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Professional Focus

Dr. Xia's research interests focus on three areas of research:

(1) Development of optimized IMRT plan parameters, including beam directions, efficient treatment delivery while keeping the same plan quality. Her team has developed an optimization routine that is interfaced with a research planning system (developed at the University of North Carolina, PLUNC) used for dose calculation and display result. Using this established research tool, they are planning to develop a computer aided beam angle selection methodology to minimize the number of beam angles and to reduce the total treatment time. Their hypothesis is that the criteria of the best beam angles should include the selection of the shortest pathway to the tumor target, the avoidance of direct radiation to the critical structures, and sufficient separation between beam directions.

(2) Development robust methods in detection of temporal changes in patients during treatment delivery. In the current treatment, it is assumed that anatomies of patients are static during the entire course of treatment. Recent developments in image-guided radiotherapy allow Radiotherapist to acquire two-dimensional projected images or three-dimensional images more frequently, thus giving them the ability to obtain abundant image information about the changes in patient anatomy and changes in treatment positions. Using these two-dimensional and three-dimensional images, they are planning to develop robust detection methods for temporal changes during radiotherapy: (a) in the rigid body regions, such as the brain and head regions; (b) in the semi-rigid body images, such as head and neck regions; (c) in the non-rigid regions such as the prostate, breast, and lung regions.

(3) Development of adaptive treatment strategies for image-guided radiotherapy. With image-guided radiotherapy, there is abundant information about the temporal changes in patients' anatomies and in treatment positions. The urgent problems are how to correct for and adaptive to these changes during treatment planning and/or treatment delivery. In the treatment prostate, Dr. Xia and her colleagues are planning to develop a treatment delivery protocol using tracking radiation portals to adapt to daily motion of the prostate while delivering a conformal dose distribution to the pelvic lymph nodes.

Education

1983	Beijing Normal University	BS	Physics
1986	Beijing Normal University	MS	Physics
1993	University of Virginia	PhD	Physics
1993-1994	State University of New York	Post-doctoral fellow	Chemistry
1995-1995	University of Minnesota	Graduate student	Department of Radiology
1995-1997	UCSF	Medical Physics Resident	Radiation Oncology

Professional Experience

2004-present	UCSF	Associate Professor	Radiation Oncology
1999-2004	UCSF	Assistant Professor	Radiation Oncology
1997-1998	UCSF	Clinical Instructor	Radiation Oncology
1986-1988	Beijing Normal University	Teaching Instructor	Physics

Awards & Honors

1983	Outstanding Graduate Award, Beijing Normal University, Beijing, P.R. China
9/1990-5/1991	Departmental Fellowship, University of Virginia, Charlottesville, VA
9/1991-5/1992	Departmental Fellowship, University of Virginia, Charlottesville, VA
9/1992-5/1993	DuPont Fellowship, University of Virginia, Charlottesville, VA
10/1998	Basic Science Travel Grant Award, American Society for Therapeutic Radiology and Oncology (ASTRO)
2/2008	Distinguished service and contribution to the American Society for Therapeutic Radiology and Oncology (ASTRO)’s Educational Programs

Publications - Partial Listing since 2000 (Out of 65)

Posner MD, Quivey JM, Akazawa PF, Xia P, Akazawa C, Verhey LJ: Dose optimization for the treatment of anaplastic thyroid carcinoma: a comparison of treatment planning techniques. Int. J. Radiat. Oncol. Biol. Phys. 48(2):475-483 (2000).

Xia P, Fu KK, Wong GW, Akazawa C, Verhey LJ: Comparison of treatment plans involving intensity modulated radiotherapy for nasopharyngeal carcinoma. Int. J. Radiat. Oncol. Biol. Phys. 48(2):329-337 (2000).

Sultanem K, Shu H-K, Xia P, Akazawa C, Quivey JM, Verhey LJ, Fu KK: Three-dimensional intensity modulated radiotherapy in the treatment of nasopharyngeal carcinoma: the University of California-San Francisco experience. Int. J. Radiat. Oncol. Biol. Phys. 48(3):711-722 (2000).

Shu HG, Lee TT, Vigneault E, Xia P, Pickett B, Phillips TL, Roach III M: Toxicity following high dose 3D conformal and intensity modulated radiation therapy (IMRT) for clinically localized prostate cancer. Urology 57(1):102-7 (2001).

