Advertisement

Development of a semi-automatic alignment tool for accelerated localization of the prostate

      Abstract

      Purpose: Delivering high dose to prostate with external beam radiation has been shown to improve local tumor control. However, it has to be carefully performed to avoid partial target miss and delivering excessive dose to surrounding normal tissues. One way to achieve safe dose escalation is to precisely localize prostate immediately before daily treatment. Therefore, the radiation can be accurately delivered to the target. Once the prostate position is determined with high confidence, planning target volume (PTV) safety margin might be reduced for further reduction of rectal toxicity. A rapid computed tomography (CT)-based online prostate localization method is presented for this purpose.
      Methods and Materials: Immediately before each treatment session, the patient is immobilized and undergoes a CT scan in the treatment position using a CT scanner situated in the treatment room. At the CT console, posterior, anterior, left, and right extents of the prostate are manually identified on each axial slice. The translational prostate displacements relative to the planned position are estimated by simultaneously fitting these identified extents from this CT scan to a template created from the finely sliced planning CT scan. A total of 106 serial CT scans from 8 prostate cancer patients were performed immediately before treatments and used to retrospectively evaluate the precision of this daily prostate targeting method. The three-dimensional displacement of the prostate with respect to its planned position was estimated.
      Results: Five axial slices from each treatment CT scan were sufficient to produce a reliable correction when compared with prostate center of gravity (CoG) displacements calculated from physician-drawn contours. The differences (mean ± SD) between these two correction schemes in the right-left (R/L), posterior-anterior (P/A), and superior-inferior (S/I) directions are 0.0 ± 0.4 mm, 0.0 ± 0.7 mm, and −0.4 ± 1.9 mm, respectively. With daily CT extent-fitting correction, 97% of the scans showed that the entire posterior prostate gland was covered by PTV given a margin of 6 mm at the rectum-prostate interface and 10 mm elsewhere. In comparison, only 74% and 65% could be achieved by the corrections based on daily and weekly bony matching on portal images, respectively.
      Conclusions: Results show that daily CT extent fitting provides a precise correction of prostate position in terms of CoG. Identifying prostate extents on five axial CT slices at the CT console is less time-consuming compared with daily contouring of the prostate on many slices. Taking advantage of the prostate curvature in the longitudinal direction, this method also eliminates the necessity of identifying prostate base and apex. Therefore, it is clinically feasible and should provide an accelerated localization of the prostate immediately before daily treatment.

      Keywords

      To read this article in full you will need to make a payment
      ASTRO Member Login
      ASTRO Members, full access to the journal is a member benefit. Use your society credentials to access all journal content and features.

      Purchase one-time access:

