1. Lauren Hein
In partial fulfillment of RT 412
University of Wisconsin-La Crosse
Radiation Therapy Program
Three-dimensional Imaging for High Dose Rate Cervical Brachytherapy Treatment Planning

2. Background1,2,3
Cervical cancer is the third most common cancer in women worldwide
Current standard of care for early stage node positive or locally advanced cervical cancer is external beam radiation therapy with concurrent chemotherapy, followed by high dose rate cervical brachytherapy
Intracavitary cervical brachytherapy uses tandem and ovoid applicators

3. Organs at risk: bladder, rectum and sigmoid colon2
Move around the implanted applicators daily so localization and dose verification is a crucial part of treatment planning4
Success of brachytherapy depends on accurate identification and localization of the uterus, cervix, and residual disease, as well as accurate placement of tandem and ovoid within the uterine canal3
Knowing the OAR movement can help to limit the uncertainties and potentially detrimental consequences of overdosing sensitive organs4

4. Orthogonal Images2,5
Historically, two-dimensional orthogonal x-ray images were used for treatment planning
Do not provide soft tissue visualization
Inadequate target coverage, insufficient dose delivery, and a larger percentage of treatment failure
Unknown PTV coverage and visibility, limited opportunity for flexibility of dose distribution, unknown spatial relationship between applicator and surrounding OAR
Benefit: radiation therapists do not need special training or further education to use the machines and create adequate images

5. Three-dimensional Imaging2,4,5
Delineate the soft tissue around the applicators
Localize the disease site
Visualize the PTV
Identify the OAR
Alter the target volume dose coverage to be more conformal for each individual patient

6. Visualization of the tumor and adjacent organs2
Improved target coverage
Local control
Reduced late toxicity

7. Computed Tomography1,8
Three-dimensional CT vs. two-dimensional imaging
Improved local and regional relapse free survival after treatment
Decrease in grade 3+ urinary and gynecologic toxicities
Urinary frequency, urgency, dysuria, hematuria, and pelvic pain
Increases diagnosis of uterine perforation and avoids overtreatment of the fundus and lower uterine segment

8. CT Benefits1,10 Confirmation of applicator placement
Decreased OAR dose for patients with a small cervix
Accountability for sigmoid colon dose and reducing tissue toxicity
Improved coverage for large volume disease while maintaining organ dosimetry

9. CT Limitations5
Over-estimating of tumor volumes, resulting in an increased dose delivered to the adjacent normal tissue
Less useful for PTV definition than MRI because it overestimates the treatment volume width, leading to irradiation of more normal tissue
Lack the ability to accurately assess nodal metastases, which may lead to an underdose to the gross disease and result in a worse prognosis
Image is taken first, and then the patient is transported to HDR room, making it challenging to ensure applicator position stability due to patient movement

10. Magnetic Resonance Imaging5,7,9
Offers enhanced anatomy and tumor recognition when used for treatment planning
CT images only provide limited soft tissue definition in the are of interest, while MRI offers a greater soft tissue definition
Capable of assessing the tumor size within an accuracy of 0.5cm and are capable of assessing parametrial extension

11. MRI limitations7,9
Extremely expensive and difficult to access for many clinical centers
Not suitable for patients with implanted metal devices
Individuals with severe claustrophobia or obesity may have difficulty
Lack the ability to accurately assess nodal metastases, which may lead to an underdose to the gross disease and result in a worse prognosis
Image is taken first, and then the patient is transported to HDR room, making it challenging to ensure applicator position stability due to patient movement

14. Ultrasound1,7
Trans-abdominal ultrasound is cost effective, widely available, and has been found to have no significant differences in dosimetry compared to MRI planning, with 90% local control rate for cervical brachytherapy
May be substituted for MRI in defining target volume, outlining the cervix and uterus, and planning and verifying for conformal treatment

15. Ultrasound Benefits6,7,9
Can be used to select appropriate applicator size and to guide tandem and ovoid placement during procedure
Decreases rate of uterine perforation because of real time imaging
Accessible, portable, and able to be used within the brachytherapy suite, eliminating the need to move the patient during the procedure
Non-ionizing, quick and offers real time intra-operative anatomy assessment, reducing dose to OAR while not compromising target volume dose

16. Ultrasound Limitations6,7,9
Machine needs physical contact with the patient, which creates the potential for tissue deformation
Needs an experienced operator
No three-dimensional coordinate system or fixed frame of reference to help define the spatial location of the anatomy being viewed
Does not offer volumetric analysis of the target coverage or dose to the surrounding organs, which is crucial in the treatment planning process

