Presentation Outline. Patient Setup Imaging in RT: Getting the Most Bang for your Buck. Main Errors in RT. Hypothetical Patient Examples

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Patient Setup Imaging in RT: Getting the Most Bang for your Buck Olivier Morin, PhD UC SF Comprehensive Cancer Center San Francisco, CA Presentation Outline Errors in RT. Radiographic films in RT.

Regis Hotel, San Francisco, CA New imaging development.

1 Patient Setup Imaging in RT: Getting the Most Bang for your Buck Olivier Morin, PhD UC SF Comprehensive Cancer Center San Francisco, CA Presentation Outline Errors in RT. Radiographic films in RT. On-board digital imaging. EPID, Tomosynthesis and Cone Beam CT. Clinical applications. Prostate, H&N and lungs. Saturday, April 2 nd, 2011 UCSF Annual Course St. Regis Hotel, San Francisco, CA New imaging development. 1 2 Main Errors in RT Hypothetical Patient Examples Gross errors Anatomy acquisition Target delineation Patient Setup Anatomy changes PTV was proposed to assure tumor coverage despite these 3 error types GTV CTV PTV % fractions Patient A Relaxed Good overall health No serious pain Patient B Nervous Good overall health No serious pain Patient C Nervous Poor overall health Highly symptomatic Random Systematic Patient or organ movement OAR OAR With improved setup Setup Errors

2 Hypothetical Patient Examples Are we giving these four patients the same quality of treatment? % fractions Patient D Relaxed Good overall health No serious pain Weight loss Mask no longer fits Modalities for Management of Patient Setup Errors Portal imaging with radiographic films (2D). Portal imaging with electronic portal imaging device (2D). Cone Beam CT (3D). Others (Tomosynthesis, 4D CBCT, US, etc.) Setup Errors 5 6 Films in RT ( Film Age ) Films vs. Digital Modalities Perkin Elmer (Flat Kodak panel Films manufacturer) Stock % change Eastman Kodak (EK) Perkin Elmer (PKI) Radiographic Films: Good spatial resolution (fine grain). Poor bone contrast (up to 8 MU). Difficult to incorporate in the digital record system. Won t go away tomorrow (QA, backup, etc.). Not accepted as an IGRT method by RTOG. EPID or CBCT: Lower spatial resolution than film. Higher bone contrast (2 MU). Direct digital record. Can be enhanced digitally (W&L). Require considerable training/cost. Opens the door for new QA procedures or techniques. 7 8

3 In-Room Imaging Options with EPID All new treatment machines are equipped with on-board digital imaging 9 10 Head and Neck Tomograms Projections 20 o -60 o arc Multiple tomograms Lung Digital Tomograms 20 o, 5 sec, 1.2 MU 40 o, 10 sec, 2.4 MU 60 o, 20 sec, 3.6 MU EPI, 2 sec, 2 MU Coronal Sagittal Dose, Time, Motion blurring Tomograms with 40 degree arc provide the best overall performance. Reference: Descovich et. al., Medical Physics, Vol. 35, Issue 4,

Presentation Outline Errors in RT. Using Digital Tomograms Lung: 40 o, 2 cgy H&N: 40 o, 0.

EPID, Tomosynthesis and Cone Beam CT. Clinical applications. Prostate, H&N and lungs. New imaging development.

Position of the isocenter is important for the clinical utility of the Tomograms and the specificity of the

All patients aligned every day with 2D EPID. Investigational: Fiducial-less imaging.

4 Presentation Outline Errors in RT. Using Digital Tomograms Lung: 40 o, 2 cgy H&N: 40 o, 0.6 cgy Prostate: 40 o, 0.6 cgy Radiographic films in RT. On-board digital imaging. EPID, Tomosynthesis and Cone Beam CT. Clinical applications. Prostate, H&N and lungs. New imaging development. Agreement of < 2 mm obtained at all treatment sites (prostate, HN and lungs) compared with CBCT. Position of the isocenter is important for the clinical utility of the Tomograms and the specificity of the alignment Prostate Patient Setup Current: Gold markers implanted in the prostate. All patients aligned every day with 2D EPID. Investigational: Fiducial-less imaging. 3D CBCT performed everyday. Alignment on soft-tissue and dosimetric evaluation of surrounding OARs Reference: Zeidan et. al., Internation Journal of Radiation Oncology, Biology, Physics, Vol. 67, Issue 3, 2007.

