 seconds of motion modeling data produced improve duty cycle estimations but showed no measurable improvement in residual tumor motion prediction. More patient data is needed to verify this Result.I would like to acknowledge funding from MRA, VARIAN Medical Systems, Inc.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Manning2015,

title = {SU‐E‐J‐187: Management of Optic Organ Motion in Fractionated Stereotactic Radiotherapy},

author = {M Manning and J Maurer},

doi = {10.1118/1.4924273},

issn = {2473-4209},

year  = {2015},

date = {2015-06-00},

journal = {Medical Physics},

volume = {42},

number = {6Part10},

pages = {3308--3308},

publisher = {Wiley},

abstract = {Purpose:Fractionated stereotactic radiotherapy (FSRT) for optic nerve tumors can potentially use planning target volume (PTV) expansions as small as 1–5 mm. However, the motion of the intraorbital segment of the optic nerve has not been studied.Methods:A subject with a right optic nerve sheath meningioma underwent CT simulation in three fixed gaze positions: right, left, and fixed forward at a marker. The gross tumor volume (GTV) and the organs‐at‐risk (OAR) were contoured on all three scans. An IMRT plan using 10 static non‐coplanar fields to 50.4 Gy in 28 fractions was designed to treat the fixed‐forward gazing GTV with a 1 mm PTV, then resulting coverage was evaluated for the GTV in the three positions. As an alternative, the composite structures were computed to generate the internal target volume (ITV), 1 mm expansion free‐gazing PTV, and planning organat‐risk volumes (PRVs) for free‐gazing treatment. A comparable IMRT plan was created for the free‐gazing PTV.Results:If the patient were treated using the fixed forward gaze plan looking straight, right, and left, the V100% for the GTV was 100.0%, 33.1%, and 0.1%, respectively. The volumes of the PTVs for fixed gaze and free‐gazing plans were 0.79 and 2.21 cc, respectively, increasing the PTV by a factor of 2.6. The V100% for the fixed gaze and free‐gazing plans were 0.85 cc and 2.8 cc, respectively increasing the treated volume by a factor of 3.3.Conclusion:Fixed gaze treatment appears to provide greater organ sparing than free‐gazing. However unanticipated intrafraction right or left gaze can produce a geometric miss. Further study of optic nerve motion appears to be warranted in areas such as intrafraction optical confirmation of fixed gaze and optimized gaze directions to minimize lens and other normal organ dose in cranial radiotherapy.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kipritidis2015,

title = {Measuring interfraction and intrafraction lung function changes during radiation therapy using four‐dimensional cone beam CT ventilation imaging},

author = {John Kipritidis and Geoffrey Hugo and Elisabeth Weiss and Jeffrey Williamson and Paul J. Keall},

