Clinical issues addressed by Clarity

Bladder size and shape changes

Even with bladder full or empty protocols, the bladder size and shape can vary widely from day to day. Recent research has suggested that 25% or more of bladder cancer patients will not maintain a reasonably similar bladder volume throughout treatment.*

The posterior edge of the bladder is close to the bowel, rectum and prostate for men or the bavel, rectum, cervix and uterus for women.

Tracking and positioning the bladder based on real time imaging at the time of treatment is now possible.

Inconsistent bladder volumes

Many radiotherapy protocols rely on consistent day-to-day bladder volumes. For instance, some gyne or prostate EBRT protocols require full bladders to limit dose to the bladder and bowel. Clarity can verify and ensure consistent treatment.

Find your V.O.I.C.E.

Volume of interest coverage estimate

To provide the confidence that the GTV is in the treatment volume, Clarity automatically calculates the portion of the treatment scanned bladder volume included in the irradiaded planned volume.

The Volume Of Interest Coverage Estimate (VOICE) will immediately show if part of the treatment scanned bladder volume is outside the MLC irradiation volume in any direction.

* A. M. Henry, J. Stratford, C. McCarthy, J. Davies, J. R. Sykes, A. Amer, T. Marchant, R. Cowan, J. Wylie, J. Logue, J. Livsey, V. S. Khoo, C. Moore, and P. Price, X-ray volume imaging in bladder radiotherapy verification, Int J Radiat Oncol Biol Phys 64 (4), 1174 (2006).

S. J. Harris and R. B. Buchanan, An audit and evaluation of bladder movements during radical radiotherapy, Clin Oncol (R Coll Radiol) 10 (4), 262 (1998).

Bladder IGRT

Multimodality image fusion for bladder

Clarity provides 3D U/S IGRT to enable IMRT for bladder treatment by aiding in definition of the GTV with CT-U/S automatic image fusion. It also addresses the uncertainly in bladder radiotherapy and radiotherapy of other cancer (e.g. cervix, uterus, prostate) that use a consistent bladder volume in their protocols.

Clarity U/S Sim exploits the benefits of ultrasound by combining its superior soft tissue imaging characteristics with other imaging modalities such as CT-SIM. Its unique Implicit Registration™ facilitates accurate and automatic fusion, thereby providing more comprehensive anatomical information from both imaging modalities.

Voxel based contouring provides intuitive tools to define the cervix GTV and PTV. Images and contours may be exported to treatment planning system in DICOM RT format.

Volume coverage verification and positional verification

Clarity provides 3D U/S IGRT for daily position verification using ultrasound to ultrasound comparison of reference and daily bladder shape and volume. Clarity also provides daily tracking of bladder volumes for use in validating treatments of cancerous organs whose protocol is based in-part on consistent daily bladder volumes.

Using Clarity to vizualise the bladder just prior to treatment everyday helps verify that bladder filling is as expected. Patient repositioning the is made easy to ensure it the bladder covered by the treatment portals.

In addition, using Clarity to track the bladder can be useful for surrounding treatment areas. For example, the posterior/inferior border of the bladder can be used as positioning verification for prostatectomy patients undergoing external beam treatments.