      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Zelefsky M.J.
        • Leibel S.A.
        • Baudin P.B.
        • et al.
        Dose escalation with three-dimensional conformal radiation therapy affects the outcomes in prostate cancer.
        Int J Radiat Oncol Biol Phys. 1998; 41: 491-500
        • Hanks G.E.
        • Hanlon A.L.
        • Schultheiss T.E.
        • et al.
        Dose escalation with 3D conformal treatment.
        Int J Radiat Oncol Biol Phys. 1998; 41: 501-510
        • Pollack A.
        • Smith L.G.
        • Von Eschenbach A.C.
        External beam radiotherapy dose-response characteristics of 1127 men with prostate cancer treated in the PSA era.
        Int J Radiat Oncol Biol Phys. 2000; 48: 507-512
        • Zelefsky M.J.
        • Fuks Z.
        • Hunt M.
        • et al.
        High dose radiation delivered by intensity modulated conformal radiotherapy improves the outcome of localized prostate cancer.
        J Urol. 2001; 166: 876-881
        • Zelefsky M.J.
        • Fuks Z.
        • Happerset L.
        • et al.
        Clinical experience with intensity modulated radiation therapy (IMRT) in prostate cancer.
        Radio Oncol. 2000; 55: 241-249
        • Mohan D.S.
        • Kupelian P.A.
        • Willoughby T.R.
        Short-course intensity-modulated radiotherapy for localized prostate cancer with daily transabdominal ultrasound localization of the prostate gland.
        Int J Radiat Oncol Biol Phys. 2000; 46: 575-580
        • Lattanzi J.
        • McNeeley S.
        • Hanlon A.
        • et al.
        Ultrasound-based stereotactic guidance of precision conformal external beam radiation therapy in clinically localized prostate cancer.
        Urology. 2000; 55: 73-78
        • Pollack A.
        What’s your position? We have a need to know.
        Int J Radiat Oncol Biol Phys. 1999; 43: 705-706
        • Serago C.F.
        • Chungbin S.J.
        • Buskirk S.J.
        • et al.
        Initial experience with ultrasound localization for positioning prostate cancer patients for external beam radiation therapy.
        Int J Radiat Oncol Biol Phys. 2001; 51 (abstr): 94
        • Zellars R.C.
        • Roberson P.L.
        • Strawderman M.
        • et al.
        Prostate position late in the course of external beam therapy.
        Int J Radiat Oncol Biol Phys. 2000; 47: 655-660
        • Balter J.M.
        • Lam K.L.
        • Sandler H.M.
        • et al.
        Automated localization of the prostate at the time of treatment using implanted radiopaque markers.
        Int J Radiat Oncol Biol Phys. 1995; 33: 1281-1286
        • Vigneault E.
        • Pouliot J.
        • Laverdiere J.
        • et al.
        Electronic portal imaging device detection of radio-opaque markers for the evaluation of prostate position during megavoltage irradiation.
        Int J Radiat Oncol Biol Phys. 1997; 37: 205-212
        • Shimizu S.
        • Shirato H.
        • Kitamura K.
        • et al.
        Use of an implanted marker and real-time tracking of the marker for the positioning of prostate and bladder cancers.
        Int J Radiat Oncol Biol Phys. 2000; 48: 1591-1597
        • Nederveen A.
        • Lagendijk J.
        • Hofman P.
        Detection of fiducial gold markers for automatic on-line megavoltage position verification using a marker extraction kernel (MEK).
        Int Radiat Oncol Biol Phys. 2000; 47: 1435-1442
        • Older R.A.
        • Synder B.
        • Krupski T.L.
        • et al.
        Radioactive implant migration in patients treated for localized prostate cancer with interstitial brachytherapy.
        J Urol. 2001; 165: 1590-1592
        • Bergström P.
        • Lofröth P.
        • Widmark A.
        High-precision conformal radiotherapy (HPCRT) of prostate cancer.
        Int J Radiat Oncol Biol Phys. 1998; 42: 305-311
        • Teh B.S.
        • Mai W.-Y.
        • Uhl B.M.
        • et al.
        Intensity-modulated radiation therapy (IMRT) for prostate cancer with the use of a rectal balloon for prostate immobilization.
        Int J Radiat Oncol Biol Phys. 2001; 49: 705-712
        • Mackie T.R.
        • Holmes T.W.
        • Reckwerdt P.J.
        • et al.
        Tomotherapy.
        Int J Radiat Oncol Biol Phys. 1995; 6: 43-55
        • Uematsu M.
        • Fukui T.
        • Shioda A.
        • et al.
        A dual computed tomography linear accelerator unit for stereotactic radiation therapy.
        Int J Radiat Oncol Biol Phys. 1996; 35: 587-592
        • Mosleh-Shirazi M.A.
        • Evans P.M.
        • Swindell W.
        • et al.
        A cone-beam megavoltage CT scanner for treatment verification in conformal radiotherapy.
        Radio Oncol. 1998; 48: 319-328
        • Jaffray D.A.
        • Drake D.G.
        • Moreau M.M.
        • et al.