doi = {10.1118/1.4907991},

issn = {2473-4209},

year  = {2015},

date = {2015-03-00},

journal = {Medical Physics},

volume = {42},

number = {3},

pages = {1255--1267},

publisher = {Wiley},

abstract = {Purpose:Adaptive ventilation guided radiation therapy could minimize the irradiation of healthy lung based on repeat lung ventilation imaging (VI) during treatment. However the efficacy of adaptive ventilation guidance requires that interfraction (e.g., week‐to‐week), ventilation changes are not washed out by intrafraction (e.g., pre‐ and postfraction) changes, for example, due to patient breathing variability. The authors hypothesize that patients undergoing lung cancer radiation therapy exhibit larger interfraction ventilation changes compared to intrafraction function changes. To test this, the authors perform the first comparison of interfraction and intrafraction lung VI pairs using four‐dimensional cone beam CT ventilation imaging (4D‐CBCT VI), a novel technique for functional lung imaging.Methods:The authors analyzed a total of 215 4D‐CBCT scans acquired for 19 locally advanced non‐small cell lung cancer (LA‐NSCLC) patients over 4–6 weeks of radiation therapy. This set of 215 scans was sorted into 56 interfraction pairs (including first day scans and each of treatment weeks 2, 4, and 6) and 78 intrafraction pairs (including pre/postfraction scans on the same‐day), with some scans appearing in both sets. VIs were obtained from the Jacobian determinant of the transform between the 4D‐CBCT end‐exhale and end‐inhale images after deformable image registration. All VIs were deformably registered to their corresponding planning CT and normalized to account for differences in breathing effort, thus facilitating image comparison in terms of (i) voxelwise Spearman correlations, (ii) mean image differences, and (iii) gamma pass rates for all interfraction and intrafraction VI pairs. For the side of the lung ipsilateral to the tumor, we applied two‐sided t‐tests to determine whether interfraction VI pairs were more different than intrafraction VI pairs.Results:The (mean ± standard deviation) Spearman correlation for interfraction VI pairs was , which was significantly lower than for intrafraction pairs (, p = 0.0002). Conversely, mean absolute ventilation differences were larger for interfraction pairs than for intrafraction pairs, with  and , respectively (p < 10−15). Applying a gamma analysis with ventilation/distance tolerance of 25%/10 mm, we observed mean pass rate of (69% ± 20%) for interfraction VIs, which was significantly lower compared to intrafraction pairs (80% ± 15%, with p ∼ 0.0003). Compared to the first day scans, all patients experienced at least one subsequent change in median ipsilateral ventilation ≥10%. Patients experienced both positive and negative ventilation changes throughout treatment, with the maximum change occurring at different weeks for different patients.Conclusions:The authors’ data support the hypothesis that interfraction ventilation changes are larger than intrafraction ventilation changes for LA‐NSCLC patients over a course of conventional lung cancer radiation therapy. Longitudinal ventilation changes are observed to be highly patient‐dependent, supporting a possible role for adaptive ventilation guidance based on repeat 4D‐CBCT VIs. We anticipate that future improvement of 4D‐CBCT image reconstruction algorithms will improve the capability of 4D‐CBCT VI to resolve interfraction ventilation changes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Shieh2015,

title = {Improving thoracic four-dimensional cone-beam CT reconstruction with anatomical-adaptive image regularization (AAIR)},

author = {Chun-Chien Shieh and John Kipritidis and Ricky T O'Brien and Benjamin J Cooper and Zdenka Kuncic and Paul J Keall},

doi = {10.1088/0031-9155/60/2/841},

issn = {1361-6560},

year  = {2015},

date = {2015-01-21},

journal = {Phys. Med. Biol.},

volume = {60},

number = {2},

pages = {841--868},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Seth2015,

title = {Cytogenetic Low-Dose Hyperradiosensitivity Is Observed in Human Peripheral Blood Lymphocytes},

author = {Isheeta Seth and Michael C. Joiner and James D. Tucker},

doi = {10.1016/j.ijrobp.2014.09.020},

issn = {0360-3016},

year  = {2015},

date = {2015-01-00},

journal = {International Journal of Radiation Oncology*Biology*Physics},

volume = {91},

number = {1},

pages = {82--90},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ravkilde2014,

title = {Fast motion-including dose error reconstruction for VMAT with and without MLC tracking},

author = {Thomas Ravkilde and Paul J Keall and Cai Grau and Morten Høyer and Per R Poulsen},

doi = {10.1088/0031-9155/59/23/7279},

issn = {1361-6560},

year  = {2014},

date = {2014-12-07},

journal = {Phys. Med. Biol.},

volume = {59},

number = {23},

pages = {7279--7296},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kim2014,

title = {Motion management within two respiratory-gating windows: feasibility study of dual quasi-breath-hold technique in gated medical procedures},

author = {Taeho Kim and Siyong Kim and Yang-Kyun Park and Kaylin K Youn and Paul Keall and Rena Lee},

doi = {10.1088/0031-9155/59/21/6583},

issn = {1361-6560},

year  = {2014},

date = {2014-11-07},

journal = {Phys. Med. Biol.},

volume = {59},

number = {21},

pages = {6583--6594},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gemici2014,

title = {In Regard to Muijs et al},

author = {Cengiz Gemici},

doi = {10.1016/j.ijrobp.2014.06.004},

issn = {0360-3016},

year  = {2014},

date = {2014-11-00},

journal = {International Journal of Radiation Oncology*Biology*Physics},

volume = {90},

number = {3},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{O’Brien2014b,

title = {Optimizing 4DCBCT projection allocation to respiratory bins},

author = {Ricky T O’Brien and John Kipritidis and Chun-Chien Shieh and Paul J Keall},