17. Future Advances1
Multi-institutional international trial (EMBRACE) is underway to establish a standard for cervical cancer management in terms of tumor control, complications, dose specification, and prospective assessment of quality of life
Trial anticipates to advance image based brachytherapy and optimize its outcomes, hopefully by mandating the use of soft tissue three-dimensional imaging for treatment planning

18. “BodyTom”12
Portable CT scanner which can be transported from room to room, allowing it to be used for verification of the applicator and implanted catheter positions before treatment delivery everyday, without having to physically move the patient
Will help to eliminate any error or uncertainty caused by patient transportation during the procedure

19. Conclusion6,7
Traditional orthogonal x-ray imaging remains the most commonly used imaging modality for planning cervical brachytherapy treatments in areas where incidence of cervical cancer is high
Incorporating soft tissue three-dimensional imaging into brachytherapy programs is a slow process due to the decreased availability of planning software, increased cost, and lack of optimal training

20. Three-dimensional image treatment planning improves the technical accuracy of implants, leading to improved local control and decreased toxicity6
Ideally, an imaging modality should be available for each brachytherapy fraction, and provide good organ and applicator definition with the ability to delineate residual tumor6
This modality should have good soft tissue imaging capabilities, be widely available, portable, and economically attainable6

21. References
1. Vargo JA, Beriwal S. Image-based brachytherapy for cervical cancer. World Journal of Clinical Oncology. 2014;5(5): doi: /wjco.v5.i Madan R, Pathy S, Subramani V, et al. Comparative evaluation of two-dimensional radiography and three-dimensional computed tomography based dose-volume parameters for high-dose-rate intracavitary brachytherapy of cervical cancer: A prospective study. Asian Pacific Journal of Cancer Prevention. 2014;15(11): doi: /APJCP Banerjee R, Kamrava M. Brachytherapy in the treatment of cervical cancer: A review. International Journal of Women’s Health. 2014;6: doi: /IJWH.S Mazeron R, Champoudry J, Gilmore J, et al. Intrafractional organs movement in three-dimensional image-guided adaptive pulsed-dose-rate cervical cancer brachytherapy: Assessment and dosimetric impact. Brachytherapy. 2015;14(2): doi: /j.brachy Pouliot J, Sloboda R, Reniers B. Two-, three-, and four- dimensional brachytherapy. In: Venselaar JLM, Baltas D, Meigooni AS, Hoskin PJ, eds. Comprehensive Brachytherapy: Physical and Clinical Aspects. 1st ed. Boca Raton, FL: CRC Press; Accessed February 26, 2015: Dyk SV, Schneider M, Chennakesavan S, et al. Ultrasound use in gynecologic brachytherapy: Time to focus the beam. [published online ahead of print January 22, 2015]. Brachytherapy. doi: /j.brachy Dyk SV, Chennakesavan SK, Schneider M, et al. Comparison of measurements of the uterus and cervix obtained by magnetic resonance and transabdominal ultrasound imaging to identify the brachytherapy target in patients with cervix cancer. International Journal of Radiation Oncology, Biology, Physics. 2014;88(4): doi: /j.ijrobp Katz A, Eifel PJ. Quantification of intracavitary brachytherapy parameters and correlation with outcome in patients with carcinoma of the cervix. International Journal Radiation Oncology, Biology, Physics. 2000;48(5):1417–1425. PMID: Accessed February 26, Dyk SV, Narayan K, Fisher R, Bernshaw D. Conformal brachytherapy planning for cervical cancer using transabdominal ultrasound. International Journal of Radiation Oncology, Biology, Physics. 2009;75(1): doi: j/ijrobp Holloway CL, Racine ML, Cormack RA, et al. Sigmoid dose using 3D imaging in cervical-cancer brachytherapy. Radiotherapy and Oncology. 2009;93(2): doi: /j.radonc Haie-Meder C, Pötter R, Van Limbergen E, Briot E, De Brabandere M, Dimopoulos J, Dumas I, Hellebust TP, Kirisits C, Lang S, et al. Recommendations from Gynecological (GYN) GEC-ESTRO Working Group (I): Concepts and terms in 3D image based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV. Radiotherapy and Oncology. 2005;74(3):235–245. PMID: Accessed February BodyTom. NeuroLogica Web Site Accessed February 10, Aubry JF, Cheung J, Morin O, et al. Investigation of geometric distortions on magnetic resonance and cone beam computed tomography images used for planning and verification of high-dose rate brachytherapy cervical cancer treatment. Brachytherapy. 2010;9(1): doi: /j.brachy