The relationship between the unmodified initial tissue pH of human tumours and the response to combined radiotherapy and local hyperthermia treatment

Tissue hypoxia is a common and important feature of rapidly growing malignant tumors and their metastases. Tumor cells mainly depend on energy production thru anaerobic glycolysis rather than aerobic oxidative phosphorylation in mitochondria [1]. Intervening the tumor metabolic process via thermal energy infusion is worthy attempting. And hyperthermia, mildly elevated local temperature above the body temperature, is one of such kind. Previously, after being heated for a short period of time, tumor glucose and lactate level increased and ATP level decreased, which suggested energy metabolism was modified following hyperthermia through increased ATP hydrolysis, intensified glycolysis and impaired oxidative phosphorylation [2]. Many researchers designed experiments to determine thermal dose in hyperthermia [3], but few focused on the relationship between tumor and energy, especially for a long-term local hyperthermia treatment. One clinical trial indicated the effective long-term hyperthermo-therapy for maintaining performance status, symptomatic improvement, and prolongation of survival time in patients with peritoneal dissemination [4].

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Comments on "The relationship of high energy phosphates, tissue pH and regional blood flow to diastolic distensibility in the ischemic dog myocardium".

Circulation Research ◽

10.1161/01.res.59.6.712 ◽

1986 ◽

Vol 59 (6) ◽

pp. 712-713

Author(s):

K G Warner ◽

M D Butler ◽

S F Khuri

Keyword(s):

Blood Flow ◽

Regional Blood Flow ◽

High Energy ◽

High Energy Phosphates ◽

Tissue Ph ◽

Relationship Of ◽

The Relationship

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Optimal Control of Thermal Damage to Targetted Regions in a Biological Material

Volume 4 ◽

10.1115/ht-fed2004-56426 ◽

2004 ◽

Cited By ~ 1

Author(s):

F. Scott Gayzik ◽

Elaine P. Scott ◽

Tahar Loulou

Keyword(s):

Objective Function ◽

Thermal Damage ◽

Numerical Technique ◽

Damage Model ◽

Gradient Algorithm ◽

Bioheat Equation ◽

Hyperthermia Treatment ◽

Potential Applications ◽

Damage Field ◽

The Relationship

A numerical technique with potential applications in hyperthermia treatment planning is presented. The treatment is simulated using a 2D transient computational model of the Pennes bioheat equation within an optimization algorithm. The algorithm recovers the heating protocol which will lead to a desired damage field. The relationship between temperature, time and thermal damage is expressed as a first order rate process using the Arrhenius equation. The objective function of the control problem is based on this thermal damage model. The adjoint method in conjunction with the conjugate gradient algorithm is used to minimize the objective function. The results from a numerical simulation show good agreement between the optimal damage field and the damage field recovered by the algorithm. A comparison between the recovered damage field and the commonly used thermal dose is also made.

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