doi = {10.1088/0031-9155/59/19/5631},

issn = {1361-6560},

year  = {2014},

date = {2014-10-07},

journal = {Phys. Med. Biol.},

volume = {59},

number = {19},

pages = {5631--5649},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kirkpatrick2014,

title = {Recurrent Malignant Gliomas},

author = {John P. Kirkpatrick and John H. Sampson},

doi = {10.1016/j.semradonc.2014.06.006},

issn = {1053-4296},

year  = {2014},

date = {2014-10-00},

journal = {Seminars in Radiation Oncology},

volume = {24},

number = {4},

pages = {289--298},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Goodall2014,

title = {Technical Note: A method for improving the calibration reproducibility of an ionization chamber detector array},

author = {Simon Goodall and Steve Morgan},

doi = {10.1118/1.4892607},

issn = {2473-4209},

year  = {2014},

date = {2014-09-00},

journal = {Medical Physics},

volume = {41},

number = {9},

publisher = {Wiley},

abstract = {Purpose:This paper describes an extension to a wide field calibration method implemented on a commercial detector array in order to improve the reproducibility of the calibration procedure.Methods:Following the standard array calibration procedure, two additional 10 × 10 cm exposures were acquired for each array axis with the detector array shifted by ±10 cm in the transverse or axial axes, or by ±10 cm in the positive or negative diagonal axes. These exposures were compared with a final baseline 10 × 10 cm exposure captured with the detector repositioned at the isocenter. The measurements were used to calculate a linear off‐axis correction gradient which was then applied to the stored calibration factors.Results:The mean coefficient of variation between five repeat calibrations was reduced from 4.17% to 0.48% and the maximum percentage error in individual calibration factors was reduced from 6.46% to 0.77%.Conclusions:The reproducibility of the calibration factors of an ionization chamber array was increased by capturing a baseline exposure and two further off‐axis readings per calibration axis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Colvill2014,

title = {DMLC tracking and gating can improve dose coverage for prostate VMAT},

author = {E. Colvill and P. R. Poulsen and J. T. Booth and R. T. O'Brien and J. A. Ng and P. J. Keall},

doi = {10.1118/1.4892605},

issn = {2473-4209},

year  = {2014},

date = {2014-09-00},

journal = {Medical Physics},

volume = {41},

number = {9},

publisher = {Wiley},

abstract = {Purpose:To assess and compare the dosimetric impact of dynamic multileaf collimator (DMLC) tracking and gating as motion correction strategies to account for intrafraction motion during conventionally fractionated prostate radiotherapy.Methods:A dose reconstruction method was used to retrospectively assess the dose distributions delivered without motion correction during volumetric modulated arc therapy fractions for 20 fractions of five prostate cancer patients who received conventionally fractionated radiotherapy. These delivered dose distributions were compared with the dose distributions which would have been delivered had DMLC tracking or gating motion correction strategies been implemented. The delivered dose distributions were constructed by incorporating the observed prostate motion with the patientˈs original treatment plan to simulate the treatment delivery. The DMLC tracking dose distributions were constructed using the same dose reconstruction method with the addition of MLC positions from Linac log files obtained during DMLC tracking simulations with the observed prostate motions input to the DMLC tracking software. The gating dose distributions were constructed by altering the prostate motion to simulate the application of a gating threshold of 3 mm for 5 s.Results:The delivered dose distributions showed that dosimetric effects of intrafraction prostate motion could be substantial for some fractions, with an estimated dose decrease of more than 19% and 34% from the planned CTVD99% and PTV D95% values, respectively, for one fraction. Evaluation of dose distributions for DMLC tracking and gating deliveries showed that both interventions were effective in improving the CTV D99% for all of the selected fractions to within 4% of planned value for all fractions. For the delivered dose distributions the difference in rectum V65% for the individual fractions from planned ranged from −44% to 101% and for the bladder V65% the range was −61% to 26% from planned. The application of tracking decreased the maximum rectum and bladder V65% difference to 6% and 4%, respectively.Conclusions:For the first time, the dosimetric impact of DMLC tracking and gating to account for intrafraction motion during prostate radiotherapy has been assessed and compared with no motion correction. Without motion correction intrafraction prostate motion can result in a significant decrease in target dose coverage for a small number of individual fractions. This is unlikely to effect the overall treatment for most patients undergoing conventionally fractionated treatments. Both DMLC tracking and gating demonstrate dose distributions for all assessed fractions that are robust to intrafraction motion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Grimes2014,