Xia P, Verhey, LJ: Delivery systems of intensity modulated radiotherapy using multi-leaf collimators. Med. Dosimetry 26(2):169-177, (2001).

Xia P, Pickett B, Vigneault E, Verhey LJ, Roach III M: Forward or inversely planned segmental multileaf collimator IMRT and sequential tomotherapy to treat multiple dominant intraprostatic lesions of prostate cancer to 90 Gy. Int. J. Radiat. Oncol. Biol. Phys. 51(1):244-154 (2001).

Xia P, Chuang C, Verhey LJ: Communication and sampling rate Limitations in IMRT delivery using a dynamic multi-leaf collimator system. Med. Phys. 29(3), 412-423 (2002).

Xia P, Huang AB, Verhey LJ: A leaf sequencing algorithm to enlarge treatment field length in IMRT. Med. Phys. 29(6) 991-998 (2002).

Lee N, Chuang C, Quievy JM, Phillips TL, Akazawa P, Verhey LJ, Xia P: Skin toxicity due to intensity-modulated radiation therapy for the treatment of head and neck carcinoma. Int. J. Radiat. Oncol. Biol. Phys. 53(3): 630-637 (2002).

Lee N, Xia P, Akazawa C, Akazawa P, Quivey JM, Weinberg V, Fu KK: Intensity-Modulated Radiotherapy in the Treatment of Nasopharyngeal Carcinoma: An Update of the UCSF Experience. Int. J. Radiat. Oncol. Biol. Phys. 53(1):12-22 (2002).

Chuang C, Verhey LJ, Xia P: Investigation of the use of MOSFET for clinical IMRT dosimetric verification. Med. Phys. 29(6):1109 (2002).

Pirzkall A, Carol MP, Pickett B, Xia P, Roach III M, Verhey LJ: The effect of beam energy and number of fields on photon-based IMRT for deep-seated targets. Int. J. Radiat. Oncol. Biol. Phys, 53, 434-442 (2002)

Lee N, Hoffman R, Xia P, Phillips TL, Quivey JM, Weinberg V, Hsu J: Managing Nasopharyngeal Carcinoma With Intracavitary Brachytherapy — One Institution's 45 Year Experience. J of Brachytherapy, 1(2):74-82 (2002).

Cardenas R, Cheng KH, Verhey LJ, Xia P, Davis L, Cannon B: A self consistent normalized calibration protocol for three dimensional magnetic resonance gel dosimetry. Magn. Reson. Imaging, 20 667-679(2002).

Nakamura JL, Pirzkall A, Carol MP, Xia P , Simth V, Wara W, Petti P, Verhey, JL, and Sneed P: Comparison of intensity modulated radiosurgery to gamma knife for challenging skull base lesions. Int. J. Radiat. Oncol. Biol. Phys, 1;55(1):99-109 (2003).

Huang, D, Xia P, Quivey MJ, Verhey JL, Kaplan M, Akazawa P, Akazawa C, Lee N: Comparison of treatment plans using intensity-modulated radiotherapy and three dimensional conformal radiotherapy for paranasal sinus carcinoma. Int. J. Radiat. Oncol. Biol. Phys, 56(1):158-68 (2003).

Ezzell GA, Galvin JM, Low D, Palta JR, Rosen I, Sharpe MB, Xia P, Xiao Y, Xing L, Yu CX,: Guidance document on delivery, treatment planning, and clinical implementation of IMRT: report of the IMRT Subcommittee of the AAPM Radiation Therapy Committee. Med Phys. 30(8):2089-115, (2003).

Lee N, Xia P, Fischbein NJ, Akazawa P, Akazawa C, Quivey JM: Intensity-modulated radiation therapy for head-and-neck cancer: the UCSF experience focusing on target volume delineation. Int J Radiat Oncol Biol Phys, 57(1):49-60 (2003).

Lee N, Akazawa C, Akazawa P, Quivey JM, Tang C, Verhey, LJ, and Xia P: A forward-planned treatment technique using multsegments in the treatment of head-neck cancer. Int J Radiat Oncol Biol Phys, 59(2):584-94 (2004).

