TY - JOUR
T1 - Inverse-planned modulated-arc total-body irradiation
AU - Kirby, Neil
AU - Held, Mareike
AU - Morin, Olivier
AU - Fogh, Shannon
AU - Pouliot, Jean
N1 - Funding Information:
The authors would like to thank Sherman Lim for his help designing the MATBI treatment setup and Professor Daphne Haas-Kogan for her fruitful clinical advice. This work was supported in part by Siemens OCS.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2012/5
Y1 - 2012/5
N2 - Purpose: To develop a simple and robust method for inverse-planned total-body irradiation (TBI) that is more comfortable and has better dose homogeneity than the conventional forward-planned techniques and that can be delivered in a standard-sized treatment vault. Methods: Modulated-arc TBI (MATBI) utilizes an arc of static open-field beams to irradiate patients as they lay on a stationary couch beneath the gantry, with cerrobend blocks suspended over organs at risk to provide shielding. Prior to treatment, full-body computed tomography (CT) images are acquired of each patient and imported into the PINNACLE3 planning system, which modulates the monitor units for the open-field beams to optimize the body dose uniformity. The volume of the body within 10 of the prescription dose, V(±10), is used as a metric to evaluate the dose uniformity. For comparison to MATBI, the dose distribution of a conventional forward-planned treatment is also calculated. Quality assurance measurements are acquired before treatment by delivering the plans to a phantom and during treatment with an ionization chamber inside a buildup block, placed between the patient's ankles. Results: For MATBI, the achieved values of V(±10) were 75.8%, 90.2%, 84.6%, and 79.8% compared to 60.3%, 77.4%, 65.6%, and 68.5% for the conventional TBI technique, respectively. The pretreatment ion chamber measurements in the phantom had an average error of 1.2%. Those acquired during treatment had larger errors, with most points being within 3% of predictions. Conclusions: MATBI provides better dose uniformity and comfort than the conventional forward-planned TBI techniques. In addition, the technique can be implemented on most linacs, in standard-sized vaults, without the use of a translating couch.
AB - Purpose: To develop a simple and robust method for inverse-planned total-body irradiation (TBI) that is more comfortable and has better dose homogeneity than the conventional forward-planned techniques and that can be delivered in a standard-sized treatment vault. Methods: Modulated-arc TBI (MATBI) utilizes an arc of static open-field beams to irradiate patients as they lay on a stationary couch beneath the gantry, with cerrobend blocks suspended over organs at risk to provide shielding. Prior to treatment, full-body computed tomography (CT) images are acquired of each patient and imported into the PINNACLE3 planning system, which modulates the monitor units for the open-field beams to optimize the body dose uniformity. The volume of the body within 10 of the prescription dose, V(±10), is used as a metric to evaluate the dose uniformity. For comparison to MATBI, the dose distribution of a conventional forward-planned treatment is also calculated. Quality assurance measurements are acquired before treatment by delivering the plans to a phantom and during treatment with an ionization chamber inside a buildup block, placed between the patient's ankles. Results: For MATBI, the achieved values of V(±10) were 75.8%, 90.2%, 84.6%, and 79.8% compared to 60.3%, 77.4%, 65.6%, and 68.5% for the conventional TBI technique, respectively. The pretreatment ion chamber measurements in the phantom had an average error of 1.2%. Those acquired during treatment had larger errors, with most points being within 3% of predictions. Conclusions: MATBI provides better dose uniformity and comfort than the conventional forward-planned TBI techniques. In addition, the technique can be implemented on most linacs, in standard-sized vaults, without the use of a translating couch.
KW - gantry motion
KW - hematopoietic stem cell transplant
KW - inverse planning
KW - patient comfort
KW - total-body irradiation
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U2 - 10.1118/1.4705366
DO - 10.1118/1.4705366
M3 - Article
C2 - 22559647
AN - SCOPUS:84861606040
SN - 0094-2405
VL - 39
SP - 2761
EP - 2764
JO - Medical Physics
JF - Medical Physics
IS - 5
ER -