title = {Comparison of internal dose estimates obtained using organ‐level, voxel S value, and Monte Carlo techniques},

author = {Joshua Grimes and Anna Celler},

doi = {10.1118/1.4892606},

issn = {2473-4209},

year  = {2014},

date = {2014-09-00},

journal = {Medical Physics},

volume = {41},

number = {9},

publisher = {Wiley},

abstract = {Purpose:The authors’ objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient‐specific anatomy on the final dose estimate.Methods:Six patients injected with99mTc‐hydrazinonicotinamide‐Tyr3‐octreotide were included in this study. A hybrid planar/SPECT imaging protocol was used to estimate 99mTc time‐integrated activity coefficients (TIACs) for kidneys, liver, spleen, and tumors. Additionally, TIACs were predicted for 131I, 177Lu, and 90Y assuming the same biological half‐lives as the 99mTc labeled tracer. The TIACs were used as input for OLINDA/EXM for organ‐level dose calculation and voxel level dosimetry was performed using the voxel S value method and Monte Carlo simulation. Dose estimates for 99mTc, 131I, 177Lu, and 90Y distributions were evaluated by comparing (i) organ‐level S values corresponding to each method, (ii) total tumor and organ doses, (iii) differences in right and left kidney doses, and (iv) voxelized dose distributions calculated by Monte Carlo and the voxel S value technique.Results:The S values for all investigated radionuclides used by OLINDA/EXM and the corresponding patient‐specific S values calculated by Monte Carlo agreed within 2.3% on average for self‐irradiation, and differed by as much as 105% for cross‐organ irradiation. Total organ doses calculated by OLINDA/EXM and the voxel S value technique agreed with Monte Carlo results within approximately ±7%. Differences between right and left kidney doses determined by Monte Carlo were as high as 73%. Comparison of the Monte Carlo and voxel S value dose distributions showed that each method produced similar dose volume histograms with a minimum dose covering 90% of the volume (D90) agreeing within ±3%, on average.Conclusions:Several aspects of OLINDA/EXM dose calculation were compared with patient‐specific dose estimates obtained using Monte Carlo. Differences in patient anatomy led to large differences in cross‐organ doses. However, total organ doses were still in good agreement since most of the deposited dose is due to self‐irradiation. Comparison of voxelized doses calculated by Monte Carlo and the voxel S value technique showed that the 3D dose distributions produced by the respective methods are nearly identical.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lee2014b,

title = {Dynamic keyhole: A novel method to improve MR images in the presence of respiratory motion for real-time MRI},

author = {Danny Lee and Sean Pollock and Brendan Whelan and Paul Keall and Taeho Kim},

doi = {10.1118/1.4883882},

issn = {0094-2405},

year  = {2014},

date = {2014-07-00},

journal = {Med. Phys.},

volume = {41},

number = {7},

publisher = {Wiley},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Connell2014,

title = {Delivery validation of an automated modulated electron radiotherapy plan},

author = {T. Connell and A. Alexander and P. Papaconstadopoulos and M. Serban and S. Devic and J. Seuntjens},

doi = {10.1118/1.4876297},

issn = {0094-2405},

year  = {2014},

date = {2014-06-00},

journal = {Med. Phys.},

volume = {41},

number = {6Part1},

publisher = {Wiley},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Freudenberg2014,

title = {On the dose calculation at the cellular level and its implications for the RBE of^{99m}Tc and^{123}I},

author = {R. Freudenberg and R. Runge and U. Maucksch and V. Berger and J. Kotzerke},

doi = {10.1118/1.4876296},

issn = {0094-2405},

year  = {2014},

date = {2014-06-00},

journal = {Med. Phys.},

volume = {41},

number = {6Part1},

publisher = {Wiley},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tomic2014,

title = {Characterization of calibration curves and energy dependence GafChromic^{TM}