Galvin JM, Ezzell G, Eisbrauch A, Yu C, Butler B, Xiao Y, Rosen I, Rosenman J, Sharpe M, Xing L, Xia P, Lomax T, Low DA, Palta J; American Society for Therapeutic Radiology and Oncology; American Association of Physicists in Medicine: Implementing IMRT in clinical practice: a joint document of the American Society for Therapeutic Radiology and Oncology and the American Association of Physicists in Medicine. Int J Radiat Oncol Biol Phys. 58(5):1616-34 (2004).

Xia P, Lee N, Liu YM, Poon I, Weinberg V, Shin E, Quivey JM, and Verhey LJ: A Study of Planning Dose Constraints for Treatment of Nasopharyngeal Carcinoma Using a Commercial Inverse Treatment Planning System. Int J Radiat Oncol Biol Phys, 59 (3): 886-896 (2004).

Poon I, Fischbein N, Lee N, Akazawa P, Xia P, Quivey J, Phillips T: A population-based atlas and clinical target volume for the head-and-neck lymph nodes. Int J Radiat Oncol Biol Phys.59(5):1301-11 (2004).

Sun X, Yu N, Xia P: Effects of the Intensity Levels and Beam Map Resolutions on Static IMRT Plans. Med Phys, 31(5) 1158-1165 (2004).

Sun X, Xia P: A new smoothing procedure to reduce delivery segments for static MLC-based IMRT planning. Med Phys, 31 (9) 2402-2411 (2004).

Pouliot J, Bani-Hashemi A, Chen J, Svatos M, Ghelmansarai F, Mitschke M, Aubin M, and Xia P, Morin M, Bucci MK, Roach M III, Hernandez P, Zheng Z, Hristov D, Verhey L. Low-Dose Megavoltage Cone-Beam CT for Radiation therapy. Int J Radiat Oncol Biol Phys. 61(2), 238-246, (2005).

Xia P, Yu N, Xing L, Sun X, and Verhey LJ : Investigation of Using A Power Function as A Cost Function in Inverse Planning Optimization. Med. Phys 32(4) 920-927 (2005).

Park C, Kim Y, Lee N, Bucci, KM, Quivey JM, Verhey LJ, Xia P: A Method to Account for Dose Fractionation in Analysis of IMRT Treatment Plans: Modified Equivalent Uniform Dose. Int J Radiat Oncol Biol Phys, Vol. 62, No. 3, pp. 925-932, (2005).

Hansen EK, Bucci, MK, Quivey JM, Weinberg V, and Xia P: Repeat CT Imaging and Re-Planning During the Course of IMRT for Head and Neck Cancer. Int J Radiat Oncol Biol Phys, Vol. 64 (2), pp. 355-62 (2006).

Hansen EK, Larson DA, Aubin M, Chen J, Descovich M, Gillis AM, Morin O, Xia P, Pouliot J. Image guided radiotherapy (IGRT) using megavoltage cone-beam CT (MV-CBCT) for treatment of paraspinous tumors in the presence of orthopedic hardware. Int J Radiat Oncol Biol Phys  Vol. 66(2), pp. 323-6 (2006).

Wang-Chesebro, A, Xia, P,  Coleman, J, Akazawa, C,  Roach III, M, IMRT Improves Lymph Node Coverage and Dose to Critical Structures Compared with 3D Conformal Radiation Therapy in Clinically Localized Prostate Cancer, Int J Radiat Oncol Biol Phys  Vol. 66(3), pp. 654-62 (2006).

Morin O, Chen, J, Aubin M, Bose S, Chen H, Descovich M, Xia P, and Pouliot J, Dose calculation using megavoltage cone-beam CT. Int J Radiat Oncol Biol Phys. Vol. 67(4):1201-10 (2007).

Daly ME, Chen AM, Bucci MK, El-sayed I, Xia P, Kaplan MJ, and Elsele DW, Intensity-modulated radiation therapy for malignancies of the nasal cavity and paranasal sinuses. Int J Radiat Oncol Biol Phys.  Vol. 67(1):151-7 (2007).

Takamiya R, Missett B, Weinberg V, Akazawa P, Akazawa C,  Zytkovicz A,  Bucci MK, Lee N, Quivey,JM, Xia P, Five Beam Angles Can Produce Feasible IMRT Plans in the Treatment of Oropharyngeal Carcinoma, J. Applied Clinical Med. Phys. 8(2), 26-36 (2007).

