Total Body Irradiation Using Pre-Existing Dose Dynamic Fields

Description:

Technology: TA library of pre-commissioned dose dynamic fields offers a simple method for delivery of total body irradiation (TBI) given in preparation for transplant. This simple technique is available for any VMAT-capable machine, regardless of the treatment room size or span of the MLCs, yet does not require complex planning or patient-specific MLC patterns. Unlike other similar TBI techniques that require whole-body CT scans, this technique can use simple measurements of patient size for treatment planning.

The researchers have generated four pre-defined dose dynamic arcs that can produce an acceptably uniform total body dose across a range of body habitus, while minimizing the need for patient-specific compensation. In a retrospective study, dose uniformity at mid-depth along the craniocaudal axis was compared between a hypothetical TBI field of uniform fluence and one of the four dose dynamic fields selected to optimize dose uniformity. Dose uniformity in the patient population is enhanced in the lower extremities using the dose dynamic field technique. Overall, the library of TBI fields can be readily incorporated into any radiation treatment planning software similar to the incorporation of dynamic wedging. The technique was designed to simplify delivery of TBI on any VMAT capable machine without reliance on translating tables or patient-specific MLC patterns.

 

Overview: For a multitude of reasons, there is no universally practiced TBI method. Each facility offering TBI develops an in-house procedure, hardware and technique.  An extended distance of 4 m is regarded as a minimum requirement for TBI techniques delivered to a patient on a stretcher, and even further if the patient is standing.  However, many facilities lack a vault large enough to meet this and must seek an alternative.  Additionally, AAPM report No. 17 recommends facilities maintain a back-up machine in the event the primary goes down for service.  Transplant preparation is carefully timed sequence of treatments and must continue without interruption.  Rarely do facilities have two vaults designed to accommodate TBI at an extended distance.  There is a clear need for a TBI technique that can be more universally applied. 

A competing technique uses an in-house mechanized table that translates the patient through a stationary treatment beam.  While the patient lies on the table set on the floor below, a custom machine interface indexes the MLC control point to the table position.  Unfortunately, this technique is quite complex and requires creating an optimized MLC pattern unique to each patient and maintaining dual sets of custom-built hardware to fully comply with recommendations of AAPM Report No. 17.

 

Applications: Transplant (bone marrow or blood transplant)

Advantages:  Readily incorporated into existing software, bypasses need for translating table, simple technique for any VMAT-capable machine, Independent of room size or MLC span, no complex planning or patient-specific MLC patterns, bypasses CT scans, saves time, delivers more uniform dose without compensators, compatible with pediatric patients requiring sedation, large effective treatment field area of 220×70 cm2.

Key Words: Total body irradiation, transplant, Dose Dynamic Fields, TBI, uniform dose, large field irradiation

 

Publications: Koch, N., et al. Total Body Irradiation Using Dynamic Arc Delivery. Int J Radiat Oncol Biol Phys, 2016; 96:E640., Koch, N., et al. Toward electronic compensation for TBI using dose dynamic arc delivery. Med Phys, 2017; 44:3306.

Inventors: Nicholas Koch

Intellectual Property Status: Copyright         

MUSC-FRD Technology ID: P1782

Licensing Status: Available for licensing

 

Patent Information:
Category(s):
Therapeutic
For Information, Contact:
Troy Huth
Sr Licensing Manager
MUSC Foundation for Research Development
huth@musc.edu
Inventors:
Nicholas Koch
Keywords:
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