        A radiographic and tomographic imaging system integrated into a medical linear accelerator for localization of bone and soft-tissue targets.
        Int J Radiat Oncol Biol Phys. 1999; 45: 773-789
        • Lattanzi J.
        • McNeeley S.
        • Hanlon A.
        • et al.
        Daily CT localization for correcting portal errors in the treatment of prostate cancer.
        Int J Radiat Oncol Biol Phys. 1998; 41: 1079-1086
        • Mumper J.
        • Bieda M.
        • Tilton D.
        • et al.
        Determination of organ motion and patient setup error using an in-line CT in external beam radiation treatment.
        (abstr)43rd Annual Meeting of the American Association of Physicists in Medicine. 2001 (July 22–26 Salt Lake City, Utah)
        • Press W.H.
        • Teukolsky S.A.
        • Vetterling W.T.
        • et al.
        Numerical recipes in C. 2nd ed. Cambridge University Press, Cambridge, UK1993
        • Zelefsky M.J.
        • Happersett L.
        • Leibel S.A.
        • et al.
        The effect of treatment positioning on normal tissue dose in patients with prostate cancer treated with three-dimensional conformal radiotherapy.
        Int J Radiat Oncol Biol Phys. 1997; 37: 13-19
        • McLaughlin P.W.
        • Wygoda A.
        • Sahijdak W.
        • et al.
        The effect of patient position and treatment technique in conformal treatment of prostate cancer.
        Int J Radiat Oncol Biol Phys. 1999; 45: 407-413
        • Ling C.C.
        • Burman C.
        • Chui C.S.
        • et al.
        Conformal radiation treatment of prostate cancer using inversely-planned intensity-modulated photon beams produced with multileaf collimation.
        Int J Radiat Oncol Biol Phys. 1996; 35: 721-730
        • Van Herk M.
        • Bruce A.
        • Kroes A.P.
        • et al.
        • Guus
        Quantification of organ motion during conformal radiotherapy of the prostate by three dimensional image registration.
        Int J Radiat Oncol Biol Phys. 1995; 33: 1311-1320
        • Stroom J.C.
        • Koper P.C.M.
        • Korevaaar G.A.
        • et al.
        Internal organ motion in prostate cancer patients treated in prone and supine treatment position.
        Radio Oncol. 1999; 51: 237-248
        • Padhani A.R.
        • Khoo V.S.
        • Suckling J.
        • et al.
        Evaluating the effect of rectal distension and rectal movement on prostate gland position using cine MRI.
        Int J Radiat Oncol Biol Phys. 1999; 44: 525-533
        • Roeske J.C.
        • Forman J.D.
        • Mesina C.F.
        • et al.
        Evaluation of changes in the size and location of the prostate, seminal vesicles, bladder, and rectum during a course of external beam radiation therapy.
        Int J Radiat Oncol Biol Phys. 1995; 33: 1321-1329
        • Beard C.J.
        • Kijewski P.
        • Bussiere M.
        • et al.
        Analysis of prostate and seminal vesicle motion.
        Int J Radiat Oncol Biol Phys. 1996; 34: 451-458
        • Zelefsky M.J.
        • Crean D.
        • Mageras G.S.
        • et al.
        Quantification and predictors of prostate position variability in 50 patients evaluated with multiple CT scans during conformal radiotherapy.
        Radiat Oncol. 1999; 50: 225-234
        • Bel A.
        • Van Herk M.
        • Bartelink H.
        • et al.
        A verification procedure to improve patient setup accuracy using portal images.
        Radiother Oncol. 1993; 29: 253-260
        • Shalev S.
        • Gluhchev G.
        Decision rules for the correction of field setup parameters.
        Med Phys. 1994; 21 (abstr): 952
        • Yan D.
        • Wong J.
        • Vicini F.
        • et al.
        Adaptive modification of treatment planning to minimize the deleterious effects of treatment setup errors.
        Int J Radiat Oncol Biol Phys. 1997; 38: 197-206
        • Mechalakos J.
        • Mageras G.S.
        • Lovelock DM.
        • et al.
        Monte Carlo simulation of CT guided radiotherapy.
        (abstr)42nd Annual Meeting of the American Association of Physicists in Medicine. 2000 (July 23–28, Chicago, Illinois. (CD-ROM).)

      Comments

      Commenting Guidelines

      To submit a comment for a journal article, please use the space above and note the following:

      • We will review submitted comments as soon as possible, striving for within two business days.
      • This forum is intended for constructive dialogue. Comments that are commercial or promotional in nature, pertain to specific medical cases, are not relevant to the article for which they have been submitted, or are otherwise inappropriate will not be posted.
      • We require that commenters identify themselves with names and affiliations.
      • Comments must be in compliance with our Terms & Conditions.
      • Comments are not peer-reviewed.