 XR-QA2 model based radiochromic film dosimetry system},

author = {Nada Tomic and Chrystian Quintero and Bruce R. Whiting and Saad Aldelaijan and Hamed Bekerat and LiHeng Liang and François DeBlois and Jan Seuntjens and Slobodan Devic},

doi = {10.1118/1.4876295},

issn = {0094-2405},

year  = {2014},

date = {2014-06-00},

journal = {Med. Phys.},

volume = {41},

number = {6Part1},

publisher = {Wiley},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lee2014,

title = {Audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI},

author = {D Lee and P B Greer and J Arm and P Keall and T Kim},

doi = {10.1088/1742-6596/489/1/012033},

issn = {1742-6596},

year  = {2014},

date = {2014-03-24},

journal = {J. Phys.: Conf. Ser.},

volume = {489},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Norris2014,

title = {A set of 4D pediatric XCAT reference phantoms for multimodality research},

author = {Hannah Norris and Yakun Zhang and Jason Bond and Gregory M. Sturgeon and Anum Minhas and Daniel J. Tward and J. T. Ratnanather and M. I. Miller and D. Frush and E. Samei and W. P. Segars},

doi = {10.1118/1.4864238},

issn = {2473-4209},

year  = {2014},

date = {2014-03-00},

journal = {Medical Physics},

volume = {41},

number = {3},

publisher = {Wiley},

abstract = {Purpose:The authors previously developed an adult population of 4D extended cardiac‐torso (XCAT) phantoms for multimodality imaging research. In this work, the authors develop a reference set of 4D pediatric XCAT phantoms consisting of male and female anatomies at ages of newborn, 1, 5, 10, and 15 years. These models will serve as the foundation from which the authors will create a vast population of pediatric phantoms for optimizing pediatric CT imaging protocols.Methods:Each phantom was based on a unique set of CT data from a normal patient obtained from the Duke University database. The datasets were selected to best match the reference values for height and weight for the different ages and genders according to ICRP Publication 89. The major organs and structures were segmented from the CT data and used to create an initial pediatric model defined using nonuniform rational B‐spline surfaces. The CT data covered the entire torso and part of the head. To complete the body, the authors manually added on the top of the head and the arms and legs using scaled versions of the XCAT adult models or additional models created from cadaver data. A multichannel large deformation diffeomorphic metric mapping algorithm was then used to calculate the transform from a template XCAT phantom (male or female 50th percentile adult) to the target pediatric model. The transform was applied to the template XCAT to fill in any unsegmented structures within the target phantom and to implement the 4D cardiac and respiratory models in the new anatomy. The masses of the organs in each phantom were matched to the reference values given in ICRP Publication 89. The new reference models were checked for anatomical accuracy via visual inspection.Results:The authors created a set of ten pediatric reference phantoms that have the same level of detail and functionality as the original XCAT phantom adults. Each consists of thousands of anatomical structures and includes parameterized models for the cardiac and respiratory motions. Based on patient data, the phantoms capture the anatomic variations of childhood, such as the development of bone in the skull, pelvis, and long bones, and the growth of the vertebrae and organs. The phantoms can be combined with existing simulation packages to generate realistic pediatric imaging data from different modalities.Conclusions:The development of patient‐derived pediatric computational phantoms is useful in providing variable anatomies for simulation. Future work will expand this ten‐phantom base to a host of pediatric phantoms representative of the public at large. This can provide a means to evaluate and improve pediatric imaging devices and to optimize CT protocols in terms of image quality and radiation dose.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hansen2014,

title = {Improved proton computed tomography by dual modality image reconstruction},

author = {David C. Hansen and Jørgen Breede Baltzer Petersen and Niels Bassler and Thomas Sangild Sørensen},