Kim Y, Verhey LJ, and Xia P: A Feasibility Study Of Using Conventional Jaws To Deliver Imrt Plans In The Treatment Of Prostate Cancer, Phys. Med. Biol. Vol. 52. 2147-2156 (2007).  

Morin O, Gillis A, Descovich M,  Chen J,  Aubin M,  Aubry JF, Chen H, Xia P, and Pouliot J : Patient Dose Considerations for Routine Megavoltage Cone-Beam CT Imaging, Med. Phys. 34(5) 1819-27 (2007).

Ezzel LC, Hansen EK, Quivery JM, and Xia P, Detection of Treatment Setup Errors Between Two CT Scans for Patients with Head and Neck Cancer, Med. Phys. 34 (8) 3233-42 (2007).

Chen AM, Daly ME, Bucci MK, Xia P, Akazawa C, Quivey JM, Weinberg V, Garcia J, Lee NY, Kaplan MJ, El-Sayed I, Eisele DW, Fu KK, Phillips TL: Carcinomas Of The Paranasal Sinuses And Nasal Cavity Treated With Radiotherapy At A Single Institution Over Five Decades: Are We Making Improvement?, Int J Radiat Oncol Biol Phys.  Vol. 69(1):141-7 (2007).

Poon I,  Xia P,  Weinberg V, Sultanem K, Akazawa C, Akazawa P, Verhey L, Quivey MJ, and Lee N: A Treatment Planning Analysis Of Inverse-Planned And Forward-Planned Intensity-Modulated Radiation Therapy In Nasopharyngeal Carcinoma, Int J Radiat Oncol Biol Phys. 69(5):1625-33 (2007).

Ludlum E, Mu G, Weinberg V, Roach III M, Verhey L, and Xia P: An Algorithm for Shifting MLC Shapes to Adjust for Daily Prostate Movement during Concurrent Treatment with Pelvic Lymph Nodes, Med. Phys. 34(12):4750-6 (2007).

Chung TH, Lee B, Park E, Lu JJ, Xia P, Can All Centers Plan IMRT Effectively? An External Audit of Dosimetric Comparisons between 3DCRT and IMRT for Adjuvant Chemoradiation for Gastric Cancer, Int J Radiat Oncol Biol Phys. 71(4):1167-74 (2008).

Ludlum E and Xia P, Comparison of IMRT planning with two-step and one-step optimization: a way to simplify IMRT, Phys Med Biol. 53(3):807-21 (2008).

Mu G, Ludlum E, and Xia P, Impact of MLC leaf position errors on simple and complex IMRT plans for head and neck cancer, Phys Med Biol. 53(1):77-88 (2008).

Chan LM, Xia P, Gottschalk AR, Akazawa M, Scala M, Pickett B,  Hsu IC, Speight J, and  Roach III M, Proposed Rectal Dose Constraints for Patients Undergoing Definitive Whole Pelvic Radiotherapy for Clinically Localized Prostate Cancer, Int J Radiat Oncol Biol Phys. 72 (1): 69-77 (2008).

Huang K, Xia P,  Chuang C, Weinberg V, Glastonbury CM, Eisele DW, Lee NY, Yom SY, Phillips TL, and Quivey JM, Intensity-Modulated Chemoradiation for Treatment of Stage III and IV Oropharyngeal Carcinoma: The University of California-San Francisco Experience, Cancer. 113(3):497-507 (2008).

Chung, HT, Xia P, Chan, L, Park-Somers E,  and Roach III, M, Does IGRT improve the toxicity profile in whole pelvic-treated high-risk prostate cancer? A comparison between IG-IMRT and IMRT, Int J Radiat Oncol Biol Phys 2008 (in press).

Hossain S, Xia P, Chuang CF, Verhey LJ, Gottschalk A, Mu G, Ma L, Simulated Real Time Image Guided Intra-Fraction Tracking-Delivery for Hypofractionated Prostate IMRT, Med phys 2008 (in press).

Vitolo V,  Millender LE,  Quivey JM,  Yom, SS,  Schechter NR,  Jereczek-Fossa BA, Milani F,  Orecchia R,  Xia P, Assessment of Carotid Artery Dose in the Treatment of Nasopharyngeal Cancer with IMRT Versus Conventional Radiotherapy, Radiother Oncol. 2008 (in press).