H&N Patient Setup Current: Patient alignment using bony landmarks.

Verification of gross anatomical changes (3D).

Evaluation of the dosimetric impact of anatomical changes.

, Internation Journal of Radiation Oncology, Biology, Physics, Vol.

Before Now Patient Setup Strategies (H&N) IGRT Strategy IG% Frequencies

$fraction only 3 79 47 Mean of five fraction 15 58 26 Weekly imaging 20 60$

5 H&N Patient Setup Current: Patient alignment using bony landmarks. Weekly imaging (CBCT or EPID). Verification of gross anatomical changes (3D). Investigational: Patient specific correction strategies. Evaluation of the dosimetric impact of anatomical changes Reference: Zeidan et. al., Internation Journal of Radiation Oncology, Biology, Physics, Vol. 67, Issue 3, Before Now Patient Setup Strategies (H&N) IGRT Strategy IG% Frequencies Errors > 3 mm Frequencies Errors > 5 mm No imaging Imaging first fraction only Mean of five fraction Weekly imaging First five fraction + weekly It remains difficult to identify rotations and distortions on portal images 6 mm Imaging every other fraction, running mean Reference: Zeidan et. al., Internation Journal of Radiation Oncology, Biology, Physics, Vol. 67, Issue 3,

Lung Patient Setup Current: Large margins (up to a few

(daily?). Carina vs. bony anatomy for setup.

First 5 days, then weekly. Bony alignment nt vs. carina.

6 Lung Patient Setup Current: Large margins (up to a few cm). Margins based on 4DCT (MIP). Weekly imaging (CBCT or EPID)? Investigational: Patient specific correction strategies (daily?). Carina vs. bony anatomy for setup. Lung Patient Setup Study 15 patients so far. 4DCT for planning. Imaged with EPID, Tomosynthesis and CBCT. CT. First 5 days, then weekly. Bony alignment nt vs. carina D shift (cm) Lung Study - Preliminary Results Systematic errors greater than 1 cm were observed. Motion of the carina is small (< 5mm). CBCT and Tomograms are superior to visualize the carina than portal images. Alignment on the bony anatomy may not assure tumor coverage Days of radiation treatment Setup errors vary greatly between patients. New On-board Imaging Technology Stationary Tomosynthesis Array for Radiotherapy (STAR) High-current cold CNT cathode technology 4 x 18 cold x-ray sources Reference: Yom et. al., 14th World Conference on Lung Cancer,

Clinical Applications with STAR 52 images portals

Periodic image verification Real-time tracking

for prostate and H&N. Probably not for lungs.

and frequency) are not only site but also patient

Tomosynthesis may be a good alternative to CBCT

25 26 Acknowledgments UCSF Jean Pouliot Michelle

7 Clinical Applications with STAR 52 images portals acquired (5 s) Reconstruction of tomograms Periodic image verification Real-time tracking Reference: Maltz et. al., Medical Physics, 36(5), In Summary The age of radiographic films for patient setup has passed. Portal imaging is a good first order correction for prostate and H&N. Probably not for lungs. Correction strategies for setup errors (modality and frequency) are not only site but also patient dependent. Tomosynthesis may be a good alternative to CBCT for lung setup but more development is needed Acknowledgments UCSF Jean Pouliot Michelle Aubin Martina Descovich Sue Yom Vivian Weinberg Neil Kirby Christine Malfatti Complete team of therapists Siemens Ali Bani-Hashemi Jonathan Maltz Bijumon Gangadharan Ajay Paidi Supratik Bose 27

CBCT of the patient in the treatment position has gained wider applications for setup verification during radiotherapy.

CBCT of the patient in the treatment position has gained wider applications for setup verification during radiotherapy. Gülcihan CÖDEL Introduction The aim of this study is to evaluate the changes in bladder doses during the volumetric modulated arc therapy (VMAT) treatment of prostate cancer patients using weekly cone