doi = {10.1118/1.4864239},

issn = {2473-4209},

year  = {2014},

date = {2014-03-00},

journal = {Medical Physics},

volume = {41},

number = {3},

publisher = {Wiley},

abstract = {Purpose:Proton computed tomography (CT) is a promising image modality for improving the stopping power estimates and dose calculations for particle therapy. However, the finite range of about 33 cm of water of most commercial proton therapy systems limits the sites that can be scanned from a full 360° rotation. In this paper the authors propose a method to overcome the problem using a dual modality reconstruction (DMR) combining the proton data with a cone‐beam x‐ray prior.Methods:A Catphan 600 phantom was scanned using a cone beam x‐ray CT scanner. A digital replica of the phantom was created in the Monte Carlo code Geant4 and a 360° proton CT scan was simulated, storing the entrance and exit position and momentum vector of every proton. Proton CT images were reconstructed using a varying number of angles from the scan. The proton CT images were reconstructed using a constrained nonlinear conjugate gradient algorithm, minimizing total variation and the x‐ray CT prior while remaining consistent with the proton projection data. The proton histories were reconstructed along curved cubic‐spline paths.Results:The spatial resolution of the cone beam CT prior was retained for the fully sampled case and the 90° interval case, with the MTF = 0.5 (modulation transfer function) ranging from 5.22 to 5.65 linepairs/cm. In the 45° interval case, the MTF = 0.5 dropped to 3.91 linepairs/cm For the fully sampled DMR, the maximal root mean square (RMS) error was 0.006 in units of relative stopping power. For the limited angle cases the maximal RMS error was 0.18, an almost five‐fold improvement over the cone beam CT estimate.Conclusions:Dual modality reconstruction yields the high spatial resolution of cone beam x‐ray CT while maintaining the improved stopping power estimation of proton CT. In the case of limited angles, the use of prior image proton CT greatly improves the resolution and stopping power estimate, but does not fully achieve the quality of a 360° proton CT scan.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Veiga2014,

title = {Toward adaptive radiotherapy for head and neck patients: Feasibility study on using CT‐to‐CBCT deformable registration for “dose of the day” calculations},

author = {Catarina Veiga and Jamie McClelland and Syed Moinuddin and Ana Lourenço and Kate Ricketts and James Annkah and Marc Modat and Sébastien Ourselin and Derek D'Souza and Gary Royle},

doi = {10.1118/1.4864240},

issn = {2473-4209},

year  = {2014},

date = {2014-03-00},

journal = {Medical Physics},

volume = {41},

number = {3},

publisher = {Wiley},

abstract = {Purpose:The aim of this study was to evaluate the appropriateness of using computed tomography (CT) to cone‐beam CT (CBCT) deformable image registration (DIR) for the application of calculating the “dose of the day” received by a head and neck patient.Methods:NiftyReg is an open‐source registration package implemented in our institution. The affine registration uses a Block Matching‐based approach, while the deformable registration is a GPU implementation of the popular B‐spline Free Form Deformation algorithm. Two independent tests were performed to assess the suitability of our registrations methodology for “dose of the day” calculations in a deformed CT. A geometric evaluation was performed to assess the ability of the DIR method to map identical structures between the CT and CBCT datasets. Features delineated in the planning CT were warped and compared with features manually drawn on the CBCT. The authors computed the dice similarity coefficient (DSC), distance transformation, and centre of mass distance between features. A dosimetric evaluation was performed to evaluate the clinical significance of the registrations errors in the application proposed and to identify the limitations of the approximations used. Dose calculations for the same intensity‐modulated radiation therapy plan on the deformed CT and replan CT were compared. Dose distributions were compared in terms of dose differences (DD), gamma analysis, target coverage, and dose volume histograms (DVHs). Doses calculated in a rigidly aligned CT and directly in an extended CBCT were also evaluated.Results:A mean value of 0.850 in DSC was achieved in overlap between manually delineated and warped features, with the distance between surfaces being less than 2 mm on over 90% of the pixels. Deformable registration was clearly superior to rigid registration in mapping identical structures between the two datasets. The dose recalculated in the deformed CT is a good match to the dose calculated on a replan CT. The DD is smaller than 2% of the prescribed dose on 90% of the bodyˈs voxels and it passes a 2% and 2 mm gamma‐test on over 95% of the voxels. Target coverage similarity was assessed in terms of the 95%‐isodose volumes. A mean value of 0.962 was obtained for the DSC, while the distance between surfaces is less than 2 mm in 95.4% of the pixels. The method proposed provided adequate dose estimation, closer to the gold standard than the other two approaches. Differences in DVH curves were mainly due to differences in the OARs definition (manual vs warped) and not due to differences in dose estimation (dose calculated in replan CT vs dose calculated in deformed CT).Conclusions:Deforming a planning CT to match a daily CBCT provides the tools needed for the calculation of the “dose of the day” without the need to acquire a new CT. The initial clinical application of our method will be weekly offline calculations of the “dose of the day,” and use this information to inform adaptive radiotherapy (ART). The work here presented is a first step into a full implementation of a “dose‐driven” online ART.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Belley2014,

title = {Toward an organ based dose prescription method for the improved accuracy of murine dose in orthovoltage x‐ray irradiators},

author = {Matthew D. Belley and Chu Wang and Giao Nguyen and Rathnayaka Gunasingha and Nelson J. Chao and Benny J. Chen and Mark W. Dewhirst and Terry T. Yoshizumi},

doi = {10.1118/1.4864237},

issn = {2473-4209},

year  = {2014},

date = {2014-03-00},

journal = {Medical Physics},

volume = {41},

number = {3},

publisher = {Wiley},

abstract = {Purpose:Accurate dosimetry is essential when irradiating mice to ensure that functional and molecular endpoints are well understood for the radiation dose delivered. Conventional methods of prescribing dose in mice involve the use of a single dose rate measurement and assume a uniform average dose throughout all organs of the entire mouse. Here, the authors report the individual average organ dose values for the irradiation of a 12, 23, and 33 g mouse on a 320 kVp x‐ray irradiator and calculate the resulting error from using conventional dose prescription methods.Methods:Organ doses were simulated in the Geant4 application for tomographic emission toolkit using the MOBY mouse whole‐body phantom. Dosimetry was performed for three beams utilizing filters A (1.65 mm Al), B (2.0 mm Al), and C (0.1 mm Cu + 2.5 mm Al), respectively. In addition, simulated x‐ray spectra were validated with physical half‐value layer measurements.Results:Average doses in soft‐tissue organs were found to vary by as much as 23%–32% depending on the filter. Compared to filters A and B, filter C provided the hardest beam and had the lowest variation in soft‐tissue average organ doses across all mouse sizes, with a difference of 23% for the median mouse size of 23 g.Conclusions:This work suggests a new dose prescription method in small animal dosimetry: it presents a departure from the conventional approach of assigninga single dose value for irradiation of mice to a more comprehensive approach of characterizing individual organ doses to minimize the error and uncertainty. In human radiation therapy, clinical treatment planning establishes the target dose as well as the dose distribution, however, this has generally not been done in small animal research. These results suggest that organ dose errors will be minimized by calibrating the dose rates for all filters, and using different dose rates for different organs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{O’Brien2014c,

title = {Respiratory motion guided four dimensional cone beam computed tomography: encompassing irregular breathing},

author = {Ricky T O’Brien and Benjamin J Cooper and John Kipritidis and Chun-Chien Shieh and Paul J Keall},

doi = {10.1088/0031-9155/59/3/579},

issn = {1361-6560},

year  = {2014},

date = {2014-02-07},

journal = {Phys. Med. Biol.},

volume = {59},

number = {3},

pages = {579--595},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{O’Brien2014,

title = {Respiratory motion guided four dimensional cone beam computed tomography: encompassing irregular breathing},

author = {Ricky T O’Brien and Benjamin J Cooper and John Kipritidis and Chun-Chien Shieh and Paul J Keall},

doi = {10.1088/0031-9155/59/3/579},

issn = {1361-6560},

year  = {2014},

date = {2014-02-07},

journal = {Phys. Med. Biol.},

volume = {59},

number = {3},

pages = {579--595},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tehrani2013,

title = {Real-time estimation of prostate tumor rotation and translation with a kV imaging system based on an iterative closest point algorithm},

author = {Joubin Nasehi Tehrani and Ricky T O’Brien and Per Rugaard Poulsen and Paul Keall},

doi = {10.1088/0031-9155/58/23/8517},

issn = {1361-6560},

year  = {2013},

date = {2013-12-07},

journal = {Phys. Med. Biol.},

volume = {58},

number = {23},

pages = {8517--8533},

publisher = {IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}